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Why you need 500Wpc for good sound


Islander

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High-sensitivity speakers let lower-powered amps do the job more easily, so Klipsch owners usually don't need 500Wpc, but certain models, like RF-7s, seem to work best with lots of watts available, in spite of having very high sensitivity ratings.

Someone please comment on that......because that has been exactly what I've experienced with my 7's. Higher wattage amps with the gains/attenuators turned down to about 25%.

I'd argue that the majority of what you're hearing is the lower output impedance that usually results when designing a higher output amplifier.

A lower output impedance gives you less frequency variation at points where there are impedance spikes.

Lower output impedance also gives you more damping on your woofers, though that won't be nearly as audible until you move over to active bi-amping with no passive xover between the amp and drivers.

Also, a higher output amplifier will normally have a better power supply, which means less ripple induced by larger current draws...which is an issue with speakers like the RF-7 that have low impedance dips.

There's probably more at play, but those are some items that I've personally dealt with at a design level.

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Nothing like a pair of big Macs! Looks like you've got some major headroom. Are those for the Scalas, or will they be used with your big speakers?

Hmm, headroom. I guess that's why those amps need to be so tall... [:^)] [:P]

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I recall Carver claiming many years ago that a careful live recording in his lab of a pair of scissors snipping paper needed in excess of 800 watts to almost get rid of clipping, and there was still measurable clipping (attributed to transient response) at 800W, but that was the most powerful amp available in the lab. Anyone remember that?

I don't think there were any speakers involved at all - the analysis may have been done with just the signal from the amp itself, probably at or near the capability of the equipment of that time. I think the point he was trying to make had to do with the near instantaneous need for tremendous power to capture the leading edge of even a very quiet sound.

Assuming this is true, what does this imply about what is required to hear a real pair of scissors snipping paper?

Do our ears have the resolution to detect the leading edge of a very fast transient, do speakers?

Is the clipping 800W amp really indicating something we can't hear, or something speakers can't reproduce?

Do our ears clip?

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In response to Carver, I think it had more to do with the amp and the inefficient speakers of the day as well. So the mega 800 watt amp on a very poor system SPL at 1 watt would need just that.

With Klipsch, a lot less obviously!

The third part would be, can the speakers handle that rise as well?

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Same reason a car with 600 hp is better than one with 200 hp.... bragging rights!!!!

Anything worth doing is worth overdoing. No bragging involved.

Maybe I should have quantified: A 600 hp daily driver street car to get you from a-b....you can't tell me that's not 100% bragging rights.......Thats what marketing divisions of all consumer products rely upon....Mr. Jones wanting to outdo Mr Smith..the only thing "overdone" in that situation are the ego's involved.

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In response to Carver, I think it had more to do with the amp and the inefficient speakers of the day as well. <snip> With Klipsch, a lot less obviously!

Huh???? There were no efficient speakers when Carver did his experiment? If memory serves me, the Khorn was around almost before Carver was born!

Tom

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Maybe I should have quantified: A 600 hp daily driver street car to get you from a-b....you can't tell me that's not 100% bragging rights.......Thats what marketing divisions of all consumer products rely upon....Mr. Jones wanting to outdo Mr Smith..the only thing "overdone" in that situation are the ego's involved.


Ego may well be a factor in the decision to buy a 600hp car, but a bigger factor would (or should) be that a 600hp car is a lot of fun to drive. It also makes passing much safer and less dramatic.

I've never driven a 600hp car, but I rode my 130hp motorcycle for years, and it was a lot of fun. Nowadays, of course, they're up to 180hp, and they're probably even more fun.
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Is the clipping 800W amp really indicating something we can't hear, or something speakers can't reproduce?

Do our ears clip?


Well, ears do have upper limits in what they can receive and relay to the brain. I can recall noticing at rock concerts that I was hearing a quite distorted sound when standing near the stack of speakers. When I started wearing earplugs, the sound was a bit muffled, but the distortion was much less, so it wasn't caused by overdriven speakers, but by my overdriven ears.
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If the music has a big dynamic range, it will sound more realistic with more headroom available.

Precisely correct. People clip their amps quite a lot, on peaks. Most of the time they are unaware that it is happening because of the transient nature of the signals involved.


Hey, artto didn't say that, I did, on page 2 of this discussion.
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