Unison coupling

[Richard Moody]

----------
> From: Roger Jolly <baldyam@sk.sympatico.ca>
> To: pianotech@ptg.org
> Subject: Re: Unison coupling
> Date: Saturday, January 22, 2000 11:20 PM
> 
> Hi Ron
> >* This is contrary to what Ric's quoted article said. What's
your source?
> >This isn't a trap, honest, I'm just trying to resolve
conflicting
> information.
> 
> Yes, and I was suprised. Remember the class in KC. when I detuned
Gina's
> octave by voicing a note down. Softening the hammer reduced the
> inharmonicity and octave started to beat.
> The whole class heard it, and those in front saw the results on
the
> spectrum analyser.

What is "the spectrum analyser", who makes it?  ---ric