Murray, just a question or two.
Paul Miller made his name by formulating accurate test procedures to illustrate the subjective affect of jitter in digital replay equipment. He has since expanded the MAR repertoire to encompass all facets of the audio chain. And yet he has not been able to formulate a test to illustrate the subjective differences proposed by manufacturers for conductor material, for skin effect or for microphony. Given that they have actively sought to assimilate objective and subjective affects in all fields of audio, does it not strike you as odd that nothing has been forthcoming for these supposed phenomena? For someone so thorough, is it not unusual that no FR plots were supplied for the cable tests, and no attempt made to reconcile that with your subjective findings?
Secondly, were you at any point asked to identify cables under blind conditions or were you just asked for subjective impressions after you were told that the cable had been changed?
Hi Mike,
You'd need to ask MAR why they've developed the particular test equipment they have. I suspect they are simply driven by the demands of their customers.
While some correlation could sometimes be made between the objective & subjective appraisal of certain items like CD players, (one superb sounding and particularly well measuring Sony machine springs to mind) as I recall, those listening panel's qualitative subjective findings often bore little relation to the then best measurement criteria that could be applied to the electronics (particularly amplifiers) under test. I always rather enjoyed that aspect. I think PM found it frustrating sometimes.
I think the equipment they supply to manufacturers for r&d/QC use now helps in minimising the effect of RF on circuit design/layout and also readily highlights problems with consistency (FR, noise, distortion etc) during production but it doesn't actually design the products. Its just a tool, albeit quite a sophisticated one.
With regard to FR plots, I don't know. You'd need to ask him. The format of this publication was as a small supplement to the main magazine. The page size may have limited what could have been included in any detail. I'm sure if he had included them he would have at least labelled them (You'd fail GCSE Physics for that Paul!)
We were asked for subjective impressions after hearing a cycle of 5 or 6 musical excerpts from various genres. I think in total around 8 people took part over a period of 5 days although only 3 perhaps 4 would be listening at one time. As was the way with all the blind listening tests HFC conducted, items would be re-introduced later in the test to check that a consistent subjective appraisal had been reached.
The differences between some of these cables were quite marked and readily apparent to those listening. The facility (as described earlier) to switch between 'cable' and 'no cable' was also very helpful.
In answer to one of your questions Paul, I don't recall being asked to listen for a change in the directionality of NACA5. And I wouldn't. That wasn't how the test was done. We weren't told what we had listened to until the end of the day. If reversed NACA5 was included (on one or more occasions) it would have been appraised like any other sample in that test.
