How much can be measured -- and how much cannot?


There has been a lot of discussion over the years on Audiogon regarding the measurement of components and other audio products. Some people claim everything is either measurable now or will one day become measurable with more sophisticated measuring equipment. But others say there are things in high end audio that will never me measurable and that measurements are really not that important.

Here is a typical example -- a quote taken from the Stereophile forum regarding their review of the Playback Designs MPS-5:

"JA 2/17/10 Review Measurements of Playback Designs MPS-5
Posted: April 13, 2011 - 8:42am

John Atkinson's 2/17/10 review measurements of the Playback Designs MPS-5 revealed less than stellar technical performance even though Michael Fremer really liked the player. I've included JA's closing measurement remarks below followed by the manufacturer's comments.

To my knowledge there was never any followup in Stereophile regarding the manufacturers reply the MPS-5 could not be adequately measured with traditional measurement techniques.

I believe Stereophile should respond to this reply in the interests of its own measurements credibility.

Len"

How important do you think measurements are? Are the ears really the only true arbiter?
sabai
>But others say there are things in high end audio that will never me measurable and that measurements are really not that important.

Speaker preference has a very strong correlation (if you weren't a scientist you'd say it was causal) with with uniformity of amplitude response curves at angles representative of a direct listening window and where front-wall, side-wall, and floor/ceiling reflections come from in average rooms.

Sean Olive has reportedly taken that to the next level producing a formula that predicts peoples' speaker ratings based on such measurements.

Stored energy is important too, although that shows up in polar response curves (ripples in the on-axis response can come from diffraction effects that aren't that audible, but ripples at many angles tend to be resonances which are) with fine enough frequency resolution.

>How important do you think measurements are?

Very. Good enough to predict that you're not going to like a speaker before you go to the trouble of listening.

>Are the ears really the only true arbiter?

If you can hear it you can measure it and if you can measure it you can fix it or decide it's not worth the price tag which goes with the fix.

You'd do well to read _Sound Reproduction: Loudspeakers and Rooms_ by Floyd Toole.
I think the original question and all the responses miss the central point of the modern audiophile pursuit. Despite audiophile claims to the contrary the science of of sound reproduction is extremely well understood, particularly if we're talking analog signals. Audiophiles focus on what sounds good, which has become more a function of marketing and mass psychology. As a group we have been indoctrinated and conditioned to think about sound quality in very specific patterns and a group of talented entrepreneurs are profiting by exploiting these patterns. The products we buy are luxury goods and marketing involved is well understood - product differentiation and market segmentation predominate.

Audiophiles have two fundamental challenges to their world view, musicians and engineers. Each group basically thinks we're delusional. To paraphrase comrade Marx, "who you gonna' believe, me or your lying ears?"
"Despite audiophile claims to the contrary the science of of sound reproduction is extremely well understood"

No doubt. One is always at risk when proven scientific principles are ignored or not applied in solving a problem.

Here are the most useful audio specifications/measurements for me that I tend to always take into consideration:

Input and output impedance so these can be matched between components for better dynamics and lower distortion.

In addition, for amps, I look at power ratings, damping factors and current delivery related specs to get an idea of how well an amp might be able to drive a particular set of speakers.

Sensitivity related information can be useful as well,especially when dealing with various phono section designs and speakers.

I do not usually pay too much attention to distortion specs. I will look at various charted lab measurements if availble from a reliable source in order to gain more insight when possible.

That's mostly it that I can think of off hand.

I would say that a basic understanding how to interpret and apply audio metrics is a very advantageous skill for any true audiophile who wants a systematic means of improving their sound reliably to develop. It's something I am still working on and I try not to lose any sleep over these things though I probably have in practice from time to time.
03-19-12: Ahendler
Actually I have never found measurements to help me in any audio decision to by a certain product. Measurements are helpful in the design process but do not tell you anything how a component will sound.
They won't tell you that the component will sound good, but they will often enable you to predict that the component will sound bad in a particular application, as a result of the kinds of mismatches that have been cited.

Basically, they allow you to narrow the field of potential candidates for purchase, to minimize trial and error, and to reduce the likelihood of expensive mistakes.

Regards,
-- Al
"Audiophiles focus on what sounds good"
Of course we do if it does`nt sound good why bother?
I don`t know what your priorities are but I only want audio components that allow me to 'enjoy' the beauty and emotion of music. If you can`t connect to the music what are you listening for?
Regards,