CardinalFang;322349 Wrote: > Does is still happen if you turn down the volume on the digital output? > I had this for a while on some recordings until I made sure that all > volume adjustment was turned off. There must have been some bad data in > the recordings that caused the final output to clip when adjusted - > that's my theory anyway! > > Before I found the cause, I tried turning down the volume to about 80% > on the digital out and the popping went away.
There's no such thing as "bad" PCM data as far as a s/pdif interface is concerned, but some interesting things can happen to the electrical waveform depending on what is being transmitted. If an interface is borderline, often these special cases will reveal the problems: 1. If the signal is digital silence (all zeroes), this causes the waveform to have the smallest possible number of transitions in the signal. A zero is represented by one transition, and a one is represented by two transitions. To a problematic s/pdif receiver, this can cause the input to try to lock on at half the frequency that it should be, because the only ones in the signal will be in the out-of-band data, which may not be enough to drive the PLL to the correct frequency. I have seen this happen when using improper cabling. 2. If you're playing 16-bit material, whether or not the digital volume control is used with cause a couple of special cases. The reason is that the 16-bit signal will have all zeroes in the least significant bits, whereas if the volume control is being used then there may be ones in those bits. If the receiver has a bug that causes it to misbehave when those lower bits are populated then you would see problems when the volume control is not at 100%. This is not a problem I've ever seen, but it's theoretically plausible and may explain what you saw. What kind of DAC was it? -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=50151 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
