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Recording bird song; equipment problems

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Anonymous
July 3, 2005 6:10:54 PM

Archived from groups: rec.audio.pro (More info?)

Hi all,

I'm completely new to sound recording, so please forgive my ignorance.

My wife is a biologist and is conducting an experiment that invovles
counting the number of times a bird sings in a 24 hour period. She has
eight birds, each in a separate cage, and needs to record them all at
the same time. Her plan is to record the birds, then scan through the
sonograms of each, counting the number of times she sees bird song.

She bought a MOTU 828mkII and a pre-amp (I'm not sure what brand or
model). She's using inexpensive lapel microphones from RadioShack that
she's had good experience with in the past on simpler experiments. Each
1/8" mic plug goes into a long extension lead (20 feet), which ends in
a 1/4" plug, which is plugged into XLR adapters which are plugged into
the pre-amp, which is plugged into the MOTU. Phew! The MOTU is
connected to a PowerBook running the latest version of AudioDesk.

We've got two problems:

1. The sound levels coming from the lapel mics (which are clipped to
the sides of the cages) are very low. A tap directly on the end of the
mic is picked up but no talking, much less birdsong.

2. We know pretty much nothing about audio equipment!

Before we got all eight mics, I did a test to see how long AudioDesk
could record for (a 2 GB file per track, as it happens). For that test,
I had an iPod and a computer with iTunes continously playing music.
Each device was plugged in via a male-to-male cord with 1/8" plugs: one
end in the device, the other going into an 1/8" to 1/4" adapter, which
was then plugged into the 1/4" to XLR adapter and into the pre-amp.
That worked perfectly: the sound levels were fine and AudioDesk did a
great job on the long recording.

However, today, after getting all the mics and hooking them up in the
lab, we've realized that the sounds levels coming into the Macintosh
are very low. We don't know why. Each mic has a small battery and each
mic is turned on. We left the settings on the 828 and pre-amp at their
defaults and while that worked fine for the test with the computer and
iPod, it doesn't with the mics. Phantom power is turned on for each mic
though I don't think that should matter; could it be hurting? We've
tried...well, honestly, "fiddling with the knobs" is the best
description though we've done it pretty carefully and we've changed one
thing at a time to see if it's made a difference. It doesn't seem to
have.

I've going to try a few more things - turning off the phantom power,
bypassing the pre-amp - but I'm pretty lost and my wife wants to start
the experiment soon. I'd really appreciate any suggestions people might
have or even pointers to places that might give us a quick audio
recording education.

Regards,
Fergus
Anonymous
July 4, 2005 2:45:31 AM

Archived from groups: rec.audio.pro (More info?)

Fergus Hammond wrote:

> She bought a MOTU 828mkII and a pre-amp (I'm not sure what brand or
> model).

The 828mkII has pre-amps.

> She's using inexpensive lapel microphones from RadioShack that
> she's had good experience with in the past on simpler experiments. Each
> 1/8" mic plug goes into a long extension lead (20 feet), which ends in
> a 1/4" plug, which is plugged into XLR adapters which are plugged into
> the pre-amp, which is plugged into the MOTU. Phew! The MOTU is
> connected to a PowerBook running the latest version of AudioDesk.

It doesn't sound like you are going through a battery box
such as is required for the mics to power the internal FET
impedence buffer. Usually the box comes with them but in
this day of "plug-in-power" it may be ommited. The 828
won't give you the required voltage, about 2V, and phantom
could fry them.

These mics are typically unbalanced with a single signal and
a ground. The 1/4" plug to XLR adapter should pass ground
to XLR pin 1 and 3 and the signal to pin 2.

They are usually pretty hot capsules so when powered and
connected properly you will get plenty of signal under
normal conditions. For birdsong I'm not so sure.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 4, 2005 10:25:56 AM

Archived from groups: rec.audio.pro (More info?)

In article <1120425054.250493.204030@z14g2000cwz.googlegroups.com> fergus.hammond@gmail.com writes:

> I'm completely new to sound recording, so please forgive my ignorance.

Well, we might forgive your ignorance, but somebody's got to
straighten out your setup if you want to get some results.

> My wife is a biologist and is conducting an experiment that invovles
> counting the number of times a bird sings in a 24 hour period.

> She bought a MOTU 828mkII and a pre-amp (I'm not sure what brand or
> model).

This is important. Find out. Read the make and model from the front
panel or label on the back or the box it came in or (heaven forbid you
should actually read it) the instruction manual or sheet.

