Enclosure size question

[Flyin11]

I got something similar to this type of foam from my old work tonight but it's thicker:

http://cgi.ebay.com/40-Sheets-of-foa...QQcmdZViewItem

Wanted to try and use maybe 2 pieces of it...Just stuff into the hole and to the back. Wondering if the sound will still bounce off of it and sound good or will it get absorbed and sound like junk? I guess I'll probably just have to test it out and see. Found a page on the net where they were showing people's subs in action and one guy had a pair of 12W3v2 speakers in a 1.7 cu ft box and the specs say 1.25 for them as well. So I don't feel too worried now as if it worked for him it just might for me as well...

[shagone]

Originally posted by Flyin11
I got something similar to this type of foam from my old work tonight but it's thicker:

http://cgi.ebay.com/40-Sheets-of-foa...QQcmdZViewItem

Wanted to try and use maybe 2 pieces of it...Just stuff into the hole and to the back. Wondering if the sound will still bounce off of it and sound good or will it get absorbed and sound like junk? I guess I'll probably just have to test it out and see. Found a page on the net where they were showing people's subs in action and one guy had a pair of 12W3v2 speakers in a 1.7 cu ft box and the specs say 1.25 for them as well. So I don't feel too worried now as if it worked for him it just might for me as well...

as far as i know, inside the box you don't want the sound to be bouncing off of the walls and cancelling out the sound of the woofer. these are called standing waves. some people try to avoid this by building a box with odd angles included to diffuse the stading waves inside. others use fiberglass insulation, wool, polyfill, and other paddings or even spray on sound deadening to change the sound of a box. you can experiment with different ammounts of material until you get the desired sound. the old rule of thumb used to be 1 pound of polyfill for every one cubic foot of air space. more polyfill will make a box that is too small for a given woofer appear larger. you can use this for up to a 40% increase in air space from what i'm told. don't use too much or it will affect the cone movement or be too compacted and overheat your woofers. it must be somewhat loosly packed into the box. you can find polyfill very cheap at any fabric store or walmart.

you may want to use a solid object (like 2x4's as braces) to make your box smaller or you might try it the way it is. i think it is better to have a slightly larger box that one that is too small. just my opinion. deeper bass in some cases.

[Flyin11]

Yeah...Stuck them in last night. Forgot to grab the foam pieces so didn't put them in and left it be. It sounds very loud but I didn't notice too much difference in the wattage that was being put out after I paralleled the 4ohm speakers to make a 2 ohm load. Not sure where the extra 180watts went but it still did hit pretty hard. Maybe I need time for the subs to break in. I never paid any attention to that stuff about playing them with low volume for like 16hours before you crank them. Just my experience. Yes, they sound a lot better later and do hit harder later on but if I'm putting speakers in, they are to be played loud right away, not for another 2 weeks or something. Maybe it needs to get use to the enclosure as well? Not sure...I turned the gain on the amp up slightly and noticed a good difference when I went out during lunch today. Will see how it sounds cranked and when I'm going home I just need to do some tweaking with the amp to probably get it right now. Still thinking about the foam as a option though....

[Flyin11]

I know this is a old thread but I just tried the foam yesterday like I was talking about and just took the pieces of it and wrapped in a little bit of Polyfil to try and maybe have it hit a little harder and change the frequency but the results aren't what I was looking for. It doesn't sound bad but it kind of took away from the loud bass response of the bass guitar I had before and made it sound less punchy. It was a little bit more punchy on the kick drums but I love hearing the bass guitar lines hit in my legs up front and all so I'm just going to take it out and leave it be. Atleast I know now that it wouldn't be the sound I was looking for with it in it and I wouldn't be wondering myself to death about how it will sound. Oh well, live and learn and it only cost me about $4.00 for the Polyfil....

[jol50]

The fill will do about the same thing as your slightly larger box does, just drops the curve a little and damps a little of the highs out. Best thing is to play with it though, you don't like it so its better empty and now you know. With the 1.25 box it may have helped, maybe depending on what you like. I'd guess a slightly larger than spec sealed box with little or no packing would be closer to a ported box though. Being larger gives more bottom, not a problem unless you thrash it really hard as it may lessen power rating a hair....if you get it to topping out. Standing waves are worse in a square box, that is why most are not square on all sides. Then again with a sub it is not that big of a problem.

[shagone]

you could always try some loose polyfill without the foam and see how it sounds but if you like it empty then at least now you know.