1. ## Smaller enclosure for SPL, and Larger for SQ? Or vice-versa?

most manufacturers' recommended cubic airspace have a range (ie. 1.0-1.5 cu. ft.)... so which is true for a sealed enclosure???

smaller for spl, and larger for sq?

-or-

smaller for sq, and larger for spl?

2. ## Re: Smaller enclosure for SPL, and Larger for SQ? Or vice-versa?

I had a debate with someone regarding this. The person who I was debating with wrote to Dan at Adire Audio and received following reply. ..

Originally Posted by Dan Wiggens
When you go with a smaller box, you do gain peak output (higher Q enclosure), but lose bandwidth and overall efficiency. A larger box raises total system efficiency (the overall efficiency averaged across the entire bandwidth), and also extends bandwidth. So what you're doing is trading off a very narrow peak where you may gain a dB or two (over perhaps 1/3rd
or 1/2 octave) for a loss in overall bandwidth (an octave or so), and total
average efficiency across the full bandwidth (say 2-3 octaves).

3. ## Re: Smaller enclosure for SPL, and Larger for SQ? Or vice-versa?

You will need to look at the driver's spec and determine what "Q" a box will provide with that driver. You can use a formula to help determine the Qtc of a certain box with a certain driver. If you look on the sheets for JL's drivers it shows the recommended box size for sealed and ported as well as the Qtc. A Qtc of .7 to .8 is very common. For a deeper less peaky bass you might want to go down to a Qtc of .6.

http://www.bcae1.com/
take a look at #115/116/117 on the right, this helped me out.

4. ## Re: Smaller enclosure for SPL, and Larger for SQ? Or vice-versa?

so it differs between subs?

5. ## Re: Smaller enclosure for SPL, and Larger for SQ? Or vice-versa?

Yes, a 1 cube box with a JL10w3 will yield a different Qtc than a RE SE10 in that same box. Just like different subs require different box sizes to operate correctly. On the link below there is a formula that you can use to find the Qtc.
Select speaker enclosure calculations (#116) from the right tool bar. Then look almost to the bottom of that page and it has an area that explains this better than I can and also has the calculators you need.

http://www.bcae1.com/

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