Thread: Volume scale
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Old 05-04-2011, 06:14 AM  
schwa's Avatar
Join Date: Mar 2007
Location: NY
Posts: 9,909

From another thread ... there is more discussion of the subject in that thread, but this thread is a better place to continue the conversation.

Originally Posted by schwa View Post
This has been requested forever, but it isn't simple, or else it would have happened a long time ago. When I say "not simple", I don't mean that the math is impossible, instead I mean that the user experience would become complicated.

Volume envelopes in REAPER have always been linear with amplitude. If you have an envelope point at -12dB and an envelope point at +0dB, and you have a straight envelope line between the points, the envelope will increase with linear amplitude -- not linear decibels, and not linear with respect to the volume fader scale.

There is no linear transformation between the existing volume scale and linear decibels or fader scale. In other words, a straight line in an existing volume volume envelope would no longer be a straight line if the envelope were transformed so that it matches the volume fader scale. If the envelope remained as a straight line, the volume at the halfway point on the line would be different depending on what scaling mode was used.

There is no great solution for this. We could (eventually) add a separate type of volume envelope that matches the fader scale, but you wouldn't be able to convert between the existing volume envelopes and the new type -- they would need to be separate envelopes.
Originally Posted by schwa View Post
It's also the case that a straight line in a volume envelope with linear-dB units will not be a straight line in a volume envelope with PGF8k units. Since REAPER lets you select from various scales for the volume faders, this issue would be coming up no matter what scale units REAPER used by default in its envelopes.
Originally Posted by l0calh05t View Post
I figured as much because linear space is the only one that can be compatible with all fader settings. Personally I see two options:

a. Just display the envelope in fader space. Yes, this means linear interpolation between dots will be displayed as a strange curve, but since that IS the fader behavior you'd get, I think most people could live with that.

b. Instead of having envelope type and fader shape a global setting, both could be turned into per-project settings (like pan already is), including a legacy true linear setting which behaves as before and a fader dependent envelope setting which performs interpolation in fader space (thus necessitating per-project storage of fader shape)
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