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Does the shape of a cabinet enclosure matter?

post #1 of 25
2/25/12 at 3:12pm
Thread Starter 
I am wondering if the shape of the cabinet that houses a speaker matters? Floorstanding speakers are for the most part upright rectangles. Does this need to be or would a perfect cube on a stand have the same effect?
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post #2 of 25
2/25/12 at 3:53pm
The dimensions of the baffle matter. It's just one of many variables that affects the sound of a speaker.
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post #3 of 25
2/25/12 at 4:45pm
http://techtalk.parts-express.com/sh...d.php?t=219617
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post #4 of 25
2/25/12 at 7:29pm
Quote:
Originally Posted by michaelkingdom View Post

I am wondering if the shape of the cabinet that houses a speaker matters?

Yes. Siegfried Linkwitz demonstrates

http://www.linkwitzlab.com/diffraction.htm

Quote:


Floorstanding speakers are for the most part upright rectangles. Does this need to be or would a perfect cube on a stand have the same effect?

A perfect cube is the worst shape you can build using right angles (circular baffles are worse unless acoustically small enough that driver directivity prevents their illumination - a 2" circle works great for a 1.6" mid-tweeter).
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post #5 of 25
2/26/12 at 7:12pm
Interesting question! It seems that speaker shapes are changing every few years to suck people into thinking they need to 'upgrade'. Standing waves are a problem for bass, thats why right angles are usually not the best. I have a HSU research sub that is round with flat top and bottom. Not only is that design very strong (minimal flex, and vibration) but the standing wave problem is also lessened. I believe they quit making them because they were a hard sell. If I were to build my own cabinet I would have a separate cabinet within a cabinet for the midrange/tweeter.
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post #6 of 25
2/26/12 at 7:29pm
Non parallel walls may help with higher frequency standing waves, but for bass frequencies where the cabinet is small relative to wavelength anyway, not so much. At those frequencies you have more of a pressure vessel behavior and the volume is more influential on modes than any one dimension. Upper bass may still have standing waves in very tall towers of course. The frequency where this ceases to be a concern for any given cabinet size can be quickly ascertained.
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post #7 of 25
2/26/12 at 7:44pm
Does the shape of the enclosure matter? Well, does roll center height and roll axis locations matter in car suspension? The answer to both of those questions is very much if performance matters. If performance isn't important, than it doesn't matter too much and a basic rectangular design will get you by so long as the baffle width and driver locations remain per the design specs.
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post #8 of 25
2/27/12 at 6:52pm
Quote:
Originally Posted by michaelkingdom View Post

I am wondering if the shape of the cabinet that houses a speaker matters?

Sure does. It changes the characteristics of a number of acoustic properties...and thus the design criteria.

Quote:
Originally Posted by michaelkingdom View Post

Floorstanding speakers are for the most part upright rectangles. Does this need to be or would a perfect cube on a stand have the same effect?

They can both be made to sound good, if not identical. For largely aesthetics/decor reasons, you will find a heck of a lot more of one than the other.
You'll see(hear) examples of both at Axpona.

cheers,

AJ
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post #9 of 25
2/27/12 at 7:17pm
I read and re-read the post but still need it spelled out a bit. For use n00bz that want to build an enclosure (just a subwoofer box), beyond finding the proper size, should be design the shape to be more rectangular? (even if it turns out to only be by a few inches)
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post #10 of 25
2/27/12 at 7:31pm
Quote:
Originally Posted by splmachine View Post

I read and re-read the post but still need it spelled out a bit. For use n00bz that want to build an enclosure (just a subwoofer box), beyond finding the proper size, should be design the shape to be more rectangular? (even if it turns out to only be by a few inches)

Nope. For a subwoofer box (not what the OP referenced), you would only do that for aesthetics.

cheers,

AJ
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post #11 of 25
2/28/12 at 6:19am
Thanks AJinFLA... I was already a little overwhelmed with trying to design it if they had to be different dimensions. Now I'll go back to planning on a cube (Easier IMO if all the sides can be the same length)
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post #12 of 25
2/28/12 at 7:10am
It'll sound better if you make a rectangle instead of a perfect cube.

It will also sound better if the driver is an "odd" distance from the edges. Perfectly centered would be the worst, the best would be if the left distance wasn't equally divisible by the right, and vise-versa. Basically, equal lengths to the edges on the inside can cause the waves to reflect and resonate. Stuff it with polyfill and it'll reduce this effect.

