calling audio guru's
 

how does one go about calculating the needed cubic feet needed for a subwoofer? (not just LxWxH lol)

i want to replicate a sub box for a regular 5x7.

what are the specs i need of the specific speaker to calculate the required volume? i have always went to the brand's site for subs and they give you recommended inner volume.

any and all help is appreciated, i can do any conversions etc and to do calculations but not sure on what all goes into the "recommended volume"

so far i know it's a:
50 Watt RMS
160 Watt peak
5x7 speaker
4 Ohm
2.25" top mount depth
50-20K Hz
90 dB sensitivity


im conjuring up another project :)
thanks guys!
Dean

You want to build an enclosure for a set of speakers? I don't see the point...

Here are speaker baffles. Not exactly the size your looking for, but you get the jist.

http://cgi.ebay.com/Metra-81-6900-Un...item2eac4bd1c6

thats what i was going for...i was going to create a basket like that for my 5x7's in the rear deck...on a smaller scale how the Mach systems have that giant black enclosure which the speakers mount in...somewhat like a woofer box.

i was mostly doing it to keep as much sound IN the car as possible and dont want it escaping into the trunk. so i am going to build a basket out of fiberglass and MAYBE throw a small peice of dynomat right behind the speaker.

but the more i think, the less i may need to "design" a box for them.....but rather to just make some basket like you posted, as this is not some competition system im putting together (overthinking this)

speakers in that size were not designed to be in a sealed enclosure, they need to be mounted free air

I wouldn't. You're going to get the best sound just mounting them the way they are designed and tested to be mounted.

touche fellas, thats why i came here to ask. i did not know you couldn't do that with these types of speakers.

thanks a lot.

but at any rate, how DO you calculate the volume for any given subwoofer with its given specs? for future referance, and i think its something interesting to know.

when they give the recomended airspace for a speaker, that would meant that it can play in a sealed environment. You will not gain much sound from it but it will change and may help. The volume they give is the internal volume of the box, minus the displacement of the subs basket/magnet which is also given. Normally when building a box you have two dimensions of the box that you can't change(the front heigh and width) and one you can such as the depth. By using algebra you can then solve for the depth needed to get the airspace required for your woofer. Now you need to remember that this is the internal volume so that when you add the .5"-3/4" wood it will be even wider yet.

I built a box for 4 - 8" woofers that mimics the mach enclosure that hangs from the deck. Sounds and looks nice but it was a pain.......... you can see it on my cardomain page.

right i get all that, makes sense, but what about a specific speaker (8", 10" etc) that determines the internal volume of the box.

do all 8" subs no matter what brand requre the same intenral volume (assuming same type of box....sealed or ported)

when you go to a brands website, you look up the sub you have and they give you the recommended volume for THAT sub, what goes into calculating that? like the freqiency it operats at, the watts it is rated at etc?

i have built some custom boxes for my tbird and mark 8, but used the same Rockford sub and was able to find the volume off their website.

i may still make these for the 5x7's to try and keep the sound out of the trunk but not make them sealed....i dont plan on kidnapping people where they need to hear music in the trunk :)


ohh and ttocs..you gotta change the black/blue letting and background of your cardomain...its a PAIN to read lol