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Recording Tips: Microphones and Mini-disc recorders



This is a compilation of responses that I have got. Thank you very much to all who have replied. It has been most helpful. Below is the message that I have sent out previously.


Tan Chia Ying
jytan75(a)hotmail.com


>From: "tan chia ying"
>To: choralist(a)lists.colorado.edu
>Subject: microphones to record choir onto mini disc recorder
>Date: Fri, Dec 6, 2002, 23:57
>

> Dear choralist,
> I have been having problems trying to record songs sung by the choir on the
> mini disc recorder. I use
> a sony uni-directional condenser microphone (ECM-MS907)of frequency
> response of 100-15000Hz, that is plugged directly into the recorder through
> a mini jack. However,the recorded sound is a distorted one especially when
> the choir is singing in its higher register (ie. from above middle C
> onwards). Please advise whether it's a limitation of the microphone used,
> setup or the mini disc recorder.Look forward to receving suggestions on any
> recommended microphones that might improve the situation. Thank you in
advance.
>
> Tan Chia Ying
> jytan75(a)hotmail.com

Hi,

For our HearFones research, we've been using a Sony mini-disc recorder Model
MZ-R37SP with great success. The buttons are MUCH too small, but we need
the portability so we can set up quickly and record choirs "with" and
"without" HearFones, and still let them get their full rehearsal time in.

There are three important technical factors to consider when you record
digitally, and one psychological factor:


1. The type of microphone you connect to the input jack of the recorder
MUST match the amplifier that deals with the signal from the microphone.

Our user manual suggests three Sony models:

ECM-717
ECM-MS907 (the one you are using)
ECM-MS957

The specifications section shows the microphone (MIC) input must be between
0.35 and 1.38 millivolts. There is no mention of microphone impedance
(measured in ohms) but this can be important when choosing non-Sony
microphones. We use a pair of Radio Shack PRO-301 (catalog number 33-3001
-- about $40 each) with good results.

Assuming the Sony ECM-MS907 is compatible with your recorder, then the
microphone should not be the problem


2. Signal level, both into and out of the recorder, must be within limits.

A microphone's job is to convert sound pressure into an electrical signal
-- for example, one volt per decibel of sound level. Regardless of the
microphone, zero sound equals zero volts; but depending on the microphone,
the output signal is entirely dependent on the sound input. If you hold it
to your lips and scream into it, more than 1.38 millivolts will come out of
it.

The recorder's job is to digitally encode the microphone voltage as a byte
of data on the minidisc. Because each byte can only hold a maximum number
of digits (imagine "All of your answers must be less than 9,999."), when too
loud a signal comes in, as too many volts, the recorder can no longer
represent that number.

Most likely, it just keeps recording at maximum allowable level (though this
lies in the design of the recorder) until the signal gets quieter. Or until
someone moves it farther away from the choir. Look carefully at the level
indicator on the recorder, to be sure it only reaches maximum when the
cymbals clash!

Our Sony recorder has a button to choose "Automatic Volume Limiter System"
(AVLS) to protect your hearing. We never use it, because our HearFones
studies demand linearity, but (again, depending on design choices) it may
limit either the input level OR the output level of the recorder. Indeed,
it may only affect the headphone output level. We don't know.

But if (and only if) it affects the input level before recording onto the
disc, then it will serve to anticipate louder sounds and record them
gradually more quietly. This could then limit the output power from the
disc when it's played back -- on any player.

I wouldn't expect this refinement, but at least you should try it one time
and see what happens. It may be just what you need.


3. The output power of the minidisc player must be less than the maximum
rated input power of the amplifier (if you use a separate one). Ours has a
rated "line" output of 194 millivolts, which is the maximum output voltage
the recorder can send to an amplifier when a full byte of data is recorded
on the tape.

Our amplifier (also a Sony) has a rated input, at its "CD" jacks only, of
200 mV, so if (and only if) we plug the minidisc recorder into the "CD"
inputs, can we be sure we never overwhelm the amplifier's input.

The amplifier input rating for "TAPE/MD, TV, VIDEO" is listed at 150
millivolts. So, EVEN IF you follow Sony's own instructions, it is possible
to jam 194 mV into the "MD" (minidisc) input, exceeding the 150 mV rating by
nearly 30 percent.

This means the upper volume levels of the recording will overwhelm the
electronics in the amplifier and distort the output going to the speakers.
We use the "CD" input instead, to avoid this. (As you probably know, the
maximum loudness of "analog" recordings is much less than what a CD can
record -- hence the more concert-like sound of a CD recording.)


