marcoc1712 wrote: > Not sure LMS is using SOX for volume control. > As far as I know one of the first advise about using LMS for 'HiFi' is > to disable volume control, maybe in not becouse SOX but multiple LOSSY > conversions needed when in and out is MP3, I don't know. > > BTW, even if it's made by SOX, it's inside a separate 'effect chain', so > with precision as low as the input bit depth ant that is not good when > you have other DSP to be applied (* keep reading). > > > The one implemented in C-3PO - Manual gain reduction (in dB) - is > using SOX AFTER the pcm conversion and BEFORE the (optional) conversion > to the output format (when a different one is selected) im the same > "effect chain" togheter with all the other DSPs. > > > SOX is considered one of the best tool for doing that. Internally all > the effect chain is working at 64 bit depth so the 'rounding error' is > much, much lower than piping different steps at 16 or even 32 bit, so I > really advise NOT to pipe a digital volume control AFTER the C-3PO work, > BUT use the provided one instead (that's why *, also). > > PLEASE ALWAYS leave some headroom (at least 3 db, 6 is better) when > upsampling os using any effect. > > You could also consider the loudness control instead/in combination of > gain reduction, it's the same BUT ISOPHONICS curves are applied instead > of a 'flat' gain reduction. Used as it should be, is great. > > Same for ANY other effect, like convolution for instance, much better to > use the 'slots' in C-3PO to add SOX effects and the reason is always > that inside a single effect chain the 'precision' is 64 bit, rounded > (and possibly dithered, depending on your choice) at the selected output > precision only once, at the end. > > Hope is clear and please forgive my english, as usual. > > Marco.
Hi Marco, Thank you for the clear explanation (your English is excellent). It is clear that doing it inside SOX/C-3PO is the way to go without a loss of resolution. But currently, to simply change the volume I have to apply changes to C-3PO in the LMS interface and this jumps to the start of the next track. Since the objective it to remove analogue volume control completely, I would like to be able to simply be able to change it directly from my App (I use Squeeze Control, but others possible) without stopping or jumping to the next track. Perhaps I have to wait for someone to provide an LMS plug-in to enable this... By the way, I have tried a few different loudness settings/gain reduction combinations and will experiment further. ------------------------------------------------------------------------ fsger's Profile: http://forums.slimdevices.com/member.php?userid=15977 View this thread: http://forums.slimdevices.com/showthread.php?t=105309 _______________________________________________ Squeezecenter mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/squeezecenter
