Addressing correct instrument timbre?

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whydontumarryit

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Addressing correct instrument timbre?
« on: 17 Oct 2021, 06:15 am »
Hi,

What means of room treatment directly address correct instrument timbre? Does this quote from one of Floyd Tooles articles have any relevance and can anyone interpret it?

… the perceived timbres of sounds in rooms are the result of spatial averaging, that is, reflected sounds arriving at our ears from many angles. These reflected “repetitions” of the direct sound have a second benefit, increasing our sensitivity to the subtle resonances that give sounds their distinctive timbres.
So when an investigation reveals that a reflection at a certain level relative to the direct sound is just audible, as in a threshold experiment, this is not necessarily an indication that problems have begun. More likely, it could indicate the beginning of something perceptually interesting and beautiful. As we get into the details, it will be seen that reflections from certain directions, at certain amplitudes and delays, are more or less advantageous than others, and that collections of reflections may be perceived differently from isolated reflections.

My current speaker location is finally optimized for the most accurate low frequency response and as a result the only method I can think of to further improve things is room treatments? (limited to mid/hi frequncies). I need a starting point or links to another thread here that covers the subject.

thanks

youngho

Re: Addressing correct instrument timbre?
« Reply #1 on: 17 Oct 2021, 02:58 pm »
I wonder if you may be conflating two different issues here:
1. the perceived timbre of reproduced sounds in rooms, the idea being that off-axis frequency response contributes to what we hear in non-anechoic rooms
2. the timbre of different musical instruments (or the human voice), which is generally attributed to overtones/harmonics and attack

What reproducing musical instruments or voices "correctly" means is a matter of some controversy...

whydontumarryit

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Re: Addressing correct instrument timbre?
« Reply #2 on: 17 Oct 2021, 10:58 pm »
I may be, in the first paragraph the claim is that spatial averaging is responsible for timbre, accurate or not. And that these repetitions from many angles elicit an impression (increase our sensitivity) of an actual live performance (resonances with a distinctive timbre) only if the amplitude and delay are correct. In pursuit of that distinctive timbre I want to know how and what room treatments will address my very specific requirement since this method deals directly with correcting reflections for the better. I have never used any room treatment intentionally and remain sceptical for the most part.

In the second paragraph Mr. Toole appears to be hinting that something magical may happen under some circumstances I don't quite understand so, I must have quoted it out of context since he appears to be an objectivist.

To answer your question, everyone, without exception, can distinguish live from reproduced sound there's absolutely nothing controversial about it. If what you say were true how would any audiophile's ambition be resolved if there were no way to know when he “got there”?

FullRangeMan

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Re: Addressing correct instrument timbre?
« Reply #3 on: 17 Oct 2021, 11:18 pm »
I also dont understand how the musical instruments timbre can be modified after the recording is made  :scratch: using room acoustics correction.

I suspect he may be referring to sound stage size in the listening room.

Tyson

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Re: Addressing correct instrument timbre?
« Reply #4 on: 18 Oct 2021, 03:42 am »
I think Toole is just pointing out that the flat, on axis anechoic frequency response measurement doesn't tell the full story of how a speaker will sound in a room.  Then he gives some tips on how the room and the speaker will interact, in predictable ways.

JWL.GIK

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Re: Addressing correct instrument timbre?
« Reply #5 on: 18 Oct 2021, 02:28 pm »
This is an interesting subject for sure. I have a ton of respect for Toole's work, but I also disagree with him on a few key issues. For me this issue is related to one of the areas in which we disagree -- the importance of treating early reflections and controlling how much they are heard.

For me it comes down to this assertion from Toole: "These reflected “repetitions” of the direct sound have a second benefit, increasing our sensitivity to the subtle resonances that give sounds their distinctive timbres."

If this assertion is the case (ie, true) then it follows that we would be less sensitive to subtle resonances that gives sound their distinctive timbres in rooms without early reflections, ie, listening outdoors or in a room with a well-designed reflection-free zone. And we know this is NOT the case.

Early reflections are known to create distortion, comb filtering, and psychoacoustic challenges. These are sonic artifacts not present in the original recording, so anything the room adds will be definition be less accurate, not more. And much of the comb filtering happens in the midrange, which as Toole notes, is where our ears are most sensitive.

For me this is a step away from accuracy, not toward.

