You can dig out some old treads about this too . But here it goes... Back when I thought this was very important Ive used some test to indirectly verify that the transfer really was bitperfect .
There are signals thats usually are packed/disguised in regular pcm namely hdcd & DTS or ac3 ( Dolby digital ) thats how for example a DVD player sends ac3 over spdiff or toslink to a ht-reciver . The thing is this must be bitperfect or the encoding gets lost and you get gibberish. So a great test is to get some ac3 encoded wav files, dial in stuff to what you think are zero gain, 100% bitperfect and then conect the digital out to a home theatre processor or reciever and listen you get 5.1 sound or noise . On one of the side topics here , im More or less convinced that a good well dithered digital volume control is actually performs better than any analog implementation a good digital systems noise if of the same character as good old analog noise , s/n ratio is the same if achieved by analog or digital means ( forget al those staircase graphs in sterephile thats not its actually working ). Its also an issue of implementation of the rest of the system . The whole gain structure must be reasonable so that full scale signal is just as loud as you ever want to listen . Then quieter volume are well quieter :) the volume is so low that any possible degradation is inaudible anyway . And then you have your 24 bit dithered digila system with an s/n ratio of say 144dB and then you play some old 70s rock album 70dB s/n ratio thats less than 13 bits .... there are ofcourse better records , but what I mean that in practice the system noise produced by a digital volume adjustment is far below the noise in your actual recordings you listen to , even if you bougth 24 bit or DSD album , what most of the data actually is are random noise from the recording . -------------------------------------------------------------------- Main hifi: Touch + CIA PS +MeridianG68J MeridianHD621 MeridianG98DH 2 x MeridianDSP5200 MeridianDSP5200HC 2 xMeridianDSP3100 +Rel Stadium 3 sub. Bedroom/Office: Boom Kitchen: Touch + powered Fostex PM0.4 Misc use: Radio (with battery) iPad1 with iPengHD & SqueezePad (spares Touch, SB3, reciever ,controller ) server HP proliant micro server N36L with ClearOS Linux http://people.xiph.org/~xiphmont/demo/neil-young.html ------------------------------------------------------------------------ Mnyb's Profile: http://forums.slimdevices.com/member.php?userid=4143 View this thread: http://forums.slimdevices.com/showthread.php?t=108191
_______________________________________________ unix mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/unix
