Canyon Echo part 2 Echo & Delay
A look at how to
get your flute
to sound like it's in a canyon
|
Please support these articles with your purchases
|
CANYON
ECHO part 2: ECHO &
DELAY In the
last
post we looked at reverb,
or reverberation, the cloud of sound produced when
reflecting surfaces produce a layer of many echoes
that are indistinguishable from each other. We also
looked at how different physical spaces create
different reverberation and how to break down the
component parts of reverb. In this post we're going
to talk about one or more reflections of sound that
can be discreetly heard from others. An
Echo.
The word echo
comes from the name of a Greek Nymph. Zeus gave her
the job of talking incessantly to Hera, the Queen
of the Gods to distract her from finding out about
his many affairs. Hera became wise to Echo's
deception and put a curse on her so that she could
only repeat what others had just said.
So an echo is the repeat of a sound. Originally
this was only found in nature. Certain natural
formations, like cliffs, overhangs and caves cause
sound waves to bounce/reflect off of them, strong
enough to be heard as a separate repeat. There is
always a delay of time between the original sound
and it's echo. This delay in time between the
original sound and it's echoed repeat is the
distance between the two divided by the speed of
sound. However, if an echo happens in less than
1/10 of a second the human ear can not distinguish
it from the original sound. Therefore the
reflecting surface must be at least 53 feet away
from the original sound to be perceived as an echo.
This is at a temperature of 68 degrees, as air
temperature will affect the speed of sound, which
in these conditions is 1,125 feet per second. This
works out to 768 mph or one mile in five
seconds.
Okay enough math. It has no impact on what we're
going to talk about.
Natural
Echoes
In my experience real echoes in nature are very
unpredictable. Places that would seem to be perfect
for producing an echo don't always yield good
results, while places where you might not think one
would naturally occur have strong echoes. One would
assume, for example, that if you stood right on the
edge of a cliff at the Grand Canyon and played a
NAF you'd get a really strong, long echo. But I've
done this many times in different parts of the
canyon and have always been very disappointed.
There is a usually a short, very faint, slap of
sound, but mostly it seems to just dissipate into
the canyon. In Canyon de Chelly some parts of the
canyon system do not produce any echo, but other
parts will produce very strong echoes that bounce
all around and seem to swirl about you. Air
temperature, as noted above, and air pressure also
play a factor. When I was a kid my family sometimes
vacationed at the beach. There was a small bay that
we liked to visit. I remember that early in the
morning you could easily hear people's voices from
across the bay, but as the day got warmer that
would stop. Most likely there was an inversion
layer that the sounds would bounce off of, sending
the voices back down to the ground on our side of
the bay. (I'm not sure this was technically an echo
as no one heard both the original sound and its
reflection.)
So now we know about echo. That it is a natural
phenomenon consisting of the discreet repeat of a
sound off a reflective surface. But what about
delay? Well Delay is the artificial reproduction of
echo. This is done by various methods. Tape delay,
solid state delay and digital delay. Tape delays
came about in the 1950's and really hit their
stride with the Echoplex and Roland Space Echo
starting in the early 70's. Digital Delays began
showing up in the mid 80's and are now the most
used type of delays. Many digital delays now also
reproduce the sound of a tape delay, as their
distinctive sound has become highly desirable,
especially with the greater control and stability
that digital reproductions have over. The main
point here is that the terms echo and delay are
frequently used interchangeably, something I will
continue to do in this post.
Read
the full article and listen to examples of
Dely
|
© 2010 Cedar Mesa Music. This article, all images and sound files sound files are the property of Cedar Mesa Music, BMI. All rights reserved. |
Listen
to samples and purchase them online. |
Home | Mailing List
Recordings
by
Scott
August
