Alternative perspective on the Harman loudspeaker preference curve.

[Ellebob]

Another thing to consider with these preference studies is at what volume are they conducted. Our preference changes at different volumes.

 

[sigbergaudio]

Maybe for the sake of clarity, especially to newcomers, also state that these are in-room responses (vs the underlying flat anechoic responses) and that the “bass hump” is the result (simply room gain) of the otherwise anecoicaly flat speaker.

As for the number of test subjects, afaik those 11 where the very initial test group. Other studies followed. One of which (by S Olive ) if I remember correctly, roughly quantified the proportion of listeners preferring more (ca 21%), less bass (ca 15%) bass by letting listeners adjust bass to their preference. It also showed that older listeners prefer less bass on average.

Again, as I am quoting from memory, I might be wrong and it is difficult to summarize all the studies as I have not seen such a summary. Overall I once read that several hundred had been conducted with various objectives and states of progression.

Maybe @Floyd Toole can chime in and give some hints or clarification?

There was another thread who gave some commentary on the study here: https://www.audiosciencereview.com/...ut-room-curve-targets-room-eq-and-more.10950/

And the actual paper is here: https://www.aes.org/e-lib/browse.cfm?elib=17839

And the way I understood the study, the listeners were allowed to adjust bass and treble to their preference, so the curves are actually EQed to the preference of the listener. Would they have chose something else (and more conservative) after prolonged listening or at home? Perhaps. But I think the curves are somewhat representative of what I typically see(hear) in the wild, despite the limited number of participants.

@JoachimStrobel I don't think "untrained" is meant to be derogatory. The whole point of this thread is also to point out that the difference isn't that big. "Trained" is not specified or defined in the paper, but I assume those may be people working at Harman and having some experience. Harman actually have an app to help you discern frequency deviance that can be quite useful, it's called How to listen, available here: https://harmanhowtolisten.blogspot.com/2011/01/welcome-to-how-to-listen.html

 

[AstroMik]

Target curve? Good subject, great discussion!
However, without SPL spec on the third axis, the 'target curve' is meaningless IMHO. A 5"-er can be EQ-ed to 20Hz, but no chance to hear it. A good 6" get reasonable from 50Hz. But to recreate concert (rock or classical) level bass, need a JBL2226 for the punch. Off course, need a compromise in the size and cost, but this will change the 'curve' at different SPL. So any study should include details of the reproducing gear. And that gear should be able to produce much more SPL in linear than actually needed. This study can conclude the 'preferred curve' in an objective way.

my 2c

 

[abdo123]

I didn’t know anyone took these graphs seriously.

They are to show that there is a difference but not to describe what the difference is exactly as that will require much more work.

 

[Bjorn]

Optimal curve is quite dependent on several factors.

If speakers have very low distortion, there's no typical floor bounce and a general more even response, plus the acoustics is great; the curve can be much flatter than the Harman preference respons without sounding too lean or bright with most music.

 

[YSC]

I forgot where did I read but I somehow recall if it’s nearfield above like 200hz it should be flat rather than sloping down?

 

[Sokel]

I think that there's some confusion between Harman loudspeaker preference curve and the Estimated In Room Response we see in Amir's charts.
The former is a preference,the later is a math computation which one of the parameters is the response of a bunch of rooms.

We shouldn't confuse those two.

 

[sigbergaudio]

I forgot where did I read but I somehow recall if it’s nearfield above like 200hz it should be flat rather than sloping down?

I guess it's more that when you get closer the response will naturally become flatter as there is more direct sound.

 

[YSC]

I guess it's more that when you get closer the response will naturally become flatter as there is more direct sound.

I think along that line, so if used nearfield the target should only be on the bass slope up, but not the higher frequency sloping down

 

[sigbergaudio]

I think along that line, so if used nearfield the target should only be on the bass slope up, but not the higher frequency sloping down

So to be clear, this is still not a target. It's what some guys (I'm going out on a limb and guessing there were no women in this study ) preferred when listening to some good speakers over at Harman.

