How much does box size effect sound quality?

5.9Limited · Post by **5.9Limited** » Sun Apr 19, 2009 8:23 pm

Hey all, I was talking with a friend today about my system, and he was amazed at how small my box was for my two RSDc 10's. He asked how much difference box size makes to SQ, and how sensitive it is...for instance...my box is approx. .944 cubic feet, as spec'ed by PG for the subs...So how much bigger would the box have to been to effect the sound??? I didn't really know how to answer him with anything but " I always go with what the manufac. specs..."

so again, my box is roughly .95 cubic feet, say it was like 1.25 cubic feet...would that increase in size effect the sq, or would it risk damaging the subs???

Post by **stipud** » Sun Apr 19, 2009 8:49 pm

.95 per sub, or .95 total?

The RSDC 10's like smaller boxes. If it's indeed .95 per sub, try experimenting... throw some styrofoam blocks in to take up airspace and get it to around .6 per sub. See how you like it then.

Yes, box size definitely does affect the woofers. Bigger generally means it will play lower, but it might lose control on higher notes. Certain woofers like the Xenon series excelled in large boxes. Others are designed for smaller ones.

baddog671 · Post by **baddog671** » Sun Apr 19, 2009 8:51 pm

Only .95 for 2 subs? How are they not hitting each other, lol...

Post by **ttocs** » Mon Apr 20, 2009 1:43 am

it all depends on the speaker.... I have my diamond audio D6 sub in a really small box that is just barely over .5 cu ft but it really likes it and still performs great in it. I have installed subs in the past that had very little output in a small box.

bretti_kivi · Post by **bretti_kivi** » Mon Apr 20, 2009 2:30 am

Depends on the specs. Model it and you'll see; If the box is too large, it may well start sounding soft, if it's too small, it won't drop.

I might do some modeling later and show you graphically what I mean. Point was, not always are manufacturers correct for what YOU want.

Bret

5.9Limited · Post by **5.9Limited** » Mon Apr 20, 2009 2:48 am

well unless im completely off (which is possible) my manual says the reccomended air space for each off the 10's is .382 cubic feet , plus the displacment of the sub itself which is .09 cubic feet, putting the total interior volume needed at .4774 cubic feet, double that for two subs in a shared air space and you have a desired space of .944 cubic feet. trust me I checked and double checked and ran the #'s and i had a hard time building the box for the 2 10's to that size, after I measure it I remembered I stretched it a bit so my box is a tad bigger than spec.... its a small little box thats for sure....they sound really great, Im gonna try the foam blocks and experiment a little...they do play low but they don't seem to snap as much as I though they would being 10's.

Post by **stipud** » Mon Apr 20, 2009 6:28 am

5.9Limited wrote:well unless im completely off (which is possible) my manual says the reccomended air space for each off the 10's is .382 cubic feet , plus the displacment of the sub itself which is .09 cubic feet, putting the total interior volume needed at .4774 cubic feet, double that for two subs in a shared air space and you have a desired space of .944 cubic feet. trust me I checked and double checked and ran the #'s and i had a hard time building the box for the 2 10's to that size, after I measure it I remembered I stretched it a bit so my box is a tad bigger than spec.... its a small little box thats for sure....they sound really great, Im gonna try the foam blocks and experiment a little...they do play low but they don't seem to snap as much as I though they would being 10's.

I see... in that case I wouldn't recommend foam blocks, because you're already on the small end of what they were designed for. The subs work well in about 0.4-0.6cuft. Any bigger and they start to get boomier, any smaller and you start to lose on your bottom end. Same goes for the 12... 1-1.25cuft is about all they need.

Post by **ttocs** » Mon Apr 20, 2009 10:36 am

what is everyones opinion on polyfill?

bretti_kivi · Post by **bretti_kivi** » Mon Apr 20, 2009 11:00 am

this: http://www.diysubwoofers.org/talkshop/m ... /41415.htm

Post by **stipud** » Mon Apr 20, 2009 11:19 am

That's a good point to bring up. My 1cuft box was a bit on the small side for my RSDC 12, so I added a good dose of polyfill. Seemed to sound better, though I could never perform a conclusive A/B test.

So you might want to try stuffing 1lb of polyfill in your box. That should make it seem like 0.6cuft or so, which is what I found ideal for my 10". At worst if you don't get an audible improvement in sound quality, it helps against standing waves, etc, so it's pretty useful stuff.

baddog671 · Post by **baddog671** » Mon Apr 20, 2009 11:36 am

Since everyone is talking about enclosure size, and mine seems to be a bit larger than whats been said so far, would 1.52ft^3 internal volume be ok for a Xenon 12d4? I'm new, so still learning, but the manual says between 1 and 3. What are the advantages of each? I think 2 would be my max becuase of the trunk opening...

thedeal7235 · Post by **thedeal7235** » Mon Apr 20, 2009 11:58 am

on my 2 rsdc 10s, i beleive, if i rememebr, i have each chamber at .80, but damn they sound good, and they hit really hard! dbincognito has heard them before and he was amazed-i know thats out of pg spec, but i ported 'em too, & im happy-

Post by **stipud** » Mon Apr 20, 2009 11:59 am

baddog671 wrote:Since everyone is talking about enclosure size, and mine seems to be a bit larger than whats been said so far, would 1.52ft^3 internal volume be ok for a Xenon 12d4? I'm new, so still learning, but the manual says between 1 and 3. What are the advantages of each? I think 2 would be my max becuase of the trunk opening...

