In this episode, Danny Richie tackles the topic of Fast Bass! What Audiophiles need to know! Check out our site: www.gr-research.com Contact: info@gr-research.com 1-940-592-3400
Back in the 70's - 80's I grew up next door to a guy 5 years older than me. He was the wheeler-dealer type who was always trading/buying and selling audio equipment. He liked to invite me over to listen to his new acquisitions and I was always eager to hear what he had. Sansui, JBL, Kenwood, Klipsch, Pioneer, etc. And back then the bigger the woofer meant bigger, better bass. Thought I'd heard the best of the best until one day he invited me over to hear his new find, a pair of Bose 901 series ll's. My first impression was, "No way these are going to produce the type of bass I had come to expect". When he turned them up to about the 9 o'clock position they didn't impress me at all. Sounded like any other speaker until he cranked the volume up to eleven... Holy Jesus!! The attack of the drums literally took my breath away. I've never experienced the bass smack my chest like that ever, except at a live concert. Other home speakers always seemed to make you feel the bass in your ass by being coupled to the floor. But the 901's delivered an almost gunshot like effect square to your chest. Say want you want about 901's, but they sure rocked my world at higher volume levels.
Try the subs that Danny is selling here. No way the 901 compares to this open baffle subs. I measured the 901 and wasn’t impressed since it wasn’t fast and tight. 901s we’re boomy but low and muffled.
Listened again. I'm in the adjustment phase of my spectacular failure to accomplish my goal. What's going to be best for me and my family is to quit my compulsive technical orientation. Hopefully I will do this. In the future after I have established enough room treatments to make it worthwhile I might decide to go for a beautiful open baffle solution. If I do I'll just buy one of yours and some rythmiks. Thanks again for all you do Bill Davis
thank you amigo ! Pls respond when you can to what this guy said in a Allison speaker forum about this video i am sure he is wrong about somethings ? HF said : "First, if we are talking about reproducing bass instruments, it is very unlikely that a typical acoustic instrument that is dealing with bass will itself "stop" fast enough to leave a good subwoofer behind. Certainly, if we are talking about organ music there is no way an organ pedal sequence is going to taper off faster than what a good subwoofer can deliver. However, even big bass drums do not stop all that fast, and if we are talking about things like kettle drums or even kick drums, they do not stop so fast that an amplifier backing off the power feed to a subwoofer will not be able to retain a grip on the cone mass. And it is that grip that is important. Indeed, he mentions how there will be an input signal that will excite a subwoofer or woofer, and then cut off, with the driver then having to settle down on its own. That DOES NOT HAPPEN. The amplifier controlling the driver will not only increase the feed to the driver, but it will also continue to control the driver as the signal tapers off. The driver does not just become abandoned by the input signal and have to stop moving under by its own accord. The amplifier will be controlling the driver during the increase in power and also during the decrease in power. The driver is not punched into position and then have to settle back to a neutral point on its own. The amplifier pushes the driver in both directions as it both speeds up and slows down. A decent subwoofer amp never stops controlling the driver. And, again, as I have noted, the bandwidth being handled by the subwoofer driver (probably going no higher up than 100 Hz, and more likely 80 or even 50 Hz) is itself controlled by the feed from the processor to the amplifier up until the crossover point is reached, whereas the frequencies above the crossover point continue to go higher and higher and things are taken over by the satellite speakers, with their smaller woofers that are under the control of the satellite system amplifiers. Those satellite amps also lock onto the satellite drivers and control the increases and decreases in their feed power. Now, what you can get is resistance from the driver both as the power increases and decreases, and it can indeed lag a bit behind in movement, especially given the shape of a cone that itself has linearity issues (surface flexing, for instance, as well as terminations at the surround interface), and the result is not so much a speed issue as it is a harmonic-distortion issue. What you get are harmonic artifacts that color the overall output if the distortion levels are high enough. This is where the servo approach mentioned in the video come into play, and their feedback to the amplifier allows it to provide extra power to compensate for the second-order and third-order non linearities. Servo control is an indeed viable technology, but the audible net result is a measurably cleaner bass output that has nothing to do with the perception of woofer speed. Regarding those distortion levels, Tom Nousaine once did quite a bit of work on the audibility of bass distortion (Roy Allison did this kind of research, too) and Tom's conclusion was that unless the distortion at any bass frequency exceeded about ten percent it will, due to masking from the fundamental and also masking from the multitude of satellite-generated frequencies still higher up if we are talking about wide-bandwidth musical reproduction, be inconsequential. I checked this out myself years ago when I did level-matched comparisons between a very nice Velodyne HGS-12 servo-controlled subwoofer and a Hsu Research VTF-3, ported box-style sub with a ten-inch driver. While the Velodyne could run solidly down to 20 Hz (its 1,200-watt amp included electrical EQ that pushed things hard down really low), the Hsu started rolling off very fast below 30 Hz, although it could generate a decent fundamental clear down to 20 Hz. In any case, when doing the A/B comparison work with pure test tones down to 30 Hz it was impossible to hear any harmonic oriented differences between the two subwoofers. The Hsu, with what Nousaine had determined in one of his own reviews, had up to 10 percent harmonic distortion down to 30 Hz, sounded just as clean as the Velodyne, which probably had one tenth the distortion. Musical sources showed the same results. And remember, this was with pure test-tone sweeps between 100 and 30 Hz: I used the Delos Surround Spectacular test disc. If the Hsu sub had any "speed" issues up to 100 Hz, I sure could not hear them. With any system incorporating subwoofers, no higher-frequency musical signals would matter to the subwoofer, but those frequencies would make it even harder to hear distortion artifacts from the subwoofer."
I appreciate what you give us in this video. I'm a bass player and use high end equipment, however my preferred speakers are a 4 -12 cab and a second amp to a couple of 15" singles. The 4-12 give me the quick response and really great live sound. George from Indiana:
Interesting thing to point out, I think 12" guitar speakers are highly suitable for distortion because they have slow treble from the complex motion of such a large driver. A small hifi driver can have weak treble and still be harsh.
Danny, your GREAT for any and ALL of the good things you have shared. I've contemplated fast bass CONTROL also Servos Amps. Didn't actually know Servos was an Amplifier .Good stuff...
I always wondered why pro audio went to line array. now we know. I also saw a video about a "panel" speaker, which had one small speaker mounted to a panel of something, and it sounded pretty good. seems like a cool space saver. could make it an art piece, anyway. Good video, I am learning a ton from Danny and love his work.
