Pages: [1]   Go Down
Author Topic: wooden box size/proportions for best acoustics?  (Read 381 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 5
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Anyone know much about acoustics?

I'm basically building a kind of musical instrument that's a wooden box (thinking birch plywood? - I don't want to spend too much money) with some solenoids and vibrating motors inside that generate noise on various materials' surfaces. The kind of size i picture the box is 30cm x 30cm x 45 cm (1.5ish cm thick)

I'm not particularly knowledgeable about acoustics, would there be a particular optimums size/proportions for the best acoustics?  and is there a better (cheapish) material i could use?
Logged

0
Offline Offline
Shannon Member
****
Karma: 161
Posts: 10431
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I don't think there's anyway to answer this question - how does one define "best acoustics"??
Logged

[ I won't respond to messages, use the forum please ]

Offline Offline
Edison Member
*
Karma: 22
Posts: 1164
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

That gets REALLY complicated!  You'll just have to experiment! The shape and materials for a (acoustic) guitar or violin were developed empirically over a long period of time.   As far as I know, with modern science and computers, we have not come up with any new-better designs.

From the approximate wavelength, I'd say your box is going to resonate around 500Hz or 1kHz...  I don't know if a "closed box" resonates at 1/2 wavelength or a full-wavelength.

Quote
(1.5ish cm thick)
cm or mm?   Again, most wood instruments are quite thin (with the exception of woodwinds & pianos where the resonance of the wood itself isn't that important).
Logged

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 331
Posts: 16514
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I know there are sites with automated speaker dimension sizing programs for proper ported box size if you input the needed speaker parameters and your desired low frequency cut-off value. But that is probably not relative to your exact application. But one similar requirement is that stiff or thick box material be used to cut down on unwanted resonances. Good hi-fi speaker boxes use very thick wood.

Lefty

Logged

Topsham, Vermont USA
Offline Offline
Edison Member
*
Karma: 23
Posts: 1759
... in The Woods In Vermont
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
The kind of size i picture the box is 30cm x 30cm x 45 cm (1.5ish cm thick)

From designing recording studios, I can tell you that you do NOT want any two dimensions to be the same, as that will make a pronounced resonance at one frequency.   The RATIO of the lengths is what's important to keep different acoustic modes from adding to each other.

Two classical ratios are:  1:1.25:1.6   and 1:1.4:1.9 

Since you are building this you can scale the whole things as you see fit.

But DON'T do the 30cm x 30cm for two modes!
Logged

Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

Pages: [1]   Go Up
Jump to: