I was thinking again the other day about realism in audio reproduction after re-reading an article in TAS 117 (1999) from HP regarding dynamics and the 4th dimension of soundspace in audio reproduction. He was thinking about how dynamics and specifically restriction in dynamics, plays a role in the reduction of realism from playback systems. He put forward an interesting notion that dynamic restriction in particular frequency bands is one potential cause of sonic character in gear that nominally measures "perfect".
"However, with most home audio components, we get
nothing like the dynamic truth. We can, with the best components,
get overall a very wide (perceived) range of dynamic
contrasts, and these we have called “macrodynamics.” But
these are never distributed equally throughout the frequency
spectrum."
For loudspeakers I have heard this very clearly in the past when one driver doesn't have the same dynamic envelope as others you will get a change in character in the speaker at different output levels. For electronics this becomes a bit harder to understand but could be still a factor, particularly if the power supply is not up to the challenge with demanding material. For electronics, I am still of the mind that distortion and changes with frequency are making the character of a particular piece of gear but I can see how dynamic restriction in certain bands could change the character. What I don't get though is how this would be consistent regardless of level and rather than a preamp or amp always sounding "dark" or "bright" it would only manifest this character when that dynamic restriction is being run into and at lower levels the gear would behave differently. I have not observed this too much other than sometimes the sound gets hard or glassy when gear is pushed too hard, but then it is likely a sharp increase in distortion and not dynamic restriction per se.
Just wanted to through this one out there because I think the idea of HP has some merit on the face of it but I am not sure from a technical POV how it would manifest in electronics. For speakers I have a clearer idea how it can be so.
One interesting point he makes, and I tend to agree with him, is that no low sensitivity speakers can achieve dynamic realism and that there are no standard driver or planar speakers that can truly deliver as well.
"Furthermore, few designers, to my knowledge, use measurements
that allow them to determine the resolution floor
of their speaker systems. Without knowing how well a speaker
system can resolve low-level signals, we can’t have a measurable
idea of its usable dynamic range. We often find ourselves,
particularly with speaker systems of extremely low
efficiency, unable to bring the sound to life until we have
turned the volume up past a comparable level in the hall that
would give us the same sense of impact. Which means we’ll
be playing the system too loudly. Ironically, some of the electrostatic
speakers – I fondly recall the old Beveridge Model 2
– will give us far greater resolving power and allow us to find
equivalents to similar concert-hall levels at low levels, while
denying us realistic playback at high levels; thus we miss the
loudest levels that can make a performance electrifying and its
impact well-nigh overwhelming."
"The return to high-efficiency speakers, prompted by the
rise of triode amplifier designs, is also a return to a more realistic
scale of overall dynamics. Dynamic truth became the
poor stepchild, the Cinderella perhaps, when low-efficiency
speakers, designed for extremely flat frequency response,
became the industry norm. This was occasioned by the rise of
widespread home stereo playback in the late Fifties. That they
were smaller and more compact made them seem more “practical”
and relegated the big corner horns to the swap-and-slop
shops or to the Japanese market, where even today, the James
B. Lansing Ranger Paragon and ElectroVoice Patrician can
still be imported. And as a matter of practical fact, designers
have yet to combine high efficiency with very flat frequency
response in commercially practicable designs. Need I note
that these old behemoth horns could be driven to quite loud
levels with as few as five watts?
What may lie behind the entire triode movement is a
desire for more immediacy – an immediacy that comes from
dynamic “jump” – in the reproduction of sound, a sense that
one is getting closer to the music, to the absolute itself. That
sense of immediacy is difficult to achieve with most conventional
moving-coil speaker systems, and even with high-resolution,
low-efficiency designs like the electrostatics outside a
relatively narrow band of midrange frequencies. If we follow
this line of reasoning to its logical jumping off place, we come
face to face with the argument that the first few watts of
amplifier power may, in fact, sound better (the triode argument),
but maybe not for the reason some suppose. With a
highly efficient speaker, the headroom of the amplifying
device would be greater in the first few watts, and the distortion
the lowest. If immediacy and dynamic headroom are two
heads of the same chicken, then we could say that only with a
convincing reproduction of music’s dynamics could be there a
sense of immediacy and perhaps even intimacy. ***
Thus, we might say that the sense of true immediacy
(not brightness and not exactly presence of the non-living
kind) is, at least in the midband, also another key to the
dynamic trueness of a system’s reproduction."
