When you put a subwoofer in a smaller box than it is designed for, what happens? I was going to put an IDmax in a .7 cu ft sealed box. The recomendations are 1.1-1.5 cu ft sealed. What do i lose with a smaller box? Performance or longevity or loudness or what? I e-mailed image dynamics for their opinion on it and they haven't written back yet. Help me please! Thanks alot.

 

you will definitely lose low frequency extension (they won't play as low), and you run more of a risk than normal of destroying the speaker if you drive them hard. it's possible that it will sound ok, but most likely it will sound like crap.

now, you can probably get away with that size of a box if you put 2 subs in an isobaric configuration, because isobaric setups reduce the air space that the subs need by 1/2.

Here's an explanation of isobaric, in case it's new to you.

 

Thanks for the reply, that isobaric stuff is pretty nuts. More for me to think about. Thanks again.

 

Well, like said your low-end extension will be restricted. But typically this isn't a problem, there is very little musical information below 40Hz. To use popular recording artists of a few years ago, Madonna's lowest information is around 38Hz and ZZtop has a 5-string bass that plays into the 32-34Hz range on 4 of their songs. Otherwise its classical music with kettle drums and pipe organs that need bass that low. If you use anything AudioControl, it pretty much rolls all that off anyway to save woofers and amplifier power, and people don't complain. If you don't know its there (and most people don't) you don't miss it, especially when its rare. Most bass drums are 50-60Hz and 4-string bass guitars only go to 44Hz.

The power handling goes up in a small box. So you can drive it with more power but still won't get much more output. Obviously this will shorten the life considerably if you do it.

The square Kicker solobaric woofers are always installed in too small a box by design. It increases their power handling and the low end rolloff is replaced with an upper bass boost that gives them the 'slam' sound that many many consumers enjoy.

There is a way to describe how much too small/big a woofer's sealed box is called a Q (an electrical engineering term for a filter) and by going to a box your size the IDMAX will have a Q of .931 which is comparable to the Q you'd get with the smaller recommended box size for a JL W3. Obviously many people like that sound and it works well for rock, alternative, and rap genre's of music. The recommended size from ID is 1.2 to get a Q of .771 which is pretty close to ideal for a musical sub that is going to play classical music well and sound good doing it.

my two cents,
Cliff

 

Wow, cliff, you really know your stuff. Thanks for the info. Even more to think about.

 

I saw this thread the other day and sent Cliff the link so he could respond to you. I knew he'd be able to give you a better answer than I could give!

Cliff and I were talking to Matt Borgardt from Image Dynamics the other day and he said that the 10" IDMAX is suppose to be a pretty bad **** little sub. Which size were you thinking of when you asked originally, the 12" or the 10"?

 

I was originally going to use a single 12 in a .7 cu ft box. Image Dynamics never replied to my e-mail so i don't know what their thoughts on it are. I might try them again. My backup plan is to use two IDmax 10's in a different box that works great for the 10's but i'm not sure yet.