Understanding sound reproduction - and how it is evaluated

[AlmaataKZ]

As you may know I am one of those who is convinced it is the speakers that have the most influence on how well a hifi can reproduce sound. Naturally, I am most interested in speakers and try to educate myself in how they are designed, made, used and evaluated while I also tend to keep as objective approach as possible.

To this end, I found this reading very useful and encourage everybody who is interested in accurate reproduction of sound to give it a good read:

http://www.zaphaudio.com/evaluation.html

 

[AlmaataKZ]

Yes, it is a bit 'direct' but if you look beyond that (please do not react just to the directness) very educational and useful for understanding of sound reproduction.

 

[Crossie]

An excellent read :clap: . Zaph has "lifted the veil" from my previously confused understanding of sound reproduction .

 

[busb]

I'm still in the process of reading but this statement worries me straight away:

"Don't let a proponent of subjectivity tell you that the right measurements don't exist to properly describe performance. That is a wrong statement, occasionally stated unknowingly but more often stated blatantly on purpose. The right measurements do exist and it's time for people to get with the program. The field of audio is very well known and has been for 50 years. My advice to those who say the right measurements don't exist: Get a decent measurement package, start measuring some drivers, and then start listening to them, in different applications and without filters, alone and in systems with other drivers, just so you can hear exactly what you see. In time, understanding will come"

I wouldn't call myself a Subjectivist but I find such a statement that we have a complete grasp on audio measurements a little premature - I'm not convinced. Although the distortion exhibited by speakers is far higher than with amplifiers by orders of magnitude does this fact mask ampifier distortion completely? The reason for asking is that most competently designed amps, measure similarly so should sound the same according to many people but goes against the experience of many on this forum that feel most or many amplifiers sound different.

This Wiki page is a good primer on audio measurements:

http://en.wikipedia.org/wiki/Audio_quality_measurement

One point we should all remember is how easily fooled our brains are regarding audio otherwise the whole concept of stereo reproduction would not work at all.

 

[AlmaataKZ]

I wouldn't call myself a Subjectivist but I find such a statement that we have a complete grasp on audio measurements a little premature - I'm not convinced. Although the distortion exhibited by speakers is far higher than with amplifiers by orders of magnitude does this fact mask ampifier distortion completely? The reason for asking is that most competently designed amps, measure similarly so should sound the same according to many people but goes against the experience of many on this forum that feel most or many amplifiers sound different.

agree. the link covers only driver perfromance measurment rather than the whole reproduction chain.

 

[Sliced Bread]

While the author has a few good points, I disagree with a lot of what he is saying.

For example:
“How often has someone said "Forget the measurements and tell me how it sounds." Or "Learn to listen with your ears." Well I hate to say it, but stubborn and uninformed is rearing it's ugly head again. A lack of understanding without an open mind leads to a refusal of the facts and an embrace of whatever view happens to further that individual's cause. Or worse yet, it may lead to a view that's simply an attempt to make a knowingly guilty person appear smarter or more interesting than they actually are."

This paragraph is simply an obnoxious way of saying that you do not know what sound you like, and if the author was with you with a PC and a microphone he will prove you wrong.

People like different sounds. That’s absolutely fine, you just have to look at the conflicting user reviews on this site to see evidence of that. It’s their money and their music.

 

[Craig M.]

People like different sounds. That’s absolutely fine, you just have to look at the conflicting user reviews on this site to see evidence of that. It’s their money and their music.

Did you read all of the linked post?

"

During the driver evaluation process, any sort of subjectivity is a bad idea. But on the other hand, subjectivity during the system evaluation process is going to be required. At some point, a designer has to decide on tradeoffs. That could mean deciding what types of distortion are more annoying to the designer personally. For example, what sounds worse: a broad, large increase in even order harmonic distortion in the lower midrange and bass or sharper but narrow band odd order harmonic distortion in the upper treble? Sound familiar? It's the old metal vs paper cone debate and it comes down to personal preference. The choice is a subjective one. Some prefer metal cones while many others prefer paper or poly. That's OK. Measurements can tell the truth about a driver but remember that they can't tell you what you like.

