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Those two questions need some sort of answer before the question of quantifiable measurement can take on any sort of meaning.
Exactly, which brings me back to my original thesis: A measurement alone has no meaning until we have given it one. |
Thank you for the kind words. quality associated with it. Clearly, these numbers represent specific physical things. What i meant was, is 4 Volts warm? Is 0.8A precise imaging? Do 30 watts sound hard? Inventing a measure, such as your cholesterol level, is not yet the same as being able to ascribe a quality or desirability to it. Now we clearly use certain limits to describe healthy, at risk, and unhealthy cholesterol levels, but that did not just come into being the moment the cholesterol could be measured. That took a lot more work. Best, E |
Stereophile understands that people hear differently and desire different things.
That's a very generous interpretation. |
I was going to leave this subject alone, feeling we had covered it well enough, but then this appeared in my feed: https://parttimeaudiophile.com/2019/01/06/border-patrol-dac-revisited-audio-fur/Lots there I agree with, and I have barely started reading. In particular: - Perception and a specific measurement are not correlated until they are correlated - Stereophile has a trend / fashion to sell. Their version of "neutral" is not really neutral. |
@erik_squires, since you are a teacher of experimental psychology
Ahem ... no no no, that was not me! :) @edstrelow This is attempted, but the measurement is not standardized. I routinely see Stereophile publish measurements from an accelerometer taped to the sides of a speaker cabinet. Best, E |
I taught statistics and experimental psychology...
This is a field in which measures are constantly evolving and being added to. I'm afraid that in audio our measures are decades old and have not been updated, just cheaper to collect. What I mean is, we can do better, but the will and effort isn't universally taken very far. I'll give you an example. I once replaced tweeter caps in a Focal speaker. The sound was really good, but for the first 48 hours I was having weird surround sound effects. I thought I could hear things happening behind me and to the right. Eventually the problem went away. Could I express this as a measure of standard measures like uF, ESR or something else? Probably not. But with some effort and time and money I might have been able to come up with a time / phase based explanation for the effects I was hearing. I didn't have any of it. My point is, we perceive something, then we find a way to measure it, then we use that measurement to tell us something. That doesn't mean all perception has been measured. Best, E |
You're being entirely arbitrary in your definition of what constitutes a measurement device. You seem to be hung up on intent.
What I'm trying to focus on is that a measurement (i.e. measure, number) has to be invented. They get invented when an experimenter needs a new way of thinking about a problem. Volts, Watts, Amperes. Even those don't really exist in nature. Volta, Watts and Ampere all started from not having a number, to having a number. Those numbers made math and engineering possible. I love numbers, but just because I have a number, does not mean I have a quality associated with it. That's the next step, and that's where I think we fumble.
Erik - how do you figure 1 Ampere at 1 watt has a S/N of 90dB? There is no S/N correlation between Amperes and Watts.
Sorry for the confusion, I meant Amplifier. :)
For instance, one amp at 1 watt has a S/N ratio of 90 dB.
Though I think when these are taken, it really should be at 2.83V, not 1 Watt. Best, E |
jea48, aren't microphones and tape recorders essentially measurement
devices/test equipment? If it wasn't for these measurement devices
would you even know what the timbre of a performance were?
At least for the intentions of this thread, no. They are recording devices. A measure is a number. So what I meant to talk about here is that a number, like signal to noise (S/N) by itself has no real meaning in terms of desirability. We, humans, use these to tell us a little about the equipment and signal quality, and we must give that number meaning. For instance, one amp at 1 watt has a S/N ratio of 90 dB. How much better is it than 900 dB? I mean, yes,we can do math and express this in volts, but is it now at the point of ridiculous? Would you pay 10x as much? Could you hear it? Numbers are great for automating testing, and creating manufacturing standards. They also validate whether or not we are making a meaningful change, but ultimately there's a separate step where we must ascribe value and perception to it. Best, E |
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I'd like to move this a little more forward: @spatialking wrote: I can tell you the reason we have jitter problems, besides the fact
that the basic CD clocks are not all the accurate,
Clocks are much better now than they were before at the same price range. Maybe this is why DAC's got magically better? is the sample clock
is encoded in the data stream. The clock is not a
separate signal path
from the data which makes jitter an inherent problem in the system. I think maybe this is the transmission method, not the data. I think the issue is who is in charge though. I2S and USB allow the DAC to be in charge of the clock. |
Good points.
I guess my focus is on the distance between a measurement, which could be done by an automated device, and human perception/value.
I agree we've measured jitter for a while, but was that all? Were there some kinds of jitter worse than others? How low before we can no longer tell?
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A good example of this is the redbook standard set in the late 70s early
80s for the then emerging CD format. The standard was fine, but it took
until the late 90s to figure out that distortion in the time domain
(jitter) was a major factor Jitter is interesting. I mean, yes, we can certainly point to it as one measurement that has improved over time, and Redbook had a markedly big jump in audible performance in the last 10 years. Is that enough? I mean, we never proved it really, and we don't actually have any idea of what is audible, or if there are other parameters around jitter which are important. I mean, AFAIK, there's not even an agreement from manufacturer to manufacturer as to how exactly jitter is measured. So if jitter IS the problem ... what is inaudible? |
@spatialking
Not asking ... so much as stating a point of view and inviting others to chime in.
Your reply is perfect.
E
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