CD pre-emphasis/de-emphasis

[miguelito (Miguel Barrio)]

@Speed_Racer

I think that properly decoding HDCDs is more important that handling pre-emphasis.

Pre-emphasis means you need to attenuate by:

So the correction is pretty massive, certainly more impactful than HDCD decoding.

For people reading this thread, check out the De-Emphasis filter that can be added to Roon as a Parametric Eq / High Shelf filter:

De-Emphasis curve (Was:Parametric Eq functions?)

Figured out a way to do it WITHOUT knowing the functional form. You can do this by: 1- Digitizing the parametric EQ curve in Roon from a screenshot. This means getting dB numbers out of Roon’s plotted curve. You can do this using WebPlotDigitizer. 2- Get the above for the base case (F=5300 and Q=0.5 which was close) and then one F shift and one Q shift. (G is the 20KHz value regardless so you don’t have to fit this). With this we get slight variations on the curve around the theoretical de-em…