Feel free to use Swedish!
Anyway, for something to decay "faster than it should", there would either have to be a pretty significant amplitude non-linearity (making quiet sounds be even quieter than they should be), and that would definitely show up in normal harmonic distortion measurements, or some kind of "time gating" function that would have to detect the decay of signals - somewhat unlikely.
I think what you are hearing is *absence* of distortion - many amplifiers have a low-level harmonic distortion that emphasizes (or "warms up") lower-level signals.
You can only judge the sound quality from the standard harmonic distortion measurements if the measurements show significant amounts of harmonic distortion - and if it is predominantly low-order harmonics, such as with many tube amps, many people perceive the distortion as pleasant or "warm".
"Distortion" is a very general term. There are so many forms of distortion. There is harmonic distortion and intermodulation caused by amplitude non-linearity, then there is frequency response distortion caused by a non-uniform frequency response curve, and phase distortion caused by some parts of the signal being out of phase with other parts.
They can all be measured, but the audibility of them is a different issue.
See my earlier response about how low-level harmonic distortion can over-emphasize reverberation.
Maybe you are right. If so, I would like a little bit of that distorsion
In that case I suggest a tube pre-amp, a digital DSP processor, or an electric guitar fuzz pedal
This low-level distortion is a speculation. It may be true in some cases, especially with underbiased class B, but such reasoning may not be used as a general explanation. And I know quite well what miero was listening to
So what is your suggested explanation for the "chopped decays"?
Professional and sophisticated tools are still based on DAC and ADC which still have its own distortion even for a Agilent X-Series
I not very hard up on super accuracy, but even if the measurement contain distortion from DAC or ADC and the accuracy still can be obtained within +0.005% ~ +0.008%, which I view it as acceptable.
An observation on the "lack of reverb" or "too fast decay" issue. We replaced a class AB amp with a UcD400, and observed that the bass seemed reduced, and much "tighter" (less overhang). Using a microphone to compare frequency responses, it turned out the class AB amp driving the speakers had ripples in the frequency response where the driver impedance had ripples, whereas the UcD400 response was smooth. So the point here is to use a microphone and compare frequency responses of your speakers with each amp before coming to any conclusions. Ripples in the frequency response will lead to some degree of ringing at each peak.
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How, in your opinion, would the tweeter be influenced, and how would it reduce perceived reverberation?
Of course any measurement system will have its own distortion. That is why it is so important to make sure you are measuring real effects.
Right. And as those values are several orders of magnitude lower than your typical speaker (not to mention vinyl pick-up), they don't really tell anything about audible sound quality any more. All they do is they verify that the amps work as designed and within the manufacturers specifications.
Maybe the point is to realize that what we prefer has very little to do with objective, measurable fidelity. Some of us like tube-based vinyl rigs that have absolutely horrible specifications from an engineers point of view, and there is of course nothing wrong with that, as long as we don't start claiming that the vinyl rig has "better sound quality" in some absolute, objective sense.
The nc400 has extremely good measurable, objective performance. That might not be everyone's cup of tea.
Yes, you're right. I'm just making the point that when comparing performance, it's very helpful to verify sonic differences by measurement, even if the lower fidelity version is a personal preference.
I agree. But the measurements I have seen pretty much confirm the specs published by hypex.
Julf: respectfully, these are pretty funny statements coming from you. First of all, the idea you propose that additional low order harmonic distortion (such as with a tube amp, or certain class a SS amps) results in a euphonic "warm" sound has never been proven at all. In fact, in blind tests done by Stereophile, this myth was was dis proven. But you seem comfortable speculating that any time someone prefers a different amp to the Ncore, that the preference must be because of a fault (coloration) of the other amp.
Further, it is only speculation to assume that some people prefer the sound of certain tube amps because of the faults (coloration), this is unproven as well. It could easily be that some people actually prefer the sound of certain tube amps because they are actually more accurate than (Ncore) in certain areas of performance which standard measurements do not illustrate (despite higher noise/THD).
I think, to be consistent with your POV that science should be used to evaulate performance, that you should probably not be speculating about these things, and making these assumptions.
Really, there are some very, very smart folks here at DIYaudio. I think it is time that some of these really smart folks start working at ways to improve how we measure amplifier performance. It is more than clear to me that steady state signal tests, and the occasional 10 kHz square wave are entirely inadequate to describe the differences in sonic results of different amplifiers. I suspect that there is some area of measurable performance where the Ncore actually has problems, it is just a matter of finding the right way to measure for those problems.
It is time for someone to come up with some new paradigms in measurement, which really test time domain perfromance with highly complex mixed signals approximating complex music.
I love some of the things the Ncore does (low noise, microscopic detail retrieval) but acknowledge that it also seems to be missing some of the musical picture, and I do not think what is missing is 2nd order harmonic.
Except Hypex can't tell you how your particular speaker will interact, and sound with their amp. In our case the tighter bass was desirable, but I suppose some people may prefer the looser version.
Yes..
Hahaha! I know what you mean, and I have neither the education, nor the equipment to even consider this development. I only recognize that we clearly do not know how to adequately measure amplifiers for all aspects of sonic performance (or at least, perhaps someone does, but that approach is not in common use).
We see many amplifiers wich exhibit meausured performance with "faults" which are far below accepted levels of audability; according to science, if these measurements were all that mattered, all of these amps should sound the same... clearly they do not though.
So, if we accept that these differences in sound quality exist, we have only two choices: accept that we evalauate the sound quality through subjective listening tests, or, endeavor to develop measurements which can actually describe these differences. There just seems to me a problem with suggesting that differences in sonic performance should just be blindly attributed to a +/- .0x% THD product alone.
Hahaha! I know what you mean, and I have neither the education, nor the equipment to even consider this development. I only recognize that we clearly do not know how to adequately measure amplifiers for all aspects of sonic performance (or at least, perhaps someone does, but that approach is not in common use).
We see many amplifiers wich exhibit meausured performance with "faults" which are far below accepted levels of audability; according to science, if these measurements were all that mattered, all of these amps should sound the same... clearly they do not though.
So, if we accept that these differences in sound quality exist, we have only two choices: accept that we evalauate the sound quality through subjective listening tests, or, endeavor to develop measurements which can actually describe these differences. There just seems to me a problem with suggesting that differences in sonic performance should just be blindly attributed to a +/- .0x% THD product alone.
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