Can Objective Loudspeaker Measurements Predict Subjective Preferences?

Can measurements predict listening preferences in loudspeakers?

  • Yes. If the proper measurements are conducted

    Votes: 33 70.2%
  • No. What we hear is far too complex to fully quantify empirically.

    Votes: 8 17.0%
  • Who cares. Just get what sounds good to you and be done with it.

    Votes: 6 12.8%

  • Total voters
    47
Art Vandelay

Art Vandelay

Audioholic
Ratings
36
#61
While I did not know how many speaker manuafacturers were specing distortion, I did know B&W does. In any case, my main point in this a case was more about understanding the system. Not much point in pursuing amplifiers that have really low distortion, when your speakers are order of magnitude worse. Anyway, good choice on your part.
FTR I performed my own measurements with an Earthworks microphone and a low distortion analyser.


As for measuring speakers in a room, distortion is more of a relative measurement. Frequency response is clearly more of a direct measure and while the real challlenge is at lower frequencies, you make a interesting point about the impact of ceiling reflections. While they do impact FR measurement, there are major questions over their audibilty. If you have not already done so, suggest you read this https://www.audioholics.com/room-acoustics/room-reflections-human-adaptation or better yet, get Dr Toole’s book.
I haven't read the entire book but I have read excerpts as well as many of his forum posts. Like most people with an audio system I've spent a reasonable amount of time trying to get the best possible sound at the listening chair, and to that end I regard his work as an invaluable reference. It definitely can't hurt to have some understanding of speaker and listening room interactions, to the point of being able to predict what tonal colorations are likely, but we're also fortunate these days to have an abundance of low cost tools to perform measurements and simulations.

In a more simple way, consider a performer playing a violin in your room. If your room treatment really improved the sound quality of the live performer, it may be worthwhile.
But how valid is the comparison between an instrument and a speaker, when the two radiate sound energy in very different ways?

FWIW, I constructed my own convolver filter from live measurements to correct a dominant room mode at 38Hz and it made a big difference; removing a bass boom issue that was negatively impacting many recordings. However, high frequency reflections are not necessarily as measurable as they are audible, due to the fact that they impact more on time domain performance.

I tend not to use much in the way of sound absorption treatment, but there are curtains, carpet and sofas etc that do reduce mid and high frequency reflections.
 
W

Winkleswizard

Audioholic
Ratings
50
#62
FTR I performed my own measurements with an Earthworks microphone and a low distortion analyser.




I haven't read the entire book but I have read excerpts as well as many of his forum posts. Like most people with an audio system I've spent a reasonable amount of time trying to get the best possible sound at the listening chair, and to that end I regard his work as an invaluable reference. It definitely can't hurt to have some understanding of speaker and listening room interactions, to the point of being able to predict what tonal colorations are likely, but we're also fortunate these days to have an abundance of low cost tools to perform measurements and simulations.



But how valid is the comparison between an instrument and a speaker, when the two radiate sound energy in very different ways?

FWIW, I constructed my own convolver filter from live measurements to correct a dominant room mode at 38Hz and it made a big difference; removing a bass boom issue that was negatively impacting many recordings. However, high frequency reflections are not necessarily as measurable as they are audible, due to the fact that they impact more on time domain performance.

I tend not to use much in the way of sound absorption treatment, but there are curtains, carpet and sofas etc that do reduce mid and high frequency reflections.[/QUOTE

My original posting was referring to room/speaker frequency response measurements. So I took your comments about reflections in that measurement context. You will have a first reflection from the ceiling (notably for a typical eight foot one). This does affect FR measurement. If you did your ceiling treatment for some other reason, that was not clear to me. Toole’s book does not discuss much about ceiling treatment, but does state “...numbers and graphs are not always simply or logically related to what we hear”.

