What part of sound is not measurable? - Page 8

Most people don't care about how a system measures. Frankly I don't care how a system measures. Take any of your favourite albums. Are you listening to the music or listening to the recording? What the measurement brings is the the flexability of the sound system to sound good for a variety of recordings.
Say for example I only listened to solo violin recordings. So I built a speaker inside a Strad. Then every recording I heard sounded like it came from a Strad. Is that not the most ass kicking speaker? How crappy would it measure? The manufacturers mold and react to what the market demands. It would be a travesty if we were forced to purchase "flat" speakers.

To seriously answer your orignal question I need to modify it.
What part of musical sound is not measureable?
Toe-tapping factor
Head banging factor
Emotion
Passion

What part of movie sound is not measureable?
Excitement
"I was there" factor

Certainly if your amp and speaker and room are really bad any part of these elements is lost and on a nice system they are enhanced. When I look at a brochure for a new amp this is what I'ld like to see.

You are treating the recommendation problem as though it were the scientific problem of predicting what the listener will choose. I understand why a scientist would do this, but I think it misses the point that most engages us consumers. If I, as a layman, ask you, as an expert, to tell me what the best speaker is, I probably don't mean that I want you to predict what I will buy. Instead, I want you to tell me what's best -- what I should buy.

If by a "strad" you mean a stradivari violin.... then i would suggest that a flat speaker would be better. Its similar to those omni directional speakers that mean to spread sound in many directions to create the reverb, to "make you feel you're there" at the hall of the recording. But all that does, and all your strad box would do is in effect double on the existing effects and harmonics that were captured by the recording. The recordings would then feel exaggerated and unrealistic. That is, unless this part was meant in jest, in which case please excuse me.

Fidelity to the music is truly not measurable. But there are related matters that are potentially measurable, but are commonly not measured, such as fidelity to the performance or (for HT) the event. In any case, measuring fidelity to the recording is, I agree, of no intrinsic interest.

Maybe you should. Some good reasons have been presented in this thread.


No, it wouldn't. It would sound like a Strad sitting inside a Strad. Not the same thing at all.


None of these are part of a "musical sound." All are mental reactions to a musical sound. That's a key distinction.


Ditto.


Then you're looking in the wrong place. Try a fMRI.

For the most part the measurements have less value to me as I have little experience to couple them with. I'm not saying they have little value to others.


Then to qualify, a speaker designed around a strad to excite its resonances and create the illusion it is being played. Maybe put a bunch of motors on the bridge and excite them with heavy signal processing.


Then how is the "saddness" of the performance transmitted to me without any sound?

I want to be glib and say it isn't—that you listen to the performance, and you decide it sounds sad to you. But of course it may well be that the performer is trying to convey "sadness," and we have conventions for doing that which you interpret as the performer intends you to. But there's no guarantee that you'll interpret something the way the performer intended it, nor would you be in any way "wrong" to interpret it differently. So to say that the emotions you feel as you listen to music are "transmitted" to you seems wrong to me.

But let's assume that you and the performer are on the same wavelength, and you get what he's driving at. How does he do it? Well, he controls aspects of the sound—loudness, tempo, timbre, etc. All of those things are definitely measurable. And therefore we can measure the extent to which an audio system preserves those elements so that you might interpret them as intended.

You seem to be hung up on answering the wrong question.

However, if you want to go there, fidelity to the music is not even an issue. After they get the basics right peforming music is about a musican making the music his own, which is the opposite of fidelity. Musicans who play with perfect fidelity to the music as written are often called "hacks".


That's not a related matter on a forum like this, it is the whole show.


As confused at several basic levels as this post it, well yes! :-(

Predicting what the listener will prefer is of vital interest to many people, not the least of whom is the listener.

As far as applying science to the interests of the listener, why would you have a problem with that, perhaps other than some problem with understanding science?


You're clearing making things more complex than they are. In fact both questions are of interest, what you will buy and what you should buy. Ideally they would be the same.

Part of the process of audiophile education is getting the two to converge.

