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Here are some measurements of three DACs I have on hand. This is a 2k FFT spectrogram. In the below view the background goes to light gray at -100 db FS. Just above that it becomes faintly blue then purple then red then white as level goes up.
The measures are a full scale single tone sweep 0-20 khz. And a twin tone full scale sweep with the tones 1000 hz apart or an IMD sweep.
For completeness all these DACs are very linear to -120 db, the Jtest is very clean for two and quite good for one. No big issues.
All the above are pretty similar. Let us assume my speakers are max 105 db SPL in room. Since all the above DACs are very nearly 100 % clean at - 100 db FS will they sound different? DAC B does show just a trace of 2nd and 3rd harmonic at upper frequencies. -98.5 db and 97 db respectively. There is just a trace of IMD sidebands at upper frequencies at like -99 db.
So will they all sound the same, sound interchangeable? I mean there are no spurious tones, USB bleed thru or any other kind of distortion poking above -100 db effectively. What could possibly sound different about them?
Now let us look a little further into things. This is the same spectrogram except I have moved the the spectrogram floor to - 130 db FS.
Peering deeper we see some differences now. DAC B has all the harmonics though at a very low level. After the 3rd harmonic everything is -110 db FS or lower. Will they matter at all?
The other DACs have only 2nd, 3rd and a little 4th harmonic. Those are at - 110 db and less.
DAC B has a constant tone near 16 khz. It isn't USB noise as it is actually at 16,438 hz at -123 db FS. It only occurs when connected to my Macbook. Will that be a problem? Should I not use it with a Macbook?
Also you see aliasing/imaging (it is some of both) where the harmonics turn back downward in the spectrogram. They are gone below -130 db by 20 khz and lower. Will that matter?
Why is this in psycho-acoustics? I wanted to get some perspective about how good is good enough. I'll take the best performance I can get, but should I only do that if it is cheap past a certain point? And what is that point in measured performance? Where to draw the line?
The measures are a full scale single tone sweep 0-20 khz. And a twin tone full scale sweep with the tones 1000 hz apart or an IMD sweep.
For completeness all these DACs are very linear to -120 db, the Jtest is very clean for two and quite good for one. No big issues.
All the above are pretty similar. Let us assume my speakers are max 105 db SPL in room. Since all the above DACs are very nearly 100 % clean at - 100 db FS will they sound different? DAC B does show just a trace of 2nd and 3rd harmonic at upper frequencies. -98.5 db and 97 db respectively. There is just a trace of IMD sidebands at upper frequencies at like -99 db.
So will they all sound the same, sound interchangeable? I mean there are no spurious tones, USB bleed thru or any other kind of distortion poking above -100 db effectively. What could possibly sound different about them?
Now let us look a little further into things. This is the same spectrogram except I have moved the the spectrogram floor to - 130 db FS.
Peering deeper we see some differences now. DAC B has all the harmonics though at a very low level. After the 3rd harmonic everything is -110 db FS or lower. Will they matter at all?
The other DACs have only 2nd, 3rd and a little 4th harmonic. Those are at - 110 db and less.
DAC B has a constant tone near 16 khz. It isn't USB noise as it is actually at 16,438 hz at -123 db FS. It only occurs when connected to my Macbook. Will that be a problem? Should I not use it with a Macbook?
Also you see aliasing/imaging (it is some of both) where the harmonics turn back downward in the spectrogram. They are gone below -130 db by 20 khz and lower. Will that matter?
Why is this in psycho-acoustics? I wanted to get some perspective about how good is good enough. I'll take the best performance I can get, but should I only do that if it is cheap past a certain point? And what is that point in measured performance? Where to draw the line?
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