There is no fault to liking 15" woofers since it's all a matter of distortion. The human ear starts to detect distortion at 0,5-1% for 2nd harmonic and around 0,25% for 3rd harmonic. Anything above that will be detectable, even in the bass range. Some might say that we can't hear that , but I have research this in great detail and most have detection levels at these figures from 20-4000 Hz. Big drivers like 15" have low distortion in the bass. Normally 2-3% at 90dB which is quite high for normal listening. Some 12" and a few 10" drivers can have similar figures, but smaller drivers starts to get higher distortion, and when getting down to 5-6,5" it can reach 10-25% distortion @90dB@40Hz and that sounds boomy and can't by no means be called FAST bass. To get really FAST bass you need to get down to around 1-1,5% distortion in the bass and very few commercial loudspeakers do that. Big drivers come the closest. A 6,5" driver have no chance to handle that, BUT by using a lot of them distortion can be lowered. The best 6,5" drivers can get down to approx. 10% distortion in the lower end (30Hz at 90dB) but with every doubling of the count of drivers you will half the distortion (-6dB). So by using 12 of them the distortion can be lowered approx. 20dB which equals 10 times. 10% distortion / 10 = 1% distortion. So by using a lot of drivers you can match or pass the performance of a single big driver in the bass region and have the benefit of having a more linear response in higher regions. With a servo controlled bass you create a feedback loop around the bass which will lower distortion even further. That goes for both big and small drivers. But it's not useful to hunt distortion levels below 1% because it's not detectable by the human ear. So a single 15" woofer CAN compete with multiple smaller drivers, and easily beat single smaller drivers. I assume that is why you prefer a big low distortion driver. Until now :-) Danny is great at explaining things, but I hope I have increased your understanding even more with the piece of text above. Multiple drivers and servo controlling is great ways to lower distortion and that's what getting FAST bass is all about. Multiple drivers in a line source application also have the benefit to avoid a lot of first reflections from floor and ceiling which will get a much more linear frequency response in the 80-200 Hz region compared to a single big driver which also help to prevent distortion in that region. IMHO.
Hi Danny, am I understanding you correctly, that multiple 6.5” drivers can reproduce the lowest of audible bass notes ~ 20-40hz, which is normally associated OR only achieved with a 12/15” bass driver? Thanks and subscribed 🏴
I ordered your X-Statik's kit Will be here in a few days can’t wait to build it. can’t wait to add your servo subs as a complement to the X-Statik. But building your NX-Optica or NX-Treme Will give me a good reason to remodel remove the kitchen wall from the living room remove the hallway walls remove the two back bedroom walls remove and raise the ceiling to give me a 25‘ x 35‘ x 12‘ listening room
An amplifier with a higher damping factor will also control cone movement better. Professional amps have a damping factor into the hundreds whilst a lot of older Hifi only have damping factors of 30 or 40.
response ? "I recall Roy saying that a woofer more than 10” in diameter could not be uniformly moved to avoid distortion and this is why he didn’t use anything larger. Do you have any input/update on this? "
So, in the end, you ARE talking about using a speaker with a higher resonant frequency after all - the smaller speakers! But I would think there is more than resonant frequency that matters. There is magnet strength, and suspension compliance, the amplifier damping factor...not to mention the presence or absence of bass reflex and the like, which smear bass. Now, servo control, THAT is really an excellent idea.
Danny's right. Go into a professional mastering studio. That one experience equals to about 10 years of guessing and thinking what things sound like, great ear to brain training.
Great video - thanks! Are these servo controlled drivers something you'd use in a home system or in a bigger setup like for concerts? And it sounds like most of the work (calculations etc) are being done by the amp - are they generally combined into active speakers or just need the right pairing? I do partner dancing as my main hobby and it always bugs me when events have sloppy subs - we go to dance to great music and the bass is really messy. Seems like it would help if they had sub boxes with multiple drivers rather than just one big one, but I don't know how many of the organisers would bother going to those lengths...
Probably the best site for all diy speaker lovers. I agree with the speed but I don't agree with the bass depth, it's not so simple, that more 6 "units go linearly up to 20hz. No 6" unit goes so deep because for the first time too little moving weight, small unit composition size unit and too high fs factor usually have a lot high bass around 90hz and big drop to 20hz. A really deep bass requires a unit of at least 10 ", preferably a 12" unit with a large vc and a strong magnet and a low and linear fs. Thenks,
It's not that easy. With a normal listening room you do not want to have a straight frequency response to 20 Hz because of the room gain. Room gain depends on the rooms size and form, but in general you want a loudspeaker with a -3dB point at 40-65Hz depending on room size and then room gain will add approx. 10dB for every octave below that. Some 6,5" drivers in ported cabinets can reach -3dB at around 45-50 Hz and with room gain you will get a percieved -3dB at 20-30Hz which basically is all that you want. BUT a 6,5" in such an application will have quite some distortion which will sound boomy and quite bad. So I'm not surprized that you state that it's necessary to use a 10" to 12" driver becuse you are right when we talk about a single driver. The bigger driver also need to have the -3dB at the same frequency as I mentioned above to get a really straight frequency response in the room, but you will get a better result because it have a lower distortion. By parallelling a lot of drivers you can lower the distortion to the levels that a single 10-12" have. So as long as the driver can reach approx. -3dB at 40-50 Hz you can match the performance of a single bigger driver with multiple parallelled smaller drivers.
