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How To Wire Mono Amp To 2 Subs???

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Old 05-12-2009, 04:58 PM
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Default How To Wire Mono Amp To 2 Subs???

I'm upgrading my single 12" Alpine Type E (model 1242) to twin 12" Type Es and still planning on using my single Alpine MRP-M450 (400 watt amp)

My question is how should I wire up the subs to get the most power, and do you think my amp will be too small for 2 12" subs?
Old 05-12-2009, 05:04 PM
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BTW diagrams would be helpful

Ok I found this, but do you think my amp will be big enough for 2 12s???


Last edited by Turnin20s; 05-12-2009 at 05:09 PM.
Old 05-12-2009, 05:12 PM
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The Alpine MRP-M450 produces 400 W-rms @ 2 Ohms.

The Alpine 1242 are single 4 Ohm voice coil subs.

---

Wiring the subs in PARALLEL will produce a 2 Ohm load for the amp to see, giving you the most power.

Your amp will be fine for this setup - though be sure to set to gains properly to avoid clipping. Whether or not the results are enough for you and if the amp is too small, you'll have to decide later... but with the increase in power you'll be able to use and the fact that you'll be using two subs rather than one, it should make you happy.
Old 05-12-2009, 05:14 PM
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I believe the subs are 4 Ohm SVC based on links I'm seeing.... correct me if I'm wrong. -- So your diagram would be incorrect.
Old 05-12-2009, 05:20 PM
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This would be the diagram you want, if the subs are SVC 4 Ohm:

Old 05-12-2009, 05:42 PM
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^^^ Thanks man, I just noticed that and came back to post the pic that you just added LOL

But I'm looking at a few different amps, 1 to match what I have right now so I would have 1 amp per sub and I found an alpine 800 watt for a good price, but I think I'll wait and see how it sounds before I buy more amps.

But now I have a box again for my tahoe, so I guess another sub and amp would be cool

Thanks for the reply
Old 05-12-2009, 06:38 PM
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I wouldn't add another amp IMO. Just use 1 amp thats sufficient for both subs.
Old 05-13-2009, 12:30 AM
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Originally Posted by ImpSS07
I wouldn't add another amp IMO. Just use 1 amp thats sufficient for both subs.
Really? I thought that they would be a little underpowered, but I'm sure they will still sound good.

Well I'll be sure to post some pics after the install is all done in a week or two.

Thanks again guys

BTW what size are my door speakers and the rear speakers? I'd like to get new ones, but my stockers still are crisp, but could use an update
Old 05-13-2009, 07:46 AM
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Your Type-E Alpine SWE-1242 subs are 50-250watts RMS. If you wired them in parallel at a 2ohm load, they'd be seeing about 200watts RMS which is fine for those subs. The Type-E subs is Alpine's entry level sub so I wouldn't push them much over that.
Old 05-13-2009, 07:48 AM
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I would have gone to one decent sub over 2 of those any day...
Old 05-13-2009, 08:53 AM
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Originally Posted by dragonrage
I would have gone to one decent sub over 2 of those any day...
Well good for you now I personally really like them. I have had my one Type E for 2 years now and haven't had any complaints. And everyone that rides with me always compliments on the sound quality of the sub. I'm not saying they are the greatist thing ever or that I have never heard anything that sounded better, but for the price I really like them.

From crutchfield....
power range: 50-250 watts RMS
peak power: 750 watts

I have been powering my single 12 with the 400 watt amp for 2 years without any problems, thats the reason for considering another amp.

But mabye someday when I have more disposible income I'll get a better setup, but right now I can't complain for the money I have into it

Last edited by Turnin20s; 05-13-2009 at 08:59 AM.
Old 05-15-2009, 12:10 AM
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Originally Posted by Turnin20s
Really? I thought that they would be a little underpowered, but I'm sure they will still sound good.
It will be fine, as mentioned. Ian explained it, but maybe it wasn't clear:

Currently you have a SVC 4 ohm sub...at 4 ohms, your amp puts out 220 W rms (per spec). By adding another 4 ohm sub and wiring in parallel, you will have a 2 ohm impedance which your amp produces 400 W rms at (so each sub will receive approximately the same power that your one sub now receives).

So yes, of course your sub can handle the setup currently because it is only using around half of the power the amp is capable of producing. Adding another 4 ohm sub is the most efficient thing you can do with your current setup.

