SoftwireEngineer wrote: > That sounds ok to me. But I think the jitter is not only signal > correlated, but also related to the source, cabling and DAC/processor > etc. Stopped by at Barnes and Noble today and browsing through a > Stereophile, they show graphs of jitter spectrum for various inputs > (SPDIF, AES, USB etc). I think this is a good guidance for making any > buying decisions. If the spectrum looks bad and you think it still > sounds good, you need to listen again. Stereophile has improved or what > in the last few years ? (after I got sick of the high priced gear they > reviewed and stopped my subscription).In the Feb issue, they provide > details of the chips, algorithms etc of the equipment they are > reviewing >
This is precisely why I still bother subscribing to Stereophile - John Atkinson's technical take on the hardware. Notice that the jitter measurements are taken out of the analogue output from the DAC (in the Feb issue you probably were looking at the review of the AVM Evolution C9). This is the summation of all the jitter from the computer/CDP --> cable --> DAC. Notice those peaks on Figure 6 and 7 for that review representing jitter sidebands. The highest of them all is at -100dB or lower whether USB or TosLink! As per the graph, the 11khz primary signal was at -6dB. This means that ALL those sideband distortion products (ascribed to jitter) were 94dB or more below the signal itself. Notice also how the graph starts at the top at -70dB, hence giving the impression that these sidebands are larger than they should be compared to the center frequency. Is this audible? As Ethan W argued in the debate, this amount of distortion/noise below the primary signal is inaudible to humans (heck there's no music that needs anywhere close to this dynamic range!). Realize also that the measurements overall for the product above looks decidedly average; that is, there could be problems with the audio performance, but jitter as per the graph is not an issue whatsoever. ------------------------------------------------------------------------ Archimago's Profile: http://forums.slimdevices.com/member.php?userid=2207 View this thread: http://forums.slimdevices.com/showthread.php?t=96407 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