The Xenons respond well to very large boxes, since they are bottom end monsters. They seem to do best in 1.5-2.0 per sub for the 12's. IIRC the 10's liked 1cuft and up as well. So your box should be great, but perhaps add 1.5lbs of polyfill as well

baddog671 · Post by **baddog671** » Mon Apr 20, 2009 12:10 pm

stipud wrote:
baddog671 wrote:Since everyone is talking about enclosure size, and mine seems to be a bit larger than whats been said so far, would 1.52ft^3 internal volume be ok for a Xenon 12d4? I'm new, so still learning, but the manual says between 1 and 3. What are the advantages of each? I think 2 would be my max becuase of the trunk opening...
The Xenons respond well to very large boxes, since they are bottom end monsters. They seem to do best in 1.5-2.0 per sub for the 12's. IIRC the 10's liked 1cuft and up as well. So your box should be great, but perhaps add 1.5lbs of polyfill as well

Cool, thanks for the response. I also read the link about the fiber and that cleared some stuff up. So, you just throw it in the box? It would get stuck in the back end of the sub or cause any problems if it does?

I noticed my manual says "Lining the walls with a polyester matting 1-3" thick is suffiecient.", but thats all it says on the subject...

Post by **stipud** » Mon Apr 20, 2009 12:23 pm

You certainly want to avoid it getting sucked into the sub. The stuff I use in my boxes is a solid polyester sheet. I have used the typical wadding though with no issues either... just keep it a couple inches away from the back of the sub and you should be fine.

baddog671 · Post by **baddog671** » Mon Apr 20, 2009 12:27 pm

Oh, ok. I was picturing the fluffy pillow filling material, which I figured would make the inside of a box look like a snow globe. I assume Walmart would carry that poly-mat..?

bretti_kivi · Post by **bretti_kivi** » Mon Apr 20, 2009 12:29 pm

I've used old pillows before, but then I tend to listen relatively quietly....

for home speakers, that's fine, as you can stuff it hard and away you go. For car ones, I'd prefer sheets.

Bret

dako · Post by **dako** » Mon Apr 20, 2009 12:48 pm

Wal-mart sells a "high grade" polyfill which I really like to use. Also, if you're in no huge hurry to mount the sub, the inside can be sprayed with 3M Super 77 and then you can stick the polyfill in, preventing later clumping or having gobs of it get caught in the sub. If you go this route, definitely let that sucker air out so you aren't trapping adhesive fumes within the enclosure.

Post by **ttocs** » Mon Apr 20, 2009 3:18 pm

I was afraid at .5 cu ft that my box would be a little small so I stuffed it full of polyfill. It is a pain to get in and out so I never listened to it with out but I have been suprised how well it sounds for a single 10. I got mine from a jo-ann fabric on a trip when I was getting material to cover it with. They also sell the sheets that you can staple to the inside of the box there cut to length.

baddog671 · Post by **baddog671** » Mon Apr 20, 2009 4:27 pm

ttocs wrote:I was afraid at .5 cu ft that my box would be a little small so I stuffed it full of polyfill. It is a pain to get in and out so I never listened to it with out but I have been suprised how well it sounds for a single 10. I got mine from a jo-ann fabric on a trip when I was getting material to cover it with. They also sell the sheets that you can staple to the inside of the box there cut to length.

They sell material to wrap the box aswell?

thedeal7235 · Post by **thedeal7235** » Mon Apr 20, 2009 6:10 pm

baddog671 wrote:
ttocs wrote:I was afraid at .5 cu ft that my box would be a little small so I stuffed it full of polyfill. It is a pain to get in and out so I never listened to it with out but I have been suprised how well it sounds for a single 10. I got mine from a jo-ann fabric on a trip when I was getting material to cover it with. They also sell the sheets that you can staple to the inside of the box there cut to length.
They sell material to wrap the box aswell?

-
nope-ive checked there too-i suggest looking in your local yellow pages for auto upholstry shops/distributors-the place i use locally is a distributor called abco, out of orlando,fla

Post by **ttocs** » Mon Apr 20, 2009 11:01 pm

depends on which stores you go to. I happen to have a megastore around the corner and they do stock some vinyl, and almost any material you could want. I wrapped my amprack in a grey ribbed material that I got there as the color match was really close.

5.9Limited · Post by **5.9Limited** » Wed Apr 22, 2009 7:35 pm

hey guys...I've been out of town for a bit...but Im back.

so here's the deal...measured my box again and did the math...spec fo the subs again is .944 cubic feet...my box is bigger, bigger than I wanted, bigger than I intended... (measure twice, cut once as they say)

my total interior volume is actually 1.22 cubic feet..my heighth and depth are what I indended, but somehow I stretched the length of it quite a bit... my back seat is a 60/40 split, and the box is the exact size of the 40 part...so maybe i biffed and made it that size... not sure... so.....WILL THIS EFFECT MY SOUND?? i can't rebuild a box...a pain but I will if necessary...or i could cut some pieces of MDF or put on the interior.... any Ideas???

ps. thanks for all the help thus far.

Post by **stipud** » Wed Apr 22, 2009 8:57 pm

1.22 should be perfect. I was thinking your box was too small before...

5.9Limited · Post by **5.9Limited** » Thu Apr 23, 2009 4:37 am

ok...Im gonna spend some time today checking all my x overs and frequencies and see if I can't get these things to snap more...its been a while since I've had a system so maybe Im remembering things wrong but, these seem to boom more than they really snap and punch...