Last edited by fredmr39; 05-15-2009 at 12:16 AM.
Old 05-15-2009, 01:35 AM
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Originally Posted by fredmr39
It will be fine, as mentioned. Ian explained it, but maybe it wasn't clear:

Currently you have a SVC 4 ohm sub...at 4 ohms, your amp puts out 220 W rms (per spec). By adding another 4 ohm sub and wiring in parallel, you will have a 2 ohm impedance which your amp produces 400 W rms at (so each sub will receive approximately the same power that your one sub now receives).

So yes, of course your sub can handle the setup currently because it is only using around half of the power the amp is capable of producing. Adding another 4 ohm sub is the most efficient thing you can do with your current setup.
LOL I'm slowly picking it up. I have been doing some reasearch and its making alot more sense now. A few years ago I couldn't understand it for some reason, but mabye now I have more patience to figure it out.

I'm also currently working on a system for my dad's truck and have been looking up info for him too and its alot different than what I'm used to, but cool stuff for sure

Thanks guys
Old 05-19-2009, 05:35 PM
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Go with a pair of type rs 10s or 12s and about 900 rms
Old 05-20-2009, 08:04 PM
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Originally Posted by gt35built
Go with a pair of type rs 10s or 12s and about 900 rms
Why, because that's what you have? Just isn't an appropriate response when he is asking about adding a sub to his additional setup... but anyway, OP: let us know if you get the results you're looking for
Old 05-21-2009, 02:50 PM
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Originally Posted by fredmr39
Why, because that's what you have? Just isn't an appropriate response when he is asking about adding a sub to his additional setup... but anyway, OP: let us know if you get the results you're looking for
I receved my other sub and I'm currently building my box, but it may just be a prototype to see how everything works.

But could someone help me out with how many cubic feet mo box would be?

Measurements are as follows.....

45" wide x 14" deep at the bottom

Front side is 6.5" tall and the rear is 10.5"

The top is 45" x 16"

The 45" will have to be devided since there is a barrier in the middle to keep both sides seperate.

Heres a pic for reference
Attached Thumbnails How To Wire Mono Amp To 2 Subs???-00000000.jpg  
Old 05-21-2009, 05:25 PM
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Are those outer measurements? Remember that the MDF has a thickness, which needs to be subtracted for your total volume.

For volume just break your box apart into cubes, prisms, whatever....then convert to ft^3. For in^3 --> ft^3 conversions, just type in Google: "434 cubic inches in cubic feet"...
Old 05-21-2009, 07:49 PM
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I think it came out to about .82 cubic feet which is right at the bottom of the list for the Type Es. They suggest .8-1.7 so there is a big range compared to others I have seen. I think I'll stick with the setup I have now and not add a drop down on the box and add some polyfill to the box and just see how it sounds before I mess with anything else.

Thanks for the help though guys, I really appreciate it and I'm actually learning something LOL
Old 05-21-2009, 08:38 PM
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Originally Posted by fredmr39
Why, because that's what you have? Just isn't an appropriate response when he is asking about adding a sub to his additional setup... but anyway, OP: let us know if you get the results you're looking for
Yes i am running two 12 type r's off a kicker kx1200.1
I am recommending him a better line of subs of a company he is already pleased with. he also mentioned a possibility of a 800 watt amp. So anywhere from 800-1000 true rms will be sufficient in a fbody. Definetly giving him the results hes looking for.

So im not sure why ur so butthurt about my comment but that would give him plenty of room to expand with a better sounding system. JUST MY OPINION
Old 05-24-2009, 11:58 PM
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Originally Posted by gt35built
Yes i am running two 12 type r's off a kicker kx1200.1
I am recommending him a better line of subs of a company he is already pleased with. he also mentioned a possibility of a 800 watt amp. So anywhere from 800-1000 true rms will be sufficient in a fbody. Definetly giving him the results hes looking for.

So im not sure why ur so butthurt about my comment but that would give him plenty of room to expand with a better sounding system. JUST MY OPINION
I already have the 2 type Es and thats what I'll be sticking with for now. Eventually they will be in my tahoe and I'll get some eclipse aluminums for the Camaro, or I'll leave the Es in the Camaro and get a Kicker L7, but I don't have money for that **** LOL


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