I would just like to add that most of us in the business truly get the genius of Dave. But Dave is also an incredibly good human! As a small production company who has needed from time to time the services of Rat Sound, every encounter made what we did better!!! Much respect SimonPro!
A scientist: I will do an experiment to try to disprove an experiment someone else did. Social media: I'm mad because he didn't do the thing I think he should have done.
Dave, your retirement with Red Hot Chili Peppers has brought a lot of eye opener to Live sound engineering through your videos,the test, illustrations, demonstrations and the lite,I sincerely appreciate your kind efforts on all your videos,the time,the initiative,and the money, please Dave keep doing your best for us,what you are doing is not a waste hundreds if not thousand are greatly benefiting from it.....kudos 👍👍👍👍
I have moved on from touring. I've mixed some of the largest shows on the planet and some of the most popular bands and though I enjoy the 2 hours mixing every few days, the other 46houra of being transported around the world on shitty schedules and being on call year round was no longer a fun adventure Instead I run my sound company, design sound tools products, am a consultant and adventure on my schedule instead of someone else's.
Makes sense to me. The phasing and cancellation is reduced and made less obvious because the signals are smiliar but not exactly the same. Live sound is never going to be perfect, the goal is to get it as good as you can with what you have to work with. If the two source signals sound close enough to being the same, then the people on each side are still getting the same experience as each other. The peaks and null between the stacks are made less obvious and hence have less of a negative effect on the experience of every other person between the stacks. Thanks Dave for breaking the universe for us 😊
I always come back to Dave Rat's corner when I need to understand sound. Thanks a lot Dave, I always learn a lot more than what I came by for. Very inspiring to see experimentation - more and more rarely seen anywhere. If Dave Rat was a musician, he would be someone like Look Mum No Computer.
Don't listen to people on Reddit, it's a cesspit of negativity and "I know better than you" attitudes. Keep doing what you're doing! Very cool demonstration 👍👍
This might be my firtst comment on CZcams. Wonderfull response and attitude. I have been mixing live sound since 1998, and your video’s have been Very useful for all the challenges! Please know that to many of us, you are much respected and loved.
Thanks Dave! Your polite and patient response to these comments is admirable. Then you go the extra mile to provide a real world test to demonstrate & clarify & teach the concept. So awesome, love your work!
Oh thank you, and I see the comments as expressing legit doubts in perhaps less than polite ways. So I address the doubts and ignore the unkindness as it is irrelevant to me
I think there are two primary issues with engineers (myself included initially) understanding this concept of decorrelating sources. First is the inability to reconsider the live sound axiom of achieving uniformity of audience experience (a desirable goal) through mixing in mono. Decorrelating in Dave's suggested way doesn't undermine this goal, as both sides of the mix will get the same instrumentation, but live engineers are so used to thinking of double miking with the end of creating complex "mono" sounds (i.e. snare top mic for body, snare bottom mic for snap), that this idea might escape us. Secondly, the general insistence in mono live mixing on "maximum" summation between like sources in the electrical domain (i.e. in the mix itself) might be impeding our ability to consider the benefits that introducing differences between like sources might have for us in the acoustic domain (i.e. the room/venue), which Dave's tests obviously show.
@@DaveRat What about a small amount of delay say 4ms on one of sources IE mics? Wouldn't that decoralate it even more? Some times when I have phase issues with the kick mics delaying on just a bit is better then flipping it 180.
Decorrelation is when the signals are un related or minimally related such that inverting polarity on one signal a time shift on one signal vs the other does not result in significant audible/measurable cancellations and summations.
@@DaveRat I couldn’t agree with you more. You actually demonstrate this whey they are just bickering with no video comments to back them up. You are my hero! I have learned so much from your videos
I work on a tiny scale compared to Dave (and Iikely many of the members here), but it has been really fun to try a few of these tips and tricks lately and see the tangible results even in that environment. Well worth the exorbitant $5 fee we pay for membership LOL. One thing I know from spending a lot of time around scientists is that many more experiments don't work as predicted than those that do - even when thought through by experts in the respective field. It would be fun to see a few videos about things you've tried that didn't work out the way you'd envisioned.
As a long time roadie, now learning sound engineering , your insights are so valuable to keep in mind while honing the craft. I started my home stuido with 2 yamaha 5 inch powdered speakers, a Harmon Karden sub, A JBL monitor control and a Midas M-32. I decided on the Midas over the X-32 ( I went digital and Midas so to pick up live mixing gigs ) after your extensive side by side comparison. Thank you for the simplicity of your experiments, its made me dive headlong into the science of sound. That you take the time to share your wealth of knowledge freely here for the masses shows your integrity and humbleness. Safe Travels.
It doesn't take much to decorrelate two signals. With the wavelength of middle A (440Hz) at 78cm or 30 inches in air (@20 deg C), you won't have to move very far to experience a difference in phase. Phase correlations often work like step functions, from highly correlated to hardly correlated with a relatively small source change. A phase change manifests as a small frequency shift to our ears as we move towards or away from a source. Often observed as the doppler shift of a train horn caused the compression or expansion of the waveform as the train moves towards or away. Even the body temperature of a crowd heating up air in a venue has an effect on the wavelengths.
I have noriced that effect, if I have time (not always) I do like to go back n forth with pink noise to see what the speakers each sound like and the beauty is pink noise (sometimes white noise) can show where the eq may need to sit for one of the speakers - it makes it very easy to get a feeling for the room too.
I knew what would happen with this experiment, because I've played with stuff like this before, and I still really enjoyed seeing this. Also your "double mic and hard pan an electric guitar and then delay one side" trick is -fantastic-, been doing that fairly often since I learned about it, and ohhhh man, a telecaster has never sounded so sweet.
Not on reddit so I'll respond a bit here. To those who keep bashing what Dave Rat is showing us here and in some of the referenced past videos... Books, math and science based on theory is good and necessary, BUT, nothing beats real world tests. Yes it can take longer and be more expensive, BUT, your ears are the most important piece of test equipment, use them. Keep in mind "perfect" sound doesn't exist, nature is not "perfect" but full of unique deference that make all that we hear just a little different. I've found that doing real world testing like Dave does, and shares with us, is satisfying and confidence inspiring. As a hands on enthusiast, confidence is instilled when you test it yourself and get results you can understand. Dave's test results hear are undeniably effective and fullnof useful and audible results. Those who are still questioning need to try for themselves. I have so much to still learn and test but I'm enjoying what I know and looking forward to learning more. Keep having fun Dave and thanks for sharing more of your time and experience with us.
Dave, all respect to you and your knowledge. I'm very thankful for sharing these knowledge and making sound world better. I wish to you good health, joy and peace in mind.
The lack of gentlemanly manners in the discourse is un need. This is a conversation with a demo for me a proper conta response is to demo how it in fact works or not . This demo showed both the effects of changes and how thing could go wrong or right . Theories are just that however repeatable results can serve one better even without knowing why . Knowing how some thing happens is very important being able to repeatable do it pays better.
Fantastic demo. This made perfect sense of the concept for me. I’m curious how one might go about decorating a DI source such as an electronic kick or snare. Without the luxury of having a second kick or a physical drum to put two mics on would a simple stereo delay with one side a couple ms late do the trick?Perhaps even the color of the delay unit could simulate the second mic?
The way to sort of tell if a signal is decorrelated with another signal is to sum them in and out of polarity and if there is cancellation or it sounds phasy, then they are not decorrelated. Putting a delay is the same as moving one speaker a bit farther away. Using two different sampled kick sounds that sound similar should work though
I think it's the extremes that are wrong. It's not a complete decorrelation yet that significant decorrelation can be achieved is evident. Mainly I want to increase awareness and experiment. Thank you!!!
Fletch44 is clearly a subscriber to Audio Science Review, and prefers listening to music on an oscilloscope where his warm and fuzzy little theories are not challenged.
