What is timbre and can we measure it?

[kemmler3D]

I've seen this mentioned several times. Does anyone realize how lousy a speaker has to be before it resonates enough to be audible? Midrange leakage through a port is audible, but is it audible in a manner that it affects the timbre of instruments on the recording? Has anyone done a scientifically controlled test of any sort whatsoever to see whether a listener can identify speaker timbre? Does anyone have numbers or measurements?

This site supposedly advocates principles of science. Not only that, but we have criticized anecdotes that are not backed up by controlled tests. It seems that we should produce more data here, and make fewer assumptions.

Otherwise, we're just fumbling around in the dark.

This is all true, a speaker that has enough nonlinear behavior to have a robust timbre of its own is of course trash.

The other normal variations in frequency response are enough to get people to call it "timbre" anyway, though.

 

[sonitus mirus]

Expecting a speaker to change timbre is like expecting it to rewrite the guitar solo in a rock song. Timbre is intrinsic to instruments and performances, not the playback equipment. Speaker construction may slightly affect sound reproduction, but these are seen as imperfections, and the goal should be accuracy to the the source, and anything that has a unique "voice" should be considered a flaw.

 

[MattHooper]

Expecting a speaker to change timbre is like expecting it to rewrite the guitar solo in a rock song.

I wonder why you would say that.

If you take an acoustic guitar it’s timber is defined by a very specific balance of harmonics, frequencies, texture, resonances.

Now take a recording that has presumably captured that specific set of characteristics that define the timber of that guitar

And now play it through a loudspeaker which has a wonky frequency balance, and its own set of resonances in its drivers and cabinet.

That can alter the balance of the harmonics as you hear them, alter the frequency characteristics of the instrument, minimize or exaggerate textural qualities, as well as reduce or exaggerate the specific balance of the guitar’s resonance which was captured in the recording (and remember that resonances show up in frequency response so if you’re altering frequency response, you’re affecting the level of resonance you hear and therefore the timber).

So it’s hardly as implausible as the speaker rewriting a guitar solo.

Speaker construction may slightly affect sound reproduction, but these are seen as imperfections, and the goal should be accuracy to the the source, and anything that has a unique "voice" should be considered a flaw.

That certainly a fair perspective to have on the goal for loudspeakers. But that seems to be a different claim than the one above.

 

[MattHooper]

I've seen this mentioned several times. Does anyone realize how lousy a speaker has to be before it resonates enough to be audible? Midrange leakage through a port is audible, but is it audible in a manner that it affects the timbre of instruments on the recording?

As Dr Toole points out, the existence of audible resonances in loudspeakers is one thing that many listeners pick up on in blind testing, which lowers the scores of those speakers - the very best ones being those without audible resonances.

Audible resonances show up as alterations of the frequency response of the loudspeaker.

So they will be overlaid on or change the balance in the recording. Which can have the effect of changing the timber of an instrument in that recording. (For instance it could emphasize/alter an acoustic guitar recording so it sounds more “boxy” or emphasizing the body resonance of the guitar recording - which is changing a feature of its timber)

 

[Axo1989]

Expecting a speaker to change timbre is like expecting it to rewrite the guitar solo in a rock song.

Mixed metaphors are one thing, building similes out of straw men is something else.

Timbre is intrinsic to instruments and performances, not the playback equipment. Speaker construction may slightly affect sound reproduction, but these are seen as imperfections, and the goal should be accuracy to the the source, and anything that has a unique "voice" should be considered a flaw.

This is a theoretical proposition and useful ideal, but with obvious issues in practice. Even good speakers may have audible differences. Recall @sigbergaudio posting spins of one of theirs compared to the Genelec 8361 iirc. Both were very good, but there were some differences in the graphs and in the perceived timbre (or sonic signature, same thing) as described. Which one do we throw in the bin?

You decide, and send it to me.

*ninja'd by @MattHooper, no matter

 

[Randyman...]

A laymen's take (musician {well, drummer } with an ear for audio). I'm sure similar positions have been expressed.

Is the timbre of Miles Davis' trumpet defined by him playing it on the specific recording - or does his timbre change with every system you listen to it on? IMO - the timbre was captured as an integration of the player, instrument, and capture process - and we interpret it as best we can with the system it is reproduced on. Miles' trumpet still sounds like "him" and his instrument on any system. Even with 5% THD and a +6dB 180Hz resonance on a system that has a 90-5K response - it still sounds like Miles. But this might also be conflating timbre with artists' "voice" - but isn't that also a part of timbre - and captured with the instrument and performance?

I'm of the camp "timbre" is at the musical source. The "Source" is the player, their instrument, and how ever it was captured in the room (the least impactful part of the "timbre" IMO). Of course the room is critical to the overall presentation (in capture and playback) - but that is separate from timbre to me.

I'm just a dumb drummer

 

[Jim Taylor]

As Dr Toole points out, the existence of audible resonances in loudspeakers is one thing that many listeners pick up on in blind testing, which lowers the scores of those speakers - the very best ones being those without audible resonances.

True.

Audible resonances show up as alterations of the frequency response of the loudspeaker.

True.

So they will be overlaid on or change the balance in the recording. Which can have the effect of changing the timber of an instrument in that recording. (For instance it could emphasize/alter an acoustic guitar recording so it sounds more “boxy” or emphasizing the body resonance of the guitar recording - which is changing a feature of its timber)

This is the part that I think takes a leap of faith. Perhaps I asked the right question in the wrong manner in my previous post. Let's try again:

If a speaker resonance alters the frequency response enough to be detectable by a listener, is the listener's impression one of 1) altered instrumental timbre, or 2) altered frequency response?

Listeners are supposedly sensitive to frequency response in a speaker more than other characteristic. So if the resonance altered the frequency response, wouldn't any change in timbre be masked by the more obvious (I presume) characteristic of altered frequency response?

 

[Randyman...]

To add to my Musician's observations - Have you heard of situations where "famous musician A" will pick up "totally different genre Musician B's Instrument" and it magically transforms from sounding like Musician B's rig to Musician A's rig - just due to swapping the player?

Heard these stories hundreds of times with the likes of Eddie Van Halen and other famous musicians sounding just like themselves on radically different rigs - and the "other" musicians always being gob-smacked that their rigs sounded like the famous player and his rig - just by changing the player (an "input" issue at its most rudimentary level, lol). Where do y'all pose this falls into the "Timbre" discussion?

Or - How much of "timbre" is the artist in and of themselves? If the musician/artist isn't the single biggest influence on the SOURCE of timbre, then what is?

Switching musicians is likely to have way more impact on timbre than anything else I can fathom unless playing tightly quantized keys or similar.

What about vocal timbres?

 

[sonitus mirus]

Expecting a speaker to change timbre is like expecting it to rewrite the guitar solo in a rock song.

I wonder why you would say that.

If you take an acoustic guitar it’s timber is defined by a very specific balance of harmonics, frequencies, texture, resonances.

Now take a recording that has presumably captured that specific set of characteristics that define the timber of that guitar

And now play it through a loudspeaker which has a wonky frequency balance, and its own set of resonances in its drivers and cabinet.

That can alter the balance of the harmonics as you hear them, alter the frequency characteristics of the instrument, minimize or exaggerate textural qualities, as well as reduce or exaggerate the specific balance of the guitar’s resonance which was captured in the recording (and remember that resonances show up in frequency response so if you’re altering frequency response, you’re affecting the level of resonance you hear and therefore the timber).

So it’s hardly as implausible as the speaker rewriting a guitar solo.

A speaker should only reproduce the sound of an acoustic guitar being played within the limitations set by the laws of physics, and, if the speaker is excellent, it should not introduce any significant change to the original sound signal. The speaker does not replicate the actual instruments being played but reproduces the sound captured by the microphones used to record them. I believe this common conflation often leads to significant issues in subjective and objective disagreements regarding audio quality assessments.

 

[Titurel]

If a speaker resonance alters the frequency response enough to be detectable by a listener, is the listener's impression one of 1) altered instrumental timbre, or 2) altered frequency response?

It really depends on how well I know or expect to know the instrument(s) or voice(s) in the recording. If I don't know the performer(s), I would likely experience the resonance as coloration. If I know the performers (or the recording venue) my aural BS detector will go off because I'll hear the error as timbral. "He, She, or They don't sound like that." Familiarity alters my analysis of what I hear. I'm probably not typical, but I hope this helps.

 

[sonitus mirus]

Mixed metaphors are one thing, building similes out of straw men is something else.



This is a theoretical proposition and useful ideal, but with obvious issues in practice. Even good speakers may have audible differences. Recall @sigbergaudio posting spins of one of theirs compared to the Genelec 8361 iirc. Both were very good, but there were some differences in the graphs and in the perceived timbre (or sonic signature, same thing) as he described. Which one do we throw in the bin?

You decide, and send it to me.

*ninja'd by @MattHooper, no matter

Exactly what part of a sonic signature is the same thing as perceived timbre? These do not appear to have any technical similarity with regards to an audio transducer. Timbre should not be a term used to describe any measurable differences with a speaker.

 

[kemmler3D]

If the musician/artist isn't the single biggest influence on the SOURCE of timbre, then what is?

Well, the instrument itself.

But I agree that the musician has an impact on timbre.

 

[Randyman...]

Well, the instrument itself.

But I agree that the musician has an impact on timbre.

I'd reverse that order. Musician will have WAY more impact on the instrument than the instrument will have on the musician - and the resulting tone.

Where does vocal timbre come into this conversation?

 

[Axo1989]

Exactly what part of a sonic signature is the same thing as perceived timbre? These do not appear to have any technical similarity with regards to an audio transducer. Timbre should not be a term used to describe any measurable differences with a speaker.

The part(s) you hear when listening to the speaker? The spectrograms of an instrument's sound (timbre to you) and a loudspeaker's sound (not timbre to you) have all the same elements. Your "should not be a term used" is declarative, but not otherwise meaningful.

 

[sigbergaudio]

Mixed metaphors are one thing, building similes out of straw men is something else.



This is a theoretical proposition and useful ideal, but with obvious issues in practice. Even good speakers may have audible differences. Recall @sigbergaudio posting spins of one of theirs compared to the Genelec 8361 iirc. Both were very good, but there were some differences in the graphs and in the perceived timbre (or sonic signature, same thing) as he described. Which one do we throw in the bin?

You decide, and send it to me.

*ninja'd by @MattHooper, no matter

I don't remember where I did that or what the context was, but if we do that again and look at the differences, what we see is relatively small differences in frequency response (so the relative level of different frequencies) and dispersion characteristics (how the sound spreads around the speakers).

Timbre I guess to a greater degree is the makeup and mix of frequencies and harmonics that make up the sound beyond the fundamental (I haven't followed this discussion). I don't think either my speakers or the Genelecs add a lot of harmonics to the sound, so while they don't measure exactly the same, they don't really change the timbre of the sound, the way I understand timbre. But I guess variations in frequency response could be perceived as changes in timbre.

So I think to an extent I agree with @sonitus mirus . But all speaker manufacturers don't necessarily agree on which route to take to get there. What I have argued in the past is that flat anechoic response doesn't necessarily equate to a natural in-room representation of the source, even though that would instinctively make sense. But that's perhaps a digression on the topic.

Our SBS.1 vs 8361 for reference:

 

[solderdude]

Speakers have acoustic mechanisms that produce a certain sound, which is very similar to how musical instruments do the same thing. And then you might even say other acoustic systems are comparable, like rooms.

Exactly.
The point is that the amount of generated harmonics and decay of transducers is so low (and short lived) compared any musical instrument is that it sounds awfully 'dry' and is not perceived as having a 'sound' at all. Rooms will have longer decays though and much bigger frequency response deviations than the transducers.
All speakers have a very similar (and inaudible 'timbre') when it comes to attack, sustain and decay and at 'normal' listening levels the generated harmonics are so low in amplitude that one cannot speak of it having a sound unless it is a continuous single tone at high SPL.

The crux of transducers (and rooms) having a sound signature is simple amplitude variations (per frequency) which can modify the recorded sound in ways that make us perceive the timbre of instruments and voices as 'unnatural'.
This, however, is not the timbre of the transducer or room though despite transducers and rooms having a timbre.
A while back I posted some links to interesting videos on psychoacoustics and one of them has an experiment that shows the timbre of a speaker in a room.
What they did was record an instrument, reproduce it in a room, and then record that sound, play the recording back over the same gear, record that, play that recording back etc. etc. after 100 iterations or so the 'timbre' of room and speakers was clearly audible.
Can't remember which of the videos it was and what time stamp.

So yes, there is a 'timbre' but that's mostly frequency response deviations so not timbre but sound signature/tonal balance/tone.
Timbre implies more than 'tone' so should not be used in audio reproduction.

 

[Randyman...]