This plays to my point in the context of the OP. I can tell you I have heard great sound in setups that were never measured and had no room treatment or any frequency/time domain processing. While there is some substantial science about improving sound at low frequencies, beyond that, the answers are more complex as recording quality and psychoacoustics play more significant roles. In this case however, reflections are an essential part of how we localize sound. This is true whether the source is a speaker, a musical instrument or a mechanical noise. So, while in favor of science, when there is scientific uncertainty, I admit I rely on what sounds good to me. ;)

Ww
 
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Art Vandelay

Art Vandelay

Audioholic
Ratings
36
#63
My original posting was referring to room/speaker frequency response measurements. So I took your comments about reflections in that measurement context. You will have a first reflection from the ceiling (notably for a typical eight foot one). This does affect FR measurement. If you did your ceiling treatment for some other reason, that was not clear to me. Toole’s book does not discuss much about ceiling treatment, but does state “...numbers and graphs are not always simply or logically related to what we hear”.
Ceiling reflections might be in the range 6 -10 dB below the direct path signal, but they don't necessarily make a huge difference to measurements at the listening position when FR is averaged over a region, which is how it's typically done. I think there's been an assumption that ceiling reflections are less problematic because the ceiling is further away from a tweeter than the side walls in a typical compact listening room, but in rooms where that distance is more similar it stands to reason that ceiling reflections will be a contributor to the tonal balance, if for no other reason than the fact that most speakers exhibit a very uneven frequency response at angles >30 degrees above the tweeter axis. It's really just a rearrangement of the argument that speakers which exhibit a more uniform polar response in the horizontal plane will sound more accurate in a typical small room.


This plays to my point in the context of the OP. I can tell you I have heard great sound in setups that were never measured and had no room treatment or any frequency/time domain processing. While there is some substantial science about improving sound at low frequencies, beyond that, the answers are more complex as recording quality and psychoacoustics play more significant roles. In this case however, reflections are an essential part of how we localize sound. This is true whether the source is a speaker, a musical instrument or a mechanical noise. So, while in favor of science, when there is scientific uncertainty, I admit I rely on what sound good to me. ;)
I actually voted for option 3, because in the end our ears and brain make the best fft analyser.
 
W

Winkleswizard

Audioholic
Ratings
50
#64
Ceiling reflections might be in the range 6 -10 dB below the direct path signal, but they don't necessarily make a huge difference to measurements at the listening position when FR is averaged over a region, which is how it's typically done....

Yes, just realized a significant difference in what we are measuring. I use REW to measure a single speaker in a room. So am usually gating a measurement based on a ceiling reflection. The goal in this case is to remove the effect of the ceiling interaction from the measurement and it does make a significant difference. I gather you are measuring different speakers from one or more listening positions with the goal of determining how room modes affect the overall sound. This would be a lot more work to do well. To equalize meaningfully at frequencies above 300 Hz, Toole states that (the notion the traditional 1/3 octave analyzer) can reliably predict what is perceived by two ears and a brain is “preposterous”. Since I am pretty sure that at least 2 of my AVRs attempt to do just this, I only use the DSP for home theater and use direct mode for music listening.

I will admit being biased against too much processing. I have heard some interesting results from surround modes, but to me, has never seemed consistently natural sounding with different music recordings.

Ww
 
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Ridire Fáin

Ridire Fáin

Enthusiast
Ratings
4
#65
Accurately measuring loudspeaker performance is pretty much a universal problem among most loudspeaker manufacturers and ALL AV review publications. Harman on the other hand under the guidance of Dr. Floyd Toole and Sean Olive have developed a purely scientific methodology that actually allows them to objectively measure and predict listener preference. This article explores the measurements while also providing the secret formula of the characteristics necessary for producing loudspeakers that score highly in subjective listening tests. This is a must read with a call to action to your favorite loudspeaker company to give us more useful information about their products.

Update (6/11/15): I added a poll question so please cast your vote and give us a reason behind your choice.



Read: How To Objectively Measure Loudspeaker Performance
Measurements can indicate the soundness of the engineering principles involved, quality of the materials, and confirm how well the design is thought out. In most cases it is a smoking gun that a product will sound good but IMHO they are not always a predictor that it actually will. They only instrument that can asses that, is the listener.

There is just too much subjective bias, psycho-acoustic affect, and personal taste when it comes to how good transducers sound. I also do not think we fully understand how both the biological (Body) and psychological (Mind) science works and then comes together within our brains. Sure, we have a grasp of the physics, physiology, and anatomy of the working parts. But what one actually perceives as good sound really differs from one person to another. This is something I believe you cannot measure.
 

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