Excellent comments by all, IMO. Charles, re the volume levels I listen at, Wolf's comment that:
05-21-13: Wolf_garcia
Hearing issues come from sustained high levels, and unlike something like a gunshot next to your head, a short musical burst (from classical music for example) isn't going to hurt you usually
is exactly applicable. My average listening level on most classical music is probably in the mid-70's. But I have, for example, a great many of the Telarc digitally mastered vinyl releases from the 1980's, which employed zero compression of dynamic range. Many of their symphonic recordings were notorious for their very loud bass drum beats, which can easily exceed 100 db at my listening position with the volume control set such that average levels are completely safe.
Also, as I mentioned in a previous thread here:
One of the widest dynamic range recordings in my collection (although there are many others that are close) is the Sheffield Labs recording of Prokofiev's "Romeo and Juliet," conducted by Erich Leinsdorf. Out of curiosity, a while back I examined its waveforms on a computer, using an audio editing program. The difference in volume between the loudest notes and the softest notes was around 55 db!
On that recording, and quite a few other classical symphonic pieces I have on high quality labels that tend to use minimal or no compression, I frequently measure brief peaks at my listening position in the 100 to 105 db area, using a Radio Shack digital SPL meter, although the average level is by no means particularly loud.
Those peaks are not nearly as loud, btw, as those I heard when I once listened from the very front row at Tanglewood to the Boston Symphony Orchestra performing that same Prokofiev work. My guess is that the peaks easily reached 115 db.
Regarding the definition of "speed," many good comments have been made. If I were to summarize my understanding of the term in just a few words, I would say it means that fast musical transients are reproduced ACCURATELY.
05-21-13: Csontos
Judging from your responses it's fairly clear that it is in fact a technically quantified attribute and therefore realizing it is not subjective at all. The reason I don't care much about specs is because amps don't necessarily live up to them. But I am aware of which ones they are.
I wouldn't go as far as to say that "speed" is technically quantifiable. The bandwidth specs I referred to earlier of course tell just a small part of the story. Bandwidth extending several-fold beyond the limits of our hearing is necessary to maintain phase relationships between harmonics that are at frequencies in the upper treble region, and lower frequencies that will be present in the same musical notes. But that and other speed-related technical parameters, such as slew rate, certainly don't tell the whole story IMO.
For instance, it is well established that excessive use of feedback is conducive to Transient Intermodulation Distortion (TIM), which as its name implies will, if present to a significant degree, result in inaccurate and sloppy reproduction of fast transients. As far as I am aware, TIM is never specified, and I'm not sure that standards defining how it should be measured even exist.
How to minimize or eliminate TIM? Design an amplifier that doesn't need much or any feedback, such as many tube amps and some (but relatively few) solid state amps.
Best regards,
-- Al
