[Harp-L] Re: The "Hush-Hush" trick

[David Fairweather <dmf273@xxxxxxxxx>]

I was just resurrecting an old Harp-L discussion from 2007 for the benefit
of any youngers who might not have been aware of it.   Here's what Winslow
had to say about it way back when:

Actually, it's a difference tone. any time you play two notes together,
they generate both difference tones (higher frequency minus lower
frequency = a lower frequency, the "difference") and combination tones
(higher frequency + lower frequency = higher note, the "combination").

Listening to the clip, the player (is it Corky Siegel?) is playing a C
harp. He's starting with Draw 3 bent from B to down A, and playing Draw
4 as well. The difference tone that comes out is a low D. This is
consistent with a perfect fourth between A (Draw 3 bent) and D above it
(Draw 4 unbent). While it's unlikely that Draw 4 remains completely
unbent, it's possible to temper the bend to create the right interval
at a pitch close enough to A and D that it sounds in tune with the
implied key of G.

What he then does is to release the bend so that he end up playing B
(unbent Draw 3) and D (unbent Draw 4). When these two intervals are
acoustically in tune, they generate a difference tone of a low G.

Note that as he releases the bend upwards, the difference between the
two notes becomes smaller and therefore generates a lower frequency,
resulting in the difference tone sliding from low D down to low G.

You don't need an amplifier to create this effect, though it helps to
make it more easily audible. It helps to have good bending technique
and to have a harmonica in just intonation, as the acoustically pure
intervals (i.e., those derived from the simplest mathematical rations)
will generate the loudest and most in-tune sounding difference tones.

Winslow