@@flex-cx9bi Thanks for the detailed explanation, I agree. But for large orchestral and concert music, it was definitely more realistic with a larger 12 ” unit. Really unbiased speaker measurements show how low they go, like they do it in hifinews so for wilson audio with 8 "unit shocking only 52hz (-6db). www.hifinews.com/content/wilson-audio-sabrinax-loudspeaker-lab-report
@@borisjelenc1217 Yes, I'm not surprized that you found a 12" bass can give a very good feeling of the real thing, because we need to have a straight frequency response all the way to 20Hz in the room to not percieve short comings in the bass. But to get that straight bass response the loudspeaker need to cut approx. at 45 Hz and have a gentle slope of approx. -12 dB per octave. The rooms gain will increase the bass. It also very much depends on the rooms size. Only sealed boxes have -12dB/octave. By theory vented cabinets roll off with -24dB/octave, but that is not completely true. -12 to -20dB is more likely, but in general only closed enclosures will match the inverted slope of the room gain. A 30 m2 (270 square feet) room starts to gain at around 60 Hz and have these general gains at different frequency points. 50Hz +3dB, 40Hz +6dB, 30Hz +12dB, 20Hz +18dB. It's also important that the driver itself have low distortion and a 12" driver generally have much lower distortion than a 8" driver. So SabrinaX is not a complete disaster even if it absolutely cut a bit too high and too steep to get that really good bass in the room. I assume it would end up with a (in room) -3dB shelf from 60Hz down to 30Hz and then drop fast to -12dB at 20 Hz, and that will absolutely give a "light weight" bass. SabrinaX need a approx. 15-20 m2 room to have a chance to sound balanced. It would not suite a 25-30 m2 room. So understanding room gain is very essential both when designing and buying loudspeakers. Take a look at measurements in Stereophile. Most of them have both nearfield and in the room measurement. There you can see the what the loudspeaker sends out and how that will end up in the actaul room. That will give you a sence how much room gain there normally is, and I think many will be quite surprized with how much it really is. If I would buy a loudspeaker (will not happend since I design them myself) I would look at a -3dB at 47-48 Hz for a closed design and -3dB at 45Hz for a ported design, and preferable with at least 2 bass drivers to prevent some of the 6 to 12dB suck out because of the first floor reflection. And I would also look for a +3dB hump in the 80-200 Hz region in a nearfield measurement to further prevent the effects of that suck out and dip that in most loudspeakers divide bass in low and upper bass. A good loudspeaker design need to compensate for that first floor reflection, and when looking at nearfield measurements in Stereophile you will see a +3-4dB hump at approx. 100-150 Hz and that is a signum of a skilled designer... Here are a good example of a Stereophile measurement: www.stereophile.com/content/kef-blade-two-loudspeaker-measurements Here you have nearfield (what the loudspeaker sends of from drivers and ports) -3dB @30Hz for port, -3dB @70Hz for driver and -20dB @20hz for both driver and port. You also have a anechoic response which show the output without the room gain and there you have -3dB @35Hz and that is actually TOO low to get a perfect sound in the room. Finally you have a in room measurement with a severe hump of +6dB @30Hz, and that is the result of the room gain. Not many loudspeakers are designed this well to get such a straight response in the room, but personally I think a slightly higher -3dB at 45 Hz would be even better and give that perfect life-like feeling of being in the actual hall of the recording. This KEF Blade will have a little overhang in the bass in Mr. Atkinson's listening room and sound a tiny bit too soft in the bass. It would prefer a bigger room to get that out of the world great bass... Hope this helps you to further understand that small drivers also can get a very good very linear bass reponse in the room, but most likely you need several in parallell to get down to distortion levels that also need to be in the 1-2% range to get that feeling of a pure and highly resolved bass. The normal +10% distortion of a single 5-6,5" driver will NOT give you that perfect bass so I'm not surprized that you feel that a 12" bass do a much better job in the bass region.
@@flex-cx9bi Nice, we also have something in common, I have been using my own diy speakers since 1990, I currently have 5 different variants at home. Thank you for a really comprehensive report and knowledge of a connoisseur without BS and despite my long journey in this hobby, I can always learn something from what is you written, but it is true that I have a basis and I know exactly what you want to say. Can I get your email address for any exchange... Greetings,
Hi Danny. Great channel! Question regarding "fast bass". How much does the stored energy and time delay of a ported enclosure affect the decay of bass notes? Is the detriment offset by the lower group delay afforded by playing louder in the lower reaches of the system? Is it even relevant in the sub-bass region?
Dear Danial Yes I have subscribed but , even if I stand on a chair some bits go over my head LOL With the current situation & the dismal supply chain you are having to live with you may have a little time on your hand. Food for thought The X-Static speakers, with what I have read over the last 2 months the open baffle speakers has like electrostatic speakers have a tendency of being a bit light in the bass region is it possible to use 1 of the basses that you use in the subs in the cabinets maybe play with the rest of the open side & cross overs to create a super duper X-Static. like 50 to 60 % you have already done. Knowing you I am sure you have thought about this at some time but finding the time to develop such a product what with Covid & everything else as I said food for thought. Rodney Duncan Ps I don't think that Jay has any concept of how to conduct a blind test you should NOT be able to identify all the speakers this is all about quality of sound , definition & sound stage not how much he paid for his speakers, $13,000 & he has no idea if that also includes the price of the stand for that price Come on your have got to be joking
Ilive in Germany and i really enjoyed your video. would you recommend a Klipsch R-115 ? i have a 5.1 system mit an AV receiver. thanks alot for your Help and i wisch you the best with your channel
I have a pair of Thiel 1.5's,I like them a lot,while l may buy some relatively inexpensive stand mounters,mounted, Thiels will always stay.l think,or thought they used top quality components,your videos have me wondering.If you owned a pair of 1.5's,which seem to be holding there monetary value,l seem to be seeing the 1.6's,and to some extent 1.7's not holding their value quite as much.None the less,are there any upgrades routes for the 1.5's,l would like to hear your thoughts on these speakers and what would you do to improve them,thank you in advance,Steve Craft.
So, let me see if I've got this. If you have "fast base" that is a function of the woofer which has a sensing coil and the Amp which has Servo Control? So I've heard reviewers talk about a speaker that has "Fast Base". But it's not the speaker alone that is responsible for this, it's the speaker combined with an Amp that is equipped to take advantage of the drivers sensing coils? Have I got this right?
@@dannyrichie9743I am a fan of yours. I really would like your insite. I finally got a used pair of Maggie 1.7i fairly cheap. They are pretty exceptional with what they do well but good lord they lack dynamics and placement is crucial. I am trying to keep the holographic imaging and clarity but add dynamic frequency responses from say 3500 hz to 20 hz. I ordered a few cheaper Goldwood 15s and have been experimenting with a cardboard box to replicate different OB designs. I'm thinking of making a bottom driver crossed over at 400hz in an H Frame but it is slightly shouty (placed centered with roughly 6 inches in front and back). I tried the mid up to 3500 and it is extremely shouty. I turned the speaker 90 degrees inside the h frame cabinet and it seems to help. Is their a way to make this blend with Maggie's and not beam sound while maintaining clarity? Thanks
@@ufarkingicehole First of all the crossover parts on the Maggies really need to be upgraded. Then you should get much better results with a much lower crossover point. Filter the lows off of the Maggies (first octave) and shoot for about 60Hz crossover point.