First of all, i love what you do and i'm a huge fan. In this case scenario i think that the mic on the front pick up positive, and on the back reverse polarity. So switching polarity on one of two you got positive construction
The signal is what comes out of the mics and not what comes out of the source. People treat physical models as the truth without realizing the limitations and how to correctly apply them. Apples don't fall because F=m1*m2*G/d² - the equation represents the falling apple in a universe where only the apple and the earth exists (not even the apple tree exists). If you put the apple tree then we have a three body problem for which there's no symbolic solution and only numerical ones can be calculated. Since every measurement carries an error (because we can only measure in rational numbers) the numerical calculations will have an error that increases exponentially with time. If I drop the apple from very high then the area where the apple might hig the ground will be bigger than if it fell from an apple tree. To correctly apply models we must take into account the limitations of the model and the complexity required to achieve the desired results. If I want an apple to fall inside a bucket from a tree I need a very simple model but if I want an apple to fall on the tip of a needle I will need a very complex and error prone model. In circuit analysis we have R, C and L - elements the don't exist in reality! A resistor will always have capacitance and inductance and the other two will also have the three characteristics. If I want to make a fluerescent bulb to light I can consider the capacitor to be ideal but if I'm doing an ECG I have to consider all the complexities of the real elements when applying the model. Reality is not the model - reality is the experimental result. The model is not incorrect - the guy on Reddit is oversimplifying it. This is a very serious problem because it impairs the perception of reality and, therefore, impairs even our ability to make political decisions. What the reddit guy did is done by neo-liberal and marxist economists and reproduced by those who follow their ideas. Empirical results show that none of the two systems work and both are flawed. People believe in the supremacy of biology to determine intelligence and personality aspects because they cherry pick data to fit their own subconscious prejudices, for instance. People say vaccines are 100% safe when we all know nothing is 100% safe - and even knowing that I take all my vaccines because I can compare the risk to myself when I take it to the risk of a immuno supressed person or a baby if I don't take it and conclude it to be worth the very small risk I take to help those who have a high risk of dying if I don't take the vaccine. The comment on Reddit is a symptom of a much larger problem that can make the human race go the way of the T-Rex! Some videos I love that talk about the subject: Stanford - Biology and Human Behavior classes 1 and 23 (I think - the one about complexity) A Yale online lecture about Complex Non-linear systems and the correlation problem.
I have no idea about physics! But this experiment absolutely convinced me! Thank you for opening my eyes (or rather my ears 😉 )! I'll try this technique at the next show Thanks!
Thanks for these. I'm micing (ratting?) up a couple gongs with a bunch of mics with the idea that I'll create an artificial stereo field, without a matched pair of mics (won't use all the mics that are set up, obv). I have the advantage of not wanting realism or needing to achieve a specific sound. So, some of these vids are helpful for inspiration and also pitfalls to watch out for, even though I'm not working in live sound reinforcement. Thanks.
I had a guy with a vox amp that i put a D6 on one speaker and a Sennheiser 609 on the other. It sounded amazing. This was early in my career and haven't done it again since. Most people I work with in live sound aren't adventurous enough to experiment. Even if it improves their experience.
To decorrelate you either need a differing version of the signal or induce a differential. Adding delay combined with EQ and all pass filters, and effects can alter things a bit but actual decorrelation will require some more complex processing that I don't have a good suggestion for
Again thank you David for your ability to provide an in-depth analysis of the concept. Any chance you could could show us EQ'ing the two Mic to sound similar. I do find it hard to fully pan hard left and right. I normally end up paning 2 o'clock and 10 o'clock. Gratefully a sound human.
No need to fully pan everything, it's about having the additional tool of decorrelation to add to your toolbox of EQ, panning, delay, efx, mix position and so on. Doung the same thing too much like using the same EQ on every mic, hard panning on every mic, same mic on every input, and so on usually does not give optimal results.
The proof is in the pudding, so to speak, and I think you demonstrate it well. It's an easy test to make and it gives me some ideas to improve a smaller portable setup for a show I have coming up. We always get some combing and I want to figure out a way to eliminate or at least minimize the effect and make the show even better than what it is.
Dave, you mentioned EQ'ing the two microphones so they sounded similar. Could those EQ changes also introduce phase shifts in both signals that would make them less correlated?
Yes, increasing the decorrelation between two mics on the same source is a cumulative process. Mic'ing different places, differing distances, differing mic types, differing EQ, and if possible, differing sides of a sound source all can help increase the differences such that the two signals no longer sum and cancel as drastically.
Put simply, the best and least problematic sound was two mic on the source going into two different speakers. This is double hung pa concept, but it would work with small systems also. Fill systems would get the mic from the speaker that is farthest away.
Great demo. Would love to get your opinion on effects that seem to offer a digital decorrelation of the same signal like the mimiq from tc electronics.
Have not used or tested so I don't have an opinion other that it should be something that can be done digitally. Not sure about the sonic assets and issues but would be interested in hearing how well it works or not
@@DaveRat hi Dave I love your work we called you I think the late 90s about our issue with a problem we had was blowing jbl diagrams witch was caused by sound pressure issues around our hf and shattering our hf diagrams you where not wrong
So I understand the whole concept and of course it makes sense. My question is what do you do with vocals? Since they are single mic'd what else can you do beside run it straight up the middle?
There is no reason to take everything to an extreme. Nothing decorrelated is pure mono and has issues, everything decorrelated is extremely challenging and will eliminate all of the additive sound in the venue center and will sound overy stereo wide and disparate. I would decorrelate most instruments and open up room to drop key inputs into the center
I am not sure that decorrelating all inputs is advantageous for most or many apucations. I do believe that decorrelating some or most inputs is advantageous in most or many applications to reduce having every input exhibit the same issues in the same audience locations is improbable to be desirable.
In our studio we have a Neumann U87 modded with a DPA capsule inside just below the diaphragm. Wire goes out the back of the cage. Bit of a trick mic for certain vocalists. Not sure if I should even mention this, haha. Idea is you get a second source for the mix, mostly to add some air. The same hack could probably be done with a vocal mic, but space is tight. You obviously just can't add a lapel or headset mic, as most singers will use mic positioning to change their sound. But it should be doable...
These guys criticism of Dave seem to all being in the same club as supposed audiophiles and their dry know it all attitudes. Just because someone knows some physics doesn't mean they own them . Dave seems to be the most laid back dude that would never be condescending to any of these turds criticizing him. Like they are undiscovered or less acknowledged audio genius's than Dave. Dave has the resume proving he is recognized as an artist in his field. Plus all of the gear he has developed and sells . Even if Dave goes against convention it is probably best to take his advice as a grain of salt if it rubs you the wrong way. Because once it sinks in and enough time has past Dave's approach will become the standard while critics will be stuck doing the same old same old.
Thank you and let's all not forget that sound is beautiful and fun. If we wanted serious and a bummer we would be in the military bomb build world. Which I quit to do audio!
I got a couple of sounding excited face t-shirts but the prints on the back and it doesn't say sound remix down face you still have available the ones that you're wearing in this video
So this next week i want to try this just on maybe the kick mic and the guitars, i run a dbx driverack and the subs are in mono but i want to maybe run 2 beat 52 put in the kick panned hard left n right. Will i notice more power or a difference and should i set the driverack to stereo subs, THANKS. also this is outdoor. it will be streamed live on youtube at Taber Cornfest 2022.
Two parter question: A truly decorrelated setup would be Mic 1 going to Speaker 1, and Mic 2 going to speaker 2 right? Similar to your pink noise video where discrete pink noise sources were going to discrete speakers, making them decorrelated? With all of this I think of Dolby Atmos. I’d love to hear your take on spatial audio and the decorrelation algorithms they use when a signal source is equally panned between two speakers (in a Dolby atmos setup). Thanks for these videos, your wisdom, and experience.
