• Registered: 2011-02-02
  • Posts: 39

Topic: Attenuation Explanation Request

Can someone explain "attenuation" quantification? I thought that a 40 db attenuation (as set in SoundFont presets and instruments) would reduce waveform amplitude by a factor of 100; but I'm only seeing a factor of approximately 6.1  (16 db by my calculation).  This doesn't appear to be a SynthFont/VieNa problem, because I see the same thing with SBLive/VieNNa.

What am I doing wrong?

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  • Registered: 2011-01-31
  • Posts: 657

Re: Attenuation Explanation Request

For some reason I forgot to comment on this. SynthFont/Viena tries to adore to some kind of SBLive standard, and for some odd reason SBLive defines centibell for attenuation as
  CBell(SBLive) = 1.0046; -for less attenuation = Power (10, 1/500)
when it should be
  CBell = 1.011579454  = Power (10, 1/200)
Odd, but life is.

  • Registered: 2011-02-02
  • Posts: 39

Re: Attenuation Explanation Request

OK, that's really weird.

1) The Sustain level appears to be correctly expressed.

2) In Viena, in the instrument splits, "Basic" tab, there's a "Attenuation" slider which has a tool tip which displays what I assume is the waveform amplitude. Shouldn't this reflect the actual, rather than "correct", definition of attenuation? If a 40 db attenuation is set, the tool tip shows 1%, which is incorrect.

3) Could this factor of 2.5 somehow be displayed in Viena? For instance, in the preset and instrument tabulations: "Attenuation*2.5    (db)".

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  • Registered: 2011-01-31
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Re: Attenuation Explanation Request

Yeah, I guess I need to think about it. At least document it somewhere.