It sucks, because you want it to look centered and geometric, but that's not the best sounding.
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post #13 of 25
2/28/12 at 7:51am
Quote:
Originally Posted by Paniller View Post

It'll sound better if you make a rectangle instead of a perfect cube.

It will also sound better if the driver is an "odd" distance from the edges. Perfectly centered would be the worst, the best would be if the left distance wasn't equally divisible by the right, and vise-versa. Basically, equal lengths to the edges on the inside can cause the waves to reflect and resonate. Stuff it with polyfill and it'll reduce this effect.

It sucks, because you want it to look centered and geometric, but that's not the best sounding.

Nope. At subwoofer frequencies, <150hz, where wavelengths begin to exceed 7.5 feet, none of that matters. Please get a grasp of basic physics before reciting what you read somewhere that isn't at all applicable.
Polyfill wouldn't hurt, but the rest is completely irrelevant.
Rectangular subs don't "sound better" than cubes.
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post #14 of 25
2/28/12 at 12:06pm
OK , not to sure what is being said here ??.... Rectangle or cube "Does'nt" matter??
So what does then ... "Where" the driver is placed in the box ???
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post #15 of 25
3/1/12 at 12:31pm
Quote:
Originally Posted by AJinFLA View Post

Nope. At subwoofer frequencies, <150hz, where wavelengths begin to exceed 7.5 feet, none of that matters. Please get a grasp of basic physics before reciting what you read somewhere that isn't at all applicable.
Polyfill wouldn't hurt, but the rest is completely irrelevant.
Rectangular subs don't "sound better" than cubes.

I have a grasp of basic physics. I also a grasp of advanced physics. I'm pretty sure I achieved this grasp when I got an advanced degree in the field, and 10 years of experience.

Physics is a high school class. Before high school is middle school. Before that is elementary school, where I learned to read, and where I apparently left you behind.

I read the thread title, and the original post. Neither one specified subwoofers. In fact, he said "cube on a stand," which would imply a directional component and NOT a subwoofer box.

You are correct that lower frequencies suffer less from shape, but please get off your high horse and stop insulting people.
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post #16 of 25
3/1/12 at 3:41pm
Quote:
Originally Posted by Paniller View Post

I have a grasp of basic physics. I also a grasp of advanced physics. I'm pretty sure I achieved this grasp when I got an advanced degree in the field, and 10 years of experience.
Physics is a high school class. Before high school is middle school. Before that is elementary school, where I learned to read, and where I apparently left you behind.

Beg your pardon sir. Between you and Commsysman, that's 50yrs experience!.
Interesting questions about 3" drivers in your thread, for a guy with your degree and experience. But I defer to your expertise. My apologies.

Quote:
Originally Posted by Paniller View Post

It'll sound better if you make a rectangle instead of a perfect cube.

"It" being?? Loudspeaker system? As evidenced by....???

Quote:
Originally Posted by Paniller View Post

It sucks, because you want it to look centered and geometric, but that's not the best sounding.

Can't find where the OP (or anyone else) stated anything about wanting anything to "look centered and geometric", but you are the better reader here .

cheers,

AJ
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post #17 of 25
3/1/12 at 5:35pm
WOW....amazing how some threads turn.

I asked a similar question on my thread a while back and this was suggested.
http://www.tolvan.com/edge/
It clearly makes a difference what shape is used. BUT that being said this is nitpicking that extra potential out of the driver is all. Such as room treatments and everything else.
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post #18 of 25
3/1/12 at 6:22pm
Quote:
Originally Posted by chrapladm View Post

It clearly makes a difference what shape is used.

Yep. As noted previously.

Quote:
Originally Posted by chrapladm View Post

BUT that being said this is nitpicking that extra potential out of the driver is all. Such as room treatments and everything else.

Eh? Lost me there.
When you used Tolvans Edge, did response change based on where the source was located on the baffle shape? Or was it mandatory, by law of cubes, to place it dead centered? Was there an option of selecting a non circular acoustic source? Was the axis diffraction ripple frequency dependent? Did it matter where/what angle the mic was placed to the baffle? IOW, is it a 3D issue? (btw, these are rhetorical Qs).
And that's just the HF portion, mainly HF driver portion outside the speaker, assuming a direct radiator. We haven't considered other options, or even gone inside the enclosure, to see what happens outside, yet.

cheers,

AJ
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post #19 of 25
3/1/12 at 9:18pm
OP didn't specify and the stand reference implied full range. Shape matters.

