Originally Posted by mwalton90
I talked to Onkyo Tech Support and they claim it is indeed 135 W per channel. Their power supply is good for almost 975 W so it does seem to line up. Although I imagine that operating all channels at that level I am bound to get more than 0.08% THD. I was shocked that as soon as you move to a 6 ohm speaker at 125 W a channel the THD goes up to 0.7%. Pretty brutal.
You are right about the bi-amp being between the tweeter and the mids/woofers. I am somewhat concerned about blowing the tweeter. Honestly I am not to phased by it because the in store warranty guarantees to either fix the speaker or to give me a speaker of equal or greater value. Honestly, I'm not that impressed with the TSX550t and would like to move to something different. I've looked into changing drivers and crossovers and such but it seems like to much of a hassle within the current box. And, honestly, I don't know enough to get away with that either. Haha
if you biamp you will put exactly zero more power into the tweeter. zero. Power is the result of the volume control setting more than of the amp's output limits. You just cannot make real content, with say 15% of its power in the tweeter, suddenly have 7 or eight times more power in the tweeter. If it only needs 20 watts, it'll only make 20 watts.
More power = louder. The converse has to mean that at less loud you have less power. During the silences between songs, power should be zero. During the average parts of a movie, which are kinda mazed around 85 dB at reference, you are using one percent (1/100) of the power that would be needed to hig peaks at 105 dB. It cannot be otherwise. Most of the time, the power sits there unused. If you need it, you need it, but only on the loudest parts. When people are just talking, it's a lot quieter than the explosions. If they were at full power the whispers would be explosion loud . . . .
Somewhere around 1% THD is where folks start being able to actually hear distortion (AIUI) with some real content. Truth is, depending on the content, etc., much higher THD can "sound" clean. I've read that guitar players will identify an amp at 10% distortion as "clean," i.e. undistorted . . . . I don't seriously doubt it. But that simply does not mean that a complete music or movie mix at 10% distortion will still sound clean, because a lot more stuff is happening, meaning a lot more distortion-generated harmonics are present . . . .
P.S. go to Stereophile.com and look at some amp measurements. Doesn't much matter which ones. Power versus distortion is a curve, or a line, depending on the amp, and an amp that does 135 watts at .08% distortion might well be at 175 at 1% distortion. It's kind of a marketing decision where to specify power (ie at what distortion) because distortion will just keep rising with power until you become very severely clipped . . . . So Onkyo publishes output power at lower impedance with a higher distortion in order to give a bigger number. BTW, that higher distortion level is almost certainly an indication that the power supply is running out of gas . . . .
I'd want to see third party measurements of multiple channel output power, although, as I said, it's not really relevant anyway. If you biamp, the amps connected to the tweeter will never ever put out more than 25% of the power being put out by the amps connected to the mids/woofers with any real content in the world. It's just not where any concern should go.