Jonathan ? about a post


Silver Member
Username: Koz1031

Monticello, In United states

Post Number: 233
Registered: Jul-04
In the thread titled "Subwoofer Comparison" you stated the following "Just build it as good as you can get it, and if you can brace it, do so. The more bracing, the better. Try to make the back or front(either one) angled that way the box isn't perfectly square. If the walls are parallel (square) standing waves can occur and degrade SQ."

Does this hold true for ported or vented enclosures also. Or is this just a sealed enclosure thing.
I'm actually more interested in the statement in slanting either the front or the back to avoid standing waves, as I totally agree with you on the bracing, and caulking.
If 1 can angle either the front or the back does it matter which, or should 1 anle both? Much like a ULLGH audiobahn bandpass box. Does the degree of angle matter? If so what is optimum.
I could probably go on, but this will do for now.

Gold Member
Username: Jonathan_f


Post Number: 2488
Registered: May-04
It's more of an issue with sealed, but all can benefit. You also have to understand how a standing wave is produced, the box has to be 1/2 the wavelength of the wave produced. If your box was internally 12x12x12, then the wavelength would have to be 2 feet and lower, meaning frequencies that produce a 2 foot wavelength and any frequency higher than that. 100hz has a 11.28 ft wavelength, so it's not really an issue. I believe it's around 500hz that wavelength approaches 2 ft. long. Of course, the larger the box, the lower the frequency. Most subs operate from 100hz and lower at the least, so standing waves aren't really an issue in the operating range, BUT you also have harmonics, and this distortion can be much higher than the initial sinewave. You also have crossover slope to account for, just because you're crossed over at 100hz doesn't mean the sub isn't producing 400hz, it'll just be much, much quieter than it's range. Anyway, slanting the box is a tried and true, simple way to eliminate the problem, so it's always a good idea to build a box as such.
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