Lunch with Paul: The Q of a loudspeaker
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- čas přidán 2. 10. 2020
- What do designers mean when they refer to the "Q" of a driver or cabinet or loudspeaker? Senior loudspeaker engineer at PS Audio, Chris Brunhaver gives us a lesson in the meaning of Q.
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Chris makes Q great again...
According to CCR, the Q is from Susie.
People, people... This is family channel! My entire family watches HiFi vids together. lol
@@NickP333 Lol whoops 😂
Fat Rat
Haha! Great to hear from ya, Rat!
Qorax
Lol. I can only wish I had a family that cared about HiFi!
@@NickP333 Lol yeah kids are boring! 😂
4 minutes, short, simple yet VERY INFORMATIVE. thank you Paul and Chris.
I love watching videos like this. Can see there is just SO much knowledge Chris (and indeed Paul) have, I'll never even begin to scratch what they've both long forgotten 😀
Wow! Got this finally for the first time. Highly informative, densely packed video.
Great explanation with real engineering substance and devoid of subjective goblygoop and hand waving.
This video definitely helped explain this "Q" a bit better, but I still feel in the weeds about it. Time alignment is another concept im trying to grasp as well.
Chris is the man.
Never heard of Q before, thanks for the information!
i love listening to chris
Low Q in a sealed box sounds lively, fast and tight but it needs reinforcement from the floor or the wall which will compromise other aspects to its sound but most people aren’t audiophiles and won’t pull their speakers out into the room anyway. Boston Acoustics made big shallow depth acoustic suspension speakers that worked best near a wall. Cizek model 1’s sounded good near the floor directed up like a Klipsch Hearsay or Snell. I’m surprised no one makes this type of speaker anymore with a large baffle and shallow depth for close boundary placement. I like the spaciousness of speakers out away from boundaries but like I said that isn’t how most people will position them.
There are 3 elements of speaker parameters that fundamentally determine correct enclosure :-
Qts
Vas
Fs
I find speakers with a Qts of more than 0.35 work best in vented enclosures.
I'd love to hear Chris talk about Conjugate loads and the effect resonant peak taming circuits have on phase and group delay and decay ( waterfall plots )
Didn't someone once try to pull the ol' Conjugate loads and the effect resonant peak taming circuits have on phase and group delay and decay trick on Agent Maxwell Smart?
Are microphone preamps any good as headphone amps or for driving headphones out of a DAC etc? I suppose my own answer will depend on how it goes, i just want to circumvent my noisy AVR. I haven’t found time to track down the leaky caps as it takes a lot of dismantling.
Danger Zone my headphones are only 55ohms, so it’s able to drive them just fine. I will be doing some experiments here in the near future.
Fat Rat LOL, I wish I had clones of myself to stay at home with the wife...
Q is an omnipotent entity. Please discuss Q with respect or you will experience his wrath.
Hi Paul,What the difference between 1 big woofer and dual woofer design,I've seen many speaker has very similar low frequency response but with these two design to archive it
Two woofers radiate different then one. I prefer one woofer.
Do transmission line speakers need a medium or low Q
Vintage speakers such as IMF TLS-50 seem to employ medium version KEF B200 SP1014
I was looking to increase the power of my vintage B&W DM2 by adding a KEF B200 but the more recent driver with larger magnet (the SP1039)
Chris should have a filter and a type of Q named after him! A Brunhaver filter!
Please do more of these t/s parameters videos 👍
Hi Chris , I own vintage Allison One speaker, my woofer edge is all faded . Should I recone or change to a new woofer
or just buy new speaker Thank You, Larry
What formula do manufactures use to determine the recommended size of the enclosure volume for their subwoofers?
@Danger Zone kind of.
Theres actually a host of variant "alignments" as they're called. Choice of which to use depends on both the limitations of the driver and limits to the alignment itself. There are also many alignments that use feedback circuits that actively manipulate the effective speaker paramerters. Look up Theil Small alignments, The Audio Engineering Society or at least used to.
