[sdiy] Envelope follower w/ control voltage proportional to perceived loudness?

[DAF]

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