When a proponent of subjectivity repeats what I just mentioned above, I'm not going to dispute it. Many things in the end come down to personal preference. A system design decision can be subjective, but testing and evaluating drivers individually must remain objective."

Seems to cover your objection.

 

[Craig M.]

The reason for asking is that most competently designed amps, measure similarly so should sound the same according to many people but goes against the experience of many on this forum that feel most or many amplifiers sound different.

There are a number of reasons for amplifiers to sound different. A low powered amp could be clipping, the listener will be subject to involuntary biases, the amps being compared are probably not level matched, etc.

Once the above is taken into account and catered for, amps do indeed seem to sound the same if they measure the same - judging by properly controlled listening tests. Look at Harbeths recent challenge/offer. A lot of forum chatter/noise was generated, but not one person stepped up to put their hearing where their money/mouth was.

 

[Electro]

A very interesting article thanks for posting it .

The problem is that I have no means and also lack the necessary skills to measure any piece of audio equipment and to be honest I would not know where to start so I am forced to be a subjectivist which makes me totally reliant on the designers and manufacturers to make a product that they claim is accurate and should sound good .

The only tools I own to measure the accuracy and effectiveness of any speaker are my ears which are connected to my brain and with this combination I chose loudspeakers that sound as close to real live music as possible, and they do it very well IMHO

If I want to be objective it is impossible so I am forced to be a subjectivist but I don't think that makes me "stubborn and uneducated, unaware, or uninformed" hopefully :?

So if I can't trust my ears/ brain and the only measurements I can make are the dimensions of the speaker how does John Krutke expect me to choose a loudspeaker ?

Or am I missing the point , which is quite possible .

 

[AlmaataKZ]

While the author has a few good points, I disagree with a lot of what he is saying. For example: “How often has someone said "Forget the measurements and tell me how it sounds." Or "Learn to listen with your ears." Well I hate to say it, but stubborn and uninformed is rearing it's ugly head again. A lack of understanding without an open mind leads to a refusal of the facts and an embrace of whatever view happens to further that individual's cause. Or worse yet, it may lead to a view that's simply an attempt to make a knowingly guilty person appear smarter or more interesting than they actually are." This paragraph is simply an obnoxious way of saying that you do not know what sound you like, and if the author was with you with a PC and a microphone he will prove you wrong. People like different sounds. That’s absolutely fine, you just have to look at the conflicting user reviews on this site to see evidence of that. It’s their money and their music.

I think it is absolutely OK to like whatever sound one likes. This is how it should be.

What I liked in the link is that it explained well what kind of things are at play (as far as drivers are concerned) if one is interested in accurate reproduction as such and tried to highlight/explain the importance of these things for accuracy of reproduction.

it is a bit direct and harsh language but makes a lot of sence if you ingnore the emotinal componnet.

 

[busb]

WHF site hiccupped so will start again:

A very interesting article thanks for posting it .

The problem is that I have no means and also lack the necessary skills to measure any piece of audio equipment and to be honest I would not know where to start so I am forced to be a subjectivist which makes me totally reliant on the designers and manufacturers to make a product that they claim is accurate and should sound good .

The only tools I own to measure the accuracy and effectiveness of any speaker are my ears which are connected to my brain and with this combination I chose loudspeakers that sound as close to real live music as possible, and they do it very well IMHO

If I want to be objective it is impossible so I am forced to be a subjectivist but I don't think that makes me "stubborn and uneducated, unaware, or uninformed" hopefully :?

So if I can't trust my ears/ brain and the only measurements I can make are the dimensions of the speaker how does John Krutke expect me to choose a loudspeaker ?

Or am I missing the point , which is quite possible .

No, I don't think you are. We obviously have to have some faith in our own hearing but also with the manufacturers we trust. In the case of speakers, we probably read up on a particular model as well as listen but hope the maker is competent enough to produce models that sound good across a wide range of musical styles.

