Amps and speakers!?!?!?

[DanielKelling]

Okay i'm looking to buy a new amp and set of speakers. I'm a little confused on matching up the amp power with the speaker requirements. For example if I have two 10" woofer witha power rating of 200 watts/rms do i need an amp with 400 watts?? Somebody please help me!!!!

 

[danny]

If the 10s are rated to take 200 rms each, you can run up to a 200 watt rms channel to each. I have saw (and ran) more power to a speaker than it is rated at with no problems, though. The most important thing is to make sure the amp isn't clipping (overdriven to the point that the sound waves are actually becoming squared off). That will destroy a speaker faster than anything!


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Danny
91EB
www.hit.net/~danny/explorer.html

 

[DanielKelling]

So i need an amp with the specs
200watts x 2???

 

[X-Man]

Not really, It depends on the amp, some amps under rate their power, for example MTX 2300 is 200X2 but when you bridge that amp it puts out 600+ watts, and the MTX 2150 is 75X2 and bridged at 300w, which is more than enough for 2 10" at 200W each. So the best way to do this is look at the bridged power, your 2 10's are 400W total, so you want to look for a amp that the bridged power is anywhere from 300 - 500 watts. Now this applies only to woofers, because they are usually played in mono not stereo, other speaker you would look at the X2 or X4 watts rating. Hope I didn't confuse you too much.

T-Man Dead Link Removed

 

[danny]

Just remember, if you are going to run a single two channel amp bridged to the 2 tens, make sure it is 1 ohm stable. Otherwise you'll end up having some trouble with it. I went through 6 tens due to an amp acting up occasionally in a previous car. And it was a Rockford amp with MTX subs. Aren't warranties wonderful Dead Link Removed. You can really run anything from 200 and down per channel for the subs. Anything from 75 to 200 ought to sound pretty good, just don't go to low in wattage. If you go to low you may be overly tempted to crank up the gains and start clipping. The number 1 destroyer of speakers Dead Link Removed.

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Danny
91EB
www.hit.net/~danny/explorer.html

 

[X-Man]

The only way you would have to worry about a amp being 1ohm stable, is if you have two 2ohm subs and when you wire them together it makes a 1ohm load. You want your amp to run at 4ohm which is normal for most amp and in which they are built to handle so they shouldn't heat up. your subs should be 8ohms to run a 4ohm load or 4ohms to run a 2ohm load (you may need a fan for 2ohm depending on the amp). If you buy the sub and amp at the same time the sales person should be able to help you with this matter.

X-Man Dead Link Removed

 

[danny]

Actually, if you bridge a 2 channel amp the load it sees for a 4ohm speaker is 2ohms. Therefore, if you bridge it and run 2 4ohm speakers in parallel, it will see 1ohm. Simple math.

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Danny
91EB
www.hit.net/~danny/explorer.html

 

[X-Man]

We are probably confusing Daniel even more, the best thing to do is get two 8ohm subs if they are 200W ea get a amp that the bridged power rating is at least 300W and you should be fine, more power would be better, but 300W would be good enough.

X-Man Dead Link Removed

 

[98XplorerSprt]

I thought I was getting a handle on this sub and amp stuff, now I read all of what you guys said and I don't know a thing

 

[Dignan]

dont forget that the subs are rated in rms (continuous) wattage. most amps are rated in peak wattage. ask the salesman about rms and peak wattage ratings when you buy the amp.

 

[BigDave]

This is an old thread but on topic for my ??'s

I am installing a sub to replace the JBL unit that came stock and has finally blown after 8 years of use. I have a 12" MTX 4000 series sub. It is rated at 200W RMS and 400W Peak. It is also a 4 Ohm speaker.

I am trying to get an amp that is as close to 200W RMS as possible at 4 ohms.


Here are my questions about amps and hooking it up etc..

If I get an amp that is rated at 250W RMS will this blow the speaker?

If I get an amp rated at less than 200W RMS will it cause damage to the speaker because of under powering?

If I bridge an amp that has two channels at 4 Ohms will that still be 4 Ohms? Will this hurt my speaker?

I know these are basic questions and I have read through the rest of this thread, but I was never good at Physics (at least when it came to electronics). I am trying to get something that is not too powerful, but not underpowered at the same time. This is also my first time working with subs and amps so I am still kinda scared that I am gonna screw up and ruin my sub.

Thanks for your help...

Dave

 

[Cartman]

1. An amp rated at 250 will not blow the speaker, just adjust the gain when you're setting it up and unless you're running at full volume then the sub isn't receving full power so you're fine at 250 rms.

2. If the sub wants 200 RMS and you give it 150 or more you're fine, just don't go really low like 100 watts

3. It a bridged 4 ohm load which is really like 2 ohms, you can run one sub this way and it is great, if you add a second 4 ohm amp is parellal then the amp must be 1 ohm stable.
With a bridged amp you're wiring it in parellal and combining the power of 2 channels into one, with a good 2 channel amp if it 70 watts x2 channels then if you bridge it becomes 280 watts (specs are for the MTX 4202)

If you like MTX then I'd look at the 4202 or the 4122, both are 2 channel amps and should work fine.


The rating you see printed are almost always RMS on amps, the numbers that are written on the cases are max wattage.

 

[JTang]

DK-

You're looking at two amps: Either a 2 channel amp that puts out 200 watts per channel at 4 ohms, or a 4 channel amp that puts out 50 watts per channel, and is stable to 2 ohms per channel RMS. Hover around these ratings, though you could certainly go lower if your pocketbook required.

For a beginner, I'd recommend the 4 channel at 50 watts per channel, then are bridged. That way, if you ever decide to move on to a more powerful sub/amp combo, you can use the 4 channel for your midrange speakers. It's usually the wisest way to go if you're thinking of expanding later on.

Big Dave -

1. No, as long as you respect the speaker's limitations and don't overplay it.

2. No, this is in extreme cases, and the underpowering has to be *much* less, and in this case, opposite of case number one. It's not so much because of the power as it is that people with smaller amps tend to overwork their amp, which causes distortion to cheaper subs that can lose control easily. Poor control can accidentally ground out the coils and kill the sub.

3. An amp that's 4 ohms per channel, with the intention of it being bridged must be stable at 2 ohms per channel as well. Once they're bridged, it can safely handle a single 4 ohm load. The sub won't be hurt as long as it's a 4 ohm sub - if it all matches up, it should be fine.

 

[BigDave]

Thank you both for answering my questions. I appreciate it greatly and it sets me more at ease for when I am looking at amps. I want to have a good idea of what I need when I go to the store so I am do not get the shaft by someone wanting to make a sale.

Thanks again, the information is exactly what I was looking for.


Dave