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Old 27th January 2003, 04:23 AM   #11
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Quote:
Originally posted by Nicwix
[list=a][*]Replication – designing to present a signal to the loudspeaker that is as close the original source as possible
[*]Enhancement – presenting a signal to the loudspeaker, that is different to the original signal, so that, in conjunction with other factors (eg loudspeaker characterists, room acoustics, recording deficiencies, etc), the perceived sound quality is improved - obvious examples being: equalisation, reverberation and other “surround sound” enhancements, etc
[*]Masking – aiming for the “good distortion” to mask the unwanted distortion, as noted above[/list=a]
Add to that Presentation, which puts a nice frame on the
experience, and you have a good list. For example, last night
when I saw the Stardust Cowboys live, I was sitting next to
the fiddle player, and even though the (violin) was amplified
by cheesy equipment, it was great. This is perhaps why
home theater guys have a totally alien aesthetic regarding
good sound.

But let's face it, the whole subject is a big can of worms.


pass/ - got tired of Jet Society, now listening to Comfort
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Old 27th January 2003, 10:21 PM   #12
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"In almost every field of scientific endeavour, objective measurement is fundamental to improvement. "

Quite right.
I mean, it is impossible to argue with. No one will argue that using listening tests as a measure of improvement is wrong. So why should using intermediate measures be wrong?

IMO the reason intermediate measures are not more deterministic is that they are too simplistic. I do not believe that equipment is not adequate - there are plenty of instruments that can measure things that we cannot hear; we are only flesh and blood. Even a modest digital storage scope will show some difference between a amps input and output signal. I think the issue is that we, the amateurs, don't always have the time, money or understanding to figure out what measures are most important. There is also a tendency to keep things simple by measuring the things that the off-the-shelf equipment is designed to measure. Very little commercially available test equipment was designed for audio measurement.

I believe some high-end companies do pursue objective measurements. They don't divulge them. Hifi magazines have tried hard to find good measures and have dabbled with things like dynamic spectrum analyzer plots and so on, but to be honest the people who work for the magazines are no more experienced in T&M methods than us amateurs.

I think this is an area of opportunity.
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Old 27th January 2003, 11:22 PM   #13
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I would say the ideal approach should embrace YET transcend
the things you propose.

If measure then measure. Please proceed.

But don't forget that as humans we have at least the 3 aspects,
Physical, Intellectual, Emotional.

The heart of great music is emotional.

How should we measure this? And besides it's only the mind
that wants to, the body and the emotion want nothing to do
with it.
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Old 28th January 2003, 02:33 AM   #14
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"The goal of almost everyone on this forum is surely to achieve the best "sound quality" for the money and time they are willing to spend. And yet, there is so little consensus as to how "sound quality" can be measured."

Yes, and we need to further define what we, individually or collectively regard as 'quality sound'.

I have long since come to the conclusion that infinite presicion is not really required in an audio system.
By this I mean that factors like absoloute frequency response flatness, and zero THD etc are not nearly so critical as many would believe, and indeed the colourations wrought can increase enjoyment of the music.
The exception to my ear is that IMD must be low for pleasant reproduction.

Fun Factor -
I had the opportunity to 'tweak' the instruments and PA of a live show on the weekend.
The 'tweak' is a product that I am developing currently, that when used correctly immediately transforms any live or replay system that I have tried it on.

The 'tweaking' went in stages between brackets, the first change being treating the two vocal mics, and the two guitar signal leads.
At the next break, the guys sat with my GF and myself, and gave me some initial feedback on what they heard.
During this break I treated the single 240V AC lead supplying instruments and PA, and the effect was immediately apparent to all those listening during this break on pre-recorded filler music. (Rolling stones CD).

After the next bracket, changes were to treat the kick mic, and further treat the lead guitar amplifier.
During the last set the guitarist was exploring and reaching sounds that he has not had before, and the whole time immersing himself into his instrument and GRINNING from ear to ear.

The final result of this informal experiment session was positive, positive, positive from the band, GF and me - stage sound was the best I've heard it, the PA was the best I've heard it, and the band played the best I've heard them yet.

The venue is a sandstone stage with a tarpailin roof in the outdoor beergarden of a localish pub on top of a hill out in the middle of nowhere with bush views for ten miles, a crowd of about 10, and so only natural sounds to compliment the music.
Nelson mention sitting next to the fiddle player - my GF and I were seated 20m across the beergarden under a shady tree - 39*C day.

For the last set, I laid back in my chair with my head against the paper bark tree, a beer in my hand, enjoyed live music like I have not done so before, and listened and relaxed, and grinned from ear to ear too !.