As an example, I listened to a pair of Totem Hawks in AudioT a few months back. They are two models up from my Arros. They sounded OK but cost twice as much. I also heard some B&W PM1's on their dedicated stands that initially sounded better than the hawks - vocals had more impact for instance. Playing more music through the B&Ws had me concluding that their bass was lacking. They were exceptional with certain styles of music but were hardly full-range as the Hawks attempted to be.

 

[busb]

The reason for asking is that most competently designed amps, measure similarly so should sound the same according to many people but goes against the experience of many on this forum that feel most or many amplifiers sound different.

There are a number of reasons for amplifiers to sound different. A low powered amp could be clipping, the listener will be subject to involuntary biases, the amps being compared are probably not level matched, etc.

Once the above is taken into account and catered for, amps do indeed seem to sound the same if they measure the same - judging by properly controlled listening tests. Look at Harbeths recent challenge/offer. A lot of forum chatter/noise was generated, but not one person stepped up to put their hearing where their money/mouth was.

Perhaps I should have stated "amps that measure similarly". A valve amp with higher than average output impedance will sound & measure differently to a SS powerhouse. I'm not entirely convinced that we have a complete handle on distortion measurements, I'm also not convinced that most DB ABX tests are anything but worthless - they need to prove a negative as well as a positive & short-term memory is very unreliable. They will almost never prove a positive! ABX methodology will nearly always skew the results.

The only time I'd have faith in ABX testing would be when conducted by a body such as a university carrying out tests spread over many months using mostly music that the subjects could familarise themselves with before being taught how to listen. Such testing would be very expensive & probably tedious to take part in.

 

[Sliced Bread]

Weeeell....only a little.

On one had he says " When a proponent of subjectivity repeats what I just mentioned above, I'm not going to dispute it. "

But on the other says " How often has someone said "Forget the measurements and tell me how it sounds." Or "Learn to listen with your ears." Well I hate to say it, but stubborn and uninformed is rearing it's ugly head again..."

A little contradictory, but maybe I missed something.

 

[AlmaataKZ]

I ignore the emotional and contradictory part and take out with me the informative part.

 

[CnoEvil]

Thank you for posting the link, and it's hard to argue with the logic per se; but it doesn't necessarily help with buying equipment that you actually like the sound of, rather than measures well.....the two may not necessarily coincide.

I would love to think that you could look at a series of measurements and pick the best one, without demoing.....buying hifi is about subjectivity, and probably always will be. Measurements help, but are only part of the equation, as this is not just an academic exercise.

 

[AlmaataKZ]

Thank you for posting the link, and it's hard to argue with the logic per se; but it doesn't necessarily help with buying equipment that you actually like the sound of, rather than measures well.....the two may not necessarily coincide.

I would love to think that you could look at a series of measurements and pick the best one, without demoing.....buying hifi is about subjectivity, and probably always will be. Measurements help, but are only part of the equation, as this is not just an academic exercise.

To develop your point - subjective, yes, but in addition to objective, not instead of.

 

[CnoEvil]

Thank you for posting the link, and it's hard to argue with the logic per se; but it doesn't necessarily help with buying equipment that you actually like the sound of, rather than measures well.....the two may not necessarily coincide.

I would love to think that you could look at a series of measurements and pick the best one, without demoing.....buying hifi is about subjectivity, and probably always will be. Measurements help, but are only part of the equation, as this is not just an academic exercise.

To develop your point - subjective, yes, but in addition to objective, not instead of.

I think that's fair enough.

IMO. The best way to get an idea of what something is going to sound like (eg. to compile a shortlist), is to align yourself to a reviewer or forum member who has the same taste, and regularly describes things in the way that you also hear them.

 

[sheggs]

Measuring repsonse can be a really effective way to help with a sound you don't like or to fine tune a sound you do like but you are not getting the best out of your room or system but generally speaking there is no way to measure the sound and response of the sound you do like. If you like it and enjoy it :dance:

 

[Thompsonuxb]

Not sure how strong our language can be on this forum but the author of this piece is a blitthering eddiaat!

who listens to 'speakers' as a stand alone device - of course box design, crossovers, ports etc have an enormus effect on what we hear - the same driver in two different box designs can and will sound very different to each other and when compared to the same driver used unboxed on a table.

note - its 'figures' will still read the same through 'measurement tools' if the source is fixed, I mean derr!

 

[oldric_naubhoff]

Not sure how strong our language can be on this forum but the author of this piece is a blitthering eddiaat!

who listens to 'speakers' as a stand alone device - of course box design, crossovers, ports etc have an enormus effect on what we hear - the same driver in two different box designs can and will sound very different to each other and when compared to the same driver used unboxed on a table.

note - its 'figures' will still read the same through 'measurement tools' if the source is fixed, I mean derr!

your first thought is quite right but the second one not so much. just for instance, baffle size and enclosure shape will change speaker's frequency response quite considerably, depending on shape, so a speaker designer has to take this into account when designing a speaker. this fact will most likely be compensated by crossover network.

so there you have it; figures will not read the same.

 

[jaxwired]

Great read. Thanks for posting it.

It's a subject that never ceases to fascinate me. How much self delusion is involved in hifi. Pretty much everyone admits that there is some self delusion going on. It's just the amount of it that we differ on.

 

[AlmaataKZ]

Great read. Thanks for posting it. It's a subject that never ceases to fascinate me. How much self delusion is involved in hifi. Pretty much everyone admits that there is some self delusion going on. It's just the amount of it that we differ on.

very true.

btw there is a bit on non-linear distortion on the same site that I though was also interesting and useful

 

[Native_bon]

If a system sounds good to your ears & you enjoying the sound, then no need for measurment. Even when i produce music i hardly use measurment software. I would say 95 % of the time i use my ears. But even as a producer it takes years of mastering the act of producing music.

Having said that i dont use my music production system to listen to music, I use hifi speakers cause i like my music warm. When buying hifi to listen to, i will use my ears & will never think of using measurment.

Measurments may be helpful in some insteads but i dont think it must be used for all situations.

 

[Thompsonuxb]

Not sure how strong our language can be on this forum but the author of this piece is a blitthering eddiaat!

who listens to 'speakers' as a stand alone device - of course box design, crossovers, ports etc have an enormus effect on what we hear - the same driver in two different box designs can and will sound very different to each other and when compared to the same driver used unboxed on a table.

note - its 'figures' will still read the same through 'measurement tools' if the source is fixed, I mean derr!

your first thought is quite right but the second one not so much. just for instance, baffle size and enclosure shape will change speaker's frequency response quite considerably, depending on shape, so a speaker designer has to take this into account when designing a speaker. this fact will most likely be compensated by crossover network.

so there you have it; figures will not read the same.

Sorry, but are you telling me an electrical signal going through an electrical unit its properties will change?

what you speak of is colleration of the sound produced due to surrounding materials, the actual readings should not change if the signal being fed to said device is fixed.

eg - PMC use transmission line technology to enhance bass using materials and ..er technology and such (WHF's review of the 22's explians it in the blue box at the bottom of the review, better than me) ,but remove the transmission line and the enhanced bass is removed. The speaker output does not change, nor its frequency response if the signal is unchanged - what we hear is though.

which is why speakers CAN be discribed as transparent, warm, clinical etc, we buy the design, not individual drivers, but the tech that makes them work as a whole a single unit reproducing our music.

The authors desire to remove this simple fact and break it down to individual drivers and measurments is really pretty silly

 

[Inter_Voice]

Measuring repsonse can be a really effective way to help with a sound you don't like or to fine tune a sound you do like but you are not getting the best out of your room or system but generally speaking there is no way to measure the sound and response of the sound you do like. If you like it and enjoy it :dance:

+1 I am a practical man and needs scientific references for me to "see" what is happening in my room acoustically.

Of course at the end of the day we still need to use our ears for fine tunning to suit our taste bearing in mind that the FR of individual ear drums as well as music reception by one's brain cells are entirely different :boohoo: