Neothin

here i added a few more lines showing where the boards are and some dimensions

trialsindude

you dont need separate chambers.

SCI_TC_GUY

If you want it 10.5" deep, those side boards need to be 9" deep... right now it's sitting at 10.25"

Zsanz

nice work

1SXETC

dual chambered > common chamber

when possible, always use separate chambers. Even if its two identical subs, the impedance for the two subs is amost always slightly different, so its best that each sub have its own air space.

also, the volume of the enclosure in the above diagram would be too big for each individual sub's specs. Most subs are designed for small - medium (.5-1.25 cu ft) enclosures, with 1 cu ft being optimum for most 10 or 12 " drivers.

EG. Based on the dimensions of my box (14x14x36) which total volume is 4 cu ft. well, interior dimensions are slightly smaller, and take away driver displacement each 10" sub sees about 1.5 cu ft of air space in its individual chamber. If it was one common chamber, each sub would have approx 3 cu ft of air space...WAY too much, they would probably sound like crap and eventually blow.

SCI_TC_GUY

Each sub wouldn't have 3 cu ft of space.... they'd share 3 cu ft of airspace which is the same as having seperate chambers at 1.5ea... only time I'd chamber a sealed box is if it were 3 or more drivers - generally the differences in identical model drivers are negligible and if they were big enough to make a difference then there's a serious quality issue with the drivers....

SCI_TC_GUY

and BTW - a 14x14x36 box is 3.1195746 cu ft of internal volume before driver displacement

trialsindude

I was just going to say that. 3.1cuft with 3/4" MDF

1SXETC

no.

thats all wrong bro.

thats like saying if you have 2 subs running off a bridged amp (600x1) the subs are "sharing the power" and each sub is getting 300.--WRONGO!

how do the speakers know they're supposed to split the air space in half?? they don't. they use all of the air volume available to them (in this case, 3 cu ft).

2 subs in a 3 cu ft box is NOT THE SAME as 2 subs in 1.5cu ft single enclosures...NOT EVEN CLOSE.

Do you NEED dual chambers? no. is it highly recommended? yes.

have you ever measured the actual impedance of subs on a a bench? I have. and i can tell you that basically ever alpine, rockford and mtx model subs that we tested, the impedance varied sligthly from sub to sub (within the same sub model)

you need to do some more howework.

but yeah, the 3 cu ft is teh same as 2 1.5 cu ft's comment was just retarded. So, you think the subs draw an invisible line inside teh box and say"here, you take the air on this side of the line, and i'll take the air on that side.." ??!!! ridiculous.


so based on your logic sci tc guy (the fake audio guru whom i've already seen pwned more times than i can count on one hand in terms of audio knowledge) WHY WOULD you chamber an enclosure with 3 subs...but not 2?? you are funny.

waiting for your hilarious response....

1SXETC

jesus christ. did you not see where i typed TOTAL VOLUME (not actual interior volume) was 4 (4.083333333 if YOU NEED TO BE A STICKLER ABOUT IT). i was rough estimating for the sake of the OP.


I know the magic number 1728. i didn't feel like subtracting .75" from each of my dimensions because in reallity, it really doesn't matter.

and according to my recent calculations you are wrong. 13.25x13.25x35.25/ 1728 =3.5 cu ft.

mandos

2 subs bridged off one amp, as long as they are the same VC config DO share power equally. It's basic knowledge.

Say you have an amp that has the following specs:

200x2 @ 4 ohms
300x2 @ 2 ohms
600x1 @ 4 ohms

2 4 ohm DVC subs wired series parallel in a common chambered box and bridged to the amp = 300 W per sub.

Same two subs wired in parallel in separate chambers for 2 ohm load/chamber, then wired to the amp in stereo = 300W per sub.

Which one is better, common chamber with the amp bridged. Bass isn't in stereo...and if it is, you won't hear left and right anyway, so having the EXACT same signal to each is definitely better.

As for 2 subs in 3 cubes common vs. 2 subs in 1.5 each...it's IDENTICAL. Now yes, very technically speaking due to ever so slight variances from sub to sub, you may have SLIGHTLY different characteristics to each...but 99.999% of the people aren't going to notice.

Unless that is, you've bought a sub from a manufacturer with NO QC process who will pass anything.

There are tolerances in every industry, car audio included. If you're buying subs from someone that have tolerances so far off that 2 subs of the same size from the same line perform massively different...well...you should buy stuff from someone else.

When modeling subs in a common chambered box, you actually do it as ONE big driver in a common chambered box. They are doing the EXACT same thing with the power they are given…unless again, you’ve bought the super shady subs with a 70% variance in specs from one to another on the line.

As for SCI_TC_GUY’s post about chambering subs into multiples of two…well, that’s just because even with fairly tight tolerances, if you end up with say…3 subs on the + side and 1 sub on the – side all in one box, that one poor little sub is going to act rather strange at high output levels.

If you don’t think I know what I’m talking about, I work at an audio company, I have 32 subs in a common chambered box. It’s loud and sounds great for not being done yet.

