How do I compute the LF roll-off?JR. wrote:You can put Cs in series with the Rs for your gain switch so each gain has it's own unique HPF cut-off... Rolling off the LF at high gain will "appear" quieter.
There's not such a thing, AFAIK. you mostly filter LF. But Nagra had designed a three position filter that had a roll that worked very well for film. I wonder where the response curves might be, and of course the parts they used.I am not aware of a filter that selectively suppresses reverberation. Perhaps a variation on mid-side stereo pair recording where you favor the L+R which is mostly direct sound and trim back L-R which has more ambience or reverberant content.
Of course I didn't rely just on my ears, particularly for the highs. They were thoroughly tested on a scope. I just said they sounded cleaner with the film caps, but then they were scope checked. My concern had been with one of the DC-DC 48v generators I had tried, with an LT chip, to see how much RFI they irrradiated. The one I used in the end, with the Max chip, was excellent.