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A chat with Dr. Floyd Toole

hardisj

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Thought you guys might enjoy this chat I had with @Floyd Toole earlier. I checked an item off my bucket list today for sure.

Thanks to Dr. Toole for being a sport and entertaining my questions and generally being such a nice fellow. Hopefully we can do this again sometime soon. :)

I'll try to add timestamps when I can. But for now, I simply don't have the time.

 
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audio2design

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I will watch the whole thing later, but skimmed about 10-15 minutes of it. It sounds like a good chat. Always enjoy Floyd talk even if I don't always agree with everything he says, on the basics, his confidence through experience is "reassuring". His experience mirrors mine, w.r.t. single speaker testing, long term testing, etc. Many years ago, I proved to a group of people that they would not even be able to pick their own speakers out blind. It was very eye opening for them, and I collected on the bets made.
 

Ron Texas

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I wish a transcript of many of these videos was available. It's so much faster to read than to watch.
 
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hardisj

hardisj

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Fantastic thank you for sharing! I hope I am that sharp when I am over 80 years old!

Glad to share it. I think it's good to get his perspective on the topics like nonlinear distortion and vertical reflections and I love his honesty about the subjects. I, too, hope I am that sharp at his age. Heck, I wish I were that sharp now!
 

DonH56

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Hopefully he made it back home... Great to hear from him again, and also great you are getting interviews with some of the industry icons and legends, @hardisj !
 
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hardisj

hardisj

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and also great you are getting interviews with some of the industry icons and legends, @hardisj !

My entire goal with my channel is to help people understand the importance of data. Me making a video or dumping data to my site isn't as effective as I would like it to be. If I can teach the more subjective-minded folks that data is useful and important and help them grasp some concepts then they are more likely to accept it rather than just brush it off. I don't have any notion or fallacies of me knowing more than I do. To quote Paul Simon: "I know what I know". I still have questions and there are topics that I think I can answer but I would rather have the person who literally wrote the book on to discuss things and - most importantly - provide a simple explanation rather than me butcher it with unecessarily long words. I get to learn and "my audience" gets to learn with me. And, hey, maybe Dr. Toole sells a few books to buy some wine. Definite win/win/win. :D
 
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hardisj

hardisj

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One thing I really appreciated about my chat with Floyd was that when he didn't know an answer he admitted it. I see so many people try to give answers to questions they don't know and that annoys the piss out of me. Just say "I don't know" so we can move on. It's refreshing to see such an intelligent person who is expected to know everything admit he just plain doesn't know everything. That is humility 101 and I appreciate it.

Also, since I was asked: no, I do not run ads on these interviews. That doesn't feel right.
 
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pozz

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I will watch the whole thing later, but skimmed about 10-15 minutes of it. It sounds like a good chat. Always enjoy Floyd talk even if I don't always agree with everything he says, on the basics, his confidence through experience is "reassuring". His experience mirrors mine, w.r.t. single speaker testing, long term testing, etc. Many years ago, I proved to a group of people that they would not even be able to pick their own speakers out blind. It was very eye opening for them, and I collected on the bets made.
Was the blind test in research circumstances or casual?
 

audio2design

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https://uwaterloo.ca/audio-research-group/people-profiles/stanley-p-lipshitz


A suggestion for another person to interview.
Was the blind test in research circumstances or casual?

It was a casual test in a research environment. I.e. a level matched test, a proper acoustic room, done with and without equalization and I used speakers that would be close in bass extension and avoiding anything with wicked anomalies. It was to prove a point as it was assumed it would be dead obvious.
 
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UKPI

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Great interview! Gonna listen to it again and again when I need a reference. :)
If you are planning to interview more audio engineering experts, an ASR poll or a suggestion thread might help you in choosing the candidates/topics. Or is there already such a thread?
 

Descartes

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One thing I really appreciated about my chat with Floyd was that when he didn't know an answer he admitted it. I see so many people try to give answers to questions they don't know and that annoys the piss out of me. Just say "I don't know" so we can move on. It's refreshing to see such an intelligent person who is expected to know everything admit he just plain doesn't know everything. That is humility 101 and I appreciate it.

Also, since I was asked: no, I do not run ads on these interviews. That doesn't feel right.

Dr Toole has a true scientific mindset and growth mindset! He doesn’t believe he knows everything and is always willing to learn and rethink!
 

MrPeabody

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Way to go Erin!

I was able to watch the first sixty minutes and I have to go out and do something, but I did capture some excerpts from the first sixty minutes.

At 46:20, the topic turns to the perfect loudspeaker, and particularly to the question of the importance of non-linear distortion. About five minutes later, the discussion of non-linear distortion becomes more definitive, and about five more minutes after that, there is some very interesting discussion of the importance of bass extension.

51:15 Dr. Toole: “The reality of fifty or so years of listening to loudspeakers of all kinds, in numbers of places, is that in the mainstream of well-designed consumer loudspeakers, distortion basically is not a problem. As you go down the price scale, things start getting simplified and corrupted, and distortions do creep in from time to time. You may or may not be able to predict the audibility from measurements, but that’s why we do double-blind listening tests. So unless you’re doing listening tests, I’m sorry, there are no numbers that are going to predict whether the loudspeaker exhibits audible distortion.”

56:22 Dr. Toole: “Bass is the dominant factor, thirty percent roughly of our overall rating of sound quality is based on low frequencies. This is one of Sean Olive’s interesting findings. … In a paper I published in the early eighties, the correlation coefficient between the low-frequency cutoff, the -10 dB down point, not -3, -10, was .5. The correlation between that cutoff frequency and the overall subjective rating - sound quality rating. So we go for bandwidth, not boom.”

A couple of comments. Everything that is capable of being heard is inherently capable of being measured. If it is true that distortion measurements taken in the present era do not correlate closely with audibility, this can only mean that we still have not figured out how to do it. It does not mean that it cannot be done.

With respect to the discussion of bass, the presumptive reason that the -10 dB point is more meaningful than the -3 dB point is that the -10 dB point is the better indicator of bass extension. This is something that I've believed for a very long time, and this may well be the true reason that many people, old timers especially, prefer acoustic suspension speakers over speakers that use ports or passive radiators. This is my personal preference with an exception, the exception being subwoofers where the tuning frequency is low enough to ensure that the bass extension leaves nothing to be desired and that there isn't a strong emphasis at the peak frequency of the port output. This exception obviously does not apply to small bookshelf or stand-mount speakers where bass extension is not going to get anywhere close to 20 Hz even with the port or passive radiator. I will never understand the rationale behind small speakers with ports or passive radiators. It only exaggerates the response somewhere in the mid-bass, to the detriments of bass extension.
 

Wes

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the -10 dB point for my 3.7i maggies in my room is about 35 Hz - you made me check
 

daftcombo

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below 5% distortion is a big gray area as distortion audibility differs from person to person (training, age, preferred listening volume .etc)
Yes, but Floyd was not talking about individual to individual distortion ability, I think.
 

Beershaun

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Watched it this morning. Thanks Erin for sharing this informative interview!
 

daftcombo

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well listening is done by individuals so i don't see what else could he be talking about.
How I interpreted it is that even for one person, seeing the distortion graphs of two speakers won't allow that person to deduce which speaker he/she will prefer.

IMO your interpretation is trivial and could be applied to any kind of measurement (FR, directivity...).
 
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