single 12" sealed enclosure question(s)

[jeepguylv]

sorry about not having a drawing but what I have is a 12" dual 2 ohm voice coil soundstream R3 subwoofer (please don't laugh //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif) in the manual it says min. 1.0 cu ft. optimum 1.5 cu ft. it will be run by a hifonics bxi 1200.1 . the box I am planning on building is 17" wide, 15" tall (this will be the baffle. the top of the box will be 13 1/2 " deep and the bottom will be 16" deep. reason for the wedge is so it sits flat against the rear seat back of a jeep liberty.

(measurements are outside )

my question is does it matter if it is wedge, square or any other shape as far as sound goes. I have done a lot of searching and have not found a definitive answer to this question. and if it does will be really noticeable or only to a meter.

also I have never had polyfill benefit any boxes in the past, if anything they sounded worse. would this be something I should look into further?

thanks

mike

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[CSCStang]

sorry about not having a drawing but what I have is a 12" dual 2 ohm voice coil soundstream R3 subwoofer (please don't laugh //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif) in the manual it says min. 1.0 cu ft. optimum 1.5 cu ft. it will be run by a hifonics bxi 1200.1 . the box I am planning on building is 17" wide, 15" tall (this will be the baffle. the top of the box will be 13 1/2 " deep and the bottom will be 16" deep. reason for the wedge is so it sits flat against the rear seat back of a jeep liberty.(measurements are outside )

my question is does it matter if it is wedge, square or any other shape as far as sound goes. I have done a lot of searching and have not found a definitive answer to this question. and if it does will be really noticeable or only to a meter.

also I have never had polyfill benefit any boxes in the past, if anything they sounded worse. would this be something I should look into further?

thanks

mike

That box will work fine. You get a little over 1.5 cubes before sub displacement. You won't need polyfill.

 

[CheЯRyMan]

Wedges are actually a better shape than prisms(rectangles) or cubes they eliminate a phenomena called standing waves where two or more parallel walls can reflect back and forth causing unwanted frequency's. Most damping materials have poor coefficients at low frequencies.

 

[jeepguylv]

ok. I was thinking of bracing the box with 2 pieces of 3/4 the same size as the sides of the box but cut them out like picture frames with a 2" border kinda like cutting a square out of a square and rounding off the inside edges, or will this be necessary. I would just have to make my width a little wider.

 

[CheЯRyMan]

A brace certainly will make your box more rigid but at this size two window braces is a little overkill. Maybe just one brace or just dowels.

 

[jeepguylv]

awesome. thanks for the input, makes johnny 5 very happy.

 

[jeepguylv]

ok so I did the box today and I am unhappy with it. sounds good but at certain tones kinda sounds off a bit. I did not seal the hole I drilled for the wire yet cause I wanted to test it first, the wire is twisted with a round jacket over it and I used a bit just the right size so you have to squeeze it in straight for it to go in so it's not like it would make a whole lot of difference or maybe it would, not sure, any advice on how I should approach this issue, if I took a video of it would the sound come thru properly? or maybe I should look at doing a ported box ?

oh yes, I have it wired at 1 ohm using hifonics bxi 1200w x 1 and the sub is ss r3-12 dual 2 ohmvc all 2 ga. power wire and ground, 12 ga speaker wire. and a stupid cap from boss that is for ****, it does nothing but I had expected that piece of junk wouldn't work.

 

[Louisiana_CRX 5,000+ posts]

A round box works best because there is no standing wave....

 

[Jeffdachef 5,000+ posts]

ok so I did the box today and I am unhappy with it. sounds good but at certain tones kinda sounds off a bit. I did not seal the hole I drilled for the wire yet cause I wanted to test it first, the wire is twisted with a round jacket over it and I used a bit just the right size so you have to squeeze it in straight for it to go in so it's not like it would make a whole lot of difference or maybe it would, not sure, any advice on how I should approach this issue, if I took a video of it would the sound come thru properly? or maybe I should look at doing a ported box ?
oh yes, I have it wired at 1 ohm using hifonics bxi 1200w x 1 and the sub is ss r3-12 dual 2 ohmvc all 2 ga. power wire and ground, 12 ga speaker wire. and a stupid cap from boss that is for ****, it does nothing but I had expected that piece of junk wouldn't work.

what frequencies are you missing from your bass exactly?

 

[Louisiana_CRX 5,000+ posts]

ok so I did the box today and I am unhappy with it. sounds good but at certain tones kinda sounds off a bit. I did not seal the hole I drilled for the wire yet cause I wanted to test it first, the wire is twisted with a round jacket over it and I used a bit just the right size so you have to squeeze it in straight for it to go in so it's not like it would make a whole lot of difference or maybe it would, not sure, any advice on how I should approach this issue, if I took a video of it would the sound come thru properly? or maybe I should look at doing a ported box ?
oh yes, I have it wired at 1 ohm using hifonics bxi 1200w x 1 and the sub is ss r3-12 dual 2 ohmvc all 2 ga. power wire and ground, 12 ga speaker wire. and a stupid cap from boss that is for ****, it does nothing but I had expected that piece of junk wouldn't work.

If the subs are new and stiff they will sound a lot better once broken in...that takes some time and playing to loosen the suspension ...

 

[jeepguylv]

not sure the frequencies don't have a meter to tell, I did make a crappy video(my first video im not that tech savy) but not sure if it captures sound very well and I did find a hole in the surround or foam whatever you call it that I heard air coming out of that was not filled with glue. to me it sounds like a bit of the higher freq. and a bit of between mid and low freq.



oh yea the sub only has maybe an hour or 2 of play time on it, I still need to learn how to tune the amp, I also have a multimeter I use for work that has a db meter setting so for fun I tried it out and it says only 127 to 129.9 was the range, i'm sure it cant be that accurate but is that low or high for a single 12 in a sealed box?

 

[Jeffdachef 5,000+ posts]

use silicone to fix the hole. Cant tell much from that video, its just playing sweeps. find 20-80hz test tones and see exactly what you are missing.

 

[jeepguylv]

ok i'll try that tomorrow and let ya know .

 

[jeepguylv]

ok so I played from 100 hz to 15 hz in 5 hz incraments and from 100 to 70 sounds not so good, from 65 to 45 is great and loud with 50 sounding its best and loudest, 40 is not bad 35 down not so great but still plays, I guess all in all I would love to capture the full range but not sure if that is possible. i'm a little picky because I listen to everything from rap to folk music to indie to rock, alternative, classic rock, 80's rock, trance and electronic, and once in a while I like to put on those extreme bass songs and just see how far I can push it.

 

[Jeffdachef 5,000+ posts]

sounds about normal really. 70hz and up is actually midbass category which is supposed to be picked up by door speakers, not played by subs. As for 40 hz and down, sealed enclosures arent low end maniacs, its just flat response. You are just expecting too much out of a single 12 in a sealed box. One thing that helps is on those songs with very little bass, you can use the loudness feature but in exchange, your max volume level has to be a lot lower to prevent clipping, but you'll get more bass out of those songs.