Beats

[k.swafford@genie.geis.com]

     I prepared the following reprint for my PTG chapter's newsletter.
 I know it's long, but I am hoping that some here will find it to be
of interest.

                                             Kent Swafford
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                    'The beat goes on'

                                             by Ron Nossaman, RPT

     Hi ladies, gents, and any other alternatiave genders being
represented by this assembled gathering.  Today I would like to
discuss something that I have noticed for many years but haven't read
or heard any discussion on.  It's time that changed.
     The session starts with me going into a church sanctuary to tune
the piano (most likely on an emergency basis).  My instructions are to
tune the piano to the organ.  So far, I'm already not overly thrilled
by this provision of employment (four star emergency status alone
should be enough for anyone), but I struggle past the electric
guitars, drum machines and keyboards and through the fifty furlong
tangle of power cords to get to the piano.
     Arriving at the piano, I dig out my tuning implementia and lay it
on whatever part of the instrument is flat enough to serve as a shelf,
grab my fork and a rubber mute, and start hacking a trail through the
electrical jungle toward the organ.  It occurs to me that I should
have radioed my position back to camp so they would know where to
start looking for the body if I didn't make it back, but I had already
lost sight of the bivouac.
     Arriving at what I took to be the organ, I checked the name on
the front.  Yup, that's an organ, probably given to them by an organ
donor.  Not a Hammond, though, gotta check it.  I sat down among the
crumpled Kleenexes, reams of music and mountains of hymnals to try to
figure out how to fire the sucker up.  I found the power switch and,
rocking the volume pedal back all the way, switched it on.  A whole
lot of lights came on at once accompanied by a low evil hum.  "Fire in
the hole!", I thought, at least I won't have to go back for coal.
Cheered by the relief of not having to stoke for the tuning, I began
to explore the stop setup.  I've always been curious as to how one was
to tune a piano to an organ with every tremolo, vibrato, vox, quiver,
quaver and quake function money can buy, semi-permanently locked in
turbo mode at the console.  Maybe some day I'll try it and let them
try to convince ME that the piano's not in tune.  I indulged that
little fantasy a bit as      I shut down all but the cleanest clearest
stop I could find that worked.  Taking a deep breath, I struck the
fork.  Impossible!  It's dead on pitch.  Well, anyway, that particular
note is and that's good enough for me.  I checked around the
temperament a bit satisfying myself that this was worth the trouble
and, wedging my key down with the mute, started back on the now fairly
cleared trail toward the piano.
     I'm walking along thinking how uncharacteristically lucky I was
this time in not having to try to explain to the Secretary, Pastor,
Custodian and passing UPS man about the inadvisability of knocking a
piano further out of tune to accommodate a neglected organ just
because they were too inefficient to get the organ tuned any time
since Edison plugged the thing in.  Imparting this information is easy
enough to do, it's just tough to do it gently enough that you don't
send them to your competition in a fit of pique.  Anyway, such were my
thoughts when I became aware of a strong beat in the organ note.
Alarmed, I stopped.  So did the beat.  When I started up again the
beat did too!  Wow!  Too cool.  What makes it do that?
     Thinking about it while tuning (you have to come up with
SOMETHING entertaining) I decided it was a Doppler effect of some
sort, but what made it work?  An approaching siren lowers in pitch
abruptly as it passes you just like radar modulation frequency shifts
as it bounces off moving objects.  This is how meteorologists can see
high winds in storm cells and Smoky nails you from a moving unmarked
Revenue Patrol Wagon.  If this was the mechanism, wouldn't the pitch
get lower as you walked away and rise as you approached?  Well, it
does, but not a lot from the amount of speed you can work up flailing
through the Patch Cord National Monument across the length of the
platform.  Besides, the noise of falling MIDI enhancements tends to
drown out the critical observations and obfuscate the results.  I
really hate it when my results get obfuscated, so I try not to do too
many high speed Doppler experiments among and through expensive
electronics.  This is interesting and all that, but it still doesn't
explain the variable beat.  I decided to take the experiment home
where I had some traveling room.  I shouldn't have to tell you this
but no, I didn't drag their organ home to test the principal.  I have
Tony's [that's Tony Novinski, Ron's late piano technician
father-in-law] old Accu-Fork.  Besides, Schools have Principals, not
churches.  Nya!
     The first thing I did back home was try to reproduce the results
I got in the church.  I dug out the Accu Fork, turned on the power,
put it on a handy flat spot and walked away.  Wa-wa-wa- wa, going and
coming.  So far so good, how about with one ear?  Wa-wa-wa-wa.  Hmm,
same thing.  I tried carrying it around the room.  Beats.  I waved it
around without walking.  Beats.  I went outside to try it.
     Holding it, I walked around the yard.  NO BEATS!  I waved it
around.  No beats.  Going back inside, beats appeared as I approached
the building.  About then my kids swarmed through and stopped to
watch.  I've always suspected that when they do this, they are mostly
taking notes for a possible future competency hearing, but I decided
to try to lure them into the process.  Who knows, I might need a
little testimony ammunition of my own some day.  When I explained what
I was doing and demonstrated the beat, they thought it looked pretty
harmless and considerably more entertaining than most of my forays
into basic research and/or beatings, so they agreed to help.  We tried
the walking around trick, followed by the under the paddle fan trick,
followed by the holding the pitch source while someone else walks
around trick.  This last one is like the walking toward the building
trick in that you get an echo beat as someone moves toward you even
though you are stationary.  That, we decided was the answer.  It's an
echo effect.  The beat rate increases with the speed of convergence or
divergence, not distance.  The reason would be that the Doppler shift
changes the frequency of the echo off a moving  object so that it no
longer matches that of the generator.  The  greater the difference,
the faster the beat.  That's why there isn't a detectable beat outside
on the lawn.  There aren't any sound reflective surfaces close enough
to generate a strong enough echo to produce a noticeable beat.  Ha!
It then occurred to me that a blindfolded or blind person could, in a
quiet enough environment, navigate through an unfamiliar room without
hitting anything big enough and hard enough to produce echoes.  This
effect, coupled with a little more sophisticated hearing system, would
give you an indication of both direction and distance as well as an
indication of movement toward or away from you.  Wouldn't that be
slick?  Well, it's been done.  Bats have done it for years.

     Editor's note:  What better material for the Kansas City Beat
than a discussion of beats?  I wish I had written this piece, but
instead I borrow once again from Ron Nossaman of the Wichita PTG
Chapter.  By the way, as best as I can figure, Ron Nossaman has been
the editor of the Wichita Voicing Tool since 1986.  Ron has been
blending entertainment and technical matters in his own unique style
for many years now.  After all this time, and after all the fine
pieces that Ron has written, this is, I believe, one of his finest.
Way to go, Ron!