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previous: zachary vex i don't have a copy.... yeah, try t... -- 8/6/2000 6:26 AM

Re: expansion with tubes

8/10/2000 7:18 PM
Mark Hammer	Re: expansion with tubes Rudolf Graf has compiled a number of Electronic Cyclopedias. I think we're up to Volume 6 or 7 now. These are organized in the manner you describe. They are, however, separate from the Audio Cyclopedia you mention. I'm sure I saw an ad for that one in a back issue of Polyphony. The advice about checking out the engineering section of a university library is spot on. Go to the TK section, if I remember correctly. Most schools with decent electronic engineering programs will have lots of resource materials of that type. Community colleges as well, but they tend not to have holdings as far back. Finally, note that there is a difference between a noise gate and a downward expander. Downward expanders function by doing the exact opposite of a limiter. Limiters act on signals above a given value, translating large changes in amplitude to proportionately smaller ones, such that dynamics are prewrved below a threshold value, and modified above it. Downward expanders preserve dynamics above a threshold value, and produce proportionately larger contrasts in the dynamics of the signal below that threshold. As you might expect, they are used for single-ended noise reduction (i.e., NR that doesn't require complementary encoding-decoding), and tend to be preferred because they introduce less colouration of the sound.

8/10/2000 7:18 PM

Mark Hammer

Re: expansion with tubes

Rudolf Graf has compiled a number of Electronic Cyclopedias. I think we're up to Volume 6 or 7 now. These are organized in the manner you describe. They are, however, separate from the Audio Cyclopedia you mention. I'm sure I saw an ad for that one in a back issue of Polyphony.

The advice about checking out the engineering section of a university library is spot on. Go to the TK section, if I remember correctly. Most schools with decent electronic engineering programs will have lots of resource materials of that type. Community colleges as well, but they tend not to have holdings as far back.

Finally, note that there is a difference between a noise gate and a downward expander. Downward expanders function by doing the exact opposite of a limiter. Limiters act on signals above a given value, translating large changes in amplitude to proportionately smaller ones, such that dynamics are prewrved *below* a threshold value, and modified above it. Downward expanders preserve dynamics *above* a threshold value, and produce proportionately larger contrasts in the dynamics of the signal below that threshold. As you might expect, they are used for single-ended noise reduction (i.e., NR that doesn't require complementary encoding-decoding), and tend to be preferred because they introduce less colouration of the sound.

Replies:

jon Hi Doc Hi Mark.... -- 8/10/2000 10:13 PM