What is Floyd Toole saying about extra amplifier power and headroom?

Hi OP,

Glad you are enjoying your new set up.

I still agree with Toole, in general, that excess amplifier headroom does not seem to have a big benefit, as opposed to having drivers with excess headroom, or reducing the demand on mid-woofers.

The best explanation I have of why subwoofers seem to help speakers perform better in so many ways is not headroom, but Doppler distortion.

It also seems to be why 3-way systems may have a lot more clarity than 2 way systems. 

By removing low frequency demand, you remove a great deal of Doppler distortion you'd have to deal with otherwise. The ability to EQ signals below the Shroeder frequency while you are at it is a big bonus.

Best,

Erik

Thanks for all the crossover recommendations. I've bookmarked all of them. And thanks @noble100 for the Toole link. One thing I've noticed in reading his book and even in his posts is that his observations are for multi-seat listening. In the book, almost everything he has to say about low frequencies and subwoofer placement has to do with optimizing for multiple seating positions. I think this explains a lot about his own choices in home audio. I'm mainly concerned with single-seat listening. My home theater system is good enough for my purposes. 

Next move for me is a mic to measure the response at my listening position. Then I can tinker with PEQ and see what that's all about before deciding if an analog crossover is worth a look. And then there's Butterworth vs. Bessel vs. Linkwitz-Riley filters. The force of the rabbit hole is strong. 

Excess anything by definition is not needed. It’s excess. The question with amps is always at what point is it excess?
Another way to look at excess headroom is your insurance policy against clipping. Avoiding clipping should be high on the list of things to tend to for any audiophile.

One thing I’ve noticed in reading his book and even in his posts is that his observations are for multi-seat listening.

Yeah, while I will never have achieved the academic and scientific level of achievement, or renown, of course, that Toole has and deserves, I also come from a motion picture theater background, so I really love his writing and perspective.

In the book, almost everything he has to say about low frequencies and subwoofer placement has to do with optimizing for multiple seating positions. I think this explains a lot about his own choices in home audio. I’m mainly concerned with single-seat listening. My home theater system is good enough for my purposes.

I know it may not sound as relevant, but your fixes are _almost_ always the same. Controlling reverberation time for instance is something hard to do for one spot, without also controlling it in the rest of the room. Adding effective bass traps makes EQ possible.

What Toole gets exactly right, IMHO, is that the concept of room correction is greatly oversold. attempting big corrections in EQ because your sound field sucks doesn’t end up with acceptable solutions for most. Let me explain with a common and specific problem. Let’s say you have a harsh or compressed mid/treble experience in a very live room. Measuring it hyper accurately at your seated position may flatten the curve, but it still won’t sound good. You will control the energy say, between 2kHz and 10 kHz, so it no longer sounds too bright, or too dull, but with long reverb times, all that signal is noise. It’s like watching a movie, where you get the right color and brightness but you can’t tell the actors and scenery apart.

In the bass, with a bad room, the best you can do is clip peaks. Now, that may be a really good improvement, I've seen peaks that were the equivalent of 200x the power output vs. the rest of the system, and clipping them was a major benefit, which EQ can handily do, but trying to EQ these subs into a great response requires a sledgehammer like approach with major amplitude shifts in multiple adjacent bands which, may work for exactly one place and is not all that satisfactory a solution at the end.

Fix your reverberation, and often, the tonal balance fixes itself, and then you are left with very mild, gentle corrections to make. Add bass traps, the peaks flatten themselves, the nulls stop being so severe and again, just a little EQ here and there can give superb experiences.

Hope this helps,

Erik

Concerning headroom:  Each channel of an early Bryston 200 wpc amp has a 375 watt transformer, two 4000 Mf filter caps and two outputs.  The 125 wpc Audire has a 500 watt transformer per side, plus 4 26,000 Mf filter caps and 6 output devices.  At loud volumes, teh Bryston loses some bass oomph. Later Audire gear uses many more outputs.  When the power supply is big enough, the output transistors can regulate the current provided; when too small, they have to strain to get anything out, as Julius Siksnius of Audire discovered with his first amp, which had a one thousand watt transformer, and two much smaller filter caps, plus six outputs driving both channels, not one.    Mine became a great sub amp, but the upper ranges sounded a bit taxed when playing really loud on full range speakers, but much less so than My Phase Linear 400.