I see no evidence that you have some unique qualifactions to speak for most audiophiles. You don't know what most people care about. You can only speak for yourself. You shouldn't blow yourself up like this in public - its embarassing for the rest of us.


You probably only think that way because you haven't thought things out. Presumably you do care what the system sounds like and if you understood measures, you'd understand that there is a strong relationship between how a systems measures and how it sounds.


People who listen primarly to the music could in general care less what the recording sounds like. It doesn't take a million dollar stereo system to convey musical values. It doesn't even take a $20 stereo to convey musical values. A $19.95 CD player with the $0.05 earphones that come with it will do a wonderful job of conveying musical values. The beat, the pitch, even all of the signficant musical nuances will be there.

So, talking about listening to the music is completely out of place in a discussion of high quality audio products.


..or any of them.


That's completely weird. Why would you want a strad squared?



Wrong. none of them would sound like they came from a strad. They'd sound like they came from a pretty crappy speaker.

What you are talking about is building a speaker using the case of a strad as its sounding-board instead of a normal diaphragm. In general, musical instrument cases don't make good replacements for the cone of a speaker. Speaker cones are designed to have uniform response to vibrations applied to them, but musical instruments most definately aren't designed to have uniform response to vibrations that are applied to them. Musical instruments are designed to emphasize a certain range of frequencies at the expense of all others. Otherwise, a flute would look like a bass tuba.


Not at all. It's one of the sillier things I've ever head of - probably the thinking of someone who understands very little about either musical instrument or loudpspeakers.


Depends on whether you were comparing it to the standards for a speaker or a violin case.

But, its never going to make every violin recording sound like a strad. It's going to be horrid!


It would not be nearly the travesty of a loudspeaker that used a violin case for a diaphragm. The only thing that such a speaker would make sound like a violin, would be a special recording made of the vibrations of the bridge of a violin.


Again confusion seems to reign in your post. The following are attributes of music that can easily transcend the sound quality of the equipment reproducing it, once that equipment meets certain very minimal standards:



That would be really, really bad. Fact is that all of the above are well-reproduced by a $19.95 CD player.



No, musical values are not enhanced by listening to a really good system. In general, people who are most concerned with musical values are capable of doing their musical work using fairly primitive tools by audiophile standards.

OTOH, what is enhanced by a really good system is the overall experience. It is easier for people who are not vitally involved with music to become more engaged with the whole musical performance if it is reproduced well, unless the quality of the reproduction becomes distracting.


Musicality is a property of music, not audio gear.

The more I work with music and musicans, the more I realize this.

The OP asked "What part of sound is not measurable? "

My answer: For any point in time and space there is only ONE parameter to measure:

PRESSURE

Yes, if all you want to know is pressure. There is also particle velocity, which is of course a vector. It is easily measured via a directional velocity transducer, such as a soundfield-type microphone.

- Terry

Hi Arny,

I think this comment points to the disconnect at hand.

If we take another step back from the problem, we realize that it IS possible to get at least a good indication of how a loudspeaker will sound if you took it outdoors, or even provide a means for a listener to listen to a speaker in isolation through convolution and headphones. The problem is that NO ONE listens to a loudspeaker or any other component of their system in isolation. This isn't news to anyone who has tried to measure a loudspeaker in a small room, but it is the crux of the issue.

We have lots of measurements of loudspeakers and we then have many who hear a speaker that looked to measure well and the sound they hear is terrible. The vast majority of those interested in hi-fidelity audio judge sound by the presentation of the system they hear, which as we all know, means the room acoustics, as well as placement of speakers and listener dictate how the loudspeaker's performance is translated to the listener. More often than not, the translation is not very good, and in plenty of cases preference comes down to what speaker does the least to excite offensive behavior of the room.

While it is much easier to generally define our subjective expectations in the great outdoors, real rooms suddenly require much more information to get even close to the same level of confidence. Likewise, the same aspects are not as important, as others that have no significance outdoors are highly important in our listening rooms. I know we can predict the sound in a room, I just don't think most grasp the exponential increase in complexity and number of variables a listening room adds to the problem.

That's amusing, and reminiscent of Emanuel Lasker's Machaïde (or Macheide), a being which has attained such intellect that it has lost its free will, since it can foresee that all courses of action other than the one it will pursue would turn out badly.

And since different people prefer different direct/reverberent characteristics, I don't see that a standard is even a reasonable thing to suggest. That is, at least until capture and synthesis (i.e. studio recordings) have a standard, and I think that's counter to artistic intent.

It's a start.

I try to keep words to a specific meaning. Keep distortion to refer to nonlinearities. Use frequency and phase shaping to describe frequency and phase shaping, don't call them distortion unless there is a nonlinear component.

Noise is the one ringer, I tend to lump it in with distortion since it is also a lossy process.

And, for that, I must know your preferences. This has nothing to do with "predicting", it has to do with knowing what YOU, personally, like.

For those of you who are not aware, the great outdoors is nature's own anechoic chamber. And it can have better very low frequency performance than the best acoustic laboratories!

Please allow me to point out the error a bit more strongly.

For any point in space, at any time, there are 4, yes, four measurements requred to fully characterize the soundfield.

Three volume-velocities and one pressure, to be specific.

It is for mixing rooms, which is where the sound for speaker reproduction is cast in stone (er, bits). Regardless of diverse studio or live venue recording techniques, the recorded sound is what is heard in the mixing room, through monitor speakers. And those mixing rooms have no standards.

This kind of discussion is hard to describe because music is open to much interpretation:

watch this:
http://www.youtube.com/watch?v=5fybBwlxHNc

So here the intent is to make you jump or scare you. The highest level senders comprised of the directors and actor and the highest level reciever is you. The probably of "scare" transmission, lets guess at 50%. If I were to turn off the volume the scare transmission drops to 5%. If I were to raise the volume to peak at 110 dB then the scare transmission goes up to 60%.

To get to me the scare transmission has to undergo an infinite number of transforms. Each transform is orthogonal to each other. Each transform is a sender must be undone by a reciever to correctly transmit the signal. Each reciever/sender pair operates on the same principles. When done with 100% transmission I can model the reciever/sender pair as a wire.

Pretend the video was a DVD. There is a camera/television pair, an electrical A/D, D/A pair and an optical writer/reader pair. The transmission looks like this:

Director
Camera
A/D
Optical Writer
Optical Reader
D/A
Television
Me

A poor A/D; D/A conversion will result in a loss of transmission for the camera/television pair and will affect the director/me transmission.
In between each pairing is an infinitly complex layer of transforms coexisting on different planes. Our understanding of the principles behind cameras and televisions and A/D and D/A and optics is quite high, hence why it is easy for us to measure. Our understanding of the principles behind the human mind is not so good.

Thank you Terry.

I chose the example of outdoors as this is a tangible environment available to most, vs. a theoretical anechoic chamber or one existing in only a few labs. The point is very important though... A good speaker as viewed in isolation is not the same as a speaker well suited for your room, assuming the room & locations even hold the potential for "good" results.

This is where things get tricky. I get a kick out of undefined mentions of "flat response." Flat with what scale? Zooming in or out on the vertical scale can make any real speaker's frequency response take on the shape of either the great plains or the rocky mountains using the exact same measurement.

I would argue the concept of "flat enough" gets very vague when you have the much more complex situation of a small room. In real rooms the far off axis response variations and lobing can hugely affect the subjective sound quality of a speaker with even the best response imaginable in the forward 30 degrees of radiation. Within the confines of real, affordable devices we can build, there can be compromises in some of the most commonly examined measures which will allow for a better subjective result through significant improvement in other important characteristics... Characteristics which have little significance in mother nature's anechoic chamber.

That's where we disagree.

You are correct that our understanding is not as good as in the video sense, yet we are also talking about a much wider bandwidth with much more complexity in propagation and interpretation by the listener.

Your example still allows for simple experimentation in starting with a case of good communication of these factors. Start inducing distortions or omissions and compare how significantly the communication is deteriorated. The same has already been done at great length for speech intelligibility with much learned from the process.

I presume by "loss of transmission," you do not mean "complete loss of transmission." Of course it can't scare you if you don't see/hear it.

But if that's not what you mean, then you are assuming your conclusion. Given that the D/A conversion happens at all, why should we think it would be scarier, or more likely to be scary, observed on a high-end system rather than through tinny computer speakers? I don't even think making it louder would have the impact you ascribe to it.

I don't buy the notion that highly accurate reproduction is necessary to appreciate an artist's intent. I can "get" Beethoven, and even someone's interpretation of Beethoven, on a boombox. It's not how I choose to listen most of the time, because I also enjoy highly accurate reproduction, and the sense of "being there." But to me, being an audiophile and being a music lover are two different things.

I don't want to have to buy a different speaker for each listening room. I don't want to have to buy loudspeakers based on whether they are 'well suited to my room' except perhaps in terms of SPL, any more than I want to buy an amp or CD player 'well suited to my room'.

So to me a good loudspeaker is one that measures well (as per work relating measurements to listener reports of 'good sound' under well- controlled conditions), I can then EQ the sound or treat the room to capitalize on the performance of the loudspeaker.

It may be that I turn out to be the minority that actually prefers a sound *different* from the Toole/Olive paradigm, but I can only find that out by first knowing what sorts of speakers I am listening to...by virtue of their measured performance.

I am not suggesting that you have to buy a different speaker for every room, but rather that the breakdown and skepticism of measurements by enthusiasts stems from the reality that a small set of measurements which give a decent indication of a loudspeaker outdoors, is grossly insufficient in a real room.

I most certainly believe measurements can tell us a great deal or nearly everything about the sound of a speaker. I don't believe 4-5 2D measurements will ever be sufficient to set our expectations properly in real listening rooms. Most talk of loudspeaker measurements I see don't tell us what we really need to know, and what we need to know isn't yet as simple to examine and decipher as those that apply to anechoic situations.

You're talking about mixing rooms. I agree that we need standards for mixing rooms. I've been cheering Tom Holman on for a long time on that one.

Acoustics, levels, ...

And multichannel means that a lot of older rooms are just WRONG. You don't do multichannel mixing in LEDE. No no no...

But watch the flames on that one.

And what about "smoothing" the curve? (mutter)

Standardization is definitely in order here. 3rd octave smoothing is probably a good and practical first step. EBU 3276 specifies that the ISO standard 1/3 octave discrete bands be used, but that is way too coarse for many purposes. A sliding filter window shows a great deal more detail.

We need an exact spec on how to perform such smoothing. I have never seen one in print. And what length of FFT do we use to calculate the frequency response? What about the actual length of the impulse response, vs. how many zeros are padded at the end to give it the required length for the FFT? And exactly what type of windowing do we apply to the impulse response?

Personally, I'd rather have direct access to the measured impulse response, and do my own frequency and time analysis. But this completely raw data would be totally useless to anyone trying to directly evaluate and compare performance.

Terry, I assume you are familiar with the CLF group/format which was started by most of the acoustic modeling software companies apart from EASE? I'm a big fan of their free viewing tool as a compliment to more detailed/typical data. Interestingly, most all of the data is gathered from impulses. I oversaw getting some speakers from the company I slaved for in a past life to be the first published in the format by a 3rd party testing. Pat Brown of SynAudCon/ETC, Inc. and Ron Sauro of NWAA Labs both provide validated, 3rd party testing for reasonable dollar amounts giving real 10-0.5 degree increment spherical, not just polar (H/V), data.

The perspective of the data at the moment is geared more toward the larger pro audio venue, but is still of interest, and is rather flexible in viewing. Again, understanding what it might be telling you is still a hurdle. By the end of the year I'll have my own designs tested in this manner. I have heard from Pat & Ron that a few hi-end audio manufacturers who have been asked to submit their speakers were rather surprised with what they saw in their shipping products. Of course there are a very few manufacturers who have such in-house capabilities.

We should keep some perspective that home/consumer audio is still rather naive to the 3D function of our loudspeakers, even while being so particular about other laudable aspects.