Need help in sub box sizing

[rb70383]

I have some old Cerwin Vega XL10S subs. I dont have the papers on them but a web search comes up with these numbers:

RE: 3.4
FS: 28
VAS: .09345 I am guessing liters which is 3.3 ft3 (found another site which listed it as 3.3 and a conversion comes up with 3.3 ft3 as well) as long as this number is in kiloliters.
QES: .175
QMS 3.301
QTS: .1662

From this site here:
http://users.hal-pc.org/~bwhitejr/drivers.txt

http://www.linearteam.dk/default.aspx?pageid=newdriver
Using some online box calculators it is coming up with around .19 cuft? Isnt that a bit small? I dont even think the speaker would fit in the box. All the sources I find, the speaker specs match. Cerwin vega doesnt list the speaker at all so I cant double check the specs.

Anyone build boxes and have the specs to this speaker? Am I screwing up the calcs?

Havent decided on ported, sealed or maybe even try a 4th order bandpass since I havent built one of these yet.

[astroracer]

Ported boxes generally run smaller than unported. It's been a long time since I've done any of this work but let me dig into some of my old files. I may have some numbers for you.
Mark

[dipren443]

Found a few more specs for you.


Cerwin-Vega:

Manufacturer/ Power SPL
Model Dia. RMS 1W/1m
XL10S 10" 250W 94dB

---SEALED BOX---

Volume
0.17

F3
125Hz

Per
0W

------PORTED BOX------

Volume
0.19

F3
98Hz

Fb
68Hz

Per
0W

[rb70383]

Ok so the volume is .17cuft? That is awfully small. IF my math is correct a 10" cube is (10x10x10) / 1728 = .578cuft

[dipren443]

Didn't completely make sense to me either...

http://www.rdrop.com/~billmc/enclosures

[Payton King]

There is a guy on www.diyaudio.com that will model a box for you for free. He helped me out. Sealed box is going to be the smallest and a bandpass box will be much larger, maybe almost double the size. If you do not want to go throught the trouble of trying that out, I would say about 1 cubic foot per 10 inch sub as a gross internal volume. I would also seperate the subs from each other. Other words, one box with 2 1 foot chambers.

[Payton King]

I found you a link

[Payton King]

http://www.diymobileaudio.com/forum/...g-service.html

[dipren443]

There is a guy on www.diyaudio.com that will model a box for you for free. He helped me out. Sealed box is going to be the smallest and a bandpass box will be much larger, maybe almost double the size. If you do not want to go throught the trouble of trying that out, I would say about 1 cubic foot per 10 inch sub as a gross internal volume. I would also seperate the subs from each other. Other words, one box with 2 1 foot chambers.

Payton,

Bandpass and ported are not the same. Bandpass boxes are MASSIVE and a little more complex. You may already know this, but to avoid confusion for the OP, I thought this needed to be pointed out.

[rb70383]

I know the differences. I was going to try a 4th order box. Rear of speaker sealed with the front firing into a ported chamber. According to the specs at first it wasn't that big then tried for a sealed and the box volume didn't really change. That is what me all confused now with this speaker.

I was on diyaudio reading on the fiberglass boxes as i want to incorporate a small box with a center console. Thought it was good till I tried to make a .19 cuft box. Lol

[rb70383]

Well I emailed cerwin vega and they had the specs, or at least the ones online. However it also listed that the perferred enclosure is ported with an internal volume of 1.59 cuft, with a single 3" port 8.1" in length that tunes to 35hz. I just dont get the result coming up from the online calcs?

[nekkidhillbilly]

Ported boxes generally run smaller than unported. It's been a long time since I've done any of this work but let me dig into some of my old files. I may have some numbers for you.
Mark

actually a ported box takes more space than sealed

[nekkidhillbilly]

Well I emailed cerwin vega and they had the specs, or at least the ones online. However it also listed that the perferred enclosure is ported with an internal volume of 1.59 cuft, with a single 3" port 8.1" in length that tunes to 35hz. I just dont get the result coming up from the online calcs?

that makes no sense either most 10s take a minium of like .5 cf i just cant see it being that small unless it a shallow mount or some bs

[nekkidhillbilly]

http://www.thielesmall.com/include/d...ID=197&dtype=1

[sniper]

that makes no sense either most 10s take a minium of like .5 cf i just cant see it being that small unless it a shallow mount or some bs

I am not sure what you are looking but if CW "recommended 1.59cuft ported then it only makes sense that sealed is going to be smaller. 1.59cuft, was that for a single sub or two?

