Floyd Toole book Sound Reproduction comment

Floyd Toole Book on Loudspeaker

October 2018

This book is shattering my mind on few of the concepts it proposes.

After reading it in ~ two weeks, I don’t know that I really want to recant it here.

A retired PhD, after working 40 years in the audio industry, can teach much more than one enthusiast doing it part time, can ever dream of.

Some stuff he knows, so he can explain through "blind test results" or appropriate measurement techniques.

For the rest of us, it's mostly experience based, and often we simply don’t know why.

In other words, why is it when you play pink noise through a stereo speaker, and then move your head two inches to either the left or right, the sound becomes brighter? Turns out it's one of the big flaws of stereophonic playback, and the resulting comb filtering (above 2 kHz) is to blame. The solution is to use a center channel like a home theater 5.1 or 7.1 system.

The book explained that to me. I knew the effect but was clueless as what the cause was.

The first half of book is very dry. History, concert halls, instrument radiation patterns, reverberation audibility, ideal room size, science, and multiple blind test results etc.

The second part of the book, with all the knowledge amassed, really pays off and the read is much more interesting. Without the first part, the second would not flow as easily, so it’s a necessary pain to read IMHO.

His example of an “ideal listening room" is very intuitive, and obeys the concept described in the book. In fact, while in my Trenton, Ontario house, through lots of frustration, measurement interpretations, a lot of trial/error and some luck, I can say that the room followed about 75% of his advice. If I would have read the book first, I’d had saved a lot of time, frustration and money. My next HiFi room will be much better and will likely follow 95% of his advice, as I’m not completely sold on his advice to maintain a single drywall layer, although his logic makes sense for most installations. For my set-up, I’d double or even triple the drywall thickness.

My previous room differed from his advice mostly by having a lower reverberation time of ~0.25 seconds. Toole advises longer reverberation time. It also differed by using absorption on the ceiling (Toole advises diffusion, but he recommends 9' ceilings). My basement had a 7' ceiling and therefor, was not an ideal candidate for obstructive diffusion.(you’d bang your head on them)

Yet, the sound I was obtaining in the room was bang on, with his subjective description of proper, typical room arrangement.

Toole’s opinion of multi channels is extraordinarily strong, documented and well explained. It makes stereo playback look like 1940’s monophonic listening. Progress doesn't stop…or does it?

Lots of people still spin vinyl. It’s a crazy world we live in.

I’ll certainly have a dedicated center channel in the next room. Will it be for movie only or HiFi as well? I don’t know. However, I know I'll test both. The rear speakers (surround) will be there for sure. Music and movies, with lots of delays. Looks like my sound card will require 32 channels for a full active set-up (my current Mini DSP 4x10HD with a mere eight analog channels won't cut it anymore)

That book made me build more speakers and spend money on a new sound card. What an expensive read it was :)

My next "dream" HiFi system will be multi-channel. I just have to get the hell out of Northern Alberta and get started. Can't wait.