@@dannyrichie9743 thank you! You are the man. Just curious..... Maggie's have a cult following. Have you ever considered building crossovers for them to sell? I would be willing to figure out how to get mine out to send them to you. I would be the first to buy it for sure. Either way thanks again for your reply. Btw... I'm in Louisiana and plan to travel to Arizona (Grand Canyon) with my daughter on the 20-23 and will be passing back through from Colorado around the 27ish. I believe you are I Texas. I would even drop them off to you in person. I wish I could experience the static and the extremes as well as the servo subs. I'm sure its quite the experience.
Thank you Danny. Very good explanation. It's a pleasure to have discovered your information. The CST'-1s are impressing me very well. Once I get the upgrade parts, I might explode? 😂
The measuring system computer still does. It has less to go wrong with it, is not connected to the internet, and runs faster (even though it is old and slow) than our newest and later computers.
The really great hardware based measuring systems for loudspeakers where developed during early Windows days. Personally I run a Windows 98 with LMS and I still can't find a loudspeaker measurement system that can compete with it without passing 5000 USD in investment. There simply are no computers that can handle those big ISA boards. Will run that system for designing loudspeakers until it dies. But of course it can't be used for anything else...
I am thinking about building 1 or 2 of your OB subs, and I have a very specific question: Would it be possible to change the op amps in your plate amp for discrete ones? Of course I realize that this will void the guaranty. I am a no-opamp man thru and thru, and today the only ones that are in my signal chain is in the crossover of my Hypex plate amps, that sits in my closed ScanSpeak subs. They are small SMD components and difficult to change out. So I thought I could hit 2 home runs by changing to OB subs with MFB, and plate amps with discrete op amps. Does op amps for bass matter at all ? - I think so! ... And as a DIY-selfer I am allowed to be picky. Still exited to see your upcoming sub video.
I have a Audio Pro B2-50 which uses a pair of 6.5" woofers, one facing forward and one facing backwards, here I'm putting a link with it's picture www.rehifi.se/arkivet/2018/audio-pro-b2-50
@@porkchopspapi5757 less surface area for the drivers mean that they have to travel further to reafch the same SPL, more travel = more acceleration needed and therefore more overshoot and less accuracy, and the 12" will have a much more powerful magnet + motor assembly, giving more control. There is no replacement for displacement when it comes to bass. one 12" will outperform 2 6's of a similar quality every time.
And how do you "Electricly stop" a cone from moving? Tell me coz i really have no idea..If you play positive signal cone will go upwards if you play negative inside. What you play for speaker to "brake" and stop immediately? I say " Snake oil"
He talked about a patent from ritmick. Go check out as your question makes me think you might understand it. I'm lazy...if not i would do it. It might be done digitally....tampering with the original lfe channel. Just a guess.
Simples, all you need is a speaker with Qes factor of zero (infinite Bxl) partnered with an amplifier sporting output impedance equal to 0 ohms. In this case the electromagnetic breaking due to back EMF will be infinite with no post impulse ringing.
You sould not call something snake oil simply because you don't understand the principles behind feedback and servo controlling. Actually it's quite easy. It's simply a amplified feedback system and as a result ringing (distortion) will be lowered.
We have Windows 7 and 10 on every other computer in here. But for the measuring system there is no need to use anything else. It isn't connected to the internet and actually does what we need it to do faster than the newer and faster computers in here running more complex operating systems.
I love your CZcams stuff and I would really love to see your upgrade kits that are available, but I refuse to give my friends list just to see your catalog. Sorry bud your company does great work, so I suggest you get rid of the Whole whom believes invading peoples privacy is the way to go, If I want my friends to know about your company, I would suggest it to them, not have their privacy invaded by a company I may or may Not sign off on...Really wish we could have done business but until try research stops robbing from their subscribers, I will be telling All my friends to watch your videos and to Not do Any Business with Your Company!!!!
What are you talking about? Do you have a form of dyslexia coupled ADD - I have no idea why you have any issues with an audio site trying to help you?🤷🏻♂️🤷🏻♂️
I always had the feeling that fast bass actually meant fast decay (low ringing) but I was never really sure of it. Thank you for the explanation!
don't forget Isobarik as used by Linn Products
Back in the 70's - 80's I grew up next door to a guy 5 years older than me. He was the wheeler-dealer type who was always trading/buying and selling audio equipment. He liked to invite me over to listen to his new acquisitions and I was always eager to hear what he had. Sansui, JBL, Kenwood, Klipsch, Pioneer, etc. And back then the bigger the woofer meant bigger, better bass. Thought I'd heard the best of the best until one day he invited me over to hear his new find, a pair of Bose 901 series ll's. My first impression was, "No way these are going to produce the type of bass I had come to expect". When he turned them up to about the 9 o'clock position they didn't impress me at all. Sounded like any other speaker until he cranked the volume up to eleven... Holy Jesus!! The attack of the drums literally took my breath away. I've never experienced the bass smack my chest like that ever, except at a live concert. Other home speakers always seemed to make you feel the bass in your ass by being coupled to the floor. But the 901's delivered an almost gunshot like effect square to your chest. Say want you want about 901's, but they sure rocked my world at higher volume levels.
Try the subs that Danny is selling here. No way the 901 compares to this open baffle subs. I measured the 901 and wasn’t impressed since it wasn’t fast and tight. 901s we’re boomy but low and muffled.
@@peerguy A general question to fast bass... Would it be wrong to assume that a woofer with a Qts=0,3 sounds faster that one with a Qts=0,5?
Listened again. I'm in the adjustment phase of my spectacular failure to accomplish my goal. What's going to be best for me and my family is to quit my compulsive technical orientation. Hopefully I will do this. In the future after I have established enough room treatments to make it worthwhile I might decide to go for a beautiful open baffle solution. If I do I'll just buy one of yours and some rythmiks.
Thanks again for all you do
Bill Davis
These Tech Talk segments are amazing. Thank you so much for these great explanations that you provide.
thank you amigo !
Pls respond when you can to what this guy said in a Allison speaker forum about this video i am sure he is wrong about somethings ?
HF said :
"First, if we are talking about reproducing bass instruments, it is very unlikely that a typical acoustic instrument that is dealing with bass will itself "stop" fast enough to leave a good subwoofer behind. Certainly, if we are talking about organ music there is no way an organ pedal sequence is going to taper off faster than what a good subwoofer can deliver. However, even big bass drums do not stop all that fast, and if we are talking about things like kettle drums or even kick drums, they do not stop so fast that an amplifier backing off the power feed to a subwoofer will not be able to retain a grip on the cone mass. And it is that grip that is important.
Indeed, he mentions how there will be an input signal that will excite a subwoofer or woofer, and then cut off, with the driver then having to settle down on its own. That DOES NOT HAPPEN. The amplifier controlling the driver will not only increase the feed to the driver, but it will also continue to control the driver as the signal tapers off. The driver does not just become abandoned by the input signal and have to stop moving under by its own accord. The amplifier will be controlling the driver during the increase in power and also during the decrease in power. The driver is not punched into position and then have to settle back to a neutral point on its own. The amplifier pushes the driver in both directions as it both speeds up and slows down. A decent subwoofer amp never stops controlling the driver.
And, again, as I have noted, the bandwidth being handled by the subwoofer driver (probably going no higher up than 100 Hz, and more likely 80 or even 50 Hz) is itself controlled by the feed from the processor to the amplifier up until the crossover point is reached, whereas the frequencies above the crossover point continue to go higher and higher and things are taken over by the satellite speakers, with their smaller woofers that are under the control of the satellite system amplifiers. Those satellite amps also lock onto the satellite drivers and control the increases and decreases in their feed power.
Now, what you can get is resistance from the driver both as the power increases and decreases, and it can indeed lag a bit behind in movement, especially given the shape of a cone that itself has linearity issues (surface flexing, for instance, as well as terminations at the surround interface), and the result is not so much a speed issue as it is a harmonic-distortion issue. What you get are harmonic artifacts that color the overall output if the distortion levels are high enough. This is where the servo approach mentioned in the video come into play, and their feedback to the amplifier allows it to provide extra power to compensate for the second-order and third-order non linearities. Servo control is an indeed viable technology, but the audible net result is a measurably cleaner bass output that has nothing to do with the perception of woofer speed.
Regarding those distortion levels, Tom Nousaine once did quite a bit of work on the audibility of bass distortion (Roy Allison did this kind of research, too) and Tom's conclusion was that unless the distortion at any bass frequency exceeded about ten percent it will, due to masking from the fundamental and also masking from the multitude of satellite-generated frequencies still higher up if we are talking about wide-bandwidth musical reproduction, be inconsequential.
I checked this out myself years ago when I did level-matched comparisons between a very nice Velodyne HGS-12 servo-controlled subwoofer and a Hsu Research VTF-3, ported box-style sub with a ten-inch driver. While the Velodyne could run solidly down to 20 Hz (its 1,200-watt amp included electrical EQ that pushed things hard down really low), the Hsu started rolling off very fast below 30 Hz, although it could generate a decent fundamental clear down to 20 Hz. In any case, when doing the A/B comparison work with pure test tones down to 30 Hz it was impossible to hear any harmonic oriented differences between the two subwoofers. The Hsu, with what Nousaine had determined in one of his own reviews, had up to 10 percent harmonic distortion down to 30 Hz, sounded just as clean as the Velodyne, which probably had one tenth the distortion. Musical sources showed the same results.
And remember, this was with pure test-tone sweeps between 100 and 30 Hz: I used the Delos Surround Spectacular test disc. If the Hsu sub had any "speed" issues up to 100 Hz, I sure could not hear them. With any system incorporating subwoofers, no higher-frequency musical signals would matter to the subwoofer, but those frequencies would make it even harder to hear distortion artifacts from the subwoofer."
I appreciate what you give us in this video. I'm a bass player and use high end equipment, however my preferred speakers are a 4 -12 cab and a second amp to a couple of 15" singles. The 4-12 give me the quick response and really great live sound.
George from Indiana:
Interesting thing to point out, I think 12" guitar speakers are highly suitable for distortion because they have slow treble from the complex motion of such a large driver. A small hifi driver can have weak treble and still be harsh.
Splendid! i wish that i had found your site years ago- so clear!
amazing stuff
Danny, your GREAT for any and ALL of the good things you have shared. I've contemplated fast bass CONTROL also Servos Amps. Didn't actually know Servos was an Amplifier .Good stuff...
Thanks for your videos Danny.
I just found them and for me it's like getting a second opinion on what I have learned by myself so far...
Great stuff.
I am constantly amazed by your understanding.
I always wondered why pro audio went to line array. now we know. I also saw a video about a "panel" speaker, which had one small speaker mounted to a panel of something, and it sounded pretty good. seems like a cool space saver. could make it an art piece, anyway. Good video, I am learning a ton from Danny and love his work.
Wow
Great explanation!
I WILL be building my system with you in 2020. Great teacher.
I'm a 15 inch woofer guy , but this video was very interesting. I could start to experiment. Subscribed.
There is no fault to liking 15" woofers since it's all a matter of distortion.
The human ear starts to detect distortion at 0,5-1% for 2nd harmonic and around 0,25% for 3rd harmonic. Anything above that will be detectable, even in the bass range.
Some might say that we can't hear that , but I have research this in great detail and most have detection levels at these figures from 20-4000 Hz.
Big drivers like 15" have low distortion in the bass. Normally 2-3% at 90dB which is quite high for normal listening. Some 12" and a few 10" drivers can have similar figures, but smaller drivers starts to get higher distortion, and when getting down to 5-6,5" it can reach 10-25% distortion @90dB@40Hz and that sounds boomy and can't by no means be called FAST bass.
To get really FAST bass you need to get down to around 1-1,5% distortion in the bass and very few commercial loudspeakers do that. Big drivers come the closest.
A 6,5" driver have no chance to handle that, BUT by using a lot of them distortion can be lowered.
The best 6,5" drivers can get down to approx. 10% distortion in the lower end (30Hz at 90dB) but with every doubling of the count of drivers you will half the distortion (-6dB).
So by using 12 of them the distortion can be lowered approx. 20dB which equals 10 times. 10% distortion / 10 = 1% distortion.
So by using a lot of drivers you can match or pass the performance of a single big driver in the bass region and have the benefit of having a more linear response in higher regions.
With a servo controlled bass you create a feedback loop around the bass which will lower distortion even further. That goes for both big and small drivers.
But it's not useful to hunt distortion levels below 1% because it's not detectable by the human ear.