Sending to different speakers does not decorrelate. Decorrelated signals are signals that do not impact each other when summed. Polarity, time, phase and delay one or the other and they do not sum or cancel. Identical signals are 100% correlated and will maximally sum if delay, time, phase and polarity are matches, and will maximally cancel when polarity reversed if time, phase and delay and matched. Achieving some decorrelation by using various methods will reduce the interactions. The interactions are what cause comb filtering
@@DaveRat I think we are saying the same thing ( I hope so lol). If you send mic 1 to speakers 1&2, it’s correlation time, thus comb filtering magic between the two speakers, just like what you have in your reply. But if you have one instrument, and two mics on that instrument, where in one mic (ribbon) is only in the left hang, and the other mic (dynamic) is in the right hang it’s decorrelated. Am I right on that?
Sort of. In order to decorrelate even partially you need to introduce as many differences as possible. Using different mic types helps, micing the front and the back helps, micing different parts of a cone helps, micing it different distances helps. And after all of that you can achieve some decorrelation that will vary depending on all those factors and more. Hi frequencies will decorrelate much easier then low frequencies. But to say doing something will result in de-correlated signals, would not be a correct statement unless whatever you did was very complex and designed to do exactly that So yes, you are correct but it's not a simple and clear yes/no thing but rather a gradual thing that is worked towards
I have been to the function one designer's shop with Tony Andrews. Also Danley has done gear demos at the rat shop. "Point Source" is a marketing term for a system that covers the listening area in zones. Except when there is a single output area from a single enclosure used with no other enclosures nearby. True point source systems are not scalable or arrayable, as soon as they are arrayed, they become zonal. Here is an article I wrote a while back www.prosoundweb.com/zoned-summed-line-a-discussion-of-array-structures-performance/
Yes, when not in an enclosure, the front and rear of a speaker are opposing polarity. When in an enclosure, the inside of the enclosure is the opposite polarity to the outside of the enclosure.
hmmm, a potentiometer will typically control level or set to control delay. A polarity reverse is one of the most drastic things you can do to a signal that is being combined with a similar or identical signal as it will cause maximum cancellations. So I use polarity to demonstrate worst case
@@DaveRat I gave your answer a lot of thought. And I'm not done thinking about it. But, flipping phase is one thing, shifting phase is 'delay' so if I understood you correctly, it introduces a whole bunch of other challenges. Thanks so much for your reply though. Mind boggling :)
Hmmm, adding a delay will shift phase and the phase shift will be different at different frequencies. But shifting phase is not necessarily a shift in delay. A transformer or capacitor will shift phase above and below the passband but not add delay to the passband. Regardless, polarity reversal does the same thing to all frequencies rather than different things to various frequencies
Hmmm, it can be done a bit with efx, like a chorus or Haas panning, to one side and actual panning back to center ish. But also not doing it is a way to make an input sound different from inputs that are decorrelated
maybe two different mics, despite making analogous waves, and despite being in phase, panned side to side, don't comb because the slight differences between them are sufficient because the brain assigns more weight to differences between sounds than similarities? i don't know. i think you kind of have to look for combing anyways unless it's really bad, because your brain doesn't just try to 'hear', it tries to figure out whats going on, and reject anything that doesn't contribute to a good image.
Hmmm, are vibrating surfaces truly phase coherent? Are differing parts of the speaker all perfectly in phase with each other? Are differing mic diaphragms of differing sizes, designs and materials reproducing exactly the same phase coherent signal as each other? To find out what is identical between two signals by polarity reversing one and combining them, what is left over is the difference. In this demo, what will not null 8s the differences.
@daverat at 2:18 you place a image in my mind to make a basic cheese sandwich . then i may play more pink noise . been playing pink noise since last night and watching listening to classics that have the directional dialogue effects . ice station zebra and the towering inferno . oh , that 2:18 is so much more making me want to quickly make a basic cheese sandwich . your making more hungry 2:18 lol when i think of pink noise i think of many channels on the CB radio with 10kc shifts apart but they are actually one wide of the 11m or 10m band 24mhz to 28khz or 30mhz , oh , 2:18 making more hungry for pink noise . lol i may do a short video after i had basic cheese sandwich . do pink noise of multiple microphones behringer ecm8000 anywhere from x3 to x11 of them . primarily used for my , home professional THX cinema . decorrelation used in home THX on the right surround channel to give the illusion (when LCR muted) listening only to the surrounds of 4.2.4 matrix say a classic like laserdisc letterbox scope 2.35:1 "Star Wars" Dolby Stereo , depending on the surrounds ? as there is only one original surround format , surround configuration that very few if not hardly any home theaters in usa or uk are using the , left-half right-half surround configuration . some earlier home avp like a harman kardon avp1a had surround output of side surrounds and back surrounds playing the same signal . with the correct number of same speakers used for the surrounds down the sidewall x3 or x4 of them and back wall x2 or x4 of them . then "Star Wars" to a trained listener ear , which is few and far between that there are some that recall that surround number of speakers for the surrounds and the goal in which they achieve . diffused and localization all at the same sort of at the same time . so no need for THX with few speakers , x2 for sidewalls and x2 for back wall . that is , one per sidewall and two for back wall , may give the proper "Dolby "hass-effect" to trained listening ear ? oh , 2:18 i give in . cheese sandwich . with mayo slapped on it . plus fact you made me go in the kitchen had to feed my cats again and then eat grapes . 2:18 places flashing image in my mind . lol 5:43 i noticed the cat bed . or is that your bed when you transform back into a rat and sleep in the bed ? curious to know where's the cat ? not seen your cat in the videos ? 9:25 doing that cheese sandwich stare again . i would repeat your test outdoors as i can hear the walls/ceiling and table changing the delay on the frequencies . need do the test again outdoors frame for frame . so i like to nominate you @daverat to mimic the same as you done in this video for same running time same dialog only , outdoors as the test would be free from the scattered items around the room . 10:47 oh , that was cheese sandwich dave rat trippy . now dave rat , your telling me go over the road , buy cheese onion crisps and make cheese sandwich with crisps and may slapped on it and fold the bread in half and have munches . lol
Why can't these 'all-knowing-sound experts' that post negative comments about what Dave Rat is saying in his videos understand that they appear to be be the biggest closed-mind sound people ever. Dave offers other ways to look at the way sound systems behave. Dave never says his comments are gospel and the only way you should understand live sound. Take his experience and thoughts he shares (and the time he takes to make these videos) as what they are. Why people post negative comments about something they don't maybe understand completely or are not able to be open enough to look at a new perspective is sad. As an sound engineer for many years I like to hear other ideas about live sound challenges. I'll never stop learning something from those people who their take the time to share their thoughts- whether I agree with them or not. Just my .02 cents.
The problem is that people think they understand and even know. In this case 2 mics on a single source *must* produce the same signal. But that *only* works in an anechoic chamber with a theoretical point source. And that's where the *understanding* and *knowledge* fails. If people fully modelled the set up instead of a theoretical ideal, they would come to the conclusion so amply demonstrated by Dave.
Yes, and the assumption that vibrating surfaces are perfectly phase coherent and differing mic diaphragms, designs an materials are identically phase coherent with each other, is flawed.
What’s so funny is this master of all knowledge (Reddit poster) missed the key fundamental that the reason pink noise generators are used is because they are precisely uniform correlating sources. Like how a cymbal is always in tune and in key with the band. Lol pink noise is pink noise is pink noise.
Yeah I'm getting a bit tired of the Keyboard warriors that have quote after quote from sound re enforcement handbooks and haven't bothered to do a SINGLE actual test to prove or disprove anything that Dave is attempting to show us. Don't know why you bother with this Dave. A bunch of butthurt is all it really is lol.
