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Discussion Starter #1
I just bought 2 Memphis Studio 12's and made a box using MDF. I got it all hooked up, and was listening too it. It sounds ok at low levels but when i turn it up, it loses the deep bass and is pretty much just sound. I know if have to get my spoiler to stop buzzing but thats not my problem. If i ported the box, would that give me better results? btw i'm powering the 2 12's with a Memphis PR 4400 amp. The box size is 29x24x12. There are the 2 memphis's and a JL 10. The box is completely open on the inside.

Also, the amp is a 4 channel, so i have to bridge them. The subs are DVC, so how do i wire them in paralel for more power?
 

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...FWD... said:
There should be an airproof divider in betweed each 12"
Not entirely true, but running 2 12's and 10 in 1 open air box isnt going to help the sound quality any... dividing the box into 3 indivual boxes inside that *would* help sound quality, but I would either ditch the 10 or ditch the 12's personally if the JL was any decent model of JL i'd keep it and ditch the memphis... thats just my preference though...

to wire the speakers in parallel... first off what ohm rating are each voice coil? You dont want to overload the amp... bad bad things happen.

2nd, you would take and run a hot/ground to 1 coil on each speaker (DVC's should have 1 set atleast with double male connectors on each one, then take a short piece of wire (8 inches should be plenty) and run that from the 2nd male connector to the same polarity connector on the 2nd coil of the same speaker...

also on top of all that... (just figured up your box... )
4.83 cubic feet....repeating... thats a *HUGE* box it sounds like.. where did you find those #'s you used for the box? What are the air space specs for those speakers? (I know 10's will easily run in a .75 cubic ft space sealed... and 12's dont require much more than that...)
 

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Sorry I misunderstood what he said. I read quickly and thought he had 2 different boxes, a box for 2 12's and a box for his 1 10.
 

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It would be a good idea to at least separate the 10 from the 12s inside the box, if you're gonna keep them all in the same enclosure. IMO only identical drivers with the same phasing and input signal can share airspace. I don't see a problem with sharing airspace for the two 12s, but the 10 needs to have its own chamber.

Next, like Karl said, look up the recommended airspace for your subs. There should have been a spec sheet that came with each sub, with the Thiele-Small parameters, recommended enclosures, and frequency response curves. Refer to that sheet to figure out what airspace volume you need, and design a box accordingly.

Now.. for your amp/wiring question.. what kind of amp is this? What is the nominal impedance (ohms) for each voice coil on your subs? What are the RMS/peak input figures for these subs? What is the minimum ohms/channel that your amp can work with? That will dictate how you wire this up. You will most likely need to have a mixed mono input signal to all 4 channels of the amp (you can't work this in stereo).

The best way I see to do it is to use each of the front channels to run both coils of a 12 (run one 12's coils in parallel to the LF channel.. other 12's coils in parallel to the RF channel)... then use each of the rear channels (with the gain turned WAY down) to power the voice coils of the 10. You really can't combine the 10 and 12s onto one circuit since they will need different gain settings.

Anyway that's all I can come up with, and my dinner's ready. Post more info about the subs and your amp and maybe I can help more.
 

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Discussion Starter #6
Subs: Memphis Studio 12's... 250rms.... DVC. Sealed is 1cu.ft. Unsure of ported. 2 4ohm coils.

AMP: Power Reference 4400, 150x2 RMS @ 4 ohms. [email protected]

I'm wondering the best way to wire, and should i port it, or keep it closed.
 

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Are the subs wired in phase together? That will kill your high volume. Also, you may need a x-over to get it to sound decent with 1 10 and 2 12's

Now, ditch the JL sub. Memphis makes good stuff, and 2 12's will own 1 ten, pretty much any day of the week. (or course some smartass will say so and so hit bla bla bla with 1 ten, that's better then 2 12's, but I'm talking generally)

Wire the subs like James said.

If you have the option, make sure that the amp is set to MONO, and not stereo. So in the unlikely event that someone actually records bass in stereo, you don't have to worry about cancelation.
 

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Discussion Starter #8
They are wired like James said. I notice if i go too high in volume, it sounds like they cancel out. It doesn't sound like there bottoming out, but like they dont drop all the way.
 

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Discussion Starter #10
Ok, got them all wired up, box is still huge and sealed. Should i port the box?! I'm going to make 3 seperate compartments, all that is ok. Also, i have 200w running into each of the 2 12's. so i'm 50 short of the RMS. But when i turn past volume 9, the sub sounds like it cancelling or bottoming out, or something. There is a loud thud past 9. Also, it seems like its all noise, i cant feel the bass on my chest like some other cars, will making 3 seperate compartments help with that?

Thanks for your help guys :)
 
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