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

If you "like", the sound of the Mini-DSP? You will love this.
The K-231.
And, I have no affiliation with these guys other than using this crossover and being extremely happy with it 

https://sublimeacoustic.com/products/k231-stereo-3-way-active-crossover

Because "I" could not bear the mini's change in the soundstage in any rig I tried it in, "3". Plus a few other issue's.....
I found this little company three years ago and keep a couple of the "K-231's," around. "I have needed to cascade two of them a couple of times for a 5-way". VERY, "Well designed and with a clean, high quality build
American made still too! You can still call these guy's and they "will", call you back.  But these seem to be catching on so they are busy.....
I have been bugging them for a unit with an ext. case that is at least a, "Half-rack" space. "Instead of the little box. So it will have the room for both, RCA and also XLR, In/Out And those are supposed to be coming. But haven't heard about that for a bit.
  The K-231 has had both balanced and unbalanced in/out but the balanced side utilizes (1/4 "-TRS ), currently. "Instead of the XLR.'s". 
 The last two they made for me have nice quality "IEC sockets" also. But that, "May" still be an optional, "Mod".. As Mine were. I thought at first the freq. "Modules" would be a pain but as it turned out, I really like them. They made me a bit more "serious", about where the x-over points on a few projects really, "needed" to be. But now I have a box full of them. Ha ha, Looking back? Collecting the frequency modules? It felt akin to collecting, "Baseball" cards.....!
 
  Wow, I sound like a sales rep. "Shudders".....
 So, 
And, I have no affiliation with these guys other than using this crossover and being extremely happy with it 
It is, "Nifty".

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