Amp work with Speakers?

P

pbcolt

New member
Hey, I have no idea about watts and rms's and what not so here goes...

I have 4 Alpine type s's in my 4runner. The components up front say max is 80rms, and the rear coax's say 55. I am getting an infinity 7540a amplifier for free.99 from my cousin. However, I read it pushes 111 rms x4. Is there a way to "turn an amp down" so it just fits the needs of my speakers?
 
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to turn it down, just leave the gain down on the amp itself. thats the only way. i dont think u will blow it, since u have double the power, it will sound a bit better, im running 150 watts a door and the speakers can take more power if used correctly.
 
riceandpho said:
to turn it down, just leave the gain down on the amp itself. thats the only way. i dont think u will blow it, since u have double the power, it will sound a bit better, im running 150 watts a door and the speakers can take more power if used correctly.
Click to expand...

sounds good. that's what I'll try then. Lowering the gain lowers the power going to the speakers?
 
set the hp at 80hz, maybe at 100 - 125 if u crank it high, this will help prevent from bottom out and sound nasty.
 
any update on the setup? hows the double the power make the speaker sounded? i know for me 75x4 was good, but then i changed amps and use 2 300/2 so 150 a door and it sounded orgasmic.
 
RMS or Root mean squared is in basic terms the average power your speaker can handle on a consistent basis. Your speakers also have a "peak Power" rating which tells you how much the speaker can handle in short bursts.
The dynamics of a signal are expressed in the form of the crest factor. This is determined by the ratio of the peaks (crests) to the average level of the signal. This is equivalent to a 2:1 ratio between the peak and RMS voltages, which corresponds to a 4:1 ratio between peak and average ("RMS") power, since power calculations are based on voltage squared.
Okay so what does that mean with respect to your amp question? In general, the amplifier power needs to be larger than the speaker's rated power. This is because an amplifier only delivers its rated output power with sinewave signal, and delivers much less with a real signal with dynamics. As ageneral guideline, it is recommended to use an amplifier delivering 50% more power than the speaker's average ("RMS") power. For example, for a speaker with 450W average power, an amplifier with an output of 700W may be used. If a small amplifier is used, sufficient level will not be reached, nor the perception that it is attained, so the signal will tend to be clipped to compensate, thus endangering the integrity of the speaker.
Hope that answers your question....
Andy
 
El Jefe said:
RMS or Root mean squared is in basic terms the average power your speaker can handle on a consistent basis. Your speakers also have a "peak Power" rating which tells you how much the speaker can handle in short bursts.
The dynamics of a signal are expressed in the form of the crest factor. This is determined by the ratio of the peaks (crests) to the average level of the signal. This is equivalent to a 2:1 ratio between the peak and RMS voltages, which corresponds to a 4:1 ratio between peak and average ("RMS") power, since power calculations are based on voltage squared.
Okay so what does that mean with respect to your amp question? In general, the amplifier power needs to be larger than the speaker's rated power. This is because an amplifier only delivers its rated output power with sinewave signal, and delivers much less with a real signal with dynamics. As ageneral guideline, it is recommended to use an amplifier delivering 50% more power than the speaker's average ("RMS") power. For example, for a speaker with 450W average power, an amplifier with an output of 700W may be used. If a small amplifier is used, sufficient level will not be reached, nor the perception that it is attained, so the signal will tend to be clipped to compensate, thus endangering the integrity of the speaker.
Hope that answers your question....
Andy
Click to expand...

Damn, thats a great explanation!! I really appreciate it. Just one question though. If a smaller amp is used, how could that endanger the speaker? If it can handle more, then less should not be a problem? It just seems like common sense to me, but again, I don't know much about all of this stuff.
 
pbcolt said:
Damn, thats a great explanation!! I really appreciate it. Just one question though. If a smaller amp is used, how could that endanger the speaker? If it can handle more, then less should not be a problem? It just seems like common sense to me, but again, I don't know much about all of this stuff.
Click to expand...

PBCOLT- Thanks I hope it helps. In answer to your next question IF clipping occurs (you lose the top part of the sinusoidal wave form (cuts off) and the speaker, because you are driving the amp harder (here is where the perception thing comes in), doesn't know what to do with that and you get what sounds like your speaker coming apart. Operating your amp at the top of its power curve constantly can damage it. An amp operating at the middle or 3/4ths of its range runs cooler and more efficiently, thus delivering a cleaner signal to your speaker and that make for cleaner crisper sound, Make sense?

Just had an after thought. Speakers have a minimum rating as well that the will work efficiently at as well, they typically call this the nominal power rating. Your amp needs to exceed that. Anything will work for a short time.
Andy
 
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