This is the seminar I used to give thirty plus years ago when I introduced the AR 9's to dealers and customers. AR took their earlier drivers and gave them 3db forward gain with molded horns around the mid and tweeter drivers. They developed the Acoustic Blanket to absorb the surface acoustic wave energy. No edge diffraction. And placed the woofers at sides/ bottom to use 2 pi space loading. Kept all drivers in a verticle axis to elminate time arrive/ comb filtering differences between ears.

Great video. Thanks so much for the information. I learned quite a bit about wavelength and diffraction.

I loved this video, thank you.

It probably isn’t quite as bad as Olson’s frequency graphs makes us believe. Because at frequencies where the driver is predominantly directional it will not cause substantial cabinet edge diffraction. Olson’s graphs are made with a small driver with an almost omnidirectional dispersion. However diffraction is a true problem which should be addressed more than it is. A problem not mentioned in the talk is the problem of diffraction and comb filtering between the drivers in multi driver loudspeakers (almost all speakers). This obviously only occurs in non coaxial speakers, but for most speakers it is a real problem. The only way to get it out of the way in non coaxial speakers is to use very steep crossover slopes, which then makes havoc with the phase response. Kef’s LS50 Wireless II seems to attack most problems. Fujitsu Ten 712 does as well in a really radical way, but is more limited in the frequency domain. But then there is the problem with stereo itself as a reproduction concept where one loudspeaker diffract/comb filters the others signal, and that is even before problems with cross hearing takes place. No wonder I like mono more and more with age. No soundstage but pure and stress free listening.

@lio1234234

3 жыл бұрын

Ooh, I'm interested in how the phase response worsens since I'm doing a steep active crossover and if phase is a problem I'm hoping there is a way to fix that. By the way, when dealing with BMR drivers the diffraction is as bad as it is represented in the models since it nearly acts as a point source (in terms of directivity).

I'm doing a physics project on how the physics of speakers work for my grade 12 ap physics class and this is really helpful. Thanks!

On a scale of 1 to 10 I give a 10 for what you teach. A 1 for how you say it.

@Oneness100

9 жыл бұрын

***** He's probably jacked up on a lot of caffeine.

Is there a possibility to name the paper of how enclosures shapes influence diffraction?

can't hear this for more than a few minutes without getting a nervous breakdown. Tsjeesz man take a valium!

22.00 "when the sound wave reflects back off the wall it reflects in the oposite phase" - wrong, it simply can't change the polarity as "phase' means "time": what hits the wall first that same form and energy is reflected, no other way. If compression hits first it would be reflected first. If rarefaction hits first it would be reflected first.

Do you really need a 7 minute intro?

Man sounds like me on cocaine! He wants to tell everything at once!

I defy anyone who can sit through this for 57 minutes and 53 seconds

@thunderpooch

6 жыл бұрын

No need. He repeats himself the entire time. I listened for 30 seconds and then skipped 4 minutes ahead. I repeated this process throughout. I'm confident I have the relevant information. Nothing he says is ground breaking or takes things to an advanced level.

too much coffee! But I learn something I didn't know before. Worth 1 hour......... I'll let you know

business !!

From my experience, driver materials and their inherent colorations and distortion have a much more pronounced effect on perceived quality than edge diffraction issues.

The statement that low frequencies bend and high frequencies beam is simply wrong. It is in relation to the physical size off the barrier etc.

Great information! ... but I could only watch half of this. The presenter says a lot of unfinished sentences. I got to the "Oh FFS" stage, and skipped the rest.

There's too much disconnect between the intended lesson and presenting it so that others can digest it.Guy needs to slow down and trim some of that extraneous talk.Knowing the subject is not enough,teaching is a skill unto itself and nearly as important.

work on your speech presentation , umm's,ahhs,pauses are distracting

There is no way this guy teaches. He can't even finish a thought He needs some weed to slow him down a bit. At least he admitted to cheating because that is the only way this guy got a degree in anything.

@FrankLeonardStar

4 жыл бұрын

He may be a bad "speaker" but that doesn't mean he's not a smart guy. But I did have to set youtube to 0.75 speed to understand him

@carlosoliveira-rc2xt

4 жыл бұрын

@@FrankLeonardStar Lol. As a general rule the more educated you are, the better your grasp of language and the better your communication. How can one be a good teacher if one can't communicate? The material in this seminar is pretty rudimentary at any rate.

@FrankLeonardStar

4 жыл бұрын

carlos oliveira I said “smart” not “teacher”

of course there is not enough time when you talk about nothing for 7 minutes.;)

*_Take another look at Olson’s frequency graphs shown on one page near the end of the video, and focus on the graph top left corner... This entire 16-minute agonising and incoherent lecture about the 'Physics Of Diffraction' could have been explained in less than 5 minutes, simply by showing that a 'Sphere' has zero diffraction and zero internal resonance, which is why, much to the annoyance of my wife, all my speakers are mounted in spheres._* 👀😊💡💡

@socksumi

2 жыл бұрын

I disagree with the guy's placing more importance on diffraction than factors such as driver and crossover quality. The human ear is not as bothered by diffraction as it is by stored energy, resonant peaks/dips and unacceptable distortion levels inherent in many drivers.

@CyrilleBoucanogh

Жыл бұрын

@@socksumi everything is equally important for the pure sound

ok

relax dude take some deep breaths !!

Does anybody know of another version of this subject as it's rather interesting to me as I want to build my own speakers. I just can't listen to this guy! ( 9 minutes was enough for me ), It's already been said many times, he must be on something! Maybe he should be doing advertising as those sorts of people have rather irritating speech patterns also .................... And no, I don't listen to them either! ; ) TURK

This dudes on meth not stuck on diffraction!!!

The audience member holding his nose instead of ear, because he thinks the lecture stinks.

Is he on coke ?

Next time use lapel mic and/or stand still. a very interesting subject but an irritating presentation.

my god!!! this guy is so frustrating to listen to! It doesn't matter how much you know about a topic, what matter is the delivery. Bad preparacion kills listeners expectations and interest.

@arpakyna

5 жыл бұрын

I think in a teacher it should how much they know about a subject. Not just the delivery, which I also found very distracting. :)

this cat talks aLOT, says little. he gets out of mic range multiple times. he repeats statements repeatedly. he tells us the same thing again. he is double redundant. did i mention he likes to restate things? gets annoying quick, doesn't it? if you know why we use boxes for woofers dont waste your time. some relevant multi driver comb filtering info and finally...if the guy would get focused, he could make good vids. C+

metric system is stupid. we knew to make our measurements divisible by 2 and 3 back at the beginning of civilization. base ten is easy for measurement but for application a base 12 system makes much more sense in fact, we really need to just shift to base 12 counting altogether

@monetize_this8330

4 жыл бұрын

Having to use centimetres is always annoying. metres and mm are less prone to scaling errors.

@guyv77

3 жыл бұрын

Agree that base 12, or 16 would be better. But since you count on base 10 (probably because your ancestors had 10 fingers), please take back your comment that the metric system is stupid. You can't do physics without the metric system (actually called International System or SI en.wikipedia.org/wiki/International_System_of_Units), it is a system where when you enter the right units at the input of the formula, the correct unit end up at the other end. The inter-unit compatibility of the SI system is one of the towering achievements of science and our civilization depends on it.

@linkeddevices

3 жыл бұрын

@@guyv77 yea but while we're at it we should have switched to base 12 to make mathematical division by 3 just as easy as 2.

@guyv77

3 жыл бұрын

Yes, base 12 would have been good and one of my grand-father was stating as much, for the same reasons you explain.