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


I've been reading Floyd Toole's "Sound Reproduction The Acoustics and Psychoacoustics of Loudspeakers and Rooms" and came across a passage that I wish he went into further detail about. It has to do with whether having amplifier headroom has any noticeable improvement in sq. He happens to be talking about getting the bass right in small rooms, but in doing so, he also touches on the use of a larger amp for extra headroom: 

Remedies for unacceptable situations typically included spending more money on a loudspeaker with a “better” woofer (without useful technical specifications, that was a lottery of another kind) and a bigger amplifier (for useless headroom ...

It's the last part ("useless headroom") that I'm curious about. I have notoriously hard-to-drive speakers (Magico Mini IIs). Although the recommended amplification is 50w - 200w, in my experience, that's a bit of an underestimation. I'm driving the Minis with a Musical Fidelity M6PRX, which is rated at 230w @ 8ohms. (The Minis are 4ohm.) The combination sounds excellent to my ears at low to moderate listening levels, but I notice a slight compression in the soundstage at higher levels. My listening room, while small, is fairly well treated with DIY panels made from Rockwool, sound-absorbent curtains, and thick carpeting. So I don't think I'm overloading the room. But I have wondered if an amp with far more power than what's suggested (more headroom) would drive the speakers with a little less effort.

Those of you familiar with Toole or with driving speakers with power to spare, what are your experiences? If I went with, say, a pair of monoblocks that drive 600w @ 4ohm, would the extra headroom address the compression I'm hearing at higher levels? Or am I wasting my time and, potentially, funds that would be better spent elsewhere? 

Thanks!  


128x128diamonddupree
@diamonddupree Your post is such an appropriate post for what I was considering doing, that is get an amp with more power at 2 Ohms, the CODA #8 v1, v2, or v3 (600 - 1600 watts depending on version). I actually got some extra cash today for year end and would have been all over a new amp except for the results that happened yesterday. I no longer need a new amp.

I was reading a book on how to fix my issue. I ended up contacting the books author to remotely solve my acoustic issues. Take a look at my post here and to see what was done. Follow the links to see the graphs. This solution used a ROON Convolution file, microphone measurements of my room, and both REW and Audiolense software. Some very advanced stuff which I outsourced the to an expert. He has a business to do this type of work.

https://forum.audiogon.com/discussions/thiel-owners-2/post?postid=2066167#2066167

Send me a A'gon PM if you want to discuss any of this by email. 
@yyzsantabarbara very interesting and now I have a lot more reading to do! I just ordered a MiniDSP and I think next will be a mic that I can use to measure the speakers and room response. I think I'll probably still wind up with a new amp down the road but I'll have a much better idea of what to look for when I do. Thanks! 
@onhwy61 I downloaded a free SPL app, Decibel Meter, and holy cow, I guess I should be deaf by now! I'm averaging 100 db and occasionally hitting 105. And I'm still BELOW the level where I hear the soundstage issue I posted about. Maybe I should just listen at lower levels?!?!
diamonddupree, the Loki Mini tone control is very different than the MiniDSP in that the Loki keeps the signal in the analog realm while the MiniDSP uses a 24/96 digital sampling of the signal. The DSP route essentially offers what the Loki Mini provides but DSP has the advantages of using a software solution to how the signal is processed. That is, the frequency response of your speakers and subwoofer can be fine-tuned to a greater extent than with the Loki. But you can also get caught up in fine-tuning and lose sight of what you're trying to achieve. The advantages of the Loki is that the signal remains in the analog realm; perhaps more "pure" and easier to use for diagnostics. With the Loki I get an instantaneous response to how changing the roll off frequency affects the sound in my stereo room. It might be interesting to buy both and compare.
Be careful at 100db plus.  That’s a pretty hefty spl. Mid eighties is typically the highest considered safe for extended listening.   Not too shabby!