Later splmachine specifically asked about a subwoofer to which AJ was responding. Shape (within reason) doesn't matter.

Sometimes it is advised to perhaps read more than the first post of a thread before jumping in with advice. This might prevent a bit of confusion.
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post #20 of 25
3/1/12 at 10:15pm
Yes ....if that is directed towards me I apologize. Just saw the question about shape and knew the link so I wanted to post.

Sorry for the confusion.
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post #21 of 25
3/2/12 at 4:51am
http://www.aes.org/aeshc/pdf/how.the...enclosures.pdf


"A comprehensive analysis of the effect of cabinet configuration
on the sound distribution pattern and overall response-frequency
characteristics of loudspeakers."

the above link points to the original paper from 1950 dealing with the effect of enclosure shape. Just happened to stumble across it my own reading/research and thought I would share it when I saw this thread


Jack
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post #22 of 25
3/2/12 at 6:21am
Quote:
Originally Posted by AJinFLA View Post

Beg your pardon sir. Between you and Commsysman, that's 50yrs experience!.
Interesting questions about 3" drivers in your thread, for a guy with your degree and experience. But I defer to your expertise. My apologies.

Hey, I said my experience was in physics, not speaker building. That's relatively new to me, I'd never claim to know as much as you guys. I only have been building speakers for about 2 years, and only for myself so it wasn't many sets. I'm still a novice, I signed up here for extra advice, place is a great addition to books.

And who's Commsysman? I'm assuming it's company I don't want to keep? lol.

Anyway, you're confusing me. Are we in agreement that shape, and driver placement on the baffle matter? With the addition that it matters less at low frequencies? I'm not sure if you're questioning what I said, or the context in which I said it.
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post #23 of 25
3/2/12 at 7:20am
Quote:
Originally Posted by AJinFLA View Post

Yep. As noted previously.


Eh? Lost me there.
When you used Tolvans Edge, did response change based on where the source was located on the baffle shape? Or was it mandatory, by law of cubes, to place it dead centered? Was there an option of selecting a non circular acoustic source? Was the axis diffraction ripple frequency dependent? Did it matter where/what angle the mic was placed to the baffle? IOW, is it a 3D issue? (btw, these are rhetorical Qs).
And that's just the HF portion, mainly HF driver portion outside the speaker, assuming a direct radiator. We haven't considered other options, or even gone inside the enclosure, to see what happens outside, yet.

cheers,

AJ

And this is why I say the importance of shape and composition of the enclosure is directly proportionate to the importance of performance.
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post #24 of 25
3/2/12 at 9:49am
Hmm, I read the thread and looked at the links and it seems that the baffle dimensions and flush mounting are important but, I didnt see much about the effect of the shape of the cabinet? I was interested because I am taking a Zaph Audio speaker design and essentially flattening the cabinet and making it an in-wall speaker. I am still retaining the front baffle dimensions and the internal volume of the original cabinet though. The in-wall part of the box is installed and is about to be drywalled. The baffle and drivers are yet to be assembled. I guess I'll find out...
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post #25 of 25
3/2/12 at 9:50am
Quote:
Originally Posted by Paniller View Post

And who's Commsysman? I'm assuming it's company I don't want to keep? lol.

Probably not.

Quote:
Originally Posted by Paniller View Post

Anyway, you're confusing me. Are we in agreement that shape, and driver placement on the baffle matter?

As has been stated numerous time, yes.

Quote:
Originally Posted by Paniller View Post

With the addition that it matters less at low frequencies?

Yep.

Quote:
Originally Posted by Paniller View Post

I'm not sure if you're questioning what I said, or the context in which I said it.

It'll sound better if you make a rectangle instead of a perfect cube.

That is factually incorrect, whether in response to the subwoofer question above it as it appeared, or as we now have gathered, the OPs post, which stated nothing whatsoever about a direct radiator HF driver or baffle placement. But rather, about speaker system shape in general. My initial answer covered it all.
Yet here we are....

cheers,

AJ

p.s. now if you don't mind, I've got some work to do....
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