"However, with most home audio components, we get
nothing like the dynamic truth. We can, with the best components,
get overall a very wide (perceived) range of dynamic
contrasts, and these we have called “macrodynamics.” But
these are never distributed equally throughout the frequency
spectrum."
For loudspeakers I have heard this very clearly in the past when one driver doesn't have the same dynamic envelope as others you will get a change in character in the speaker at different output levels. For electronics this becomes a bit harder to understand but could be still a factor, particularly if the power supply is not up to the challenge with demanding material. For electronics, I am still of the mind that distortion and changes with frequency are making the character of a particular piece of gear but I can see how dynamic restriction in certain bands could change the character. What I don't get though is how this would be consistent regardless of level and rather than a preamp or amp always sounding "dark" or "bright" it would only manifest this character when that dynamic restriction is being run into and at lower levels the gear would behave differently. I have not observed this too much other than sometimes the sound gets hard or glassy when gear is pushed too hard, but then it is likely a sharp increase in distortion and not dynamic restriction per se.
Just wanted to through this one out there because I think the idea of HP has some merit on the face of it but I am not sure from a technical POV how it would manifest in electronics. For speakers I have a clearer idea how it can be so.
One interesting point he makes, and I tend to agree with him, is that no low sensitivity speakers can achieve dynamic realism and that there are no standard driver or planar speakers that can truly deliver as well.
"Furthermore, few designers, to my knowledge, use measurements
that allow them to determine the resolution floor
of their speaker systems. Without knowing how well a speaker
system can resolve low-level signals, we can’t have a measurable
idea of its usable dynamic range. We often find ourselves,
particularly with speaker systems of extremely low
efficiency, unable to bring the sound to life until we have
turned the volume up past a comparable level in the hall that
would give us the same sense of impact. Which means we’ll
be playing the system too loudly. Ironically, some of the electrostatic
speakers – I fondly recall the old Beveridge Model 2
– will give us far greater resolving power and allow us to find
equivalents to similar concert-hall levels at low levels, while
denying us realistic playback at high levels; thus we miss the
loudest levels that can make a performance electrifying and its
impact well-nigh overwhelming."
"The return to high-efficiency speakers, prompted by the
rise of triode amplifier designs, is also a return to a more realistic
scale of overall dynamics. Dynamic truth became the
poor stepchild, the Cinderella perhaps, when low-efficiency
speakers, designed for extremely flat frequency response,
became the industry norm. This was occasioned by the rise of
widespread home stereo playback in the late Fifties. That they
were smaller and more compact made them seem more “practical”
and relegated the big corner horns to the swap-and-slop
shops or to the Japanese market, where even today, the James
B. Lansing Ranger Paragon and ElectroVoice Patrician can
still be imported. And as a matter of practical fact, designers
have yet to combine high efficiency with very flat frequency
response in commercially practicable designs. Need I note
that these old behemoth horns could be driven to quite loud
levels with as few as five watts?
What may lie behind the entire triode movement is a
desire for more immediacy – an immediacy that comes from
dynamic “jump” – in the reproduction of sound, a sense that
one is getting closer to the music, to the absolute itself. That
sense of immediacy is difficult to achieve with most conventional
moving-coil speaker systems, and even with high-resolution,
low-efficiency designs like the electrostatics outside a
relatively narrow band of midrange frequencies. If we follow
this line of reasoning to its logical jumping off place, we come
face to face with the argument that the first few watts of
amplifier power may, in fact, sound better (the triode argument),
but maybe not for the reason some suppose. With a
highly efficient speaker, the headroom of the amplifying
device would be greater in the first few watts, and the distortion
the lowest. If immediacy and dynamic headroom are two
heads of the same chicken, then we could say that only with a
convincing reproduction of music’s dynamics could be there a
sense of immediacy and perhaps even intimacy. ***
Thus, we might say that the sense of true immediacy
(not brightness and not exactly presence of the non-living
kind) is, at least in the midband, also another key to the
dynamic trueness of a system’s reproduction."