So a single 15" woofer CAN compete with multiple smaller drivers, and easily beat single smaller drivers. I assume that is why you prefer a big low distortion driver. Until now :-)
Danny is great at explaining things, but I hope I have increased your understanding even more with the piece of text above. Multiple drivers and servo controlling is great ways to lower distortion and that's what getting FAST bass is all about. Multiple drivers in a line source application also have the benefit to avoid a lot of first reflections from floor and ceiling
which will get a much more linear frequency response in the 80-200 Hz region compared to a single big driver which also help to prevent distortion in that region. IMHO.
Hi Danny, am I understanding you correctly, that multiple 6.5” drivers can reproduce the lowest of audible bass notes ~ 20-40hz, which is normally associated OR only achieved with a 12/15” bass driver?
Thanks and subscribed 🏴
I ordered your X-Statik's kit Will be here in a few days can’t wait to build it. can’t wait to add your servo subs as a complement to the X-Statik. But building your NX-Optica or NX-Treme Will give me a good reason to remodel remove the kitchen wall from the living room remove the hallway walls remove the two back bedroom walls remove and raise the ceiling to give me a 25‘ x 35‘ x 12‘ listening room
Love this explanation Danny! Greetings from DFW!
Good video!
Great explanation Danny.. thank you
Superb clarity of subject.
An amplifier with a higher damping factor will also control cone movement better. Professional amps have a damping factor into the hundreds whilst a lot of older Hifi only have damping factors of 30 or 40.
response ? "I recall Roy saying that a woofer more than 10” in diameter could not be uniformly moved to avoid distortion and this is why he didn’t use anything larger. Do you have any input/update on this? "
Amplifier power delivery is proportional to bass precision where driver characteristics remain constant.
So, in the end, you ARE talking about using a speaker with a higher resonant frequency after all - the smaller speakers! But I would think there is more than resonant frequency that matters. There is magnet strength, and suspension compliance, the amplifier damping factor...not to mention the presence or absence of bass reflex and the like, which smear bass. Now, servo control, THAT is really an excellent idea.
And it's an extremely old idea. :) Closed loop control active woofers have been used throughout the 1980s.
Now i want a bunch of small woofers! ☺️
Or a handful of 15" pro woofers with high efficiency, low Q, and lots of EQ on the bottom end?
Well said ☝️
Could you do a video on different types of bass, (ie Ported vs sealed vs passive radiator).
Doesn't ts parameters also tell alot about fast bass? Like Lower the Le faster the response, Lower mms, lower fs higher qts for sealed[0.4
Love these videos.
Danny's right. Go into a professional mastering studio. That one experience equals to about 10 years of guessing and thinking what things sound like, great ear to brain training.
Thanks for the info.
interesting! that's why fr30 speakers went that route. light and small. less store energy. therefore, cleaner bass
Impulse Response covers it all.
Great video - thanks!
Are these servo controlled drivers something you'd use in a home system or in a bigger setup like for concerts? And it sounds like most of the work (calculations etc) are being done by the amp - are they generally combined into active speakers or just need the right pairing?
I do partner dancing as my main hobby and it always bugs me when events have sloppy subs - we go to dance to great music and the bass is really messy. Seems like it would help if they had sub boxes with multiple drivers rather than just one big one, but I don't know how many of the organisers would bother going to those lengths...
It is Transit response
Aha, So that's a reason for multiple woofers. Less work and faster recovery! Whew!
Probably the best site for all diy speaker lovers. I agree with the speed but I don't agree with the bass depth, it's not so simple, that more 6 "units go linearly up to 20hz. No 6" unit goes so deep because for the first time too little moving weight, small unit composition size unit and too high fs factor usually have a lot high bass around 90hz and big drop to 20hz. A really deep bass requires a unit of at least 10 ", preferably a 12" unit with a large vc and a strong magnet and a low and linear fs. Thenks,
It's not that easy. With a normal listening room you do not want to have a straight frequency response to 20 Hz because of the room gain.
Room gain depends on the rooms size and form, but in general you want a loudspeaker with a -3dB point at 40-65Hz depending on room size and then room gain will add
approx. 10dB for every octave below that.
Some 6,5" drivers in ported cabinets can reach -3dB at around 45-50 Hz and with room gain you will get a percieved -3dB at 20-30Hz which basically is all that you want.
BUT a 6,5" in such an application will have quite some distortion which will sound boomy and quite bad.
So I'm not surprized that you state that it's necessary to use a 10" to 12" driver becuse you are right when we talk about a single driver.
The bigger driver also need to have the -3dB at the same frequency as I mentioned above to get a really straight frequency response in the room, but you will get a better
result because it have a lower distortion.
By parallelling a lot of drivers you can lower the distortion to the levels that a single 10-12" have.
So as long as the driver can reach approx. -3dB at 40-50 Hz you can match the performance of a single bigger driver with multiple parallelled smaller drivers.
@@flex-cx9bi Thanks for the detailed explanation, I agree. But for large orchestral and concert music, it was definitely more realistic with a larger 12 ” unit. Really unbiased speaker measurements show how low they go, like they do it in hifinews so for wilson audio with 8 "unit shocking only 52hz (-6db). www.hifinews.com/content/wilson-audio-sabrinax-loudspeaker-lab-report
@@borisjelenc1217 Yes, I'm not surprized that you found a 12" bass can give a very good feeling of the real thing, because we need to have a straight frequency response all the way to 20Hz in the room to not percieve short comings in the bass.
But to get that straight bass response the loudspeaker need to cut approx. at 45 Hz and have a gentle slope of approx. -12 dB per octave. The rooms gain will increase the bass. It also very much depends on the rooms size. Only sealed boxes have -12dB/octave. By theory vented cabinets roll off with -24dB/octave, but that is not completely true.
-12 to -20dB is more likely, but in general only closed enclosures will match the inverted slope of the room gain.
A 30 m2 (270 square feet) room starts to gain at around 60 Hz and have these general gains at different frequency points. 50Hz +3dB, 40Hz +6dB, 30Hz +12dB, 20Hz +18dB.
It's also important that the driver itself have low distortion and a 12" driver generally have much lower distortion than a 8" driver.
So SabrinaX is not a complete disaster even if it absolutely cut a bit too high and too steep to get that really good bass in the room. I assume it would end up with a (in room) -3dB shelf from 60Hz down to 30Hz and then drop fast to -12dB at 20 Hz, and that will absolutely give a "light weight" bass.
