Vicki Powys wrote:
>
> > Walter Knapp wrote:
>
> > (snip)
>
> > I wonder if anyone records anything above 10 khz?
>
> Now there's a challenge! And there I was the other evening engrossed in
> recording the lowest possible rumblings of distant thunder in stereo and
> with all the low cut filters turned off, then a bat circled directly
> overhead giving loud, high pitched 'pink-pink-pink' calls. The contrast of
> sounds was wonderful, especially in stereo. When I later analyzed the bat
> calls they began at 10.5 kHz and extended up to 15 kHz. The growling
> thunder was mostly below 250 Hz.
How soon I forget. What comes from thinking birds. Just a couple weeks
ago Jim Morgan sent me a recording of Mexican Free-tailed bats. Recorded
on the roost with a Telinga and a sony walkman MD. That recording has
call parts going right off the top, though most of the sound energy is
below 16 khz.
Though in reality for bats we need a different sort of recorder. We can
only get a glimpse of their low calls. Really good recording of bats is
still awfully expensive. We can get translators that are cheap, but they
only give fairly crude representations of the calls. And they use really
crude mics. I was looking last night at Sennheiser's MKH 800 mic. That
gets to 50khz in a pretty high quality manner. Reading the things they
had to think about to do it from the identical looking MKH 80 that only
gets to 20khz showed the problems. At high frequencies trivial changes
in the shape of the mike mean a lot. I gave a link for a "recorder" to
go with it recently. That mic plus recorder would be 6-7 thousand
dollars US, not counting the necessary laptop computer to store the
recordings. And would only cover half of the bat frequency range. The
recorder can do it, the mic can't. For the upper half you would be back
to the lower quality mics. BTW, bats are not alone, many small mammals
have very high pitched calls.
I was more originally thinking birds. Can you think of any that climb up
to those high frequencies? There must be some above 10 khz.
BTW, I just got the mic you need for your thunder at the other end of
the scale. It's a Sennheiser MKH 110. That's a instrumentation mic, will
be fun to build a suitable power supply as it's very oddball, takes 8
volts. Another mic from Ebay, another one that sat unused on a shelf,
and cost virtually nothing compared to it's original price, especially
as no one else wanted it. If your recorder is up to it, however, the
frequency specs on this mic are 1 - 20,000 hz. I repeat the low end, 1
hz! If you can record it and play it, that will shake the timbers. The
mic can pick it up. And, of course being a MKH series it's a quality low
noise mic. It's a omni. I have no idea what I'll be using it for, but
it's going to be fun finding out. I won't be able to fully utilize it's
range as my Portadisc poops out at 10 Hz. My good Sony headphones are
supposed to make it down to 5 Hz. My low end hearing is as good as ever,
but the hearing test I have only goes down to 20 Hz.
The frogcalls work well with thunderstorms, and they often call well
then. Maybe put the MKH 30 on it to do MS Stereo and see what I get. I
know thunderstorm recordings definitely lack the low rumble that's out
there. Maybe this mic can get it.
> I am lucky to have good high frequency hearing still, so I do sometimes
> record high pitched insects because they make such interesting sounds, and
> they are part of my world. Two of my local cicada species call at around 11
> kHz. I think one of them is actually 13 kHz but I need to double check
> that.
I can only pick up some of these calls with my hearing. Unless it's real
quiet, then even really high stuff comes through. I can hear all the way
up there, but at much reduced sensitivity. They gotta really yell and
the lower stuff has to be quiet not to cover them up for me.
Yes, you are lucky. Women seem to hold high frequency hearing a lot
better than men do. I think that's more than just differences in noises
they are exposed to. My wife, who is almost the same age as me has much
better high frequency hearing.
> I record with DAT but I'm sure if MD had been available when I started to
> get serious about recording, I would have gone for MD because they are so
> lightweight and batteries last forever - ideal for backpacking, and very
> importantly, MD is a lot cheaper than DAT. The issue of how long the DAT
> tapes might last is not really relevant because it is now quite easy to
> transfer digital recordings to a more permanent medium e.g. CD.
The only place that the durability of DAT tape is a issue is to those
scientific types that are purists and insist on the original tape. In
some parts of sound work that's still the norm.
Well, there is the other place, probably more important, you have to
have the tape last long enough to get it into the CD. I'd certainly not
let it lie around before transferring. It sounds a lot like random luck
to read the experiences of the sound library types.
You have a large part of the value of MD. A portable recorder is a whole
package. MD has a huge batch of advantages as a portable recorder.
