Actually what Rob describes, sounds like he recorded at to high of a
gain and got the digital overload artifact. Sony Minidisc are not
good when the pitch is high and you wanted the AGC to control the
gain.
Actually because of the want of visualizations of "bug" calls I do
not recommend minidisc and yes I like and use minidisc a lot. Many
of these calls you will find to be broadranged sometimes as great as
4,000 through 20,000. It sounds fine to the ear when played back on
minidisc but the compression will make the visualization look strange
on the high freqs that are often chopped out.
You also have to be careful on loud playing of these calls as you
will not hear the the very high and loud when a medium volume low
pitch is also present. This makes it possible on an amplified
recording to actually play recordings that are dangerous to your
hearing. If you want an example of this I can post a "bug" who
sounds reasonable but when a filter is used to cut out all freqs
below 15,000 it becomes painfully shrill.
I also would recommend an omni mic or a hemispherical mic for this
purpose. For a recorder I would recommend that you start with a
cheap laptop (used) maybe a 233 mhz pentium. I also would just use
the built in sound card of the laptop because most of what you will
do will have a great signal to noise ratio anyway and you have time
as these guys seldom fly away when calling.
Rich Peet
--- In Walter Knapp <> wrote:
> Rob Danielson wrote:
> > Hi Sami--
> >
> > Welcome. Interesting project! One thought others may be able to
> > substantiate or refute. One can encounter peculiar distortions
when
> > recording very hi Hz sources with DAT and MD. I've encountered
this
> > numerous times when close micing field crickets and grasshoppers
with
> > flat response mics. The result sounds as if two or more
frequencies
> > are beating against each other making lower Hz pops and other
> > artifacts. I'd consider renting a good mic, an MD recorder and a
good
> > reel to reel recorder for a day and run some tests. A used, reel
to
> > reel Nagra might be fairly affordable. Record at the fastest
speed,
> > 15 ips. The Jukebox 3 is Mp3 right?.. This seems least likely.=20
Rob
> > D.
>
> Often those beat frequencies are quite real, and yes they exist.
The
> individual animals don't call at exactly the same frequency and the
beat
> frequency is generated between the calls of two animals. In fact
I'm not
> sure but what this may be a intentional purpose of simultaneous
calling.
> I see this often with Toads. I think the winner is the one who can
call
> the longest as when his competitors run out of steam he gets his
pure
> call out for as long as he can sustain it. A way of weeding out the
fit
> from the unfit. Those calls are not just entertainment, but fierce
> competition for a mate.
>
> I've not seen beat frequencies when recording a single call with
> minidisc, only when there are multiple callers. You have to check
> carefully as they can be very synchronized if it's a couple of
evenly
> matched individuals. You can generally pick it out on a higher
> resolution sonogram if no other way. And a call at much lower
intensity
> (from our location) may be what's causing the beat.
>
> I've been editing Toad tracks the last couple weeks, so am way too
> familiar with their calls right now. Since all of the editing is
being
> done with the sonogram rolling, I can say definitively that this is
only
> real with the toad calls, not a artifact. I've heard the beating in
the
> field with my own ears without thinking about it, but it was in
doing
> the editing, where at first you think something is wrong, that I
came up
> with the above theory. On the level of behavior, I'm going to have
to
> study it more.
>
> So be careful what you call artifact. (and we have not even got
into
> multiple reflection paths, which are also a real part of the
environment)
>
> Walt
>
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