Envelope follower w/ control voltage proportional to perceived loudness?

[polaris26]

I am trying to use a guitar to generate a control voltage that is proportional to the *perceived* loudness of the sound, not the actual voltage envelope itself.  Would it make sense to try using a log converter after the envelope follower to get an overall voltage response closer to what the ear hears?  Has anyone tried using a linear-to-log converter after their envelope followers to generate a control voltage for this purpose?  I was thinking a circuit with matched transistors such as is used in analog synthesizers to make 1V/Octave response.  Would this work?

thanks,
Dave

[Mark Hammer]

If by perceived loudness you mean the psychological loudness of the signal, then what you really need is some band splitting and some pooling of multiple envelopes.  The problem is that how loud we perceive something to be will be a function of the frequency content, not just the overall amplitude.  Our ears have a sort of "cruising zone" with optimized detection of some parts of the spectrum, and frequencies below and above that tend to be treated as background relative to the core content.  Like most species our auditory systems place a premium on social sounds, so generally speaking what's in the range of the human voice is "louder" to us than what's not in the range of the voice.

Tp achieve something like what you want, you probably need to start looking at how vocoders do it.  In the case of vocoders, they split the spectrum up via bandpass filters and rectify each band.  Where the vocoder uses each individual envelope to control a specific passband, what you're aiming at would appear to need pooling of multiple envelopes, and some sort of differential "slope" or response curver for the higher and lower ranges, relative to the vocal range.

[Paul Perry (Frostwave)]

I am trying to use a guitar to generate a control voltage that is proportional to the *perceived* loudness of the sound, not the actual voltage envelope itself. 

Or, perhaps, you are wanting to generate a control voltage that, when applied to another circuit (eg. a VCA) will produce a signal that has a perceived value proportional to the original signal that drove the envelope.
That is a different kettle of fish.

[StephenGiles]

un pava distinta de pescados