resonance and sealed enclosures


I was wondering: suppose you have a smallish sealed subwoofer with a resonance frequency of 40 Hz (obviously not up the quality of the things usually talked about here). This is right at the frequency of the low E on a bass. My concern is that the reponse at 40 Hz will be exagerrated. The resonance peak on a sealed sub isn't important when it's 20 Hz or below. Will the 40 Hz resonance really matter?

I am thinking about using this sub for computer speaker BTW.
daniel_newhouse5e69
It looks like we're all in agreement.

Most sealed designs come in between 0.7 and 1.0 when it comes to Q, with 0.77 problably being most common, due to the way people perceive the sound.
Poor old Dr Bose had a really neat idea long ago. Instead of trying to lower the resonant frequency as much as possible, push it UP, to 200 Hz or higher. The advantage is that rolloff below resonance, although very great, is smooth and predictable, and can be compensated by electronic means. (This is quite different from the practice of a modest (3-6 dB) boost at 30 Hz or so commonly used with sealed subwoofers). Downside is that a lot of amplifier power is needed.

This idea always appealed to me, as I am a "contrarian". If everyone thinks that one approach is best, I try the opposite. This served me well in a long engineering career.
Isn't a properly designed port supposed to counteract the resonance?

The speaker in question is the Samson Resolv 120a, part of a cheap line of "studio monitors" though I would never spend money on any recording studio that used these things. They're really marketed at wannabe musicians.

Would a 10" sealed sub be an appropriate fit for main speakers with a 5.25" mid speaker or would the sub be too big? Desktop space is a concern here.
A port is typically tuned at the point of resonance that the woofer achieves within that given box. By "counter-acting" this resonance, two smaller resonances are created. It is this elevated bass plateau due to these resonances that typically results in greater extension. At the same time, more resonance equates to less control and definition, which is why most vented designs sound "sloppy" compared to a well designed sealed box. The sealed box loses when it comes to output levels though, so you have to choose which trade-offs you want to live with and go from there. As i've mentioned before, sealed vs vented is equivalent to quality vs quantity.

I don't think that a 10" sub would be out of place filling in the bottom for 5.25" mid-woofers. If you cross it over properly, you can play around with the placement and probably get it to work pretty well. As far as using it on a desk-top, that may be a bit much depending on the size of the cabinet and the size of the desk : ) Sean
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I have read a revuew about a similar setup from M-Audio, slightly more expensive, that features an 8" ported sub. The complaint is that the sub sounds right at middle volumen levels but is too weak at high volume levels and too strong at low volume. Is this a classic case of the type of distortion that is found when using ported subs?