When I first ended up with MD, I originally was thinking replacing my
then cassette with DAT. But, I looked at it all, I was more or less
unaware of MD when I started looking. In the end, the advantages of MD
won. At first I was not sure either about the compression, it took me a
couple years to learn well enough to be comfortable with that. It's hard
to keep distrusting it when it keeps refusing to mess up. When
everything your logic says will happen does not. One thing that tipped
the scales for me was that I was already using regular optical disks, so
knew what a improvement they were over magnetic media.
> My understanding is that while MD is just great for relatively pure sounds
> below, say, 10 kHz it is not so suitable for accurately recording the high
> pitched and raspy sounds of insects? Is that the main difference
> science-wise between DAT and MD? I can definitely hear a difference,
> because MD takes out those tiny additional clues whereby one positions
> oneself aurally within the landscape - DAT retains that "breathing space"
> while MD creates more of a vacuum, a more 'perfect' world. Maybe because we
> are so used to turning off our ears due of noise pollution, we are less
> aware of those tiny aural clues that give shape to the landscape - that
> expectant "atmosphere" that happens between bouts of birdsong or frog calls.
> Maybe people who live very close to nature are more aware of those sorts of
> "irrelevant" sounds, and use them even to survive.
I'm not sure this can be laid at the feet of the ATRAC compression,
though anything a MD does that people don't like they try to blame the
compression. It's often thought that MD is too dumb to get complex
sounds, but that's not so. It gets sound detail with the same accuracy
as DAT.
Nearly all MD recordings you will hear are done with walkman MD's. Those
things have better mic pre's than the cassette ones did, but still not
wonderful. And the analog output section is also not the very best. By
contrast, DAT recorders start at about the highest end of walkman MD's
or higher and go up from there. As fits their higher price.
I know that this is the case, because that's one of the areas that
changed as you describe when I moved to the Portadisc. It get's it like
you describe for the DAT.
So, I expect if you grafted walkman MD pre's and analog output on a DAT,
it would probably sound like you describe MD's.
On the insect sounds it records them all too well and accurately. Down
here past a certain point, usually sometime in late June or early July
the insects start to get louder than the frogs. They become one of my
major noise pollution problems recording frogcalls. Suddenly my distance
I can record the frogs diminishes rapidly as they are drowned out by the
insects.
It also records the mosquitoes homing in on me very well. There are lots
of interesting sounds made by various insects as they fly. I get less of
that since going to the Portadisc as it has a lighted display I can turn
on. With the Sony's I had to use a headlamp to read the display. That
attracted a lot more insects. The Portadisc's display is even the yellow
color that does not attract insects.
When listening for little grass frogs there are crickets that are very
similar in call. Though that's lower frequency, below 10khz. So I
sometimes spend a long time studying insect calls with the telinga
working out which it is. Or which one is a frog and which one a cricket.
That's easier to distinguish going through the Portadisc's pre's
compared to those on the Sony MD's I used before.
Note that these clues as you call them are also a function of the mic.
Varies with the mic too. They do definitely work better in stereo.
> But the main thing is that people are out there recording wildlife sounds,
> whatever their equipment! We are so lucky to have access to high quality,
> portable recording equipment, DAT, MD and whatever. They are all excellent.
> The pity of it is that such equipment did not exist in those eras when
> natural soundscapes were unpolluted.
Back when Syd's Uher was the new kid on the block I would have almost
killed for one, I can clearly visualize the shiny new ones in the store
even today. They were definitely something special. And now we can
easily beat that. With virtually any of the current recorders. Same goes
for mics.
I have in the rack beside me a CD that originated on magnetic tape in
the 50's. Recorded on a spring wound tape recorder. Frogcalls, of
course. I will guarantee that recorder failed every one of our quality
tests, without even trying to find it's specs, but the recordings are
excellent. The same goes for whatever the mics were. Any time I get too
uppity about having to have some spec I can listen to that and remember
what's important.
Yes, indeed, the main thing is to get as many out recording as possible.
Not only do they provide recordings for others to hear, but they
themselves are changed, become more in tune with their world. One of my
ongoing goals is to infect as many as possible with this recording bug.
It's so easy now with the equipment available.
One of the local recordists, Steve Hulse (Soundfisher Productions) has a
trademark emblem for his work that shows him casting a mic like fly
casting. In many ways the two resemble each other. A fly fisherman
learns the ways of the fish to catch them. We learn the ways of our
animals to record them. I'd steal that emblem in a minute if I could.
I'm also a fly fisherman.
Walt
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