gregorio
Headphoneus Supremus
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- Feb 14, 2008
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1. If a DAC is connected via USB to an android device and is sound is being directed through the USB DAC, can it be concluded that the external device is being implemented correctly and will sound identical to any source (i.e. PC)?
2. Are there any audible differences when using apps like UAPP? (if so, what is the cause of the change?)
3. Does android always re-sample to a standard sample rate and does this create an audible difference?
4. Based on your responses it is implied that my perceived audio quality improvements are caused by varying volume levels and in fact the external DAC is producing exact same sound. This could very well be the case as I haven't done the required tests to rule this out. Would you extend this thinking to comparing DAC vs DAC or AMP vs AMP? i.e. are there noticeable improvements in sound reproduction with these varying components? ... I'm just trying to find out which hairs are worth splitting.
1. Assuming that the differences in output (EG. Power/impedance) of the two devices are appropriate for your transducers (speakers or headphones) then "yes" it can generally be concluded that the differences will be inaudible. However there are some potential caveats: There are some external DACs that do not isolate their analogue output very well from the high levels of noise output by some PCs on their USB ports. However, there are probably exceedingly few DACs (even with very noisy PCs) where the levels of analogue output noise is actually audible. And:
2. I don't know specifically with the UAPP app. There can be audible differences with different software: I verified a difference between Firefox and Safari (with a blind test) on a Mac and, that Safari's output was higher fidelity but didn't have time to investigate what Firefox was doing to reduce fidelity. (This was with a several year old version of Firefox).
3. I believe that android does always re-sample but that it can be bypassed with certain software. Again, I haven't specifically test what android does but as a general rule, changing sample rates creates NO audible difference. There were some exceptions to this rule, a couple of decades ago with certain sample rate converters. So, while I can't be absolutely certain, I would be very surprised in android caused any audible artefacts from it's SRC and I would need some very reliable evidence that it does.
4. As a general rule DAC vs DAC and Amp vs Amp is NOT "a hair worth splitting". Even quite cheap DACs (<$80) can be audibly transparent and differences between amps are generally inaudible (given appropriate output power/impedance). However, there are a few esoteric design exceptions in both cases, some valve amps for example.
[1] Even via Android, LDAC will not sound as good as the resampled usb audio via your phone.
[2] UAPP with no resampling sounds better than audio running through Android audio stack.
[3] That's just unfortunately how Linux/Android operate.
1. Assuming "not sound as good" means audibly poorer fidelity, we will need some reliable evidence of that assertion please.
2. Same again, some reliable evidence please.
3. If there is reliable evidence that UAPP with no resampling is audibly better (fidelity) and if so, that resampling is actually the cause, then it would indeed be very unfortunate, arguably to the point of incompetence!
G