SabrinaX need a approx. 15-20 m2 room to have a chance to sound balanced. It would not suite a 25-30 m2 room. So understanding room gain is very essential both when designing and buying loudspeakers. Take a look at measurements in Stereophile. Most of them have both nearfield and in the room measurement.
There you can see the what the loudspeaker sends out and how that will end up in the actaul room.
That will give you a sence how much room gain there normally is, and I think many will be quite surprized with how much it really is.
If I would buy a loudspeaker (will not happend since I design them myself) I would look at a -3dB at 47-48 Hz for a closed design and -3dB at 45Hz for a ported design, and preferable with at least 2 bass drivers to prevent some of the 6 to 12dB suck out because of the first floor reflection. And I would also look for a +3dB hump in the 80-200 Hz region in a nearfield measurement to further prevent the effects of that suck out and dip that in most loudspeakers divide bass in low and upper bass.
A good loudspeaker design need to compensate for that first floor reflection, and when looking at nearfield measurements in Stereophile you will see a +3-4dB hump at approx. 100-150 Hz and that is a signum of a skilled designer...
Here are a good example of a Stereophile measurement: www.stereophile.com/content/kef-blade-two-loudspeaker-measurements
Here you have nearfield (what the loudspeaker sends of from drivers and ports) -3dB @30Hz for port, -3dB @70Hz for driver and -20dB @20hz for both driver and port.
You also have a anechoic response which show the output without the room gain and there you have -3dB @35Hz and that is actually TOO low to get a perfect sound in the room.
Finally you have a in room measurement with a severe hump of +6dB @30Hz, and that is the result of the room gain.
Not many loudspeakers are designed this well to get such a straight response in the room, but personally I think a slightly higher -3dB at 45 Hz would be even better and give that perfect life-like feeling of being in the actual hall of the recording. This KEF Blade will have a little overhang in the bass in Mr. Atkinson's listening room and sound a tiny bit too soft in the bass.
It would prefer a bigger room to get that out of the world great bass...
Hope this helps you to further understand that small drivers also can get a very good very linear bass reponse in the room, but most likely you need several in parallell to get down to distortion levels that also need to be in the 1-2% range to get that feeling of a pure and highly resolved bass. The normal +10% distortion of a single 5-6,5" driver will NOT give you that perfect bass so I'm not surprized that you feel that a 12" bass do a much better job in the bass region.
@@flex-cx9bi Nice, we also have something in common, I have been using my own diy speakers since 1990, I currently have 5 different variants at home. Thank you for a really comprehensive report and knowledge of a connoisseur without BS and despite my long journey in this hobby, I can always learn something from what is you written, but it is true that I have a basis and I know exactly what you want to say. Can I get your email address for any exchange... Greetings,
@@borisjelenc1217 Sure. It's flex2@live.se
When you run a large number of smaller drivers to get to the low frequencies, what does that do to power requirements?
The problem might not be the power requirements, but the low impedance requirement for the amplifier.
Hi Danny. Great channel! Question regarding "fast bass". How much does the stored energy and time delay of a ported enclosure affect the decay of bass notes? Is the detriment offset by the lower group delay afforded by playing louder in the lower reaches of the system? Is it even relevant in the sub-bass region?
Dear Danial
Yes I have subscribed but , even if I stand on a chair some bits go over my head LOL
With the current situation & the dismal supply chain you are having to live with you may have a little time on your hand.
Food for thought
The X-Static speakers, with what I have read over the last 2 months the open baffle speakers has like electrostatic speakers have a tendency of being a bit light in the bass region is it possible to use 1 of the basses that you use in the subs in the cabinets maybe play with the rest of the open side & cross overs to create a super duper X-Static. like 50 to 60 % you have already done.
Knowing you I am sure you have thought about this at some time but finding the time to develop such a product what with Covid & everything else as I said food for thought.
Rodney Duncan
Ps I don't think that Jay has any concept of how to conduct a blind test you should NOT be able to identify all the speakers this is all about quality of sound , definition & sound stage not how much he paid for his speakers, $13,000 & he has no idea if that also includes the price of the stand for that price
Come on your have got to be joking
Transmission line vs closed baffle ?
So does that mean that something like a Bose 802 should have fast base because of the multiple small drivers?
Dubstep?
Ilive in Germany and i really enjoyed your video.
would you recommend a Klipsch R-115 ? i have a 5.1 system mit an AV receiver.
thanks alot for your Help and i wisch you the best with your channel
Having upgraded a LOT of Klipsch models I find it hard to recommend them.
Really love these videos. They are like a college course but much more enjoyable.
Do stiff surrounds make "faster" bass?
Probably yes. They will return faster dissipating stored energy. Will need more amp power to move them though.
Any thoughts about face to face isobaric subwoofer design.?
I am not a fan. You get the output of one woofer but the motor strength of two. Woofers really need to be designed for that application.
Any consideration for producing 15 inch versions?
I have a pair of Thiel 1.5's,I like them a lot,while l may buy some relatively inexpensive stand mounters,mounted, Thiels will always stay.l think,or thought they used top quality components,your videos have me wondering.If you owned a pair of 1.5's,which seem to be holding there monetary value,l seem to be seeing the 1.6's,and to some extent 1.7's not holding their value quite as much.None the less,are there any upgrades routes for the 1.5's,l would like to hear your thoughts on these speakers and what would you do to improve them,thank you in advance,Steve Craft.
I want those inductors.
So, let me see if I've got this. If you have "fast base" that is a function of the woofer which has a sensing coil and the Amp which has Servo Control? So I've heard reviewers talk about a speaker that has "Fast Base". But it's not the speaker alone that is responsible for this, it's the speaker combined with an Amp that is equipped to take advantage of the drivers sensing coils? Have I got this right?
In regards to low bass and our servo controlled drivers, yes.
how about infinity four pillar loudspeaker ?
Which is faster, Rhythmik servo 12" or an array of 6.5" (no servo)?
6.5. Surface area has to be factored in though. Seems the bigger driver would be more efficient for lower frequency response.
Close call. It kind of depends on how low the signal is too.