@@DaveRat I guess that's relevant lol. I admire your attitude man! Keep doing you Dave! I love that you actually do all this real world playing around with things to see what ACTUALLY happens. Even if the books are dead right, it's good to hear it and work with it in real time! I've learned a TON about what's going on when we shove them faders up from you! And a lot of it I used to think you couldn't do much about. How friggen awesome it was to learn I was wrong about that!! Thanks doesn't cover it!!! Cheers to you Dave!
No Reddit is not always like this. There are some great people on there and wonderful discussions though I don't visit it often. One of the cool things about Reddit is you can easily see every post a person has made and research their history on Reddit. This does a great job of providing clarity about the people posting. I chose to address these because they were particularly harsh and thought it was a great opportunity to dive into some new subjects and clarify others
One of the craziest things about noise is that it has no phase or frequency, but once you have resonated or notched it... it's NO LONGER NOISE. How does it travel? As a wavefront? Sure. Can the wave travel backwards? It rests on the air pressure behind, so sure, it all propagates spheroidally molecule to molecule, right down to the brownian noise floor, which probably isn't pink. Boundary element method is not the whole story. Stochastic mathematics is hard to get your head around, certainly. Average of a random number generator, with a big enough window to average, you should be sure of the output, regardless of the source or sequence of randomness. That is how pressure cancels and sums within the context of noise at different wavelengths, timescales, and bounded-gas-elasticity-conditions: it's like averaging. Please see standing wave tube experiments 1-42 in the unwritten manual of fourier transform methods connected to poincaré's butterfly pendulum, and gaussian distribution in the context of reverse blind bernoulli deconvolution, which won't run realtime on any of the FORTAN 1970s minicomputer crashosaurs.
@@DaveRat Hmm. Random need not have polarity to still interfere within an interference structure. The noise generator at the end of a clarinet still defies acoustics simulations. IRCAM Audiosculpt relies on noise generator addition, fourier removes essential information. Our perception of noise is not understood, either. We filter it out, mostly. We don't fully understand how the ear-brain discriminates between noise, impulse and resonation, and not everybody hears the same thing - the ear can be trained. I don't listen for elevated noise floor, I listen for that dusty lack of clarity, then hunt it down with a mic. Audible or synthetic noise is naturally pseudo-random and bounded. Real acoustic noise has a great many phenomena and flavours. Sand on the beach - it's little resonant wind chimes. Put that stuff under the microscope and it's a whole ecosystem, and orchestra. We can hear sand, it benefitted our ancient ancestors to do so. Noisy and chaotic are qualities, not an absolute definition with a single answer. Cancelling easily occurs when a random digital sequence gets put through a converter (noise shaping delta sigma most likely), then filtered by a bandpass, or sinusoidally filtered. Passing through air above the natural noise floor is such a synthetic behaviour - the white noise generated by non-electronic / non synthetic sources is a different disease - industrial active noise cancelling is incredibly difficult, especially in aerospace - NXT was a failed ANC project, where they found they mainly amplified the problem. Turbulent air flow prevents wavefronts from forming - chaotic conditions can be serious inside engines, non-laminar flow. Ultrasonic and infrasonic noise significantly influence s/n and impact sound quality even though they are basically inaudible. I would be lying if I said I believe we have a complete mathematical grasp of this atomic noise / background vs emergent structure stuff, even at CERN.
But we are dealing with singular captured versions of an instrument and noise. And the captured versions are what we send to be amplified. And the captured versions do have polarity, regardless of how complex or random the original source is
@@DaveRat precisely - once sampled to a theoretical point source pressure plot, in the same place at the same time, in an electronic space, signals should and do null completely - but the self-noise of the measurement system's output or noise floor won't - also most conversely 'port chuffing' or non-laminar turbulent flow can *crash* the ability of the air in a tube to pass sound - it becomes an acoustic eraser, and the acoustic energy cannot flow as a wave through the chaotic energy saturated environment - it gets converted to a "blasting" type of noise of lower intensity with a broadband component. This cannot be fixed by inverting the polarity of the input signal or measurement tool! A mic at either end of a bass reflex port may or may not null, and this is important information.
Dave, your retirement with Red Hot Chili Peppers has brought a lot of eye opener to Live sound engineering through your videos,the test, illustrations, demonstrations and the lite,I sincerely appreciate your kind efforts on all your videos,the time,the initiative,and the money, please Dave keep doing your best for us,what you are doing is not a waste hundreds if not thousand are greatly benefiting from it.....kudos 👍👍👍👍
I would just like to add that most of us in the business truly get the genius of Dave. But Dave is also an incredibly good human! As a small production company who has needed from time to time the services of Rat Sound, every encounter made what we did better!!!
Much respect SimonPro!
Wow and thank you!!
Definately NOT rubbish. Very valid investigation with relatable and memorable real world results demonstration. Thank you Sir.
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A scientist: I will do an experiment to try to disprove an experiment someone else did. Social media: I'm mad because he didn't do the thing I think he should have done.
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That's reddit in a nutshell... 😉
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Yup, these armchair keyboard warriors...
Oh, hang on, was that a chair with arms that Dave was sitting on....
Even armchair warriors can do tests rather than just attack others with guesses.
Dave, your retirement with Red Hot Chili Peppers has brought a lot of eye opener to Live sound engineering through your videos,the test, illustrations, demonstrations and the lite,I sincerely appreciate your kind efforts on all your videos,the time,the initiative,and the money, please Dave keep doing your best for us,what you are doing is not a waste hundreds if not thousand are greatly benefiting from it.....kudos 👍👍👍👍
Thank you so much!
wait what do you mean retirement??? Dave is retired?
I have moved on from touring. I've mixed some of the largest shows on the planet and some of the most popular bands and though I enjoy the 2 hours mixing every few days, the other 46houra of being transported around the world on shitty schedules and being on call year round was no longer a fun adventure
Instead I run my sound company, design sound tools products, am a consultant and adventure on my schedule instead of someone else's.
@@DaveRat Oh wow thats amazing! Great to hear you're doing your own thing. Do you still keep in contact with the bands you mixed?
Some, yes, some no. But all is good
Makes sense to me. The phasing and cancellation is reduced and made less obvious because the signals are smiliar but not exactly the same.
Live sound is never going to be perfect, the goal is to get it as good as you can with what you have to work with.
If the two source signals sound close enough to being the same, then the people on each side are still getting the same experience as each other. The peaks and null between the stacks are made less obvious and hence have less of a negative effect on the experience of every other person between the stacks.
Thanks Dave for breaking the universe for us 😊
You got the concept! and thank you!
I always come back to Dave Rat's corner when I need to understand sound. Thanks a lot Dave, I always learn a lot more than what I came by for. Very inspiring to see experimentation - more and more rarely seen anywhere. If Dave Rat was a musician, he would be someone like Look Mum No Computer.
Thank you and humbled!
Don't listen to people on Reddit, it's a cesspit of negativity and "I know better than you" attitudes. Keep doing what you're doing! Very cool demonstration 👍👍
Awesome and thank you!
This might be my firtst comment on CZcams. Wonderfull response and attitude. I have been mixing live sound since 1998, and your video’s have been Very useful for all the challenges! Please know that to many of us, you are much respected and loved.
Awesome thank you and honored!!
Dave shows with real world examples what others assume won’t be true from just thinking about it and never trying it.
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Thanks Dave! Your polite and patient response to these comments is admirable. Then you go the extra mile to provide a real world test to demonstrate & clarify & teach the concept. So awesome, love your work!
