Heya guys, quick question for those with more experience with this than I have. It's been a long time since I've dealt with speakers/amps, and even then, it wasn't to extravagant. I recently got a hold of two JVC 12" subs real cheap. My question(s) would be, any ideas on what kind of amp I should use to power them? And would you suggest upgrading my stock alternator to a higher output?

Speaker specs:
12" subwoofer
1200W Max Power Handling
350W RMS Power Handling
Dual-Input 4 ohms Voice Coil
Olefin Diaphragm + Aramid Reinforced Pulp Cone
Stamped Steel Frame
Butyl Rubber Edge
Rubber Gasket
53.7oz Strontium Magnet
Nickel-Plated Screw Terminals
Frequency Range: 25–2,000Hz
Sensitivity: 87dB/W.m

I am thinking of this amp:
Sound Ordnance™ M-2100 2-channel car amplifier — 75 watts RMS x 2 at Crutchfield.com

I know that it only puts out 75 watts RMS x 2 at 4 ohms, and I do not plan on it being bridged. I don't really need it to be too loud bass wise(but couldn't pass up the $30 deal on the subs), and I'm looking to not spend too much money on the amp(will probably upgrade in the future), as I still have to replace my factory head unit as well. Or will possibly use a 2-channel line output converter( Scosche LOC80 2-channel line output converter at Crutchfield.com)
Till I can replace my head unit.

Any ideas would behelpful.

*edit* Did some more searching, and with my limited knowledge, not sure, but maybe this amp would be a better choice? Since it already has the speaker input option, so I don't have to use a seperate converter.
http://www.sonicelectronix.com/item_...id-PB717X.html

 

There's no need to worry about upgrading the alternator for lower power levels. A "BIG 3" upgrade is good for every vehicle and all you need for your purpose. You really don't want to mess with those ultra cheap amps either. There's budget brands out there that will be better money spent, that's for sure. Now, those subs really aren't too shabby and will do decent on lower power with the right enclosure, however an amp that can deliver a much better amount of power can be had for only a few dollars more than the ones you've been looking at. Believe me when I say that in this hobby you're MUCH better off saving your money and spending it on what will suit you best as opposed to buying what you can afford right now and having to buy stuff more than once. It will save you money in the long run.

This amp can get you 150wrms into each sub with the subs wired to 2 ohms (parallel)
WoofersEtc.com - TXA-1502 - Cadence 2 Channel High Power 300 Watt Amplifier

This one could get you 250 into each sub. Not too shabby an amp for it's price either.
WoofersEtc.com - XA250.2 - Cadence 2-Channel 1000W Max Class AB Stereo Amplifier

These are just a couple of examples.

 

Thanks for the info....already got the stuff to do the Big 3, and based on all the threads I found looking through here, I kinda figured stock alt should be ok(couldn't hurt to ask though)as I don't plan on pushing too much power to these.

And after doing some more searching, I have already decided to hold off till tax time for the rest of the system. That way I can upgrade my head unit as well, and get a decent box or custom build one to fit in the cargo space better without taking over the whole space. I had seen someone else that did a pretty nice box like what I want, and I'm pretty sure with more searching, I can find the design online.

Thanks for the links to the amps too, I agree, not a bad price for either of them.

 

Im running an Alpine MRP-M350 at 350 watts without the big three and havn't noticed any voltage drop on the dash (I know that its not that accurate please done flame me for that statement). Haven't had any dimming of lights at night with all lights on and system cranked. I would say your pretty safe with the low wattage you're running.

 

Looks like no more waiting till tax time.

Thanks for the help again guys, got another question for ya.

Did some more looking around, and it looks like this is how I will end up having my amp/subs wired up.



Question is, I see the amp is putting out 2 ohms per channel, what should I be looking for amp wise? I.E. If I am looking at an amp that says:

50 watts RMS x 2 at 4 ohms (75 watts RMS x 2 at 2 ohms)

That means it would be running at 50 watts?(2ohmsX2) Or is it 75?

I just want to make sure I don't fry anything. I know my subs are DVC with 4ohmX2. Diagram in manual shows the sub #s like the subs in the picture with 4ohm at each connection.

Or would I be better off getting a mono amp and running it like this?

 

In this first diagram, the amp you had listed above would run at 100 watts at 2ohm. If you wired it like in the second diagram it would run at 75 watts. There are ways of wiring a mono amp at 2ohm, the most important thing to look for in an amp if your wanting to run at 2ohm is making sure that the amp is 2ohm stable, if it's not and you run it at 2ohm you will likely blow your amp.

To answer your other question the Subwoofers in the diagram are set to 4ohm, this is something that does not change with wiring. Wiring the subs up like pictured tricks the amplifier into thinking its being run on subs that have an ohm rating of 2 thus increasing the wattage that is being pushed out. Running 2ohm on the amp on 4ohm subs will not hurt anything as long as the wattage being pushed out by the amplifier isn't vastly greater than the RMS rating on the subwoofer. The combined RMS of the two subs you have is 700 watts so a good rule of thumb would be to run an amp that is lower than that. As long as you dont blast your gain and bass boost on the amp your subs should be fine.

I would recommend getting this amp
http://www.crutchfield.com/p_777M135....html?tp=35834
Twenty more bucks for 150 more watts seems like a pretty good good deal to me.

 

Thanks for the info....Not really concerned on 2ohms or 4ohms. If I get a mono and it runs at 4ohms I'd be happy. Just wanted to make sure I understood everything, as that will help me make my decision on amp choice. You answered my question. I know how it's calculated now.

 

Not a problem man, you can still run a monoblock amp at 2ohm and most amps will be able to do it without a problem, just make sure before you hook it all up. If the amp is 2ohm stable then take advantage of that and get all the extra power you can lol.