 

[ernestcarl]

What happens above 500-1khz or so depends on a combination of the speakers and the room (unless you force it of course, which you shouldn't).

I say you could "nudge" the room-speaker response to be more linear as long as the correction holds well spatially and one is not pushing the drivers elsewhere into distortion.

The preferred curve is also going to be room/venue, volume loudness, and sometimes even genre content dependent.

"There’s an awful lot of art in speaker design. It isn’t a purely technical pursuit," Gunness said. "And there’s a lot of aesthetic decisions that have to be made to really make it sound the way it needs to. So we tune speakers for a Las Vegas nightclub much differently than we do for a church, a jazz club or a theme park."

Sound reproduction does not begin and end only within the confines of our domestic living rooms.

 

[anotherhobby]

So to be clear, this is still not a target. It's what some guys (I'm going out on a limb and guessing there were no women in this study ) preferred when listening to some good speakers over at Harman.

Whether appropriate or not, I think it's pretty clear that many people use this curve as a goal, or "target" if you will, for the in-room response they want to get as close to as possible when using DSP and/or room correction. While the curve itself was not designed as a target, it still is very frequently used as one, as least in the way a lot of people think of the word "target" as being something to aim for.

 

[sigbergaudio]

I say you could "nudge" the room-speaker response to be more linear as long as the correction holds well spatially and one is not pushing the drivers elsewhere into distortion.

The preferred curve is also going to be room/venue, volume loudness, and sometimes even genre content dependent.

"There’s an awful lot of art in speaker design. It isn’t a purely technical pursuit," Gunness said. "And there’s a lot of aesthetic decisions that have to be made to really make it sound the way it needs to. So we tune speakers for a Las Vegas nightclub much differently than we do for a church, a jazz club or a theme park."

Sound reproduction does not begin and end only within the confines of our domestic living rooms.

Sure, one could adjust the overall tonality above 500hz with tilt functions as well.

To be fair I don't think this curve was meant to indicate how things should sound in a church, a jazz club or a theme park.

 

[sigbergaudio]

Whether appropriate or not, I think it's pretty clear that many people use this curve as a goal, or "target" if you will, for the in-room response they want to get as close to as possible when using DSP and/or room correction. While the curve itself was not designed as a target, it still is very frequently used as one, as least in the way a lot of people think of the word "target" as being something to aim for.

Yes, unfortunately. Data is good, but not necessarily very useful when you don't understand what it means.

 

[anotherhobby]

Yes, unfortunately. Data is good, but not necessarily very useful when you don't understand what it means.

Do you feel it's inappropriate for somebody to aim for this in-room response using DSP?

 

[NTK]

Do you feel it's inappropriate for somebody to aim for this in-room response using DSP?

This is what Dr Toole (the "originator" of the "curve") said about it in his post:

Blind Listening Test 2: Neumann KH 80 vs JBL 305p MkII vs Edifier R1280T vs RCF Arya Pro5

My take as I've done many times, speakers that exaggerate the pattern on/off-axis may sound harsh while speakers with inverted pattern sound smoother. How can a speaker exaggerate the pattern on-axis?

www.audiosciencereview.com

​

Let me state now: there is no, nor can there be, a single ideal steady-state “target” room curve. The room curve is a result of a loudspeaker delivering sound to a complex semi-reflective listening environment. If that loudspeaker is a typical forward-firing design, with desirably flat and smooth on-axis frequency response, and desirably smooth, gradually changing, off-axis frequency response, the room curve in typical rooms will have a gradual, quite linear, downward tilt above about 500 Hz. This result is strongly correlated with double-blind listening tests – but it is the anechoic measurements that are definitive of sound quality, not the room curve. If the loudspeaker is not “well designed”, and many are not, especially in off-axis behavior, the steady-state room curve will not be a smooth decline. Equalizing it to have that shape guarantees nothing. The loudspeaker is at fault, and the solution is most likely a better loudspeaker. That is why, these days, it is such a powerful advantage to have anechoic spinoramas available on so many products. It takes much of the guesswork out of getting genuinely neutral sound reproduction.​