Also, how exactly are you using ¾” MDF yet you turned a 14x14x36 box into 13.25x13.25x35.25? You missed the other sides of the box. 14x14x36, take away 1.5 for the height and the depth, and with your separate chambers, 2.25 for the width, you get 12.5x12.5x33.75 internal, that ends up at 3.0517578 feet³.

SCI_TC_GUY was right btw, using a common chamber, you’d be at 12.5x12.5x34.5 giving you the 3.1195747 ft³ he arrived at.

Finally, "total box volume" is the most pointless thing EVER to talk about. The speaker doesn't use the wood on the side of the box as airspace, so why even calculate how much airspace your box takes up with the wood?

Please, before you claim someone has been “pwned” more times than you can count, check your posts and don’t “pwn” yourself in the process.

Another public service announcement brought to you by…….me.

trialsindude

PWNED! sorry but since now we have creditable knowledge in here it is good!

mandos

Neo...build it like that, w/ the 8.75" deep internal space, you'll end up at .623 after displacement.

TECHNICALLY...if you really want to be **** about it, it's actually at .6508 if you add in the space cut into the front face of the box to mount the sub

sddykstr

Man, total threadjack, but I have to say I am impressed!

mandos

Oh yeah, I should probably have told you to put 2x4's in the box like SCI_TC_GUY said

You would need 23 10" pieces of 2x4 to cut down .7 cubes.

It's a lot, but you've got a big box.

Something that isn't quite as exact, but is much easier, expanding foam. If you go a little over filling it, once it cures you can always pull some out

Neothin

chris, i love you.


you've got a PM. I've gotta talk to you about buy amps/components/eDead

Neothin

that's a typo by me. I want it to be 10.25 deep

Burb1996

^^^ Listening to the man who does this for a living FTW!!!

MTcX

Nice work Mandos........



I would also mention though that using the same air space configuation concept on a sealed box such as just adding the air space together from two chambers to make a common chamber does not apply to a ported/vented enclosure. You cannot take two seperate chambers that are ported and combine them and then just place the same port that each chamber had twice in the enclosure so you now have two subs in one enclosure with two identical ports and expect the same tuning as they had before when they had their own chamber and their own port.

1SXETC

no. 2 subs on a 600x1 aren't both seeing 300. they are "sharing" (ie. BOTH SEEING) 600. if it was 300x2 THEN they would both be seeing 300. The are both wired in a 600w circuit. in a 300x2 config, there are two separate 300w circuits (channels), one for each sub.



back to the 3 cu ft box. So, are you honestly saying that the subs are SMART and will say, i'll use half this air space (1.5) and you use half the air space??!!!

i can't believe you just said that. and your comment about sending the EXACT SAME SIGNAL TO BOTH makes no sense either. A sub's enclosure chamber has nothing to do with the signal you are sending. The reason you want dual chambers is because if the impedance of the subs is slightly different, they will be firing at slightly different fractions of second, and will cause cancellation/distortion/noise if they share a chamber. especially if they're wired in stereo or one speaker wire is longer than the other. Whether or not the subs are in separate chambers, they both receive the same signal. chamber design does not change the signal at all.

having 32 subs in one enclosure doesn't mean you know anything. Neither does being a guru on SCIONLife audio forums.

evidenced by these incorrect or convoluded statements:
"2 4 ohm DVC subs wired series parallel in a common chambered box and bridged to the amp = 300 W per sub.

Same two subs wired in parallel in separate chambers for 2 ohm load/chamber, then wired to the amp in stereo = 300W per sub."

"As for 2 subs in 3 cubes common vs. 2 subs in 1.5 each...it's IDENTICAL. Now yes, very technically speaking due to ever so slight variances from sub to sub, you may have SLIGHTLY different characteristics to each...but 99.999% of the people aren't going to notice." ---go pick up two random ED subs and bench test them. they won't have the exact same impedance (9 out of 10 x).

"if you end up with say…3 subs on the + side and 1 sub on the – side all in one box, that one poor little sub is going to act rather strange at high output levels."

those comments don't make any sense to anyone who knows car audio (which is why i'm the only one on the forums who can argue with you.

we all know mandos and sci tc guy are butt buddies and the share/learn all their knowledge FROM EACH OTHER...so of course you're going to think the same thing.

Mandos-i don't doubt you work at an audio shop. You just aren't a tech. You answer phones and take orders and work on the computer, etc.... You probably just said to your boss, "hey, i just got a scion tc, i'm sure there will be a good market for audio equipment out there if we custom fab it for the tc. And i could hock it/talk it up on the scion forums. We could use my car as the ED Scion "test car"....You've obviously been picking stuff up as you go along, but i'm really not impressed with what i've seen.

and i can tell you really don't know what you're talking about because even if you seem to have the concept down, you can't explain yourself in negotiable terms in the least anyway.

i admit, i messed up my enclosure spec calculations, i was at work using a pad and paper as i was about to walk out the door. The bottom line was, i was just using my box (exterior) dimensions as an EXAMPLE OF WHAT SIZE TO MAKE THE BOX SO IT FITS UNDER THE HATCH COVER. it was a rough estimate of volume, didn't have to be perfect to show the point.

Being the guru of Scion Life audio forums is like winning gold at the special olympics...or the blind leading the blind.

so much bad info on here....i give up. have a blast noobs.