The question is meant to be open ended. The thread is going to be premised on listening to music, rather than measuring components, but is meant to make attempts at sorting out what measurements do matter, and at what level they matter. I will start with some simple observations, and suggest that those who might be intersted, please make some observations of your own before commenting.
Here at ASR there is published a SINAD chart, where DACs are ranked by this stat alone, how relevant is that to sound quality, meaning, in room playback performance over loudspeakers? At this point I would suggest that anyone interested, get a Stereophile test disc (I think mine is number 2), and find the -90 dB, 1 kHz tone. Set your system to a normal, critical listening level with some music, best to make this the loudest level you would actually use for listening. Now, play the -90 dB tone from the Stereophile Test Disc... can you hear it from your normal listening position? Here I can definitely hear it, but it is also very, very low in level. Note that 1 kHz is smack dab in the area where human hearing is very sensitive, so it is fairly safe to assume that a single tone of other frequencies at the same level would be no more audible than this 1 kHz tone. I do not have test tones at lower levels, but just roughly considering this, I very much doubt anything below -110 dB could be audible here in my room. My takeaway from this is that I am not too concerned about distortion products below -110 dB, and neither would I be likely to rank DACs against each other based on what goes on below -110 dB, as it is inaudible in a real world situation. If we apply this thinking to the SINAD chart, we can see that even DACs in the second tier (green) mostly exhibit levels of distortion plus noise which are inaudible. So then, we can see, that there is no audible advantage going from say, a Topping D-90, to Chord Mojo, in terms of distortion and noise (of a single tone). So now the question becomes, do these two DACs sound identical? And if not, clearly the difference is not expressed by the SINAD numbers. Could another measurement actually more readily express any sonic differences? I would like to hear some opinions, but it does appear to me from looking at a few different measurements here, that the multitone test excites more distortions at higher levels, than what appears in a simple SINAD test of a single tone, perhaps we should pay more attention to distortion spikes higher than -110 dB in the multitone test? What do you guys think?
Or would you just conclude that all DACs from the green zone and up sound identical to each other and cannot be distinguished by listening?
Here at ASR there is published a SINAD chart, where DACs are ranked by this stat alone, how relevant is that to sound quality, meaning, in room playback performance over loudspeakers? At this point I would suggest that anyone interested, get a Stereophile test disc (I think mine is number 2), and find the -90 dB, 1 kHz tone. Set your system to a normal, critical listening level with some music, best to make this the loudest level you would actually use for listening. Now, play the -90 dB tone from the Stereophile Test Disc... can you hear it from your normal listening position? Here I can definitely hear it, but it is also very, very low in level. Note that 1 kHz is smack dab in the area where human hearing is very sensitive, so it is fairly safe to assume that a single tone of other frequencies at the same level would be no more audible than this 1 kHz tone. I do not have test tones at lower levels, but just roughly considering this, I very much doubt anything below -110 dB could be audible here in my room. My takeaway from this is that I am not too concerned about distortion products below -110 dB, and neither would I be likely to rank DACs against each other based on what goes on below -110 dB, as it is inaudible in a real world situation. If we apply this thinking to the SINAD chart, we can see that even DACs in the second tier (green) mostly exhibit levels of distortion plus noise which are inaudible. So then, we can see, that there is no audible advantage going from say, a Topping D-90, to Chord Mojo, in terms of distortion and noise (of a single tone). So now the question becomes, do these two DACs sound identical? And if not, clearly the difference is not expressed by the SINAD numbers. Could another measurement actually more readily express any sonic differences? I would like to hear some opinions, but it does appear to me from looking at a few different measurements here, that the multitone test excites more distortions at higher levels, than what appears in a simple SINAD test of a single tone, perhaps we should pay more attention to distortion spikes higher than -110 dB in the multitone test? What do you guys think?
Or would you just conclude that all DACs from the green zone and up sound identical to each other and cannot be distinguished by listening?