What effect does sealed enclosure size have?

[spark plugs. 10+ year member]

i currently have my IDMAX in a 1.375 cu. ft. sealed box. out of curiousity, what effect what adding some polyfill or getting a bigger sealed enclosure have on the output/quality of this sub?

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[Immacomputer 10+ year member]

It will reduce mechanical power handling (speaking of just increasing volume) and could possibly reduce output at higher bass frequencies. As the enclosure size becomes infinite, you lower your Qtc down to the Qts of the driver and the resonance point (Fc) down to the free air resonance of the driver (Fs).

Lower Q means a wider range of peak and the lower Fc means more low frequency extension. Also, the bigger the enclosure the less loading on the driver and the more natural it will sound. The bigger you go though, the less power it takes to reach peak mechanical excursion so you can run the risk of damaging the sub if you put the same amount of power to it as you would to it in a much smaller enclosure. This happens because the air in the enclosure acts like the spider and surround do and it helps push and pull the sub back to its rest position.

 

[ultimate157 5,000+ posts]

Couldn't have said it better.

 

[spark plugs. 10+ year member]

It will reduce mechanical power handling (speaking of just increasing volume) and could possibly reduce output at higher bass frequencies. As the enclosure size becomes infinite, you lower your Qtc down to the Qts of the driver and the resonance point (Fc) down to the free air resonance of the driver (Fs).
Lower Q means a wider range of peak and the lower Fc means more low frequency extension. Also, the bigger the enclosure the less loading on the driver and the more natural it will sound. The bigger you go though, the less power it takes to reach peak mechanical excursion so you can run the risk of damaging the sub if you put the same amount of power to it as you would to it in a much smaller enclosure. This happens because the air in the enclosure acts like the spider and surround do and it helps push and pull the sub back to its rest position.

correct me if i'm wrong, but i think i'm gathering that you're saying that i will lose some output overall, but will the speaker will play more linear?

 

[ultimate157 5,000+ posts]

correct me if i'm wrong, but i think i'm gathering that you're saying that i will lose some output overall, but will the speaker will play more linear?

Edit for better explanation \/

 

[Immacomputer 10+ year member]

That may not always be the case. And, output is frequency dependent. You may gain output in the 20-30hz range but you may lose some output in the 60-70hz range. This is all varying on how big you go and how small it is to start with.

Saying "louder" is too vague to say yes or no to. I'm not sure what you mean by linear. If you're meaning that it will have a more even or flatter response, then I would say that it is vehicle dependent. Cabin gain could make it peaky in the low end or it could still be peaky in the upper end.

 

[BrianChia 10+ year member]

Basically, a larger box increases the damping of the enclosure, which in turn increases the system damping (lower Q system). The desired amount of damping will be dependent on many things--the speakers, the environment, the desired response, etc. There are many variables involved.