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
 Hello mrD,

     I really don't disagree with anything you stated.  I would just add that high efficiency speakers are not a requirement if you enjoy your music at hearing health threatening levels.  I know you didn't state otherwise but I thought some might mistakenly assume this.  I  personally  listen to music at about 70-90 dbs but on occasions I will go over 100 dbs when I get the urge.
     But I understand my speakers can safely handle very high volumes as long as the power is clean; it's normally high distortion and clipping that damage speakers.  My system is capable of playing at volumes well above levels I care to ever listen at but I like knowing my system's capable, consider it a sign of quality and view it much like a high quality car that's luxurious, a great cruiser on the highways, very powerful and fast when you feel the need but also gets good mileage when I take it easy.
     I have fairly inefficient Magnepan 3.7i main speakers driven by 1,200 watt @  4 ohm class D monoblocks that have very low distortion. I run them full range but also supplement the bass between about 20-40 Hz with 4 subs powered by a separate class AB 1K watt amp.  
     I built my system based on the concept of combining 2 systems:  a very powerful and dynamic bass system, that's also textured, tonally accurate and detailed, to establish a solid foundation for any genre of music along with a high quality pair of main speakers layed on top that provides very good midrange, treble and stereo imaging performance.
     The most difficult part, in my experience, is  getting the bass sounding right and seamlessly integrated with the main speakers.  My opinion is that at least a pair of good quality subs are a requirement for optimum results. 
     I've found getting the midrange, treble and stereo imaging sounding right is the easier part, especially if high quality and well matched amps and speakers are utilized and the speakers are precisely positioned in the room and in relation to the designated listening seat. Lastly, strategically placed acoustic room treatments work wonders.
     Overall, I believe diamonddupree has all the necessary component system parts to build a similarly very good system, possibly even better.

Tim
You may want to go even cheaper than a miniDSP. :)

Get a capacitor of around 0.04uF and put it in line with your amp inputs.

https://www.partsconnexion.com/JAM-82668.html


BTW, I have a miniDSP and I love it, but I only use it in my sub path way for the reasons you are concerned with.

Of course, if only audiophiles could give up these damn separates and go with an Anthem streamer/preamp or similar with built in room correction and bass management. :)

Best,

Erik
@erik_squires the day I try to install that is the last day my amp would ever work. 
MiniDSP comes tomorrow. I have no idea what to expect. Should be interesting. 
@erik_squires another cheap option?

https://www.hlabs.com/products/crossovers/

Inline RCA active crossover? They make high pass filters for 70hz and 100hz. Any reason why these wouldn’t work?
HI,

So the caps I was suggesting is the same exact idea.

 You'd just have to build your own RCA cable. :)