Hello everyone,
in conjunction with an old DVD player regarding pre-emphasis, I observed that the RME DAC doesn't apply the de-emphasis EQ at higher sample rates, but 44.1 kHz (and probably 48 kHz as well) only which doesn't surprise, given that in the old days, these most likely had been the only rates which went along with the pre-emphasis concept anyway.
However, to be completely consistent, the option in the menu then consequently should get "greyed out" in my opinion, as both settings "on" or "off" show no audible difference.
To make it even clearer, the behavior is the following:
Pre-emphased CD -> Panasonic S47 -> native 44.1 kHz setting: player outputs the unaltered bitstream and correctly sets the pre-emphasis S/PDIF flag. On the ADI-2 Pro 2/4 then de-emphasis "auto" equals "on" whereas "off" sounds too bright.
Pre-emphased CD -> Panasonic S47 -> "AV Enhancer" setting, leading to upsampling to 176.4 kHz: player outputs the already de-emphasised data altered and correctly doesn't set the pre-emphasis S/PDIF flag anymore. On the ADI-2 Pro 2/4 then de-emphasis "auto" equals "off" which is expected, but sounds exactly the same if set to "on", which is counterintuitive.
Panasonic S47 -> native 44.1 kHz setting: player outputs the unaltered bitstream and of course doesn't flag. On the ADI-2 Pro 2/4 then de-emphasis "auto" equals "off" and "on" sounds too muffled.
CD without pre-emphasis -> Panasonic S47 -> "AV Enhancer" setting, leading to upsampling to 176.4 kHz: player outputs the altered data. On the ADI-2 Pro 2/4 then de-emphasis doesn't change whether it is set to "auto", "off" or "on", which is counterintuitive.
Also, it would be interesting whether RME relies on the DAC chips de-emphasis circuit which I guess also only supports it for "low" sample rates or they do it with their own EQ. The manual suggests the former for me and I also think that I read somewhere that one can replicate the de-emphasis filter also by using the EQ function in fact but somehow, I can't find it right now, brrr.
