Kind of a 'rms vs peak' debate

[TheUnderFighter 10+ year member]

interesting. I'm glad people were able to help you without flaming you, not a common occurrence around here //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Also, read this site, and you will have answers to a ton more of current and future questions: Basic Car Audio Electronics

 

[ladysmanfelpz 10+ year member]

Well im trying to show im a little knowledgeable in the subject. I am just getting into car audio but not a total noob. And ya i see the flaming is pretty common as I had a question involving a capacitor and everyone had to come to the show and express their opinion.

 

[maylar 10+ year member]

I thought if you cut the ohm load in half, power doubles so it should be 100w x 2 at 2ohm, but is it something in the engineering in the amp that limits it?

One thing not yet mentioned is that an amplifier has an internal power supply that has a maximum rating. You can have a 50 x 2 @ 4 ohm amp for instance with a power supply that's limited to 150 watts. So instead of 100 x 2 with a 2 ohm load, it's limited to 75 x 2 by the power supply.

 

[LBC]

One thing not yet mentioned is that an amplifier has an internal power supply that has a maximum rating. You can have a 50 x 2 @ 4 ohm amp for instance with a power supply that's limited to 150 watts. So instead of 100 x 2 with a 2 ohm load, it's limited to 75 x 2 by the power supply.

I mentioned it good sir.

 

[TheUnderFighter 10+ year member]

Well im trying to show im a little knowledgeable in the subject. I am just getting into car audio but not a total noob. And ya i see the flaming is pretty common as I had a question involving a capacitor and everyone had to come to the show and express their opinion.

Well that's because capacitors are useless //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

And the site I linked actually gets pretty in-depth on all the bases, so I'd HIGHLY recommend reading. It's not really "basic". It's just a very useful read that does a phenomenal job at explaining everything.

 

[trumpet 5,000+ posts]

My 2 cents:

On music with a good dynamic range, and not loud all the time, your peaks of power from the amplifier are more likely to "peak" at the RMS rating than to go beyond that much power. As you were told earlier in the thread, most of the time your music is not playing anywhere close to the potential of your amplifier. A 10 dB transient requires 10x the power to reproduce the music without clipping. When the waveform begins to clip the amplifier can't make any more watts. There's more power on average over time, but a clean 100W peak is still going to be 100W as the waveform gets clipped.

The really interesting part is that we can listen to these clipped transients and not even notice the added distortion until it gets quite high. If we tuned our amplifiers to never clip on even our loudest recordings(Metallica's Death Magnetic album, for example, is ridiculously loud and not in a good way) the music would sound too quiet.

For me these concepts really made sense after I watched this video:

 

[maylar 10+ year member]

Just as a point of reference, human speech has about a 10:1 peak to average ratio. Music is about 5:1. That's what "music power" ratings are all about - the duty cycle.

 

[clickclickw00t 10+ year member]

I just watched this whole video. I think it should be a mandatory watch to join ANY of these forums, and it should definitely be stickyed. I LEARNED SO MUCHHHH

My 2 cents:
On music with a good dynamic range, and not loud all the time, your peaks of power from the amplifier are more likely to "peak" at the RMS rating than to go beyond that much power. As you were told earlier in the thread, most of the time your music is not playing anywhere close to the potential of your amplifier. A 10 dB transient requires 10x the power to reproduce the music without clipping. When the waveform begins to clip the amplifier can't make any more watts. There's more power on average over time, but a clean 100W peak is still going to be 100W as the waveform gets clipped.

The really interesting part is that we can listen to these clipped transients and not even notice the added distortion until it gets quite high. If we tuned our amplifiers to never clip on even our loudest recordings(Metallica's Death Magnetic album, for example, is ridiculously loud and not in a good way) the music would sound too quiet.

For me these concepts really made sense after I watched this video: