Timber/Timbre/Tymber/Tymmer matching for surround speakers

[Marakk]

So I get the concept of matching timbre for the front speakers. There will be small deviations and characteristics in the frequency response and the build and the drivers,, even if the general trend measures the same, and you want that match for your for your front soundstage. However, is timbre matching important for the surround speakers? Now I know it has been asked and answered with subjective opinions and experiences more than a hundred times on different forums, but I wanted a more scientific explanation of this if you will.

Consider my scenario. My front is going to be JBL Stage A120, and I can get the same for surrounds, which I will be placing on the back wall, as side wall isn't possible, 2 feet above the listeners' ears as recommended. There will be a small segment of wall, 5-6 inch, next to speakers on outer side of each speaker though, bouncing sound inwards towards listeners and hopefully help with some more diffusion.

So in such a case, is timbre matching important? Why I ask is that the listeners' ears will be almost 90° below the speakers and the 90° to the side. Isn't the frequency response terribly chewed up in such placement? Even if we consider placements that aren't this extreme, the listeners are still at off-axis positions that wouldn't be recommended for critical listening otherwise. Suckouts and other weird deviations would still be happening, unless it's coaxial configuration, right? So does timbre matching make any sense in terms of what we can measure? Is the effect just psychological?

Then when it comes to placement, would I better off if I don't worry about timbre matching, and go with downfiring speakers or speakers such as Dali Alteco C1, which can be tilted down by 45°? Or bipoles maybe?

 

[Senior NEET Engineer]

I would not use surround speakers with these constraints.

 

[Marakk]

Fair enough, but a lot people do have their surround speakers on the back wall. Dali Alteco C1's allow a lot of flexibility in positioning. For example, I can place them 2 feet above, but instead of them facing them down, I can mount them horizontally, and they also have two orientations, one about 20° inwards and the other 45° or so.

What I do lose by going with them is the supposed timber match. However, back to my original query, is timber matching really concern when listening majorly off-axis?

 

[pozz]

I'm not sure where you picked up the term "timbre matching". All that really refers to is on-axis and off-axis frequency response. Which means you're answering the same set of questions about rear/surround speakers as your mains: What do you like? How deep should the bass extend? Wide/narrow directivity?

With multichannel you're usually considering multiple listeners, so rear speaker directivity should be wide and bass should be deep enough for realism.

So the basic answer is: yes, all speakers should be the same or close to that, since the rear/side speakers usually play only ambience and effects and so you can use cheaper or smaller models with similar FR. Once you get the sound you want out of the mains, choosing others with a significantly different response will change the tonal balance of your room.

Mounting the rear speakers so that they fire down at the listeners is, again, because the idea is to produce ambient rather than direct sound. Your description isn't too clear to be honest (a diagram would help), but it would make sense to use bipoles or other purpose-made surround speakers in any case, especially if your circumstances are constrained.

 

[Marakk]

Well, I picked up the term by going through forums and posts of others. Basically the idea seemed to be that sounds moving from back to front will sound similar if they are from speakers that are "timbre matched".

Let me reframe my question with an experimental setup. My room doesn't matter. Let's say you're listening to a speaker directly on-axis. Then there's another speaker on the side facing towards you, the same distance away, but 2 feet above you. Let's assume vertical angle to be -20°.

Then place two speakers there, both with good frequency response and equal low frequency extensions, but some differences that do make them sound different on-axis. One is the exact same speaker as the front, but it's vertical response at -20° has deep dip in the crossover range along with uneven tweeter frequency at that angle too, things that aren't present in its on-axis response. The other speaker is a coaxial design with its response being better at -20° vertical than the speaker in the front.

Which would be a better fit? If we pan the sound from one the other, will the same speaker, even though its response isn't good at that angle, offer a more seamless listening and blend with the front speaker better, or will the other speaker be a better for because it's off-axis response at that angle is better?

 

[mhardy6647]

I have nothing useful to offer but I wanted to mention that the thread title made me LOL (as they say).

That said, the OP forgot tambour...

 

[pozz]

Well, I picked up the term by going through forums and posts of others. Basically the idea seemed to be that sounds moving from back to front will sound similar if they are from speakers that are "timbre matched".

Let me reframe my question with an experimental setup. My room doesn't matter. Let's say you're listening to a speaker directly on-axis. Then there's another speaker on the side facing towards you, the same distance away, but 2 feet above you. Let's assume vertical angle to be -20°.

Then place two speakers there, both with good frequency response and equal low frequency extensions, but some differences that do make them sound different on-axis. One is the exact same speaker as the front, but it's vertical response at -20° has deep dip in the crossover range along with uneven tweeter frequency at that angle too, things that aren't present in its on-axis response. The other speaker is a coaxial design with its response being better at -20° vertical than the speaker in the front.

Which would be a better fit? If we pan the sound from one the other, will the same speaker, even though its response isn't good at that angle, offer a more seamless listening and blend with the front speaker better, or will the other speaker be a better for because it's off-axis response at that angle is better?

It seems like you answered the question already: speakers well-behaved on and off axis will be better no matter how they are positioned.

The real world of speaker choice and positioning requires some knowledge of what actual on and off axis response is like, since you may not get the desired FR by sitting directly on axis but some angle off. That way you can tailor speaker or sitting positioning as needed.

Does that make sense?

 

[Marakk]

It seems like you answered the question already: speakers well-behaved on and off axis will be better no matter how they are positioned.

The real world of speaker choice and positioning requires some knowledge of what actual on and off axis response is like, since you may not get the desired FR by sitting directly on axis but some angle off. That way you can tailor speaker or sitting positioning as needed.

Does that make sense?

Let me get more specific. What if the front speaker is JBL HDI 1600 and the second speaker in contention is KEF R3? Now we know via measurements that JBL HDI 1600 doesn't perform well at -20° vertical. So in the hypothetical scenario that I mentioned, would KEF R3 be a better option for the side speaker, or is there something more at play here that'll make JBL HDI 1600 sound more seamless, even though the response is chewed up?

 

[pozz]

Let me get more specific. What if the front speaker is JBL HDI 1600 and the second speaker in contention is KEF R3? Now we know via measurements that JBL HDI 1600 doesn't perform well at -20° vertical. So in the hypothetical scenario that I mentioned, would KEF R3 be a better option for the side speaker, or is there something more at play here that'll make JBL HDI 1600 sound more seamless, even though the response is chewed up?

The KEF R3 in that specific scenario is better because you will worry less about having listeners at specific heights for optimal response. FR, directivity and bass extension covers it all.

 

[rrahmanucla]

So I get the concept of matching timbre for the front speakers. There will be small deviations and characteristics in the frequency response and the build and the drivers,, even if the general trend measures the same, and you want that match for your for your front soundstage. However, is timbre matching important for the surround speakers? Now I know it has been asked and answered with subjective opinions and experiences more than a hundred times on different forums, but I wanted a more scientific explanation of this if you will.

Consider my scenario. My front is going to be JBL Stage A120, and I can get the same for surrounds, which I will be placing on the back wall, as side wall isn't possible, 2 feet above the listeners' ears as recommended. There will be a small segment of wall, 5-6 inch, next to speakers on outer side of each speaker though, bouncing sound inwards towards listeners and hopefully help with some more diffusion.

So in such a case, is timbre matching important? Why I ask is that the listeners' ears will be almost 90° below the speakers and the 90° to the side. Isn't the frequency response terribly chewed up in such placement? Even if we consider placements that aren't this extreme, the listeners are still at off-axis positions that wouldn't be recommended for critical listening otherwise. Suckouts and other weird deviations would still be happening, unless it's coaxial configuration, right? So does timbre matching make any sense in terms of what we can measure? Is the effect just psychological?

Then when it comes to placement, would I better off if I don't worry about timbre matching, and go with downfiring speakers or speakers such as Dali Alteco C1, which can be tilted down by 45°? Or bipoles maybe?

Where did you get the impression that surround speakers should be 2 ft above listener ears? My interpretation from the Dolby site is that they should be at ear level.

Also for surround speakers I think you will be surprised how little content they actually play during movies. When they do its usually in complex action scenes where SPL matters most and the subtleties of timbre mismatch are difficult to detect. I would just pick solid speakers with good spinorama's. I doubt it would make a big difference, but since ATMOS algorithms like point sources, maybe something leaning on the higher directivity side.

 

[Marakk]

Where did you get the impression that surround speakers should be 2 ft above listener ears? My interpretation from the Dolby site is that they should be at ear level.

Also for surround speakers I think you will be surprised how little content they actually play during movies. When they do its usually in complex action scenes where SPL matters most and the subtleties of timbre mismatch are difficult to detect. I would just pick solid speakers with good spinorama's. I doubt it would make a big difference, but since ATMOS algorithms like point sources, maybe something leaning on the higher directivity side.

https://www.svsound.com/blogs/speaker-setup-and-tuning/74790851-the-art-of-speaker-placement

 

[Marakk]

I have nothing useful to offer but I wanted to mention that the thread title made me LOL (as they say).

That said, the OP forgot tambour...