Having said that, your not going for an all out SQ system, and those specs may or may not be right. But with only a sub that is rated at 250w, just build a box that is 1 cu ft internal. And run with it. Don't get all beat around with the specs, yes they are important to a certain extent, but with what you are doing, not so much.
Most of the online calculators are crap.
Keep in mind that if they are old subs, you need to check the surrounds for wear and tear.

[rb70383]

I am not sure what you are looking but if CW "recommended 1.59cuft ported then it only makes sense that sealed is going to be smaller. 1.59cuft, was that for a single sub or two?

Having said that, your not going for an all out SQ system, and those specs may or may not be right. But with only a sub that is rated at 250w, just build a box that is 1 cu ft internal. And run with it. Don't get all beat around with the specs, yes they are important to a certain extent, but with what you are doing, not so much.
Most of the online calculators are crap.
Keep in mind that if they are old subs, you need to check the surrounds for wear and tear.

Only for 1 sub. My dad had them re-coned for me a while back. Completely forgot about it till I found them. They look brand new. I want to know what they are designed for so I can build a box that works well with them. Plus using it to practice some fiberglass work so I wanted to get a range that will work in the space I have available.

[duckmanjbr]

It's been a while but I did this professionally a few years back. CW subs generally have always taken a little bigger box mainly because of not being as efficient. As already said, sealed boxes are always a little smaller and there a some tricks you can use to make the sub think the sealed box is bigger than it really is. The Ported boxes are generally larger and tuned to an exact frequency. I personally have always liked the sound and range of a sealed box myself. It really comes down to more design than just a box. A sealed box can be smaller, can use more power and likes that extra power to get better performance, and is much easier to get custom and hide in some unusually areas. The ported box and the 4th order boxes are designed to increase volume at lower power levels. They tune the box to a frequency and increase volume output at that frequency by as much as 6db. As I've said I personally like the sound of a sealed box w/ lots of power. I like rock and top 40 music and don't really get into to much rap so the sealed box gives much better performance over the large range of different music. If you like more rap or bass heavy music you might be better off w/ a ported or an even heavier 4th order box! The box will always turn out better if you design the box around the car first and the sound you're looking for second. Getting the most out of a sub box can be due to a lot of details so simple box design alone is never enough!

[duckmanjbr]

Forgot to mention the fiberglass.... If you're planning on working the box out of fiberglass I'd recommend two things. Fiberglass doesn't work w/ internal reverb as well as HDF or MDF. If you want to use fiberglass I'd recommend at lease one side be wood and use some dynamat inside on no more than three sides of the enclosure if you can. You don't need more than three sides and if the sides aren't flat even using it on one side will help you out a lot! Hope this helps... Check out my last build.....

[rb70383]

WOW that looks nice. Got a link to a build? I built this box for my truck. Did ported as that is what the speakers were said to work best with. It was kinda boomy for me. Louder volumes and the port started chuffing. Swapped speakers, one id blow, and selaed the ports with a cap on the inside. Sounded much better then. The sub box is only half across. I needed under seat storage. I also raised the rear seat 4" for the required volume. I need to redo it as the raised seat is becoming a pain.

I want to incorporate this new box, not the one in the ram, into the center console. I will use mdf where ever possible and fiberglass to fill the irregular shapes.

On the ram box, it is all mdf except the bottom where I used fiberglass to corform to the floor of the truck.

[duckmanjbr]

Be careful doing a center console sub-box. It'll work good in a reg cab but if it's an extended cab you'll probably get some wave cancelation. You'll alway get the best performance when you place the sub as close to the rear as possible. You really need to use the natural acoustics of the car/truck to get the most performance.

The truck looks nice. The box looks really big though. You can get the big stuff in the small space you just really need to use some imagination! Here's some pics of my truck box. I had 6" total height in the front so I had to get really imaginative! I wanted everything hidden and max volume cause the truck was kinda loud. Had to water-cool the amp because of no air circulation under the seat but that and a little fiberglass and it was unbelievable! 12's under the seat at stock height! Each box was a little over 1.2 cuFT and the only HDF was the front and top pieces. Everything else was glass. :D