Exactly.
The point is that the amount of generated harmonics and decay of transducers is so low (and short lived) compared any musical instrument is that it sounds awfully 'dry' and is not perceived as having a 'sound' at all. Rooms will have longer decays though and much bigger frequency response deviations than the transducers.
All speakers have a very similar (and inaudible 'timbre') when it comes to attack, sustain and decay and at 'normal' listening levels the generated harmonics are so low in amplitude that one cannot speak of it having a sound unless it is a continuous single tone at high SPL.

The crux of transducers (and rooms) having a sound signature is simple amplitude variations (per frequency) which can modify the recorded sound in ways that make us perceive the timbre of instruments and voices as 'unnatural'.
This, however, is not the timbre of the transducer or room though despite transducers and rooms having a timbre.
A while back I posted some links to interesting videos on psychoacoustics and one of them has an experiment that shows the timbre of a speaker in a room.
What they did was record an instrument, reproduce it in a room, and then record that sound, play the recording back over the same gear, record that, play that recording back etc. etc. after 100 iterations or so the 'timbre' of room and speakers was clearly audible.
Can't remember which of the videos it was and what time stamp.

So yes, there is a 'timbre' but that's mostly frequency response deviations so not timbre but sound signature/tonal balance/tone.
Timbre implies more than 'tone' so should not be used in audio reproduction.

And we all know recording a sound and listening to it in a room is not the same as being in the room with the original sound. We all know how recordings of our systems sound weird - even with 1 pass. Our ear/brain filters all that out when we are "in the environment". Mic's and reproduction won't allow us to filter that data out as the spatial cues we use for that are totally gone in the recording.

I argue that is not timbre. But I'm the minority How would you compartmentalize the timbre of a human voice, and do different systems fundamentally change that timbre? Or is the voice and performance itself what defines the timbre?

And put a "hack" drummer on a ideal drum kit and record. Put a seasoned player on the same kit and record. The timbre will be vastly different I guarantee - stick technique, power, dynamics, "oomph" with make it sound like a different kit with totally different impact and feel. Same for any guitar. I don't think that can be "measured".

 

[Galliardist]

Well, the instrument itself.

But I agree that the musician has an impact on timbre.

In the "musical" definition, no. It's a property of the instrument. There is I guess an assumption that the performer will get a sufficiently good performance from the instrument. And let's face it, most of us are not buying an expensive audio system to accurately reproduce the sound of a kid's first violin lesson.

It may seem a strange definition, but if you think about it, like many things it's not about us. The "musical" definition of timbre and the sound of an instrument is actually of most importance to the builders of the musical instruments.

We are indeed interested in the performer-instrument combination, of course. But that is called a "performance", not "timbre". And the stuff that measures how that works - mentioned in the question - are indeed the standard measurements of distortion and frequency response that have been in use since - well, Edison, I suppose.

 

[Randyman...]

In the "musical" definition, no. It's a property of the instrument. There is I guess an assumption that the performer will get a sufficiently good performance from the instrument. And let's face it, most of us are not buying an expensive audio system to accurately reproduce the sound of a kid's first violin lesson.

It may seem a strange definition, but if you think about it, like many things it's not about us. The "musical" definition of timbre and the sound of an instrument is actually of most importance to the builders of the musical instruments.

We are indeed interested in the performer-instrument combination, of course. But that is called a "performance", not "timbre". And the stuff that measures how that works - mentioned in the question - are indeed the standard measurements of distortion and frequency response that have been in use since - well, Edison, I suppose.

How to separate the musician/performance from the instrument - when the "instrument" is a human voice? Seems like no one is speaking about timbre WRT biological instruments...

 

[Chagall]

In the "musical" definition, no. It's a property of the instrument. There is I guess an assumption that the performer will get a sufficiently good performance from the instrument. And let's face it, most of us are not buying an expensive audio system to accurately reproduce the sound of a kid's first violin lesson.

It may seem a strange definition, but if you think about it, like many things it's not about us. The "musical" definition of timbre and the sound of an instrument is actually of most importance to the builders of the musical instruments.

We are indeed interested in the performer-instrument combination, of course. But that is called a "performance", not "timbre". And the stuff that measures how that works - mentioned in the question - are indeed the standard measurements of distortion and frequency response that have been in use since - well, Edison, I suppose.

Sure it's a performance, but a singer can change the timbre of his/her voice and a violin can have different timbres if the musician bows or picks the strings.