> She's using inexpensive lapel microphones from RadioShack that
> she's had good experience with in the past on simpler experiments. Each
> 1/8" mic plug goes into a long extension lead (20 feet), which ends in
> a 1/4" plug, which is plugged into XLR adapters which are plugged into
> the pre-amp, which is plugged into the MOTU.

That should work - not optimum but it should work.

> 1. The sound levels coming from the lapel mics (which are clipped to
> the sides of the cages) are very low. A tap directly on the end of the
> mic is picked up but no talking, much less birdsong.

Well, maybe they aren't very loud birds. They might sound loud but may
not actually be loud. Since you can tap on the mic and record the
tapping, you know that the signal chain is working. How about talking
into the mic? Does that work?

> 2. We know pretty much nothing about audio equipment!

Get help.

> We left the settings on the 828 and pre-amp at their
> defaults and while that worked fine for the test with the computer and
> iPod, it doesn't with the mics.

There are no "default" settings for a preamp other than where the
knobs happen to be when it was shipped. Turn it up. It's no sin. The
"defaults" for the 828 are probably unity gain. This may or may not be
optimum depending on the nominal output level of your preamp. Like I
said, you have to know SOMETHING about what you're connecting
together.

> Phantom power is turned on for each mic
> though I don't think that should matter; could it be hurting?

Since the mics have batteries, they don't need phantom power. I'd
suspect the wiring of the adapters that you're using between the mini
plug and the input to the preamp, but without knowing what the preamp
is or any of its characteristics, it's hard to tell.

> tried...well, honestly, "fiddling with the knobs" is the best
> description though we've done it pretty carefully and we've changed one
> thing at a time to see if it's made a difference. It doesn't seem to
> have.

Well, it should have changed something.

> I'd really appreciate any suggestions people might
> have or even pointers to places that might give us a quick audio
> recording education.

Try the dealer from whom you bought this stuff. At least they should
know what they sold you. But bear in mind that the birds might really
not be all that loud.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Related resources
Anonymous
July 4, 2005 12:36:05 PM

Archived from groups: rec.audio.pro (More info?)

Thanks very much to everyone who replied. I'm very impressed with how
much help you've all provided.

Since writing, I did a test using a better microphone with an XLR
connector (a RODE NT1000). I first plugged the mic directly into one of
the MOTO's preamp mic inputs (it has two of these) and put the mic near
a bird cage. This worked very well: the sound was clear and strong and
I could easily hear the birds singing. I then plugged the same mic into
the Nady PRA-8 preamp (with the preamp connected to one of the MOTU
analog inputs). To my surprise, that didn't work well at all: the sound
level was *much* lower - too low. I did make sure that preamp was
adjusted for its highest gain and that it was providing power to the
mic.

As the next test, I plugged in one of the RadioShack mics to the same
input on the MOTU that I'd used with the RODE mic (the MOTU input is a
combo XLR/TRS input). That didn't work either: again, the sound level
was too low.

These tests suggest two things to me: there's a problem with the preamp
and the mics we're using are not sensitive enough. What's odd is that
my wife has used the same mics before, with a tape recorder, to record
birds. I would have thought that the equipment we're using would be
more, not less, sensitive than tape. Plugging the mic directly into a
computer that has a mic-in plug shows the same thing though: low
sensitivity. Odd.

I'm going to do some more tests today (perhaps trying Audition instead
of AudioDesk though I don't think this is a software problem) and
tomorrow, talking to MOTO and a colleague of my wife's who's done this
type of recording. Any other suggestions would be much appreciated.

Regards,
Fergus

P.S. Lorin: we're in Princeton, N.J.
Anonymous
July 4, 2005 2:12:52 PM

Archived from groups: rec.audio.pro (More info?)

"Fergus Hammond" <fergus.hammond@gmail.com> wrote:
>
> She bought a MOTU 828mkII and a pre-amp (I'm not sure what brand or
> model). She's using inexpensive lapel microphones from RadioShack
> [...]plugged into the pre-amp, which is plugged into the MOTU.


Just a few suggestions (it's hard to know the problem with being
there... what city are you in?):

1. Make sure the string of adaptors you're using to connect the mics is
actually sending signal where you need it. If you have a way of testing
signal continuity (like an ohmmeter), make sure the "tip" of the mic
connector makes it through to pin 2 of the XLR plug, and that the
"sleeve" of the mic connector gets to pin 1 on the XLR plug. (Pin 3 of
the XLR should have either the same signal as the sleeve of the mic
plug, or nothing it all.)