Oh thank you, and I see the comments as expressing legit doubts in perhaps less than polite ways. So I address the doubts and ignore the unkindness as it is irrelevant to me
I think there are two primary issues with engineers (myself included initially) understanding this concept of decorrelating sources. First is the inability to reconsider the live sound axiom of achieving uniformity of audience experience (a desirable goal) through mixing in mono. Decorrelating in Dave's suggested way doesn't undermine this goal, as both sides of the mix will get the same instrumentation, but live engineers are so used to thinking of double miking with the end of creating complex "mono" sounds (i.e. snare top mic for body, snare bottom mic for snap), that this idea might escape us. Secondly, the general insistence in mono live mixing on "maximum" summation between like sources in the electrical domain (i.e. in the mix itself) might be impeding our ability to consider the benefits that introducing differences between like sources might have for us in the acoustic domain (i.e. the room/venue), which Dave's tests obviously show.
I agree. I thought of a fun way
To demonstrate this visually and will work on a video.
@@DaveRat What about a small amount of delay say 4ms on one of sources IE mics? Wouldn't that decoralate it even more? Some times when I have phase issues with the kick mics delaying on just a bit is better then flipping it 180.
Decorrelation is when the signals are un related or minimally related such that inverting polarity on one signal a time shift on one signal vs the other does not result in significant audible/measurable cancellations and summations.
@@DaveRat I couldn’t agree with you more. You actually demonstrate this whey they are just bickering with no video comments to back them up. You are my hero! I have learned so much from your videos
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I work on a tiny scale compared to Dave (and Iikely many of the members here), but it has been really fun to try a few of these tips and tricks lately and see the tangible results even in that environment. Well worth the exorbitant $5 fee we pay for membership LOL.
One thing I know from spending a lot of time around scientists is that many more experiments don't work as predicted than those that do - even when thought through by experts in the respective field. It would be fun to see a few videos about things you've tried that didn't work out the way you'd envisioned.
Interesting, I will ponder that
Hey Dave, love your humility and your abilities. Very inspiring and helpful
Thank you!!!
Like the use of the term "landscape" here.
The ultimate question ... "what does the mix sound like?"
Great response Dave. Enjoying this series.
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As a long time roadie, now learning sound engineering , your insights are so valuable to keep in mind while honing the craft. I started my home stuido with 2 yamaha 5 inch powdered speakers, a Harmon Karden sub, A JBL monitor control and a Midas M-32. I decided on the Midas over the X-32 ( I went digital and Midas so to pick up live mixing gigs ) after your extensive side by side comparison. Thank you for the simplicity of your experiments, its made me dive headlong into the science of sound. That you take the time to share your wealth of knowledge freely here for the masses shows your integrity and humbleness. Safe Travels.
Super cool and thank you!
It doesn't take much to decorrelate two signals. With the wavelength of middle A (440Hz) at 78cm or 30 inches in air (@20 deg C), you won't have to move very far to experience a difference in phase. Phase correlations often work like step functions, from highly correlated to hardly correlated with a relatively small source change. A phase change manifests as a small frequency shift to our ears as we move towards or away from a source. Often observed as the doppler shift of a train horn caused the compression or expansion of the waveform as the train moves towards or away. Even the body temperature of a crowd heating up air in a venue has an effect on the wavelengths.
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I have noriced that effect, if I have time (not always) I do like to go back n forth with pink noise to see what the speakers each sound like and the beauty is pink noise (sometimes white noise) can show where the eq may need to sit for one of the speakers - it makes it very easy to get a feeling for the room too.
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Awesome demo...Your experience with live sound is invaluable. Hats off to you for sharing so much! Much appreciated.
Thank you thank you!
I knew what would happen with this experiment, because I've played with stuff like this before, and I still really enjoyed seeing this.
Also your "double mic and hard pan an electric guitar and then delay one side" trick is -fantastic-, been doing that fairly often since I learned about it, and ohhhh man, a telecaster has never sounded so sweet.
So cool and thank you JT!
Not on reddit so I'll respond a bit here. To those who keep bashing what Dave Rat is showing us here and in some of the referenced past videos... Books, math and science based on theory is good and necessary, BUT, nothing beats real world tests. Yes it can take longer and be more expensive, BUT, your ears are the most important piece of test equipment, use them. Keep in mind "perfect" sound doesn't exist, nature is not "perfect" but full of unique deference that make all that we hear just a little different. I've found that doing real world testing like Dave does, and shares with us, is satisfying and confidence inspiring. As a hands on enthusiast, confidence is instilled when you test it yourself and get results you can understand. Dave's test results hear are undeniably effective and fullnof useful and audible results. Those who are still questioning need to try for themselves. I have so much to still learn and test but I'm enjoying what I know and looking forward to learning more.
Keep having fun Dave and thanks for sharing more of your time and experience with us.
Thank you DLcarburetor!!!
Awsome demo. Anyone whos ran pink noise and walked a room should know how awsome this is. Although some stuff sounds good with comb filtering.
Been watching you for a few years now. You are the man Dave! Love the new vids!
Thank you Keith!
Dave, all respect to you and your knowledge. I'm very thankful for sharing these knowledge and making sound world better. I wish to you good health, joy and peace in mind.
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I can't believe it took so long to find your channel. Love your work Dave. Thank you 🤙
Hey hey Dach!
Thanks for making your thought processes available, a lifetime of learning is appreciated
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Excellent demonstration , pretty much proves your point !! Keep up the great work Dave !!
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The lack of gentlemanly manners in the discourse is un need. This is a conversation with a demo for me a proper conta response is to demo how it in fact works or not . This demo showed both the effects of changes and how thing could go wrong or right . Theories are just that however repeatable results can serve one better even without knowing why . Knowing how some thing happens is very important being able to repeatable do it pays better.
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Thank-you for your time experimenting and explaining the results. I know enough to be a bore at a party...
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Fantastic demo. This made perfect sense of the concept for me. I’m curious how one might go about decorating a DI source such as an electronic kick or snare. Without the luxury of having a second kick or a physical drum to put two mics on would a simple stereo delay with one side a couple ms late do the trick?Perhaps even the color of the delay unit could simulate the second mic?
The way to sort of tell if a signal is decorrelated with another signal is to sum them in and out of polarity and if there is cancellation or it sounds phasy, then they are not decorrelated.
Putting a delay is the same as moving one speaker a bit farther away.
Using two different sampled kick sounds that sound similar should work though
Highly instructive, thank you!
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Awesome, supercool demo.
I knew from the start that you weren't wrong Dave.
I think it's the extremes that are wrong. It's not a complete decorrelation yet that significant decorrelation can be achieved is evident. Mainly I want to increase awareness and experiment.
Thank you!!!
Great job breaking the universe! Fun test and awesome video!
Thank you Dave!!! 👍👍
Fletch44 is clearly a subscriber to Audio Science Review, and prefers listening to music on an oscilloscope where his warm and fuzzy little theories are not challenged.
I must admit I'm kind of surprised he didn't show up and chatter more about his opinions after I posted this
Dig the Rat yacht with the Avalons.
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First of all, i love what you do and i'm a huge fan. In this case scenario i think that the mic on the front pick up positive, and on the back reverse polarity. So switching polarity on one of two you got positive construction
And when the polarity is not reversed or reversed on the back mic, why do we never get cancellation?
That is the most important part.
Tus demostraciones práctica son una obra de arte Dave. Gracias!
Buenos y muchos gracias!! 🤙👍🤙
The signal is what comes out of the mics and not what comes out of the source. People treat physical models as the truth without realizing the limitations and how to correctly apply them. Apples don't fall because F=m1*m2*G/d² - the equation represents the falling apple in a universe where only the apple and the earth exists (not even the apple tree exists). If you put the apple tree then we have a three body problem for which there's no symbolic solution and only numerical ones can be calculated. Since every measurement carries an error (because we can only measure in rational numbers) the numerical calculations will have an error that increases exponentially with time. If I drop the apple from very high then the area where the apple might hig the ground will be bigger than if it fell from an apple tree. To correctly apply models we must take into account the limitations of the model and the complexity required to achieve the desired results. If I want an apple to fall inside a bucket from a tree I need a very simple model but if I want an apple to fall on the tip of a needle I will need a very complex and error prone model.