Of course, for many audiophiles accuracy is NOT the goal. The most pleasing sound is, which may or may not be the most accurate sound. For me, the two are the same. The less the room adds to or changes the sound, the better.

In terms of treatments, again if the goal is accuracy, then for sure a balanced, well-designed treatment strategy will help a lot, with all the familiar strategies (broadband bass trapping, early reflection management, etc).

As always, I suggest experimenting in your room with your system. Evaluate what you are hearing both by ear and if possible with good measurement (like REW). I always rely on test data to put my subjective listening impressions into a more objective context.

youngho

Re: Addressing correct instrument timbre?
« Reply #6 on: 18 Oct 2021, 02:37 pm »
I may be, in the first paragraph the claim is that spatial averaging is responsible for timbre, accurate or not. And that these repetitions from many angles elicit an impression (increase our sensitivity) of an actual live performance (resonances with a distinctive timbre) only if the amplitude and delay are correct. In pursuit of that distinctive timbre I want to know how and what room treatments will address my very specific requirement since this method deals directly with correcting reflections for the better. I have never used any room treatment intentionally and remain sceptical for the most part.

I'm not sure that you've read the entire article. Again, I believe that you're conflating multiple things, here the differences between reproducing the recorded signal "accurately," creating the impression of an actual live performance, and considering reflections in terms of level, direction, and possibly treating them with respect to listener preference (but in a uniform way across the frequency spectrum).

Quote
In the second paragraph Mr. Toole appears to be hinting that something magical may happen under some circumstances I don't quite understand so, I must have quoted it out of context since he appears to be an objectivist.

I believe that this is thoroughly discussed in the article with respect to listener preference, perception of spaciousness, and speech intelligibility, but the basic idea is that lateral reflections may be preferred by many listeners.

Quote
To answer your question, everyone, without exception, can distinguish live from reproduced sound there's absolutely nothing controversial about it. If what you say were true how would any audiophile's ambition be resolved if there were no way to know when he “got there”?

You may find it helpful to read about "the circle of confusion" (http://seanolive.blogspot.com/2009/10/audios-circle-of-confusion.html). From what I understand, audiophiles' goals can range from the impression of accuracy to the recorded signal ("hearing what the engineers heard," which at the extreme end could require a custom-built control room setup, see https://gearspace.com/board/studio-building-acoustics/1333291-stereo-recordings-room-acoustics.html, but then different engineers may use different control rooms), the illusion of "they are here" as though the performers were actually present in your room, the illusion of "you are there" (but that can take various forms, going all the way up to multichannel like Auro 3D), and euphony with pleasing distortions, among other possibilities. In terms of of recordings and the reproduction thereof, my own experience is that many recordings seem to be done in a way to enhance the listener experience in the absence of visual input, e.g. the use of multiple microphones placed closer and higher than would occur in an actual live listening experience. Proximity effects and placement can affect the recorded timbre of voices and instrument, so I'm not sure what it would mean to reproduce the these "correctly." There are two additional points regarding classical music, namely the effects of floor bounce and how that affects reproduction of orchestral music, also the so-called BBC or Gundry dip (see http://www.linkwitzlab.com/models.htm#H).

Young-Ho

youngho

Re: Addressing correct instrument timbre?
« Reply #7 on: 18 Oct 2021, 02:56 pm »
This is an interesting subject for sure. I have a ton of respect for Toole's work, but I also disagree with him on a few key issues. For me this issue is related to one of the areas in which we disagree -- the importance of treating early reflections and controlling how much they are heard.

For me it comes down to this assertion from Toole: "These reflected “repetitions” of the direct sound have a second benefit, increasing our sensitivity to the subtle resonances that give sounds their distinctive timbres."

If this assertion is the case (ie, true) then it follows that we would be less sensitive to subtle resonances that gives sound their distinctive timbres in rooms without early reflections, ie, listening outdoors or in a room with a well-designed reflection-free zone. And we know this is NOT the case.

Toole is primarily discussing sound sources in rooms. It is easier to critically distinguish between loudspeakers when reflections are present. An extreme example of this would be Jorma Salmi's work from the early 1980s comparing loudspeakers in an anechoic chamber versus listeing rooms. What you're discussing are subtle resonances and distinctive timbre as present in the recordings, so what you're arguing is that these may be more difficult to distinguish when early reflections are present. Toole himself notes that lateral reflections may have some possible subjective benefits in terms of perception of spaciousness but that "(It should be noted that direct sound and a reflection arriving from the same vertical, medial, plane yielded impressions of timbre change, not spaciousness)" and "In both concert halls and listening rooms reflected sounds arriving from the front or rear do not contribute to a positive impression."

