"Measured Performance vs. Qualitative Appraisal"

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"Measured Performance vs. Qualitative Appraisal"

Postby JackD201 » Wed Dec 20, 2006 1:37 pm

Okay folks, the debate that has been raging from the time the multi-tester was invented :lol: Let's cut through the Cr@p, the Bull and the Hype. Let's get personal where nobody is right or wrong ;)

Some say measurements don't matter :!:

Some say Measurements must serve the Observations :roll:

Some say Observations must serve the Measurements :?:

Some even say only Measurements matter :!:

The truth should logically be somewhere in between. A question begs to be answered however. IS there a "truth"?

BE BOLD. Where do you stand? What mental approach do you take in determining what is right for YOU whether you be a fabricator, designer, builder or just a consumer? What form of validation do you most value, a spectral decay plot or the ears of a trusted friend?

Gentlemen, start your engines....
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Postby rtsyrtsy » Wed Dec 20, 2006 1:53 pm

What I know about volts, amperes, watts, Hertz, etc. are what I can Google. Hence, I veer strongly on the observation camp.

That said, I use measurements for very basic stuff like not plugging 110v stuff onto a 220v outlet, adding up the rated power requirements of my gear to ensure that my house circuit breakers and wires are the right capacity, and biasing my tubes to the recommended range.

In the end, I listen for what I like: warm, lush, toe-tapping, etc. Other things matter less like imaging & soundstaging, extreme top and bottom end extension, the gear being the latest and the greatest or are the stuff nice looking.
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Postby rascal101 » Wed Dec 20, 2006 2:03 pm

During development of audio circuits I always make it a point to go through simulation and bench test. Afterwards, I give it to a friend of mind for listening tests. I'd say the ratio is 60-80% simulation + bench and 20-40% listening.

This was not so a few months back because I've had the notion there's nothing that a test instrument can't measure. The ratio then was 80-90% simulation + bench and 10-20% listening.

I am slowly learning that harmonics do play a valuable role in the way we perceive sound. The presence or absence of the correct type determine if it will be good or bad. To this day, I am still figuring out which harmonics will give me best results and how to bring them out. This when added to a circuit should also measure good.
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Postby iceman90a » Wed Dec 20, 2006 2:42 pm

you mean like if i was to choose between speaker A and speaker B, with different specs (ohms, sensitivity, freq range, etc) but same price and looks (for the sake of argument) which would i choose?

well i'd have to listen to both first :D
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Postby marty_e » Wed Dec 20, 2006 2:43 pm

Hey Jack, how does Vladimir Lamm approach this matter? I understand its rather unique. He seems to be more on the quantitative camp.

I read HP's interview on Hansen he says something like tonality (whether accurate or deliberately colored) and timbre cannot be interpreted by standard quantitative metrics. I tend to believe that, although the 2 approaches do not to have to be mutually exclusive.

I am a mere consumer so hertz, ohms, watts, volts etc serve merely as a guide on what is COMMONLY known to offer synergy. Even then, exceptions apply and rules do not. I pay attention to a cartridge output of .25mv only to help me narrow down phono stage choices. I only look at watts per channel as it applies to speaker sensitivity and room size. I don't expect that getting the right specs lined up will bring me to aural satisfaction.

I don't know what a spectral decay plot so that says it all, pretty much.

BTW, Mr Thread Starter, you didn't offer your views on the matter

:D
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Postby rascal101 » Wed Dec 20, 2006 2:50 pm

With my design I always take the gain/phase plot. This is so I would know if a response is flat over the audible frequency range and there are no phase shifts. The gain plot should appear flat. A flat plot indicates that no gain or attenuation of any frequency. Phase shifts distort your perception of sound in that instruments that are near will appear closer or further depending if it is a positive phase or negative phase shift.
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Postby dogears » Wed Dec 20, 2006 3:05 pm

There is only one truth and that truth is in your ears :lol:
(insert x-files tune here)
Listen to all the systems you can hear and train your ears.
For me secondary lang ang specs and the sound is more important to me - i.e. for critical listening.
For musical enjoyment - [sabi nga sa Singapore] everything can :!:
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Postby audiofilio » Wed Dec 20, 2006 4:24 pm

If audio gears will be judged only through their measured performance on the test bench... then SETs be damned!

But I'm a true believer of the single-ended triode's "magical" sound... so my stand is quite obvious - the ONLY form of validation I most value and trust are my own ears.
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Postby Jon Agner » Wed Dec 20, 2006 4:38 pm

How does one measure music? Sure we can measure the whole frequency spectrum and ensure that the component is within the required tolerances but how does one measure music?

It's like cooking, we can follow the recipe up to the nearest milli or even micro gram, but will it suite our taste buds?

Here's my point: Measurements, yes I need to take them to ensure that I achieve the output values based on the design parameters. But it does not imply that because it is within the required design tolerances that for me, it will sound good.

We are all speaking of a flat response.... Is the fletcher munson curve flat???

