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2 Amps, 3 Subs?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=66157
Printed Date: May 05, 2024 at 8:18 PM


Topic: 2 Amps, 3 Subs?

Posted By: Need 2 b lower
Subject: 2 Amps, 3 Subs?
Date Posted: November 13, 2005 at 1:23 AM

I was just wondering if it was possible to set up two memphis power reference amps 1000/1 to run 3 jl 12w6v2's?

I was going to do 3 seperate amps but do not have the money, and i cant even think of where to start on the wiring of 3 subs off of two amps. Any help is appreciated. Thanks!




Replies:

Posted By: stevdart
Date Posted: November 13, 2005 at 4:47 PM

Start with what you know about what power the subs want and what power the amplifiers will supply.

Your ultimate goal is to put an amp on each sub, so knowing that the subs are DVC 4 ohm, you know that the choices of wiring are going to be either 2 ohm or 8 ohm.  So you know that when you get that third amplifier you will be powering each sub at 2 ohms with 600 watts each.   That's a little above what you should be giving each sub but it's possible with a careful setup.

So for now you want to see if you can put two subs onto one amp, the third sub onto the second amp, and get an equal amount of output to each sub.  You can do this by running one amp at a 1 ohm load... https://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=42

The two subs will get 500 watts each.  Run the second amp at a 2 ohm load...

https://www.the12volt.com/caraudio/woofer_configurations.asp?Q=1&I=42 ...and that sub will get 600 watts.

Be particularly careful with the amp that is powering two subs as it will be max'd out at 1 ohm.  When you do get that third amp, put each sub onto an amp at 2 ohms each and the amplifiers will perform with better specs (than at 1 ohm).  This temporary measure will at least get you very close to the same power to each sub.  It would be best to have the enclosures in the sealed category (as suggested in the manual at 1.25 cu ft) with the overpowering these subs will get.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: haemphyst
Date Posted: November 14, 2005 at 1:12 PM
Need 2 b lower wrote:

I was just wondering if it was possible to set up two memphis power reference amps 1000/1 to run 3 jl 12w6v2's?

I was going to do 3 seperate amps but do not have the money, and i cant even think of where to start on the wiring of 3 subs off of two amps. Any help is appreciated. Thanks!



Seeing as I am not terribly familiar with those subs, I will assume that they are dual 4 ohm voice coils. I am also assuming the amp is 1 ohm stable, based on the reply of stevdart, below.

stevdart wrote:

Start with what you know about what power the subs want and what power the amplifiers will supply.


Your ultimate goal is to put an amp on each sub, so knowing that the subs are DVC 4 ohm, you know that the choices of wiring are going to be either 2 ohm or 8 ohm. So you know that when you get that third amplifier you will be powering each sub at 2 ohms with 600 watts each.   That's a little above what you should be giving each sub but it's possible with a careful setup.

So for now you want to see if you can put two subs onto one amp, the third sub onto the second amp, and get an equal amount of output to each sub. You can do this by running one amp at a 1 ohm load... https://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=42

The two subs will get 500 watts each. Run the second amp at a 2 ohm load...

https://www.the12volt.com/caraudio/woofer_configurations.asp?Q=1&I=42 ...and that sub will get 600 watts.

Be particularly careful with the amp that is powering two subs as it will be max'd out at 1 ohm. When you do get that third amp, put each sub onto an amp at 2 ohms each and the amplifiers will perform with better specs (than at 1 ohm). This temporary measure will at least get you very close to the same power to each sub. It would be best to have the enclosures in the sealed category (as suggested in the manual at 1.25 cu ft) with the overpowering these subs will get.



If you are absolutely set on having three woofers, and with the gear you have specified, yes, you can reasonably safely run two amps to three woofers, if in a slightly "overpowered" situation. The amps, rated 1000w into 1 ohm, should produce approximately 700-750w into this load, two amps will provide approximately 1400-1500w, divided by three woofers, will nail your 475-500w per woofer power capacity. Amp matching will not be a problem, just raise the gain on each amp a little bit at a time (first one, then the other) until you have reached the output capabilities of the amps, or the input capabilities of the woofers. It's the same rules as setting the gain on one amplifier.

To wire this, forget the woofers are DVC. LOOK ONLY AT ONE COIL PER DRIVER. Wire these three voice coils (one from each woofer) in parallel to one amp, for a net load of 1.33 ohms. Now do the same with the remaining three voice coils - wire them in parallel to the other amp. This will (to a small extent) raise your damping factor, increase your efficiency, lower the power output available from each amp by a small amount... None of these are necessarily bad things, either. I stll recommend the sealed enclosure route, though.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: ssnds
Date Posted: November 14, 2005 at 4:37 PM
i myself would go along the lines that haemphyst put forth.

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SSounds




Posted By: oxygen65
Date Posted: November 15, 2005 at 1:36 AM

just go with another sub, trust me it is going to make your life a lot easier, then you just run 2 subs to 1 amp

its gonna be louder anyways






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