opaqueice;182491 Wrote: > Consider starting with some analogue signal. Now sample it at 96kHz; > that gives you some sequence of bits. Now keep the 1st bit, the 3rd, > 5th, etc. The new sequence is exactly the one you would have obtained > had you simply sampled the original signal at 48kHz (starting at the > same time). So where has downsampling introduced any artifacts? > Yes, but before you sample an analogue signal, you must first bandwidth limit it to half the sampling rate. In your example, if you have bandwidth limited the signal to 48kHz, so that it can be sampled at 96kHz without aliasing, then you WON'T get a satisfactory sampling at 48kHz, because the signal content between 24kHz and 48kHz will cause aliasing when you sample it at 48kHz.
The reason that simply chucking away every other sample when downsampling (eg. as happens in a Squeezebox) rarely causes an audible problem is because there is usually very little energy in the 24kHz to 48kHz region in the first place, so the aliasing artifacts are very low in amplitude. -- cliveb Performers -> dozens of mixers and effects -> clipped/hypercompressed mastering -> you think a few extra ps of jitter matters? ------------------------------------------------------------------------ cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=32958 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
