[Tim916]

Just finished reading this book today, and it was a relatively easy yet very interesting read. The first half of the book goes over the research performed by Dr. Toole and others on how humans perceive sound. The second half explains how to apply these findings in the design of listening rooms and home theaters.


Many of Dr. Toole's recommendations contradict the conventional wisdom. For example, he cites research that shows that test subjects prefer early reflections in music because it gives an enhanced sense of spaciousness. He recommends only treating early lateral reflection points if the main speakers have poor off-axis frequency response, or if the listener prefers the sound that way. Toole goes on to say that if absorption is used it should be at least 3-4" thick so that it can absorb effectively down to 300hz or so. He claims the problem with thinner material is that it only absorbs the upper frequencies and thus changes the spectrum of the reflected sound.


Toole also cites research showing that, in most cases, comb filtering does not adversely affect listening enjoyment.


One of the most fascinating (and entertaining) sections of the book covers the issue of listener bias due to the brand, size, price, appearance etc. of speakers. He cites tests performed under both blind and sighted conditions with the same group of subjects and speakers of various sizes, finishes and brands. Unsurprisingly, the results were very different when subjects could see what speaker they were judging.


Obviously, I'm barely scratching the surface of the book's content, and I'm sure some will disagree with a few of Toole's conclusions, but it is clear that he has really done his homework, and over the course of his career had access to tools that most professionals can only wish for. Definitely worth a read for enthusiasts and professionals alike.

 

[MLKstudios]

It's in my Amazon "basket", but I haven't yet put it in the shopping cart. But, I do plan on reading it soon.


Thanks for the overview.

 

[Tim916]



Quote:
Originally Posted by MLKstudios /forum/post/18170927


It's in my Amazon "basket", but I haven't yet put it in the shopping cart. But, I do plan on reading it soon.


Thanks for the overview.

Yeah I had it in my Amazon basket for about 6 months until I actually ordered it. I wish I had done it sooner.

 

[ChrisWiggles]

I've had it sitting on my counter for months. Unfortunately, there is a stack of books probably taller than me which are first on my reading list... :/


I've only skimmed certain parts of it.

 

[Gaugster]

Sorry to bring up an old thread but read this book once already and about half way through reading it again.


Great data and observation of the sometimes goofy AV industry.


I am a huge fan of bipolar mains and now know the science behind why I hate dedicated center channels. This is true even though Mr. Toole recomnends it.

 

[arnyk]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24111828


Sorry to bring up an old thread but read this book once already and about half way through reading it again.


Great data and observation of the sometimes goofy AV industry.


I am a huge fan of bipolar mains and now know the science behind why I hate dedicated center channels. This is true even though Mr. Toole recomnends it.

Do tell.

 

[Gaugster]



Quote:
Originally Posted by arnyk  /t/1228630/sound-reproduction-by-floyd-toole#post_24112410


Do tell.

In a nutshell - side wall reflections that originate from the left and right mains are very beneficial to the overall listening experience. Increasing the width of the sound stage and also adding to voice clarity. Directing all this information to a single center channel both reduces the amount of reflections as well as preventing any generation of interaural time difference for an otherwise monophonic sound event. Using a hard center prevents the 2kHz frequency response dip and allows multiple listeners to hear the same sound. But in my case this resulting sound has more drawbacks then benefits. Toole goes on to explain that recording Engineers should have kept some components of the center channel sound in the L/R mains to take advantage of what these reflections can offer.


Neat stuff for sure.

 

[Ethan Winer]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24112633


side wall reflections that originate from the left and right mains are very beneficial to the overall listening experience. Increasing the width of the sound stage and also adding to voice clarity.

I know this is Floyd's opinion, but pretty much every professional mixing and mastering engineer disagrees. It's also the only thing I disagree with Floyd about!


Maybe in a very large room side-wall (and ceiling) reflections are less damaging than in a small narrow room. But for most home-size listening rooms, absorbing those early reflections gives a larger and much more stable sound stage.


--Ethan

 

[jim19611961]



Quote:
Originally Posted by Ethan Winer  /t/1228630/sound-reproduction-by-floyd-toole/0_50#post_24113971


I know this is Floyd's opinion, but pretty much every professional mixing and mastering engineer disagrees. It's also the only thing I disagree with Floyd about!


Maybe in a very large room side-wall (and ceiling) reflections are less damaging than in a small narrow room. But for most home-size listening rooms, absorbing those early reflections gives a larger and much more stable sound stage.


--Ethan

Floyd's opinion on this could be better understood if we knew the delay (timing) and magnitude (-db in reference to the direct) that his opinion was based on. Obviously, -5db @ 6ms is different altogether than -15db @ 15-20ms.

