darrenyeats;695191 Wrote: > What I said about dither is correct AFAIK. > > The "bottom half bit", as you put it, is present in every sample > whether the waveform is big or small. So if I am right, the jaggedness > is changed from signal correlated jaggedness to random jaggedness by > dither. This occurs regardless of amplitude. > > My point is there appear to be voltage levels in the output from these > DACs, so in fact they appear to be maintaining a voltage level during a > sample interval (you can see the plateau shape in the waveforms). I > agree this approximates to a smooth waveform at higher amplitudes but > this is increasing the S/N ratio rather than reducing distortion due to > this step effect, if the signal is dithered! In an undithered signal, it > would indeed reduce distortion. (But if I'm wrong then please explain.) > Darren > > Sent from my HTC Sensation Z710e using Tapatalk Dither is only (these days) relevant when downsampling from 24 to 16 bits. It determines what happens in what I call the lowest half-bit. It pseudo-randomises it, which helps avoid quantisation distortion becoming apparent on very quite things like in fade outs, reverb tails etc.
What you are seeing in that Stereophile trace are exactly the distortions caused by the fact that the16-bit signal was NOT dithered when it was created from a 24-bit starting point. That's why they have to make the point of saying it is "undithered". It also neatly illustrates why dithering is a good idea when downsampling :-) Those jagged edges Simply do not exist as you increase the number of bits in play. You will notice that Stereophile do not show you what a sine wave looks like at higher levels... That's because it looks exactly like a by nice sine wave!!!!! I can see this clearly on my oscilloscope... The sine wave is fine all the Way down until you run out of meaningful bits... -- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... Touch(wired/W7)+Teddy Pardo PSU - Audiolense 3.3/2.0+INGUZ DRC - MF M1 DAC - Linn 5103 - full Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Pekin Tuner, Townsend Supertweeters,VdH Toslink,Kimber 8TC Speaker & Chord Signature Plus Interconnect cables Stax4070+SRM7/II phones Kitchen Boom, Outdoors: SB Radio, Harmony One remote for everything. ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=94054 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