Forgot to add. If youre looking for a source, an old standby is the Loudspeaker Design Cookbook, Vance Dickason
I'm sorry this is beyond me. I have some KEF Q550s, how does this relate to those speakers please?
Excellent
I was taught that a perfect QTS is .38 without a passive x-over. With a passive x-over, the QTS would raise slightly.
Very informative
Chris: To what Qts are you designing the PSA speakers?
It doesn't matter to you the customer .. just enjoy the new speaker
Janina Palmer hahaha it matters greatly for those of us that appreciate how this changes the sound.
I found that to be extremely interesting
thank you. ;-)
Speaker params is huge subject. I still can't wrap my fat head around this stuff. No matter how much I read or watch videos on it, I still haven't felt like "I get it now". I look at the Qts and Fs figures the most. Correct me if I'm wrong, but a low Qts like 0.3 would be a loosy goosey, flappy woofer, and a higher Qts like 0.7 would be a super stiff tight cone with little Xmas. Low Q for a sealed box or smaller vented carefully tuned, and the hi Q could be happy for an open back type box, like a guitar cab. ?? Chris's explanation helped, but I didn't get much out of it, except now he had crossovers entering the chat to throw more sand in the machinery.
also EBP (Efficiency bandwidth product) needs to be taken into account
EBP = Fs / Qes
EBP around 50 or less, then the woofer is suited for sealed.
EBP > 100 then the woofer is suited for Bass reflex.
EBP is between 50 and 100, then it is good for either Closed or Bass Reflex.
EBP > 130, suited for Horn Loudspeaker
this method generally implemented in "bass box pro" software. i highly recommend it.
You have it essentially backwards. Lower Q means higher damping, which means stiffer, not looser. Very loose woofers have higher Q.
But there are two contributors to "stiffness" so that can be a misleading description. There is spring stiffness which is simply the static restoring force which varies linearly with displacement (this is what civil and mechanical engineers define as stiffness), and which does not produce damping because it stores and releases energy rather than absorbing it. Then there is another component of "stiffness" which is velocity-dependent and that does cause damping, because it absorbs energy. The energy-absorbing type is generally weaker than the spring type in speakers, so most speakers don't have very low Q values - at least not until they are connected to a low-impedance amplifier which then allows the voice coil resistance to contribute to damping.
When speaker electrical impedance is measured, the resonant peaks tend to be quite high - typically 3-5 times the nominal impedance - which is a high-Q phenomenon.
Wasn't he that villain bloke in Startrek?
Yes, and no. The Q Continuum was the sum of the whole, so to speak. A lot like the Great Link we experience on DS9. Individuals and more.
@@jamesplotkin4674
Great Link? I missed that.
@@marianneoelund2940 RE: Deep Space 9, The Great Link are the changeling entities Odo reluctantly comes from. The Dominion is lead by them and they're natural state is similar to a large ocean body of mercury.
Andrew Jones is the Q of great low cost speakers.
Ehhh, he seems to pigeon hole himself a lot.
There's an audio amp tester whose woofers flutter like a hummingbird's wings. They sound horrible, like the license plates of cars with thump.
Is this Williston Audio Labs?
@@cbrunhaver Hi, Chris, yes.
In jazz music Q's last name is Jones
Don’t worry folks. Even James Bond didn’t always understand Q ! 😉
Divided we are weak
United we are strong
The choice to know we ultimately be yours
Research for yourself
Trust yourself
Make up your own mind.
Knowledge is power
The more you know
Everyone will have to choose a side
Nothing can stop what is coming
Nothing.
Q
Banna
Bahn Mi!!
I think you mean Bánh Mì.
@@marianneoelund2940 Yes, Marianne, I see you've become the PSA Bánh Mì police.... my apologies.
@Fat Rat I know right? I've been enjoying those sandwiches incorrectly this whole time!
Very basic stuff for any electronic engineering student.
esoteric jibberings
It's a good thing for the rest of us that some people cogitate on such matters. We get to enjoy what results from it, without a second thought about what goes into designing a quality product.
WTF, that was extremely hard to listen to, it was awful. I will never do that again 🤬🤬🤬
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