dolby equivolent

clambake · Post by **clambake** » Mon Apr 19, 2004 11:09 pm

I have some sound files I recorded that I believe were encoded with Dolby B or C and would like to filter that out. Which (if any) filter is equivolent or even close to that type of filtering? I currently have 4.26

kimbawlion · Post by **kimbawlion** » Mon May 03, 2004 10:37 pm

Dolby B and C are dynamically-variable frequency-boost algorithms that are designed to be decoded by the same proprietary circuitry. You can see examples of the frequency boosts applied at various loudness levels here:

http://www.dolby.com/cassette/bcsnr/ctype.html

http://www.dolby.com/cassette/bcsnr/btype.html

With Dolby B, the usual solution when Dolby decoders are not being used is to apply a mild treble cut. However, if the program has a wide dynamic range, the fixed treble cut will make high-level audio sound dull while low-level audio will sound bright.

Dolby C processing is more complex and simple equalization is not going to be able to approach the proper processing. Personally, if I didn't have a Dolby C deck to process the signal, I'd do some mild equalization (a midrange cut tweaked to sound best on the material at hand) and decide to live with it.

Sorry, that's probably not the answer you wanted.

clambake · Post by **clambake** » Mon May 03, 2004 10:49 pm

Well I was hoping maybe someone had figured out a digital way of doing it. I suppose I could re-record the files to tape and then DolbyC it but I think I will just live with it for now. I knew the DolbyB/C was dynamically variable and was hoping maybe there was a generic filter out there somewhere. Thanks for the links definitely fun reading for a confirmed geek!