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

No, marketing is not driving what I think sounds good. I may be enticed to purchase a product, but after it is in my listening room the marketing is all over and forgotten. If it sounds good to me, I keep it. If not, I sell it or send it back.

Markering influences the buy decision, but never the keep and enjoy decision. Marketing's influence is very short lived in the end.

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.

Let me supplement my previous response with some specific examples, that illustrate what I, Mapman, Roscoe and others have been alluding to:

1)Someone has read good things about the sound quality that SET amplifiers can provide. He or she is considering purchasing a SET amp and using it in conjunction with a speaker having a specified impedance of 8 ohms. JA's measurements reveal that the impedance has wide swings over the frequency range, including dips to low values at highly capacitive phase angles. Purchasing the SET amp would be an expensive and/or time consuming mistake.

2)Someone is considering adding a powered sub having only line-level inputs to his or her system, and driving it from a second set of output jacks that are provided on the preamp. As is commonly the case the two sets of output jacks are not separately buffered. The power amp is solid state and has an input impedance of 20K, the sub has an input impedance of 10K, and the preamp is tube-based and has a specified output impedance of 400 ohms. JA's measurements reveal that the output impedance rises to 3K at 20 Hz, which is not uncommon. Purchasing the sub would be an expensive and/or time consuming mistake.

3)Someone is considering purchasing a tube amp to use in conjunction with a speaker having a specified impedance of 6 ohms. JA's measurements reveal that the impedance is close to 4 ohms at low frequencies, and close to 8 ohms at high frequencies. That may work OK in some cases, but it definitely suggests the possibility that the speaker was designed with the expectation that it would be used with a solid state amp. The result stands a good chance of being an expensive and/or time consuming mistake.

Countless other comparable examples could be cited.

Disclaimer: I have no affiliation with JA, Stereophile, or anyone else associated with the audio industry.

Regards,
-- Al

My brother, who's a professional audio engineer, recently had to develop his own test gear, sensitive to smaller than picoseconds.

Al,
I agree with your clear reasoned examples, they will certainly have value in determining likely(or unlikely) compatability. They won`t help in determining the sound quality of various component matching.

I like to refer to a statement from Kevin Voekes (sp?) of Revel speakers fame. He states that measurements are indeed important in designing equipment but the ultimate test is double blind listening sessions. His summation? A speaker that measures bad never sounds good, but conversely a speaker that measures good does not ALWAYS sound good.(but stands a better chance of sounding good) I think this may apply more heavily to transducers than electronics, but I feel most of the improvements over the past 20 or so years are due to either improved materials and/or increased ability to take the measurements that DO matter. Without this, we are only left with the Art of design, which is falling off in favor of the Science of design as capabilities improve to measure the aspects of performance that truly do make a difference.