2. Check if the mics have on/off switches. Many with much more
experience than you have been burned by that simple oversight.

3. Turn off the phantom power. It probably isn't hurting anything, but
it definitely isn't doing any good with battery-powered microphones, and
you never know...

4. See if your preamp has any kind of switch for the inputs, like
"Line/Mic" or something (the make and model of the preamp would be
really helpful here). If so, make sure it's set to mic, or it's most
sensitive position.

5. Crank up the gain on any channel, wide open, full blast, and see what
you get. Maybe the mics just aren't very sensitive.

Lemme know what you find out.

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)
Anonymous
July 4, 2005 8:05:02 PM

Archived from groups: rec.audio.pro (More info?)

In article <1120491365.373135.261820@z14g2000cwz.googlegroups.com> fergus.hammond@gmail.com writes:

> Since writing, I did a test using a better microphone with an XLR
> connector (a RODE NT1000). I first plugged the mic directly into one of
> the MOTO's preamp mic inputs (it has two of these) and put the mic near
> a bird cage. This worked very well: the sound was clear and strong and
> I could easily hear the birds singing. I then plugged the same mic into
> the Nady PRA-8 preamp (with the preamp connected to one of the MOTU
> analog inputs). To my surprise, that didn't work well at all: the sound
> level was *much* lower - too low.

Did you make sure that the input that you connected the preamp to was
indeed turned up on the MOTU's software mixer? There are controls that
you can't always see until you look for them, but they're always
working. (see the current bantering about digital consoles)

Did you try the same inputs as the mic inputs you were using (but the
1/4" jack rather than the XLR?)? At least you know those are turned
out. How about the cables that you used to connect between the preamp
output and the MOTU input? The preamp outputs are unbalanced jacks,
the MOTU inputs are balanced. If you used the wrong kind of cable to
connect between them, you would get a marginal signal, if any at all,
to the MOTU input from the Nady output.

> As the next test, I plugged in one of the RadioShack mics to the same
> input on the MOTU that I'd used with the RODE mic (the MOTU input is a
> combo XLR/TRS input). That didn't work either: again, the sound level
> was too low.

How did you do that? The plug doesn't match the jack so you'd need an
adapter. Did you adapt the mini plug on the mic to an XLR, or to a
1/4" plug? If you used a 1/4" plug, you probalby were connecting it to
a line level input rather than a mic input, which would explain a low
signal level.

> These tests suggest two things to me: there's a problem with the preamp
> and the mics we're using are not sensitive enough.

To me, it suggests a connection problem. Try plugging your
Rode mic into the Nady preamp and then connect that channel of the Nady
to a MOTU channel. See if that works. If it does, I'll bet on the adapters
between the mini phone plugs and XLRs for your miniature mic connection.
Is this an off-the-shelf adapter you're using?

> P.S. Lorin: we're in Princeton, N.J.

Surely there's someone there, either a musician, a friendly recording
studio, or a music store with an audio department, who can help you
out. This is a problem that's going to be really difficult to solve
without being there. It's not difficult, it's just that there are a
number of possibilities.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 4, 2005 8:13:23 PM

Archived from groups: rec.audio.pro (More info?)

"Bob Cain" <arcane@arcanemethods.com> wrote in message
news:D aaidm066p@enews1.newsguy.com...

> > She's using inexpensive lapel microphones from RadioShack that
> > she's had good experience with in the past on simpler experiments. Each
> > 1/8" mic plug goes into a long extension lead (20 feet), which ends in
> > a 1/4" plug, which is plugged into XLR adapters which are plugged into
> > the pre-amp, which is plugged into the MOTU. Phew! The MOTU is
> > connected to a PowerBook running the latest version of AudioDesk.
>
> It doesn't sound like you are going through a battery box
> such as is required for the mics to power the internal FET
> impedence buffer.

All of the minitature Radio Shack mics I've used have battery holders
inline; no external power needed. As long as the batteries are fresh -- note
to original poster: they are, aren't they? -- you should be getting lots of
signal if the 1/8" - XLR adapters are wired properly.

Peace,
Paul
July 5, 2005 12:31:45 AM

Archived from groups: rec.audio.pro (More info?)

Fergus,

thats what I was wondering, are the adapters transformers or just
adapters?

I'm more of a hobby audio guy then a pro (but I am a degreed pro
electronics engineer with many years of experience) and I'm in the
Bucks county PA area not too far from you. If you get stuck, I can
help you out.

(reply here at rec.audio.pro, my e-mail address is just a spam
catcher)

Mark
!