wagner@uw-june (Dave Wagner) (08/28/85)
> It would be nice if someone, someday said that measuring parameter YYYY > translates to sound ZZZZ. A hypothetical listing of this translation follows: > > Measured Parameter Sonic result > > Damping Factor Higher factors reduce muddiness > Slew Rate Higher slews improve crispness > Signal-to-noise ratio Higher ratios improve low-level resolution > Supply Regulation Better regulation improves imaging > Supply Ripple @ full power Lower ripple improves focus > Supply Impedance vs. Freq. Linear impedances improve inner detail > Chassis Leakage @ full power Lower leakage improves low-level resolution > Phase vs. Freq. Low shifts improve inner detail > It would also be nice if someone, someday said what "focus" and "inner detail" mean! Dave Wagner University of Washington Comp Sci Department wagner@washington.arpa {ihnp4,decvax,ucbvax}!uw-beaver!uw-wally!wagner
mohler@drune.UUCP (MohlerDS) (08/28/85)
YES, LETS GET ON WITH IT...THAT WAS MY FIRST POINT BEFORE THE WRATH OF THE NET WAS APPLIED TO ME CONCERNING MY WIDELY MISUNDERSTOOD ARTICLE. A small additional request, it also would be nice to see an article on component interaction, an area I think is often totally ignored! David S. Mohler AT&T - ISL @ Denver drune!mohler
pmr@drutx.UUCP (Rastocny) (09/03/85)
[Is this an analog or digital bug?] There has been much talk and slander about subjective evaluations on the net. Here are some of my rambling thoughts about this subject. There are few areas in audio where knowing what measures differently and knowing what sounds different are unique, like the differences between dynamic and electrostatic loudspeakers. Measurable differences exist but to quote the statistics that pinpoint the audible or subjective claims is difficult. Agreement upon which statistic clearly explains what is being heard has not yet been properly correlated. But yet these differences can be easily substantiated by all who hear the two types of loudspeakers regardless of reference SPL and associated electronics/signal sources (cotton, of course, removed from the ears :-). Since horn loudspeakers inherently have low harmonic distortion from low diaphragm movement, and since horns and electrostats do NOT sound alike, there must be some other (complex) parameter(s) affecting these transducers. It would be nice if someone, someday said that measuring parameter YYYY translates to sound ZZZZ. A hypothetical listing of this translation follows: Measured Parameter Sonic result Damping Factor Higher factors reduce muddiness Slew Rate Higher slews improve crispness Signal-to-noise ratio Higher ratios improve low-level resolution Supply Regulation Better regulation improves imaging Supply Ripple @ full power Lower ripple improves focus Supply Impedance vs. Freq. Linear impedances improve inner detail Chassis Leakage @ full power Lower leakage improves low-level resolution Phase vs. Freq. Low shifts improve inner detail The list goes on, but I think you get the idea. After all, what good is it to know that a piece of equipment has 0.000001% THD @1KHz unless you know what the audible effects of such minute distortion are. On the other hand, is lower necessarily better? That is, can you hear the difference between a 10E-6% and a 10E-7% THD circuit? If the 10E-6 equipment sounds more like the real thing, what other factors are involved in why equipment sounds different? (Slew rates come to mind where some low-slew amps sounded more accurate than high-slew amps with the same THD spec. It turned out that a slew-induced distortion parameter (SMPTE) was involved but not currently being measured. As soon as it was discovered, it was remedied, but not until people started hearing strange things from these high-slew amplifiers.) If THD, the long-honored spec of an amplifier's performance, no longer tells us anything about the amplifier's sound, why bother measuring it? If phase linearity and supply impedance tell more about an amplifier's sound, why NOT measure and publish these specs instead? The bottom line is that an amplifier should neither add nor subtract ANYTHING from the signal (wire with gain), and that the effects of the loads (input or output) not influence each other or the amplifier's performance. But in reality loads do alter an amplifier's performance and amplifiers do inherently add and subtract things. Determining what to measure to reduce the audible effects of this signal modification should be of utmost concern to designers and engineers. But, as the old saying goes, the squeaky wheel gets the grease and until people start complaining about something, nothing will be done. (SMPTE was complained about and then measured.) I for one cannot rely on the present meaningless measurements or the current sales hype to explain why I hear (or don't hear) different things in different amplifiers, CD players, phono cartridges, interconnect cables, loudspeakers, etc. I hope that some day someone completes a thorough and conclusive study of the sonic signature of circuit topologies and publishes these results in JAES. Then, maybe, we could get away from this senseless bickering and get on with understanding and improving the state of the art. Yours for higher fidelity, Phil Rastocny AT&T-ISL ihnp4!drutx!pmr