 

[Gaugster]



Quote:
Originally Posted by Ethan Winer  /t/1228630/sound-reproduction-by-floyd-toole#post_24113971


I know this is Floyd's opinion, but pretty much every professional mixing and mastering engineer disagrees. It's also the only thing I disagree with Floyd about!


Maybe in a very large room side-wall (and ceiling) reflections are less damaging than in a small narrow room. But for most home-size listening rooms, absorbing those early reflections gives a larger and much more stable sound stage.


--Ethan

I remember recalling your products when reading Mr Toole's conclusions and wondering how things came to be the way they are.


For right now I am pretty much believing everything stated in the book as fact based in my own personal experience.

 

[Gaugster]



Quote:
Originally Posted by jim19611961  /t/1228630/sound-reproduction-by-floyd-toole#post_24114134


Floyd's opinion on this could be better understood if we knew the delay (timing) and magnitude (-db in reference to the direct) that his opinion was based on. Obviously, -5db @ 6ms is different altogether than -15db @ 15-20ms.

I believe these details are provided as part of his explanation. Guess you'll just have to review for yourself.

 

[Audionut11]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24114541


For right now I am pretty much believing everything stated in the book as fact based in my own personal experience.

Have you sufficiently dampened all first reflection points to make this opinion?


I have a very "dead" room (with all FRP dampened),




This room has an excellent sound stage with very clear and accurate localisation. When I listen to music in a "live" room with no dampening in the first reflection points, I hear a wider sound stage most defiantly, which is offset by vocals and instruments floating through the sound stage depending on the frequency of the source signal and characteristics of the room. There is considerably more noise in these rooms also.

 

[Ethan Winer]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24114553

Quote:
Originally Posted by jim19611961  /t/1228630/sound-reproduction-by-floyd-toole#post_24114134


Floyd's opinion on this could be better understood if we knew the delay (timing) and magnitude (-db in reference to the direct) that his opinion was based on. Obviously, -5db @ 6ms is different altogether than -15db @ 15-20ms.

I believe these details are provided as part of his explanation. Guess you'll just have to review for yourself.

I have Floyd's book and I don't recall reading those details. Maybe I missed that? If you have a page number I'll look again.


But the real issue should be what makes sense, and what can be shown empirically. As I said, I agree with Floyd on pretty much everything else. But on this one point he is very much in the monitory among audio experts and professional mixing engineers.


--Ethan

 

[Gaugster]



Quote:
Originally Posted by Ethan Winer  /t/1228630/sound-reproduction-by-floyd-toole#post_24116639


I have Floyd's book and I don't recall reading those details. Maybe I missed that? If you have a page number I'll look again.


But the real issue should be what makes sense, and what can be shown empirically. As I said, I agree with Floyd on pretty much everything else. But on this one point he is very much in the monitory among audio experts and professional mixing engineers.


--Ethan

I guess chapter 8 page 123 is a data set for review. Figure 8.5 shows time delay and relative dB reductions for first reflections. The preference by audio experts and professional mixing Engineers is not disputed by Mr. Toole. It more of a matter that control room requirements to critique and mix sound are not what the average consumer in a home environment enjoys or finds pleasurable. First paragraph on Page 259 states this directly.


As I said, I am on my second reading of this book. Lots of conclusions provided based on summaries of more in depth studies contained in other literature. Makes it difficult to understand exactly how some of the conclusions were reached. Things are makeing more sense on my second pass.

 

[amirm]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24116914


As I said, I am on my second reading of this book. Lots of conclusions provided based on summaries of more in depth studies contained in other literature. Makes it difficult to understand exactly how some of the conclusions were reached. Things are makeing more sense on my second pass.

Indeed, full understanding does not occur without reading the underlying papers. And those papers are not written in the simpler language used in the book.

 

[Ethan Winer]



Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24116914


I guess chapter 8 page 123 is a data set for review. Figure 8.5 shows time delay and relative dB reductions for first reflections.

Excellent, thanks for that. I noticed that Floyd refers at the bottom of Page 121 to people's preference when they listen in a "normal" room. This is a key distinction, because most rooms don't have absorbers at the side-wall reflection points. In my experience, adding absorbers increases the apparent width much more than the faux enhanced width you get from the left and right channels bouncing off opposite walls. In other words, a properly treated room sounds wider - and clearer - than an untreated room.

Quote:
The preference by audio experts and professional mixing Engineers is not disputed by Mr. Toole. It more of a matter that control room requirements to critique and mix sound are not what the average consumer in a home environment enjoys or finds pleasurable. First paragraph on Page 259 states this directly.

I disagree that home listeners benefit from hearing anything less clear than what the mixing engineers heard when creating the music. When a mix in progress starts to take shape, everyone in the room gets very excited at how good it sounds! I think everyone should get to experience that. I'm a good example because I'm a professional musician, mixing engineer, and also an avid audiophile listener. One problem may be that the listeners they tested simply were not sophisticated enough to appreciate the difference. Sort of like goosing the bass and treble to a "smiley" EQ makes music sound "better" to those who don't know any better. I wish you lived closer to me because I could demonstrate all this very easily in about ten minutes!

In the mean time, this is not difficult to test for yourself. If you don't have proper acoustic treatment, just hanging folded-over bath towels (to be thicker) on the walls with masking tape will give you a good sense of how the width increases when early reflections are absorbed. I'll also mention why the width is larger when those reflections are absorbed. Most recordings have the reverb and ambience of a large space embedded in the mix, either natural reverb from a classical music concert hall or artificial reverb with pop music. When that music is played in an untreated room, the "early" reflections that make for a small sound drown out the larger sounding reverb in the recording.


--Ethan

 

[Wayne A. Pflughaupt]



Quote:
Originally Posted by Ethan Winer  /t/1228630/sound-reproduction-by-floyd-toole#post_24116639

Quote:
Originally Posted by Gaugster  /t/1228630/sound-reproduction-by-floyd-toole#post_24112633


In a nutshell - side wall reflections that originate from the left and right mains are very beneficial to the overall listening experience. Increasing the width of the sound stage and also adding to voice clarity.

I agree with Floyd on pretty much everything else. But on this one point he is very much in the monitory among audio experts and professional mixing engineers.


--Ethan

This article has a passage that probably explains why most recording engineers feel that way:

Quote:
Expanding on the last sentence, there is indeed a subset of people who are sensitive to [early reflections] and hence strive to eliminate them. A prime example is recording engineers. Since they are able to electrically generate comb filtering they have learned what it sounds like and hence have well above average ability to hear them. And at any rate, the process of mixing and creating music requires being able to detect small changes to the parameters in that work. Both of these factors explain their preference for absorption of reflections.

Regards,

Wayne A. Pflughaupt

 

[erkq]



Quote:
Originally Posted by Ethan Winer  /t/1228630/sound-reproduction-by-floyd-toole#post_24113971


I know this is Floyd's opinion, but pretty much every professional mixing and mastering engineer disagrees. It's also the only thing I disagree with Floyd about!


...


--Ethan

A seemingly knowledgeable fellow (But one I've never heard of), Anthony Grimani, also agrees with Floyd on this. He lays out his reasoning in this interview with Scott Wilkinson:

http://www.avsforum.com/t/1494052/acoustics-101-with-anthony-grimani#post_23879464


Help... I don't know which way to jump!

 

[amirm]



Quote:
Originally Posted by erkq  /t/1228630/sound-reproduction-by-floyd-toole#post_24121696


A seemingly knowledgeable fellow (But one I've never heard of), Anthony Grimani, also agrees with Floyd on this. He lays out his reasoning in this interview with Scott Wilkinson:

http://www.avsforum.com/t/1494052/acoustics-101-with-anthony-grimani#post_23879464

Tony is part of the elite top 5 or so high-end home theater designers. We are talking about theaters costing hundreds of thousands of dollars (like my company Madrona does

). He doesn't have the theoretical/research background that Dr. Toole has but rather, draws from working experience. As you say, his experience in many areas matches that of Dr Toole.

Quote:
Help... I don't know which way to jump!

My rule on this is simple: if you don't know which way to jump, start with the direction Dr. Toole provides. That is what the majority of people will prefer.

 

[erkq]



Quote:
Originally Posted by amirm  /t/1228630/sound-reproduction-by-floyd-toole#post_24123729


Tony is part of the elite top 5 or so high-end home theater designers. We are talking about theaters costing hundreds of thousands of dollars (like my company Madrona does

). He doesn't have the theoretical/research background that Dr. Toole has but rather, draws from working experience. As you say, his experience in many areas matches that of Dr Toole.

My rule on this is simple: if you don't know which way to jump, start with the direction Dr. Toole provides. That is what the majority of people will prefer.

Tony and Dr. Toole both have suggestions that are more flexible than the "kill first reflection convention wisdom", so that's good. Tony has the "20% absorption, 25% diffusion" rule. Thanks for your input! I've got Dr. Toole's book. I'll read it!