​

 

[anotherhobby]

This is what Dr Toole (the "originator" of the "curve") said about it in his post:

Blind Listening Test 2: Neumann KH 80 vs JBL 305p MkII vs Edifier R1280T vs RCF Arya Pro5

My take as I've done many times, speakers that exaggerate the pattern on/off-axis may sound harsh while speakers with inverted pattern sound smoother. How can a speaker exaggerate the pattern on-axis?

www.audiosciencereview.com

​

Let me state now: there is no, nor can there be, a single ideal steady-state “target” room curve. The room curve is a result of a loudspeaker delivering sound to a complex semi-reflective listening environment. If that loudspeaker is a typical forward-firing design, with desirably flat and smooth on-axis frequency response, and desirably smooth, gradually changing, off-axis frequency response, the room curve in typical rooms will have a gradual, quite linear, downward tilt above about 500 Hz. This result is strongly correlated with double-blind listening tests – but it is the anechoic measurements that are definitive of sound quality, not the room curve. If the loudspeaker is not “well designed”, and many are not, especially in off-axis behavior, the steady-state room curve will not be a smooth decline. Equalizing it to have that shape guarantees nothing. The loudspeaker is at fault, and the solution is most likely a better loudspeaker. That is why, these days, it is such a powerful advantage to have anechoic spinoramas available on so many products. It takes much of the guesswork out of getting genuinely neutral sound reproduction.​

​

That includes a very strong qualifier that the statement is for speakers that are not well defined and don't have smooth off-axis behavior. Sorry I wasn't more specific, but my curiosity is for speakers that have smooth off-axis response.

 

[sigbergaudio]

Do you feel it's inappropriate for somebody to aim for this in-room response using DSP?

Personally I would be reluctant to alter the natural response of the speakers above the Schroeder frequency. If the speaker is decent, it should have a good natural response. But of course if the overall tonality is too bright or too dark, one could try to tilt this. What I definitely wouldn't do is to try to smoothen out bumps in the response to force it to the target.

 

[NTK]

That includes a very strong qualifier that the statement is for speakers that are not well defined and don't have smooth off-axis behavior. Sorry I wasn't more specific, but my curiosity is for speakers that have smooth off-axis response.

This is what Dr Toole also said in another post at AVSForum:

https://www.avsforum.com/threads/official-jbl-synthesis-pro-revel-home-theater-thread.2515137/page-42?post_id=57820394&nested_view=1#post-57820394

If a "target' curve has been achieved, and the sound quality is not satisfactory, the suggestion is often to go into the menu, find the manual adjustment routine, and play around with the shape of the curve until you or your customer like the sound. This is not a calibration. This is a subjective exercise in manipulating an elaborate tone control. Once set it is fixed, and in it will be reflected timbral features of the music being listened to at the time. In other words, the circle of confusion is now included in the system setup. By all means do it, but do not think that the exercise has been a "calibration". Old fashioned bass & treble tone controls and modern "tilt" controls are the answer and they can be changed at will to compensate for personal taste and excesses or deficiencies in recordings. Sadly, many "high end" products do not have tone controls - dumb. It is assumed that recordings are universally "perfect" - wrong!
​

 

[olieb]

Personally I would be reluctant to alter the natural response of the speakers above the Schroeder frequency. If the speaker is decent, it should have a good natural response. But of course if the overall tonality is too bright or too dark, one could try to tilt this. What I definitely wouldn't do is to try to smoothen out bumps in the response to force it to the target.

It is instructive to look at the data in the diagram in this respect.
Here are the traced curves for trained and untrained normalized to 2k and the difference between them.
Besides a preference difference in bass the difference curve is astonishingly linear from 500Hz onward.
So the "untrained" listeners - on average - did not EQ any bumps into the FR but preferred a continuous trend for more brightness - compared to "trained".