View attachment 63963

https://getyarn.io/yarn-clip/bc60bf99-d881-4b44-aab8-46b8b280a4e2#xvzvmqL3hp.copy

 

[pozz]

https://www.svsound.com/blogs/speaker-setup-and-tuning/74790851-the-art-of-speaker-placement

The advice is supposed to decrease direct sound in favour of reflections. It also seems to be based on their specific speakers (the rears might be downfiring?) since the angle placement don't match the ITU recommendations used for mixing/mastering/film postproduction. What that means is if the rear channels do have explicit musical content you won't be able to hear it clearly with the SVS setup.

 

[Kal Rubinson]

https://www.svsound.com/blogs/speaker-setup-and-tuning/74790851-the-art-of-speaker-placement

But why? In my experience, it is done to accommodate group listening so that there is a clean path from speaker to all listeners' ears.

The advice is supposed to decrease direct sound in favour of reflections.

Yeah. A loss of specificity is another way of describing that. Ear-level is, imho, to be preferred.

 

[JoachimStrobel]

Let me get more specific. What if the front speaker is JBL HDI 1600 and the second speaker in contention is KEF R3? Now we know via measurements that JBL HDI 1600 doesn't perform well at -20° vertical. So in the hypothetical scenario that I mentioned, would KEF R3 be a better option for the side speaker, or is there something more at play here that'll make JBL HDI 1600 sound more seamless, even though the response is chewed up?

Depends what you want. For most movies, the surrounds carry the ambience (here comes my example from Star Wars 1/4 with the space station in the opening). Centre carruse the Dialog, left and right the Action. When emerged in any movie, this is all you need. The helicopter whirling and street sounds from left behind are distracting. So anything will do as long as the movie is good.
And for immersive musical Mch, all speakers need to be time and volume aligned, and yes, “timbre” matched =>DRC.
For in between cases, like Music with ambience but no centre speaker soundstage, some middle ground might work.

 

[BsdKurt]

I've been meaning to start a thread called "Timbre Matching Fact or Fiction", then I saw this one and well, it seem like it fits here too. I was wondering if timbre matching was just another snake-oil way for manufactures to get you to buy all your home theater speakers from one company and line?

I picked up Dr. Toole's Sound Reproduction book recently and haven't gotten very far, but when I looked up timbre in the index it says 'See sound quality". Sound quality in the index has 11 references that seem pretty diverse. So what do the experts here think? Is there really a measurable thing called timbre matching that you can match up speakers for a home theater by comparing the spinorama or is this just marketing double speak to get people to just buy all from the same line?

 

[direstraitsfan98]

I would think that if you got a speaker from a completely different manufacture that the sensitivity and power handling and other stats would be completely different and the volume levels would be off and not match your fronts. But it is a fact that the human ear is extremely bad at hearing differences in sound unless it is front of you. In other words, our sensitivity to sound, our perception is massively reduced when it comes to audio to the side and behind us. Its unlikely you will hear any difference in sound if both speakers measure the same. If you're using a AVR with room correction, they will certainly apply EQ to make everything flat and even.

But almost no two speakers are exactly the same specs. That is why it is better to just pickup speakers from the same brand and line.

 

[BsdKurt]

I would think that if you got a speaker from a completely different manufacture that the sensitivity and power handling and other stats would be completely different and the volume levels would be off and not match your fronts. But it is a fact that the human ear is extremely bad at hearing differences in sound unless it is front of you. In other words, our sensitivity to sound, our perception is massively reduced when it comes to audio to the side and behind us. Its unlikely you will hear any difference in sound if both speakers measure the same. If you're using a AVR with room correction, they will certainly apply EQ to make everything flat and even.

But almost no two speakers are exactly the same specs. That is why it is better to just pickup speakers from the same brand and line.

What I want to know is: Does it matter? If is does, how through measurements can you do timbre matching?

If there's no objective way to timbre match speakers, I would think that timbre matching is marketing double speak.

 

[Marakk]

What I want to know is: Does it matter? If is does, how through measurements can you do timbre matching?

If there's no objective way to timbre match speakers, I would think that timbre matching is marketing double speak.

On-axis, I'm sure timbre matching matters because you're getting direct sound from the speakers and variations in the response will be heard.

I wanted to know if there's a scientific reason behind surrounds being timber matched even if you're listening to them off-axis. Maybe the reflections and the total sum still matters? Ear compensates? We need some blind testing for objective answers.

Let me know if you find more relevant information in the book you're reading.

 

[Marakk]

The advice is supposed to decrease direct sound in favour of reflections. It also seems to be based on their specific speakers (the rears might be downfiring?) since the angle placement don't match the ITU recommendations used for mixing/mastering/film postproduction. What that means is if the rear channels do have explicit musical content you won't be able to hear it clearly with the SVS setup.

So based on these then, if placed on rear wall above listener, which I think is also done to increase distance for listeners, so that one isn't sitting too close to a single speaker, downfiring speakers such as Dali Alteco C1 be a better fit for compromised placement?