In circuit analysis we have R, C and L - elements the don't exist in reality! A resistor will always have capacitance and inductance and the other two will also have the three characteristics. If I want to make a fluerescent bulb to light I can consider the capacitor to be ideal but if I'm doing an ECG I have to consider all the complexities of the real elements when applying the model. Reality is not the model - reality is the experimental result. The model is not incorrect - the guy on Reddit is oversimplifying it.
This is a very serious problem because it impairs the perception of reality and, therefore, impairs even our ability to make political decisions. What the reddit guy did is done by neo-liberal and marxist economists and reproduced by those who follow their ideas. Empirical results show that none of the two systems work and both are flawed. People believe in the supremacy of biology to determine intelligence and personality aspects because they cherry pick data to fit their own subconscious prejudices, for instance. People say vaccines are 100% safe when we all know nothing is 100% safe - and even knowing that I take all my vaccines because I can compare the risk to myself when I take it to the risk of a immuno supressed person or a baby if I don't take it and conclude it to be worth the very small risk I take to help those who have a high risk of dying if I don't take the vaccine. The comment on Reddit is a symptom of a much larger problem that can make the human race go the way of the T-Rex!
Some videos I love that talk about the subject:
Stanford - Biology and Human Behavior classes 1 and 23 (I think - the one about complexity)
A Yale online lecture about Complex Non-linear systems and the correlation problem.
👍👍👍 Max Headrom
Nicely done. Excellent presentation.
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Thanks. Very easy to understand.
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nice demo on both acoustics and internet-nonsense :}
this has been happening on 'audio forums' for two decades, it's both funny and depressing :{ :}
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😆So true!
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I have no idea about physics! But this experiment absolutely convinced me! Thank you for opening my eyes (or rather my ears 😉 )!
I'll try this technique at the next show Thanks!
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Great demo using simple gear. Awesome.
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Thanks for these. I'm micing (ratting?) up a couple gongs with a bunch of mics with the idea that I'll create an artificial stereo field, without a matched pair of mics (won't use all the mics that are set up, obv). I have the advantage of not wanting realism or needing to achieve a specific sound. So, some of these vids are helpful for inspiration and also pitfalls to watch out for, even though I'm not working in live sound reinforcement. Thanks.
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Very, very interesting, Dave!!! Thanks!!!!
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Brilliant idea! Thank you for sharing it.
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Great demo! Super smart!
Thank You PONCEY
I had a guy with a vox amp that i put a D6 on one speaker and a Sennheiser 609 on the other. It sounded amazing. This was early in my career and haven't done it again since. Most people I work with in live sound aren't adventurous enough to experiment. Even if it improves their experience.
Love when you test theory and put it in the real world. That’s all that matters…
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Hi Dave,
Thanks so much for the videos!
Question, how would you approach this with direct signals instead of microphones?
To decorrelate you either need a differing version of the signal or induce a differential.
Adding delay combined with EQ and all pass filters, and effects can alter things a bit but actual decorrelation will require some more complex processing that I don't have a good suggestion for
Nice! I always use two mics on gtr amps. Sometimes to create a hush effect, but mostly in digital consoles for panning….
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Great practical demonstration as always!!
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Again thank you David for your ability to provide an in-depth analysis of the concept. Any chance you could could show us EQ'ing the two Mic to sound similar. I do find it hard to fully pan hard left and right. I normally end up paning 2 o'clock and 10 o'clock.
Gratefully a sound human.
No need to fully pan everything, it's about having the additional tool of decorrelation to add to your toolbox of EQ, panning, delay, efx, mix position and so on.
Doung the same thing too much like using the same EQ on every mic, hard panning on every mic, same mic on every input, and so on usually does not give optimal results.
@@DaveRat OK great cos that's what I had discovered.
excellent demonstration!
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The proof is in the pudding, so to speak, and I think you demonstrate it well. It's an easy test to make and it gives me some ideas to improve a smaller portable setup for a show I have coming up. We always get some combing and I want to figure out a way to eliminate or at least minimize the effect and make the show even better than what it is.
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So many arm chair experts
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Thanks Dave
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Dave, you mentioned EQ'ing the two microphones so they sounded similar. Could those EQ changes also introduce phase shifts in both signals that would make them less correlated?
Yes, increasing the decorrelation between two mics on the same source is a cumulative process.
Mic'ing different places, differing distances, differing mic types, differing EQ, and if possible, differing sides of a sound source all can help increase the differences such that the two signals no longer sum and cancel as drastically.
@@DaveRat Thank you!
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Put simply, the best and least problematic sound was two mic on the source going into two different speakers. This is double hung pa concept, but it would work with small systems also. Fill systems would get the mic from the speaker that is farthest away.
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Great demo. Would love to get your opinion on effects that seem to offer a digital decorrelation of the same signal like the mimiq from tc electronics.
Have not used or tested so I don't have an opinion other that it should be something that can be done digitally. Not sure about the sonic assets and issues but would be interested in hearing how well it works or not
Very good can’t wait for the reply’s
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@@DaveRat hi Dave I love your work we called you I think the late 90s about our issue with a problem we had was blowing jbl diagrams witch was caused by sound pressure issues around our hf and shattering our hf diagrams you where not wrong
Awesome, cool cool Bruce!
now that makes sense
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So I understand the whole concept and of course it makes sense. My question is what do you do with vocals? Since they are single mic'd what else can you do beside run it straight up the middle?
There is no reason to take everything to an extreme.
Nothing decorrelated is pure mono and has issues, everything decorrelated is extremely challenging and will eliminate all of the additive sound in the venue center and will sound overy stereo wide and disparate.
I would decorrelate most instruments and open up room to drop key inputs into the center
You could pan it just a hair, or maybe split it to 2 channels and use a different eq plug in?
I am not sure that decorrelating all inputs is advantageous for most or many apucations.
I do believe that decorrelating some or most inputs is advantageous in most or many applications to reduce having every input exhibit the same issues in the same audience locations is improbable to be desirable.
In our studio we have a Neumann U87 modded with a DPA capsule inside just below the diaphragm.
Wire goes out the back of the cage. Bit of a trick mic for certain vocalists. Not sure if I should even mention this, haha.
Idea is you get a second source for the mix, mostly to add some air.
The same hack could probably be done with a vocal mic, but space is tight.
You obviously just can't add a lapel or headset mic, as most singers will use mic positioning to change their sound.
But it should be doable...
I like to play with very short reverbs to aid with the feeling of depth, plus they are decorelated left from right.
These guys criticism of Dave seem to all being in the same club as supposed audiophiles and their dry know it all attitudes.
Just because someone knows some physics doesn't mean they own them .
Dave seems to be the most laid back dude that would never be condescending to any of these turds criticizing him.
Like they are undiscovered or less acknowledged audio genius's than Dave.
Dave has the resume proving he is recognized as an artist in his field.
Plus all of the gear he has developed and sells .
Even if Dave goes against convention it is probably best to take his advice as a grain of salt if it rubs you the wrong way.
Because once it sinks in and enough time has past Dave's approach will become the standard while critics will be stuck doing the same old same old.
Thank you and let's all not forget that sound is beautiful and fun. If we wanted serious and a bummer we would be in the military bomb build world.
Which I quit to do audio!
cool - thanks
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Genius. Thanks Dave.
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I got a couple of sounding excited face t-shirts but the prints on the back and it doesn't say sound remix down face you still have available the ones that you're wearing in this video
I would be interested to know if you have any experience with mid-side processing and your thoughts about it.
It's cool and interesting and an excellent way of capturing stereo sound from a single point in space.
Especially for listening on headphones.
We don't listen with math! Hahaha
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So this next week i want to try this just on maybe the kick mic and the guitars, i run a dbx driverack and the subs are in mono but i want to maybe run 2 beat 52 put in the kick panned hard left n right. Will i notice more power or a difference and should i set the driverack to stereo subs, THANKS. also this is outdoor. it will be streamed live on youtube at Taber Cornfest 2022.
Stereo subs good. Mono subs tend to maximize coverage issues.
@@DaveRat i did it this weekend awsome.. thanks ....you can watch a bit. taber cornfest 2022
Super cool will give a look
Good demo!
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Two parter question: A truly decorrelated setup would be Mic 1 going to Speaker 1, and Mic 2 going to speaker 2 right? Similar to your pink noise video where discrete pink noise sources were going to discrete speakers, making them decorrelated? With all of this I think of Dolby Atmos. I’d love to hear your take on spatial audio and the decorrelation algorithms they use when a signal source is equally panned between two speakers (in a Dolby atmos setup). Thanks for these videos, your wisdom, and experience.
Sending to different speakers does not decorrelate.
Decorrelated signals are signals that do not impact each other when summed. Polarity, time, phase and delay one or the other and they do not sum or cancel.
Identical signals are 100% correlated and will maximally sum if delay, time, phase and polarity are matches, and will maximally cancel when polarity reversed if time, phase and delay and matched.
Achieving some decorrelation by using various methods will reduce the interactions.
The interactions are what cause comb filtering
@@DaveRat I think we are saying the same thing ( I hope so lol). If you send mic 1 to speakers 1&2, it’s correlation time, thus comb filtering magic between the two speakers, just like what you have in your reply. But if you have one instrument, and two mics on that instrument, where in one mic (ribbon) is only in the left hang, and the other mic (dynamic) is in the right hang it’s decorrelated. Am I right on that?
Sort of. In order to decorrelate even partially you need to introduce as many differences as possible. Using different mic types helps, micing the front and the back helps, micing different parts of a cone helps, micing it different distances helps. And after all of that you can achieve some decorrelation that will vary depending on all those factors and more.
Hi frequencies will decorrelate much easier then low frequencies.
But to say doing something will result in de-correlated signals, would not be a correct statement unless whatever you did was very complex and designed to do exactly that
So yes, you are correct but it's not a simple and clear yes/no thing but rather a gradual thing that is worked towards
hey dave, i wonder if you ever tried funktion one system or Danley system?, what's your thoughts on them?
Border AV
Indonesia.
Thanks
I have been to the function one designer's shop with Tony Andrews. Also Danley has done gear demos at the rat shop.
"Point Source" is a marketing term for a system that covers the listening area in zones. Except when there is a single output area from a single enclosure used with no other enclosures nearby.
True point source systems are not scalable or arrayable, as soon as they are arrayed, they become zonal.
Here is an article I wrote a while back
www.prosoundweb.com/zoned-summed-line-a-discussion-of-array-structures-performance/
@@DaveRat hey dave, Thank you for the reply and the article.
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Fact: The universe is broken, I mean entropy is a thing. Great example Dave, if you keep this up your going to break Reddit, LOL. :)
Thank you and fun and this is the last episode of this adventure. On to new!
@@DaveRat Cool, cool, it was good to test it. ;)
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miking opposite sides of a speaker make the channels in opposite polarity to begin with?
Yes, when not in an enclosure, the front and rear of a speaker are opposing polarity.
When in an enclosure, the inside of the enclosure is the opposite polarity to the outside of the enclosure.
Silly question maybe but, why do we flip polarity and not shift it to its desired position with a potmeter?
hmmm, a potentiometer will typically control level or set to control delay. A polarity reverse is one of the most drastic things you can do to a signal that is being combined with a similar or identical signal as it will cause maximum cancellations. So I use polarity to demonstrate worst case
@@DaveRat I gave your answer a lot of thought. And I'm not done thinking about it. But, flipping phase is one thing, shifting phase is 'delay' so if I understood you correctly, it introduces a whole bunch of other challenges. Thanks so much for your reply though. Mind boggling :)
Hmmm, adding a delay will shift phase and the phase shift will be different at different frequencies. But shifting phase is not necessarily a shift in delay. A transformer or capacitor will shift phase above and below the passband but not add delay to the passband.
Regardless, polarity reversal does the same thing to all frequencies rather than different things to various frequencies
2 anti-phase mics killing noise... just look at light aviation headsets used to reduce excessive cabin noise and hear the pilot..
Well that's an example of 2 mics cancelling the correlated sound they pick up
Do you ever apply this technique to a lead vocal?
Hmmm, it can be done a bit with efx, like a chorus or Haas panning, to one side and actual panning back to center ish.
But also not doing it is a way to make an input sound different from inputs that are decorrelated
Ha ha absolute genius once again Senor Dave
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You the man!
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You need to make T-shirts that simply say ''I understand Dave Rat''.
I might not be the best person to make those as I confuse myself too often
@@DaveRat Meh, just print them in reverse so you have to look in a mirror to read it. Could make for good Reddit conversation lol
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maybe two different mics, despite making analogous waves, and despite being in phase, panned side to side, don't comb because the slight differences between them are sufficient because the brain assigns more weight to differences between sounds than similarities? i don't know. i think you kind of have to look for combing anyways unless it's really bad, because your brain doesn't just try to 'hear', it tries to figure out whats going on, and reject anything that doesn't contribute to a good image.
Hmmm, are vibrating surfaces truly phase coherent? Are differing parts of the speaker all perfectly in phase with each other? Are differing mic diaphragms of differing sizes, designs and materials reproducing exactly the same phase coherent signal as each other?
To find out what is identical between two signals by polarity reversing one and combining them, what is left over is the difference.
In this demo, what will not null 8s the differences.
The kids on reddit still live in the 2nd dimension.
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@daverat at 2:18 you place a image in my mind to make a basic cheese sandwich . then i may play more pink noise . been playing pink noise since last night and watching listening to classics that have the directional dialogue effects . ice station zebra and the towering inferno . oh , that 2:18 is so much more making me want to quickly make a basic cheese sandwich . your making more hungry 2:18 lol
when i think of pink noise i think of many channels on the CB radio with 10kc shifts apart but they are actually one wide of the 11m or 10m band 24mhz to 28khz or 30mhz , oh , 2:18 making more hungry for pink noise . lol
i may do a short video after i had basic cheese sandwich . do pink noise of multiple microphones behringer ecm8000 anywhere from x3 to x11 of them . primarily used for my , home professional THX cinema .
decorrelation used in home THX on the right surround channel to give the illusion (when LCR muted) listening only to the surrounds of 4.2.4 matrix say a classic like laserdisc letterbox scope 2.35:1 "Star Wars" Dolby Stereo , depending on the surrounds ? as there is only one original surround format , surround configuration that very few if not hardly any home theaters in usa or uk are using the , left-half right-half surround configuration . some earlier home avp like a harman kardon avp1a had surround output of side surrounds and back surrounds playing the same signal . with the correct number of same speakers used for the surrounds down the sidewall x3 or x4 of them and back wall x2 or x4 of them . then "Star Wars" to a trained listener ear , which is few and far between that there are some that recall that surround number of speakers for the surrounds and the goal in which they achieve .
diffused and localization all at the same sort of at the same time . so no need for THX with few speakers , x2 for sidewalls and x2 for back wall . that is , one per sidewall and two for back wall , may give the proper "Dolby "hass-effect" to trained listening ear ?
oh , 2:18 i give in . cheese sandwich . with mayo slapped on it . plus fact you made me go in the kitchen had to feed my cats again and then eat grapes . 2:18 places flashing image in my mind . lol
5:43 i noticed the cat bed . or is that your bed when you transform back into a rat and sleep in the bed ? curious to know where's the cat ? not seen your cat in the videos ?
