Thursday, September 29, 2:15 pm — 3:45 pm (Rm 501ABC)
This is maybe about continuing a discussion that I might have tried starting 20 years ago (“The Equivalence of Various Methods of Computing Biquad Coefficients for Audio Parametric Equalizers”). I'm sure that longer ago than that, practitioners in the studio had discussions regarding the setting of the Q knob (or bandwidth) for the bell parametric EQ, but this is about settling the issue of what the biquad filters should be, from an input/output or transfer function POV, given the positions of the knobs on an EQ whether it's a good-old-fashioned analog mix board or an EQ plugin or built-in EQ in a DAW. There has been some discussions about why a seemingly identical function implemented in different products sound so different, and to the extent possible, this proposed discussion is there to try to remove “different settings” as the cause.
Perhaps another reason to have this discussion perhaps a little late, but better than never, is because of automation. At present, as best as I know from what I am told, automation in Pro Tools and other DAWs is unitless and is essentially a zero to full-scale parameter that is interpreted solely by the floor and ceiling attributes of the slider the built-in EQ or the plugin control. I dunno, but it seems like to me that the AES is involved in standardization, when possible, of parameters and performance of audio functions that are common between gear from various manufacturers. There is a Standards Subcommittee on Metadata and a Standards Working Group on Audio-File Transfer and Exchange. Perhaps there is not yet a group defining automation standards, but eventually a user should be able to move the
raw sound files of a song or session running on one platform, a specific DAW with plugins or even an analog mixer with motorized faders, and move that to another platform and compare how they like the sound. It might be nice if the platforms could interpret the recorded metadata, which is essentially what automation is, in a compatible manner, at least with parameters that are universally understood.
So before too much of this is carved into stone in a standard somewhere, it might be nice if we could, as an industry, discuss among each other exactly what we mean by Q
|This session is presented in association with the AES Technical Committee on Signal Processing|