Quote
Early reflections are known to create distortion, comb filtering, and psychoacoustic challenges. These are sonic artifacts not present in the original recording, so anything the room adds will be definition be less accurate, not more. And much of the comb filtering happens in the midrange, which as Toole notes, is where our ears are most sensitive.

For me this is a step away from accuracy, not toward.

There is a little controversy about this, which is mentioned in the Gearspace discussion I linked above, specifically the comb filter that occurs from having two ears separated by the head itself when listening to a phantom center versus an actual one.

Anyway, Toole basically suggests that most of this is a matter of preference: https://www.audioholics.com/room-acoustics/room-reflections-human-adaptation

Young-Ho

youngho

Re: Addressing correct instrument timbre?
« Reply #8 on: 18 Oct 2021, 03:12 pm »
One more possibly helpful post using Toole's own words: https://gearspace.com/board/showpost.php?p=15187387&postcount=61

Tyson

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Re: Addressing correct instrument timbre?
« Reply #9 on: 18 Oct 2021, 04:24 pm »
Some people like the sound of a lively room, some people prefer the sound of a quiet room.  I'm definitely in the latter camp.

whydontumarryit

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Re: Addressing correct instrument timbre?
« Reply #10 on: 18 Oct 2021, 07:19 pm »
Thanks for the info.
The circle of confusion article was especially interesting since out of all the engineers in all the studios and all the recording methods you would think it possible to hear an example of a live performance just once. I suppose the assumption is that many audiophiles have experienced this phenomena at one time or another, unfortunately it has happened to me exactly one time under conditions that everyone involved in the hi-end audio realm would find very disturbing. It was this revelation that prompted my search for the reasons that made this possible in the first place and seemingly completely at random. Hopefully one of you can suggest a recording that leaves you flabbergasted everytime you hear it to prove this was not just a one-off thing for me.

JWL:
For me it comes down to this assertion from Toole: "These reflected “repetitions” of the direct sound have a second benefit, increasing our sensitivity to the subtle resonances that give sounds their distinctive timbres."
(You forgot the part that includes “only if the amplitude and delay are correct”).

Is comb filtering still considered an issue these days?

thanks all

Mike-48

Re: Addressing correct instrument timbre?
« Reply #11 on: 20 Oct 2021, 08:49 pm »
Some people like the sound of a lively room, some people prefer the sound of a quiet room.  I'm definitely in the latter camp.
Me, too.

nerdoldnerdith

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Re: Addressing correct instrument timbre?
« Reply #12 on: 2 Apr 2022, 09:02 pm »
It is just to say that what gives an instrument its timbre in real life is more than its direct frequency response. A trumpet, for example, has a narrow sound dispersion pattern and focuses all its energy forward. What makes a trumpet sound like a trumpet in a room is the combination of direct and reflected energy in that room, and the reflected energy is weaker than direct energy, especially at higher frequencies. If you play the sound of a trumpet through omnidirectional speakers, it won't sound like an actual trumpet would sound in your room because the balance of direct and reflected energy is way off. Similarly, if you play the sound of something that is mostly omnidirectional, like a xylophone, through narrow directivity speakers like horns, it won't sound like an actual xylophone would sound in your room.

DannyBadorine

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Re: Addressing correct instrument timbre?
« Reply #13 on: 4 Apr 2022, 12:59 am »
It is just to say that what gives an instrument its timbre in real life is more than its direct frequency response. A trumpet, for example, has a narrow sound dispersion pattern and focuses all its energy forward. What makes a trumpet sound like a trumpet in a room is the combination of direct and reflected energy in that room, and the reflected energy is weaker than direct energy, especially at higher frequencies. If you play the sound of a trumpet through omnidirectional speakers, it won't sound like an actual trumpet would sound in your room because the balance of direct and reflected energy is way off. Similarly, if you play the sound of something that is mostly omnidirectional, like a xylophone, through narrow directivity speakers like horns, it won't sound like an actual xylophone would sound in your room.

All of this is true, but the recording of it has to address this rather than the sound system reproducing it.  If the nuances of the instrument are not in the recording then it doesn't matter what you play it through.