View Full Version : Parallel box walls and standing waves

06-05-2007, 04:46 PM
When designing speaker boxes, how important is it to take in consideration the possibility of standing waves between parallel box sides? It seems JBL sometimes takes steps to minimize them through a non-parallel box side design (f.e. 250ti, Array-series etc) and other times they don't (f.e most of the studiomonitors). Is dampening material like wool or fiberglass sufficient enough to handle this problem or is there just one way to go: designing speakers without parallel walls?

Thankfull for any info on this,

Regards: Jakob

06-05-2007, 07:54 PM
If any compartment panel dimension is greater than 1/4 wavelength of the highest frequency in that compartment, extra means to reduce standing waves may be needed. Opposing panels need to be at least 12 degrees from parallel for that method to work.

06-05-2007, 08:56 PM
The goal is to avoid wall distances that are mathematically related. The absolute worst case is all dimensions are equal such as a 2X2X2 cube for woofers.

Dampening material is usually sufficient to squish resonance peaks as long as the primary rule is followed.

This has been digested, debated and printed in MANY texts over the years.


ps - been to your area along with Orbreo, Gavella and stockholm. Nice country but I froze my butt off in mid june 2 years ago..:)

06-07-2007, 03:16 AM
Thank's guys!

Yeah, the weather here can be a bitch! I guess that was why a lot of swede's emigrated to Your continent a century ago ;)