Just my point.
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Postby jadis » Wed Dec 20, 2006 7:10 pm

I'm not a very technical guy when it comes to measurements but some 'measurements' that I pay attention to are: wattage in power amps, efficiency of loudspeakers, and gain of phono cartridges. I'm sure many other specs, or measurements, (I hope they mean the same thing here) do matter to different people, but these are the main things that I appreciate in assembling an audio system. The rest of the way, I tune it
with my subjectivism, and that is probably what I call 'my own truth' :)
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Postby JackD201 » Wed Dec 20, 2006 11:57 pm

Hi Marts,

Vladimir Shushurin (Lamm) conducted an intensive qualitative psychoacoustic study while still in Russia. This gave birth to his proprietary set of metrics which is reportedly so thorough that in simulation the predictability is extremely close to the qualitative goals. Nauna pa rin yung tenga.

Independently Harman Specialty Group is continuously developing their own and is currently used by Kevin Voecks for his design. SAme goes for Albert VS who designs his own test equipmentt for specific parameters that need to be monitored. What all have in common is heavy psychoacoustical studies first and foremost, testing evolves following the "ears".

Imagine if rascal can design a test instrument for relevant harmonics? That would be waaaaay coooooool!!!!

As an industry participant I find measurements, RELIABLE, measurements extremely important. Not because they are nescessarily determinants of sound quality but because they are extremely important for product to product consistency (LS3/5a anyone?) and quality control which also impacts warranties and quality of after sales service.

As a consumer it helps me as a rough guide for system matching and aids in the process of elimination. They still have never stopped me from trying some ludicrous combinations though :lol:

At least I haven't really blown anything up. YET. :twisted:

Russ, 110 or 220....I LOVE IT!!!! :lol: :lol: :lol: :lol: :lol:
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Postby botching » Thu Dec 21, 2006 5:53 am

when an audio gear sounds bad, and measured bad - then it must really be bad!
but when it sounds good but measured bad - then it was not measured properly :)
In audio its better to stick with the ears and not with the eyes :wink:
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Postby brady » Thu Dec 21, 2006 9:09 am

we don't listen to square wave
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Postby ichabod » Thu Dec 21, 2006 9:20 am

The science of audio can really boggle. This "Vlady" guy may have a point saying what measures good should sound good. That's it. But I understand he has evolved a dummy "ear" simulation test on his amps? I've read some good excerpts about his LAMM amps from some of my fav reviewer including Senor Kessler of the LS fame. In fact, the guy admires it for reasons like "But still, I used the Lamms with various LS3/5As from the forthcoming shoot-out, if not during the shootout for reasons of practicality, and the results were equally ear opening." Sounds conversative to me for an American in Britain writing about this "Vlady" russian fella who rocks the audio world with his genius! I sure would like to probe my ears into this Lamm of sound that taketh away the sins of audio!

To me, what sounds pleasingly natural on the ears is my "final" I-can-live- with-this-sound test. Anything else is hype, spec'd hifi. Like, "I'm not sure I see anything wrong with equipment -- speakers, amps, whatever-- that sometimes makes the music more real than it perhaps acutally is."
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Postby rascal101 » Thu Dec 21, 2006 10:26 am

Yes, the harmonics can be seen by spectrum analyzer but it is difficult to say that it will sound good. For this part, your ear will be the judge. However, having said that, test instruments are used to ascertain the amount (amplitude) and harmonic frequency you are adding. The tolerances on components may cause your computed values to vary slightly with actual.

The measurement part (for me at least) is used so that you are following engineering standards - making sure that feedback loop is stable, gain is flat (so as not to overemphasize certain frequencies) and there is minimal phase shift. These are some norms that I believe should be performed. Some customers also desire the technical specifications while some are not overly concerned and are more inclined to judge it by the way it sounds.
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Postby arnoldc » Thu Dec 21, 2006 10:43 am

Some of you have confused measurements with ratings :)
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Postby ichabod » Thu Dec 21, 2006 10:45 am

It always end up like how the designer perceives sound to be or more precisely, the musical waveform, and this is as brady puts it above "we don't listen to waveforms" more complicated as we all know in comparison to the square wave. JackD should know how Vladimir Shushurin aproaches this to make his amps totally raved by audio gurus and reviewers alike. How about those who review music and scores, and live performances? Will it evoke the same praises and sentiments as the "same" music heard by these music critics?
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Postby tony » Thu Dec 21, 2006 10:47 am

the consumer is always right, after all it is his money that he spends...

throw the test intruments out of the window, who listens to them anyway?... :lol:
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Postby rascal101 » Thu Dec 21, 2006 11:04 am

Sir Tony,

I will be glad to accept the test instruments you will be throwing. :lol:
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Postby ichabod » Thu Dec 21, 2006 11:06 am

Now, now, now, that's not being fair to all sides, specially to those who's scientific minds can't formulate ideas without the aid of scientific devices. Audio is a science and as such it needs empirical reasoning, meausre, and data to corroborate its own theory. Music as we know it is both art and science too. So we need both in order to have both! Anything less is suspect! Unless one wants his music "live" all the way!
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