@@dannyrichie9743I am a fan of yours. I really would like your insite. I finally got a used pair of Maggie 1.7i fairly cheap. They are pretty exceptional with what they do well but good lord they lack dynamics and placement is crucial. I am trying to keep the holographic imaging and clarity but add dynamic frequency responses from say 3500 hz to 20 hz. I ordered a few cheaper Goldwood 15s and have been experimenting with a cardboard box to replicate different OB designs. I'm thinking of making a bottom driver crossed over at 400hz in an H Frame but it is slightly shouty (placed centered with roughly 6 inches in front and back). I tried the mid up to 3500 and it is extremely shouty. I turned the speaker 90 degrees inside the h frame cabinet and it seems to help. Is their a way to make this blend with Maggie's and not beam sound while maintaining clarity? Thanks
@@ufarkingicehole First of all the crossover parts on the Maggies really need to be upgraded.
Then you should get much better results with a much lower crossover point.
Filter the lows off of the Maggies (first octave) and shoot for about 60Hz crossover point.
@@dannyrichie9743 thank you! You are the man. Just curious..... Maggie's have a cult following. Have you ever considered building crossovers for them to sell? I would be willing to figure out how to get mine out to send them to you. I would be the first to buy it for sure. Either way thanks again for your reply. Btw... I'm in Louisiana and plan to travel to Arizona (Grand Canyon) with my daughter on the 20-23 and will be passing back through from Colorado around the 27ish. I believe you are I Texas. I would even drop them off to you in person. I wish I could experience the static and the extremes as well as the servo subs. I'm sure its quite the experience.
Thank you Danny.
Very good explanation.
It's a pleasure to have discovered your information.
The CST'-1s are impressing me very well.
Once I get the upgrade parts, I might explode? 😂
12 drivers per side???? Where can I find those speakers??
can u do a comparison between your subs and another sub?
I think our customers post comparisons like that all the time.
What is faster ported cabinets or closed cabinets?
Neither really has an advantage because of the alignment. But that will vary with frequency.
Has anyone purchased these subs? Is it possible to get piano gloss finish on the MDF?
There are some videos of people finishing MDF speakers with a high gloss piano finish...
Seems like just as much work as finishing real wood
You can purchase them right from our website. They are DIY designs. So you can build the boxes yourself and paint them any way you want.
do people still run windows xp?! :o scary world.
The measuring system computer still does. It has less to go wrong with it, is not connected to the internet, and runs faster (even though it is old and slow) than our newest and later computers.
XP was great performing for its time, better than what came after. Just see how demand for more powerful components after XP was retired
The really great hardware based measuring systems for loudspeakers where developed during early Windows days.
Personally I run a Windows 98 with LMS and I still can't find a loudspeaker measurement system that can compete with it without passing 5000 USD in investment.
There simply are no computers that can handle those big ISA boards.
Will run that system for designing loudspeakers until it dies. But of course it can't be used for anything else...
I am thinking about building 1 or 2 of your OB subs, and I have a very specific question: Would it be possible to change the op amps in your plate amp for discrete ones?
Of course I realize that this will void the guaranty.
I am a no-opamp man thru and thru, and today the only ones that are in my signal chain is in the crossover of my Hypex plate amps, that sits in my closed ScanSpeak subs.
They are small SMD components and difficult to change out. So I thought I could hit 2 home runs by changing to OB subs with MFB, and plate amps with discrete op amps.
Does op amps for bass matter at all ? - I think so! ... And as a DIY-selfer I am allowed to be picky.
Still exited to see your upcoming sub video.
I don't think you are going to notice that much of a difference in op amps in low frequency ranges only.
I have a Audio Pro B2-50 which uses a pair of 6.5" woofers, one facing forward and one facing backwards, here I'm putting a link with it's picture
www.rehifi.se/arkivet/2018/audio-pro-b2-50
😂😂😂
Why did you get rid of that helmet head haircut?
"Fast" bass is the wrong word. There is "tight" bass, with help coming from an amp having a high damping factor.
Fast accurately is used to describe settling time.
So wouldn't say, 2 6" drivers make better bass than 1 12"?
No the surface area isn't the same do some math
@@microwave311 They could respond quicker. Do some physics.
@@porkchopspapi5757 2 6s is equal to an 8.4 inch driver. It takes 4 6s to make a 12. I did the math FOR you. :)
@@blackz06 Thanks but I didn't say more bass. Again, 2 6" drivers can accelerate & stop faster than 1 12".
Re-read as many times as necessary.
@@porkchopspapi5757 less surface area for the drivers mean that they have to travel further to reafch the same SPL, more travel = more acceleration needed and therefore more overshoot and less accuracy, and the 12" will have a much more powerful magnet + motor assembly, giving more control.
There is no replacement for displacement when it comes to bass. one 12" will outperform 2 6's of a similar quality every time.
And how do you "Electricly stop" a cone from moving? Tell me coz i really have no idea..If you play positive signal cone will go upwards if you play negative inside. What you play for speaker to "brake" and stop immediately? I say " Snake oil"
He talked about a patent from ritmick. Go check out as your question makes me think you might understand it. I'm lazy...if not i would do it. It might be done digitally....tampering with the original lfe channel. Just a guess.
@@xedasxedas TY
Simples, all you need is a speaker with Qes factor of zero (infinite Bxl) partnered with an amplifier sporting output impedance equal to 0 ohms. In this case the electromagnetic breaking due to back EMF will be infinite with no post impulse ringing.
You sould not call something snake oil simply because you don't understand the principles behind feedback and servo controlling.
Actually it's quite easy. It's simply a amplified feedback system and as a result ringing (distortion) will be lowered.
Fast drivers need to slow down for safety reasons.
Danny, its 2020. You can't use Windows XP anymore.
Why not, if this computer is not connected to any network?
We have Windows 7 and 10 on every other computer in here. But for the measuring system there is no need to use anything else. It isn't connected to the internet and actually does what we need it to do faster than the newer and faster computers in here running more complex operating systems.
🤣🤣🤣🤣
trying to learn some speaker building but your topics contain far too much pseudoscience audiophoolery
I love your CZcams stuff and I would really love to see your upgrade kits that are available, but I refuse to give my friends list just to see your catalog. Sorry bud your company does great work, so I suggest you get rid of the Whole whom believes invading peoples privacy is the way to go, If I want my friends to know about your company, I would suggest it to them, not have their privacy invaded by a company I may or may Not sign off on...Really wish we could have done business but until try research stops robbing from their subscribers, I will be telling All my friends to watch your videos and to Not do Any Business with Your Company!!!!
What are you talking about? Do you have a form of dyslexia coupled ADD - I have no idea why you have any issues with an audio site trying to help you?🤷🏻♂️🤷🏻♂️
WTH?