9:25 doing that cheese sandwich stare again . i would repeat your test outdoors as i can hear the walls/ceiling and table changing the delay on the frequencies . need do the test again outdoors frame for frame . so i like to nominate you @daverat to mimic the same as you done in this video for same running time same dialog only , outdoors as the test would be free from the scattered items around the room .
10:47 oh , that was cheese sandwich dave rat trippy . now dave rat , your telling me go over the road , buy cheese onion crisps and make cheese sandwich with crisps and may slapped on it and fold the bread in half and have munches . lol
I have two pups
@@DaveRat oh , cute nice dave , need more pups in the next videos . people like pets in videos .
On it!!
They need to add a 2 thumbs up button; preach!
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I think on the member side he explains it so my girlfriend can understand it. But I have to test this.
Yes to test!
Why can't these 'all-knowing-sound experts' that post negative comments about what Dave Rat is saying in his videos understand that they appear to be be the biggest closed-mind sound people ever. Dave offers other ways to look at the way sound systems behave. Dave never says his comments are gospel and the only way you should understand live sound. Take his experience and thoughts he shares (and the time he takes to make these videos) as what they are. Why people post negative comments about something they don't maybe understand completely or are not able to be open enough to look at a new perspective is sad. As an sound engineer for many years I like to hear other ideas about live sound challenges. I'll never stop learning something from those people who their take the time to share their thoughts- whether I agree with them or not. Just my .02 cents.
Some eole try and climb by steping on the heads of others and some people climb by unifying people to climb together.
I like the unifying plan better.
The problem is that people think they understand and even know.
In this case 2 mics on a single source *must* produce the same signal. But that *only* works in an anechoic chamber with a theoretical point source. And that's where the *understanding* and *knowledge* fails. If people fully modelled the set up instead of a theoretical ideal, they would come to the conclusion so amply demonstrated by Dave.
Yes, and the assumption that vibrating surfaces are perfectly phase coherent and differing mic diaphragms, designs an materials are identically phase coherent with each other, is flawed.
Phasiness is laziness
What’s so funny is this master of all knowledge (Reddit poster) missed the key fundamental that the reason pink noise generators are used is because they are precisely uniform correlating sources. Like how a cymbal is always in tune and in key with the band. Lol pink noise is pink noise is pink noise.
Hmmm, yes all pink is unique from all other pink noise
And yet no pink noise or signal is different from itself unless differences are induced
@@DaveRat I just realized that to whom my comment was directed isn’t clear. I was speaking to the Reddit poster not you Dave. Just in case.
Ha! I figured that puzzle out
Yeah I'm getting a bit tired of the Keyboard warriors that have quote after quote from sound re enforcement handbooks and haven't bothered to do a SINGLE actual test to prove or disprove anything that Dave is attempting to show us. Don't know why you bother with this Dave. A bunch of butthurt is all it really is lol.
It's a chance to chat about rumors, myths and doubts floating about. Thank you!
@@DaveRat I guess that's relevant lol. I admire your attitude man! Keep doing you Dave! I love that you actually do all this real world playing around with things to see what ACTUALLY happens. Even if the books are dead right, it's good to hear it and work with it in real time! I've learned a TON about what's going on when we shove them faders up from you! And a lot of it I used to think you couldn't do much about. How friggen awesome it was to learn I was wrong about that!! Thanks doesn't cover it!!! Cheers to you Dave!
So cool Steve!
Is Reddit always like this? I can’t even watch these due to the ‘blowhard’ factor. You display great forbearance.
No Reddit is not always like this. There are some great people on there and wonderful discussions though I don't visit it often. One of the cool things about Reddit is you can easily see every post a person has made and research their history on Reddit. This does a great job of providing clarity about the people posting. I chose to address these because they were particularly harsh and thought it was a great opportunity to dive into some new subjects and clarify others
WITCHCRAFTS!! 😱
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If you take the windscreen (capsule) covering off the microphone you change a variable don't you?. 🤡
Removing the windscreen should add a slight bit of high frequency but I did it just to get the mic closer
PERFECT demo! STFU to the trolls.
Good fun testing and sharing observations!
One of the craziest things about noise is that it has no phase or frequency, but once you have resonated or notched it... it's NO LONGER NOISE. How does it travel? As a wavefront? Sure. Can the wave travel backwards? It rests on the air pressure behind, so sure, it all propagates spheroidally molecule to molecule, right down to the brownian noise floor, which probably isn't pink. Boundary element method is not the whole story.
Stochastic mathematics is hard to get your head around, certainly. Average of a random number generator, with a big enough window to average, you should be sure of the output, regardless of the source or sequence of randomness. That is how pressure cancels and sums within the context of noise at different wavelengths, timescales, and bounded-gas-elasticity-conditions: it's like averaging.
Please see standing wave tube experiments 1-42 in the unwritten manual of fourier transform methods connected to poincaré's butterfly pendulum, and gaussian distribution in the context of reverse blind bernoulli deconvolution, which won't run realtime on any of the FORTAN 1970s minicomputer crashosaurs.
But it does have polarity
@@DaveRat Hmm. Random need not have polarity to still interfere within an interference structure. The noise generator at the end of a clarinet still defies acoustics simulations. IRCAM Audiosculpt relies on noise generator addition, fourier removes essential information. Our perception of noise is not understood, either. We filter it out, mostly. We don't fully understand how the ear-brain discriminates between noise, impulse and resonation, and not everybody hears the same thing - the ear can be trained. I don't listen for elevated noise floor, I listen for that dusty lack of clarity, then hunt it down with a mic. Audible or synthetic noise is naturally pseudo-random and bounded. Real acoustic noise has a great many phenomena and flavours. Sand on the beach - it's little resonant wind chimes. Put that stuff under the microscope and it's a whole ecosystem, and orchestra. We can hear sand, it benefitted our ancient ancestors to do so. Noisy and chaotic are qualities, not an absolute definition with a single answer.
Cancelling easily occurs when a random digital sequence gets put through a converter (noise shaping delta sigma most likely), then filtered by a bandpass, or sinusoidally filtered. Passing through air above the natural noise floor is such a synthetic behaviour - the white noise generated by non-electronic / non synthetic sources is a different disease - industrial active noise cancelling is incredibly difficult, especially in aerospace - NXT was a failed ANC project, where they found they mainly amplified the problem. Turbulent air flow prevents wavefronts from forming - chaotic conditions can be serious inside engines, non-laminar flow. Ultrasonic and infrasonic noise significantly influence s/n and impact sound quality even though they are basically inaudible. I would be lying if I said I believe we have a complete mathematical grasp of this atomic noise / background vs emergent structure stuff, even at CERN.
But we are dealing with singular captured versions of an instrument and noise. And the captured versions are what we send to be amplified. And the captured versions do have polarity, regardless of how complex or random the original source is
@@DaveRat precisely - once sampled to a theoretical point source pressure plot, in the same place at the same time, in an electronic space, signals should and do null completely - but the self-noise of the measurement system's output or noise floor won't - also most conversely 'port chuffing' or non-laminar turbulent flow can *crash* the ability of the air in a tube to pass sound - it becomes an acoustic eraser, and the acoustic energy cannot flow as a wave through the chaotic energy saturated environment - it gets converted to a "blasting" type of noise of lower intensity with a broadband component. This cannot be fixed by inverting the polarity of the input signal or measurement tool! A mic at either end of a bass reflex port may or may not null, and this is important information.
Interesting
Thank you for doing these!! I look forward to these every weekend ☺️ I'd love to hear more about the quiver behind you. 🛹
Skateboards!!
Dave, your retirement with Red Hot Chili Peppers has brought a lot of eye opener to Live sound engineering through your videos,the test, illustrations, demonstrations and the lite,I sincerely appreciate your kind efforts on all your videos,the time,the initiative,and the money, please Dave keep doing your best for us,what you are doing is not a waste hundreds if not thousand are greatly benefiting from it.....kudos 👍👍👍👍
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