what's de-emphasis for?

[Sutee Sangsareechon]

De-emphasis seems to down the Hifreq. but when will we use it? and what's for?

[Zeus]

That's a really antiquated thing relating to very old CD players that had bad converters/filters on them.

[Fokke van Saane]

Some old DAT recorders used emphasis in the AD conversion. The 'emphasis-flag' tells the DA converter it should use the de-emphasis. Hopefully it's on the display of the DAT machine. It is on my CD player display, thankfully. When you transfer it digitally to PT PT doesn't recognise this 'flag' and a too bright sound is the result. Use the "de-emphasise" preset of the Waves Q2 to de-emphasise.
Fokke