Along the lines of what Nelson says about his 'Stardust Cowboys' show -
My wonderful GF, cold beer, natural surrounds, and world class musos playing cooking hot blues on the nicest sounding live system that I have yet heard - I think that musical enjoyment better than this is not possible.

The downside to this weekends experiment is that I now know the sound of nicer sounding microphones and instruments, and every recording that I now listen to sounds rotten.

Anyway there are enjoyment factors in audio replay systems that currently can not be explained by standard audio measurement methods, and these are the ones that make that that difference between just nice sound and really enjoyable sound.
There is more going on in an audio system than standard electronic theory explains, and it is not due to any psychoacoustic expectation factor.

Eric / - 'Tone Stone' - you heard it here first.
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Old 28th January 2003, 09:34 AM   #15
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gtrmaker,
Emotion is the result of an individuals brain processing pressure waves that impinge upon their eardrums. It is not necessary or pertinent to measure emotions.
Measuring how accurately the pressure waves are reproduced between the original instrument and the listeners ear is what it is all about. And this is a matter of mechanics and electronics and nothing else.
Unless, of course, you are the sort of person who believes in homeopathic medicine (except in a psychological sense) in which case your method of reasoning is anathema to mine. ;-)
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Old 28th January 2003, 10:29 AM   #16
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So, is the individul brain no need? The ear without brain...?!?!

JH
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Old 28th January 2003, 10:41 AM   #17
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Quote:
Originally posted by JBL
I d'ont think that it is possible to place a number on sound quality. And if their where one manufacturer would already be using this magical figure to rate their stuff.

And even if we define a way to mesure and get a final verdict their will always be people who will tell that it's not better than something who was rated lower.

And how would will be rating solid state amp versus valve amp.
I think you hit the nail on the head. Our problem is that we don't know how to define "sound quality". Therefore, we don't know how to measure it. It is also the reason that each of has his own standards of what we find "good sound quality".
The problem for the designer is to built an amp that everyone agrees gives "good sound quality" which is as a result from the above impossible.
That is IMHO why there are so many different topologies and technical solutions. That is also, IMHO, the reason why there is so much humbug and snake oil in audio.

To summarize: if you can define it, I can measure it. Guaranteed.

Jan Didden
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Old 28th January 2003, 12:03 PM   #18
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Let's make a parallel with paint (as art). Did you think about Mr Pass as a great painter like Picasso? When you analyze all the paints from some painter in the time, you see a noticeable difference in how the colors are made and how hes describe the environment. This difference is explained by the physiological changes in the eye’s retina. So quality for a particular painter has changed. What about the great hears of Mr Pass?? Let’s say every other variables are fixed, the sound quality of his amplifier will be modified depending on the period he designed it.

Have fun
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Old 28th January 2003, 12:38 PM   #19
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Lightbulb How difficult can it be ?

Imagine yourself following the replication criteria of “quality”, described by NicWix, to determine the worth of a component (e.g. an amplifier). The amplifier you are going to test/measure is in a black box and you cannot determine what is inside as all you can see on the outside is an input socket and an output socket (it can have a blue LED as well if you like ).

What sort of measurements would you make ?

THD ?
TIM ?
Frequency sweep ?
Impulse response ?
Voltage gain ?
Power output into a number of differing loads ?
Etc, etc, etc

After many measurements you conclude that this indeed a measurably good amplifier. As a final test you plug in a CD/phono source, some speakers and put some of you favourite music on. You quickly realise there is something seriously wrong – this amplifier “bleeps” out any expletives in the source material – this is a family amplifier

The bottom line is, unless you have some (accurate) a-priori knowledge about the system under test, you do not really know what to measure. This is important as you cannot measure everything as this would need an infinitely long period test signal. In addition, the more complex the system under test (the expletive removal system would be a seriously complex example), the more difficult this will be to determine.

BTW, I don't trust my ears too much either ...

Dave - suit at the ready ...
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Old 28th January 2003, 01:03 PM   #20
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Quote:
Originally posted by François
Let's make a parallel with paint (as art). Did you think about Mr Pass as a great painter like Picasso? When you analyze all the paints from some painter in the time, you see a noticeable difference in how the colors are made and how hes describe the environment. This difference is explained by the physiological changes in the eye’s retina. So quality for a particular painter has changed. What about the great hears of Mr Pass?? Let’s say every other variables are fixed, the sound quality of his amplifier will be modified depending on the period he designed it.

Have fun
Yes Francois! And I think there is a great parallel between paintings and amps. You cannot say: OK, take a frame of such and such dimensions, paint with a contrast of such ratio, etc, etc and you will make a great painting. Why? because you cannot define what "a great painting " is any more than you can define "good sound quality".

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