ARP 2600 - Audio-Frequency; Low-Frequency

iO
And
now
to
something like 20Hz
(that's 1 200 times a minute—a
lot
of
adrenalin):
_JLjI_J_jU
And
finally
to say
60Hz:
Somewhere
just
above
20Hz you
would lose your sense of individual
EVENTS happening
very
rapidly.
Instead you
would
begin
to
hear a
very low
PITCH gradually
rising
with
the
rising frequency
of your
heartbeat. And the
opposite
would happen
if
your heart
began to
slow
down again—
first a
descending
PITCH,
then the gradually
growing
sense of no pitch at
all
but rather
of separate and countable EVENTS.
2.163 A
SYNTHESIZER CAN GENERATE
AND MODIFY both
AUDIO-FREQUENCIES (i.e. PITCHES
and
NOISE)
and LOW-FRE-
QUENCIES
(i.e.
EVENTS).
2.1 631
You ma>
think
of an event
that
happens only once as
having
an infinitely low frequency—
like picking
a guitar string once
for all
eternity,
or beating a
drum
just once and then
travelling on
.
2.1632
Playing
a
note on a
piano
and repeating
it
at
some regular
interval produces
a series
of EVENTS
at a low
frequency.
The events
have
a
certain PITCH because each
event
is
the occurrence of an
AUDIO-FREQUENCY
vibration.
Here's
a
graph
of everything that
happens:
and here's
a
graph
of the LOW-FREQUENCY
waveform involved
and the
audio-frequency that produces the
pitch looks, all by
itself,
like
this
2.1
633
Note that
in any
graph
of an event or a series
of events
such
as
the first
one
in 2.1 631
above, you
can derive
the
SHAPE of the
LOW-FREQUENCY WAVEFORM
involved
by
simply
connecting the