What amp do i need?

[I<3mYtoY4liFe]

I bought a rockford fosgate T112D4 12" sub and now that i have this i need a amp to power it.i have heard different suggestions on what amp to get but i still have some questions.people have told me to get a amp that has just a little bit more watts rms then the max watts rms the sub has just so that i have it and people have told me to get a amp that has less watts rms so that i dont blow the sub.can someone point me in the right direction on this and possible give some suggestions on what amp to get for this sub?thanks for the suggestions

[fastceli00]

http://www.crutchfield.com/App/Product/Item/Main.aspx?g=120&i=489AP1000&tp=115

You can get this from millionbuy.com for a lot cheaper than Crutchfield and the reviews for this amp are excellent; I just picked one up myself for $89.99. You can bridge the amp and run 480W x 1 at 4 ohms impedence; that will beat the heck out of your rockford sub. I am putting mine on a 10" my buddy sold me for cheap and I am sure it will be pushing it to its limits. From what I have read and heard, these are a very good amp for the price and are relatively compact as well for a 1000W 2 channel amp.

[bunkkaws84]

definitely go with an amp that puts out a little LESS that the max rms of your sub so you don't risk blowing it. If you can get it close, say 25 watts less than the max rms of the sub, you won't notice the difference.

Also as I am sure you already know, you are paying for RMS, not the max watt output. The amp that fastceli00 recommended is a good deal for the price, with 480 rms, thats a good output.

Off brands like pyramind put out like 75watts rms from a 1000 watt amp, thats crap. Really good brands can put down 400 watts+ rms from a 1000 watt amp.

[I<3mYtoY4liFe]

definitely go with an amp that puts out a little LESS that the max rms of your sub so you don't risk blowing it. If you can get it close, say 25 watts less than the max rms of the sub, you won't notice the difference.

Also as I am sure you already know, you are paying for RMS, not the max watt output. The amp that fastceli00 recommended is a good deal for the price, with 480 rms, thats a good output.

Off brands like pyramind put out like 75watts rms from a 1000 watt amp, thats crap. Really good brands can put down 400 watts+ rms from a 1000 watt amp.

thanx for the input it really cleard things up that i needed to know.

[wtcnbrwndo4u]

I've heard people saying that going under the RMS rating of the sub causes more damage to it than overpowering it.

I don't know... personally, I've run under RMS before without a problem. Just don't put the sub to it's rated max limit.

Kicker, Alpine, Rockford Fosgate, and MTX are good common found brands.

[poppasmerph]

I've heard people saying that going under the RMS rating of the sub causes more damage to it than overpowering it.

Actually, this isn't true at all... if it was the case, then every time you turn down the volume, you'd be damaging the sub. I've heard of this myth also, and it's been proven false.

I'd recommend getting an amp that can put out more power than your sub can handle, then tune it down to your RF. That way, you will be getting good clean power to your sub vs. forcing an under powered amp to put out the desired power you want.

PS: if you want to get safe RMS from any amp follow this guide:
Materials needed:
- Multi-meter
- amp
- math skills

Now follow these steps

1. Multiply the maximums watts you want going to your subs by the ohms of the subs (either RMS for the subs or RMS for the amp, which ever is lowest). The square root of that result is the voltage you want going to your speakers (or in this case, sub). So, the formula is: SQRT (watts x ohms).

2. With power off, disconnect your sub from the amp (at the point where it goes from your amp to the sub, not at the head side). Hook up a multimeter to your amp where you would normally connect the speaker cables for one of the subs. Set the multimeter to measure AC voltage.

3. Lower the gain on your amp to the minimum. Set your volume to 75% of its max (safe way - this is your new max volume level)

4. Put in a 60hz test tone and crank it up to the volume you got from step 2. You shouldn't be hearing anything right now because your subs are disconnected, but you should be seeing the voltage reading on the multimeter. (to get a 1khz test tone, go here: http://www.realmofexcursion.com/downloads.htm and download from the test tones in the middle of the page)

5. While watching the multimeter readings, start turning up the gain until you reach the voltage you got from step 1.

6. Lower your stereo volume, turn off the car, disconnect the multimeter and reconnect your subs.

7. Don't ever go over the max volume from step 3. That's your max volume.

In your case:

sqrt(600watts X 8ohms)=69.28volts (aim for 69.28 volts from your volt meter if you wire your sub at 8ohms)

sqrt(600watts X 2ohms)=34.61volts (if you wire your sub at 2ohms)

Oh and on another note: aim for a box with 1.25cu.ft. as that is recommended by RF.

If you want to do the same for your speakers, follow the same procedure, but with a 1khz test tone.

Eh... sorry for the long post :crazy2:

[wtcnbrwndo4u]

Assuming you'll get a mono-block amp, this is how you're gonna wire it.
http://www.crutchfield.com/learningcenter/car/subwoofers_wiring.html?imageID=1DVC%5F4%2Dohm%5Fmo no

You'll want to get the sub running at 2 ohms... you'll put out more power that way. Whatever you get, make sure you get an amp that'll run stable at 2 ohms. Preferably, stick with Class D amplifier for the best quality and efficiency.

:thumbup:

[lopaka]

^^^^^ what this guys said you wanna get a amp that runs @ least 800rms for that sub
so you wont fry your voice coils


so wire it to a 2 ohm load and buy a class d if possible amp thats stable at 2 ohms

[Insomniac]

If I were you, like they said, get an amp that's just under the power your sub can handle. You have a way lower chance of blowing it. I run dual 12" Pioneer Subs (which are 800W) with dual Pioneer 760W amps. It'll still thump pretty hard. :D

[I<3mYtoY4liFe]

wow guys thanks for all of the miuch needed input,this is going to help me out alot,thanks again

[I<3mYtoY4liFe]

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18338

this amp would be ideal for the sub that i have bought please correct me if im wrong.

[wtcnbrwndo4u]

Good choice. That'll work dandy. This will run 300W to each voice coil for a total of 600W, which matches the RMS.

You don't necessarily need to be under or over. Being smack at RMS is fine too.

[I<3mYtoY4liFe]

Good choice. That'll work dandy. This will run 300W to each voice coil for a total of 600W, which matches the RMS.

You don't necessarily need to be under or over. Being smack at RMS is fine too.

also when looking into a box some places have told me that i need a really big bow cus they say that the sub that i have needs alot of air for it to sound perfect,is this true cus i dont want to lose my trunk space that much.also i was thinking when i got the sub it came with the demensions on what size the box should be should i go in that direction or just buy some box for the time being?

[wtcnbrwndo4u]

It calls for a 1.25 cu. ft. closed enclosure. That means without any vents or ports.

It's not too trunk killing.