Irrational ratios/enclosure dimensions

Vikash · 11th December 2005, 01:12 PM

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/

Geek · 11th December 2005, 01:47 PM

Very handy. Thanks!

Curmudgeon · 11th December 2005, 09:33 PM

I've had good luck with the cube root of 2;

.794/1/1.26; and variants such as .794/1/2.52.

Vikash · 12th December 2005, 10:33 PM

Updated with new ratios.

Ron E · 12th December 2005, 11:29 PM

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...

Curmudgeon · 13th December 2005, 12:37 AM

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.

Cloth Ears · 13th December 2005, 12:53 AM

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

planet10 · 13th December 2005, 09:32 AM

Nice tool Vikash....

dave

Vikash · 13th December 2005, 11:47 AM

Any input on the default threshold value? How close is too close?

Vikash · 13th December 2005, 12:43 PM

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...

11th December 2005, 01:12 PM	#1
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	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/ __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)

12th December 2005, 10:33 PM	#4
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	Updated with new ratios. __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)

12th December 2005, 11:29 PM	#5
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	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... __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

13th December 2005, 09:32 AM	#8
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Nice tool Vikash.... dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

13th December 2005, 11:47 AM	#9
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	Any input on the default threshold value? How close is too close? __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)


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11th December 2005, 01:47 PM	#2
Geek diyAudio Member Join Date: Sep 2004	Very handy. Thanks!

11th December 2005, 09:33 PM	#3
Curmudgeon diyAudio Member Join Date: Nov 2005	I've had good luck with the cube root of 2; .794/1/1.26; and variants such as .794/1/2.52.

13th December 2005, 12:37 AM	#6
Curmudgeon diyAudio Member Join Date: Nov 2005	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.

13th December 2005, 12:43 PM	#10
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	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... __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)

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