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 will depend on the "Q" or tuning of the driver in that specific cabinet. Most sealed designs typically have a lower Q, meaning that they have a much smaller peak ( if any ) at resonance. This is why they sound far more natural and offer better control than a vented design, which typically has a tremendous peak ( both in output and impedance ) at the point of resonance.

While this type of speaker would be phenomenal for a computer type system, you can always vary the type and quantity of stuffing material to alter the bass response to your tastes as needed. More stuffing will reduce the peak at output, provide more extension and give the bass a tighter, drier sound. Reducing the stuffing will give you greater output at a higher frequency, making the bass sound more "lively", but also with less control. Finding the right spot for what you desire in your specific installation shouldn't be that difficult. Sean
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For non-critical listening...such as your application...i wouldnt be too concerned...and Sean is dead on...it is all based on the "Q" tuning for sealed designs...such as .70, etc...I would also agree that for truly quality deep bass response...if that is goal...a sealed design on paper would have the edge,,,I have also heard ported designs that surprised me as well...all in the construction I suppose...good luck..one last note...
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.