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Old 11th December 2005, 01:12 PM   #1
Vikash is offline Vikash  United Kingdom
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Default Irrational ratios/enclosure dimensions

I've updated the standing wave calculator to calculate dimensions based on ratios. I've added one useable ratio so far.

If anyone can help give me other irrational ratios suitable for speaker enclosures in x/1/y format, that would be very helpful.

http://www.vikash.info/audio/standing_wave_calc/
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Old 11th December 2005, 01:47 PM   #2
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Very handy. Thanks!
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Old 11th December 2005, 09:33 PM   #3
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I've had good luck with the cube root of 2;

.794/1/1.26; and variants such as .794/1/2.52.
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Old 12th December 2005, 10:33 PM   #4
Vikash is offline Vikash  United Kingdom
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Updated with new ratios.
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Old 12th December 2005, 11:29 PM   #5
Ron E is offline Ron E  United States
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The square root of 2 is ~1.414, not 1.141.

Usual quoted enclosure ratios are based on:
phi = golden ratio = 1.6180339887499 why do I remember this number to so many decimal places?
1.2
1.25

IMO, none of these is better than any other or any number you could come up with. It makes a lot more difference how you mount your drivers on the baffle (for diffraction) than what the box dimension ratios are. Lining or stuffing in the box is used to damp out the resonances.....

Your app calculates axial resonances, but there are also tangential and oblique resonances, and all are excited differently depending on where you mount the drivers...
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Old 13th December 2005, 12:37 AM   #6
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Tapered boxes are good too; but these ratios are certainly better than integers, 1/2/2 for example. AND you should also line &/or stuff. Nothin' wrong with belt and braces. And positiong drivers non-equidistant from box edges, (which should have radii > 4 inches) also helps.

But one thing at a time, this is a nifty little calculator.
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Old 13th December 2005, 12:53 AM   #7
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Quote:
Originally posted by Ron E
Usual quoted enclosure ratios are based on:
phi = golden ratio = 1.6180339887499 why do I remember this number to so many decimal places?
1.2
1.25

IMO, none of these is better than any other or any number you could come up with...
Ron,

Agreed. But I tend to use the square root of phi (c. 1.27202) for the front of my woofer and subwoofer boxes as it looks better, rather than for any sound reasons. That way the ratio W/H is 1.618/1 (and when you're looking at it from a standing position, perspective also fools you into thinking it's the same ratio W/D).

Internal standing waves I try to damp out (or confuse) by:
1) damping materials;
2) internal bracing with small (eg 2" or 3") holes in it;
3) internal bracing at odd angles and shapes (eg. dowels of different sizes, braces at 15, 22.5, 30 and 45 degrees).

UNLESS I'm doing a TL...

But, Vikash, I think you've got 1.28 in your calculator anyway - and that's close enough to 1.27202
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Old 13th December 2005, 09:32 AM   #8
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Nice tool Vikash....

dave
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Old 13th December 2005, 11:47 AM   #9
Vikash is offline Vikash  United Kingdom
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Any input on the default threshold value? How close is too close?
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Old 13th December 2005, 12:43 PM   #10
Vikash is offline Vikash  United Kingdom
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Added ability to factor ratios.

What's the best way to render a pic on the web these days. Is it somehow possible to output code into renderer that output to a gif or something...
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