And last but NOT least:

This is a sensitive subject, but it needs addressing. There is an almost
overwhelming urge for sopranos to "open up" when they get into the upper
pitch ranges. It takes a very disciplined singer to remember her position
as a choralist, rather than invoking the fine art of solo singing. But
often in the passion of the moment, at these more stirring sound levels, one
forgets. And if the director is swooning too, he or she may not recognize
what is happening. The microphone is entirely dispassionate.

If ten sopranos sing a high C (C5), then their sound is up around 500 cycles
per second (Hz), with harmonically-corresponding higher partials, and any
slight difference in intonation (pitch accuracy) will generate a beat
between these two slightly varying signals (subtract one singer from the
other) which can be "felt" by the audience (and recorded by the microphone).

Moreover, if one or two singers forget themselves and add a lovely vibrato
to their pitch, then these two singers will be out of tune a good ninety
percent of the time allotted to that note. Worse, if they "vibrat" (a new
word I just invented) in opposite directions or at a different pace, then
they are twice as out of tune. The effect is similar to a screech of chalk
across the blackboard.

Beyond intonation, in a chorus, the acoustic vowel "shape" simply MUST be
the same within the entire chorus, and especially so within any single part.
The acoustic signal of an "AH" and an "AW" (imagine the word "God") or of an
"OO" and an "OH" is completely different, and creates a clash between upper
harmonic partials which themselves would not be in chordal proportions.
This too creates a harsh sound.

Keep in mind that the vowel sound YOU hear from a singer is entirely
different from the one that singer hears (if they can hear themselves at all
in a choral setting). You might say "Betty, try to make that more of an
'AW' sound," and she'lll say "Okay, Chia Ying: AHHH" without even knowing
that it's happening.

Listen to Barbershop singing sometime, to understand the critical nature of
matching vowel sounds.

Hope this helps.


Yours in beautiful singing,

Pete Mickelson
The lady with the question about the mic, she should make sure that
she is not recording on AUTO, because
that does tend to distort when voices have high notes. The limiter
does not react quickly enough for the wide
dynamic range of classical singing. I found the AUTO setting
fine for blaring rock music since the dynamic
never changes from FFFFFFFF. For singing, place the mic at least
4 feet away and set the recording level to
MANUAL and do a sound check for the best level. The record volume
level will need to be rather low, but at
least will remain constant and without distortion at the top.

A good mic will make any recording better, so I got the one-point
stereo model ECM-MS957. A little pricey at
$300 but worth it for best results. The other lesser mics by
Sony do amazingly well for their size and price too,
but get the ones intended for use with minidisc.

hope this helps out a bit...

good luck!
--
Phil Micheal
Director of Music
Jefferson Ave. Presbyterian Church
(A great place to be!)
Detroit, Michigan
church website: www.japc.org

The lady with the question about the mic, she should make sure that
she is not recording on AUTO, because
that does tend to distort when voices have high notes. The limiter
does not react quickly enough for the wide
dynamic range of classical singing. I found the AUTO setting
fine for blaring rock music since the dynamic
never changes from FFFFFFFF. For singing, place the mic at least
4 feet away and set the recording level to
MANUAL and do a sound check for the best level. The record volume
level will need to be rather low, but at
least will remain constant and without distortion at the top.

A good mic will make any recording better, so I got the one-point
stereo model ECM-MS957. A little pricey at
$300 but worth it for best results. The other lesser mics by
Sony do amazingly well for their size and price too,
but get the ones intended for use with minidisc.

hope this helps out a bit...

good luck!
--
Phil Micheal
Director of Music
Jefferson Ave. Presbyterian Church
(A great place to be!)
Detroit, Michigan
church website: www.japc.org

Check out a place called "microphone madness" on the web. I just purchased
a microphone for my mini-disk player from them. When I called and talked to
them they recommended a special addition that takes care of the disortion.
Give them a call. Very knowlegable and lot of options.

Jane Ramseyer Miller
St. Paul, MN

I believe the problem is not a microphone issue, but something else.
Minidisk players are not intended to have the mikes plugged directly
into the unit. You must first connect the microphones to a mixer
and then send the unamplified signal to the recorder. I believe
that this will solve the problem.
For a good quality recording, try the AKG C1000S or the AKG C535B.
They are great mikes and are not terribly expensive. Good luck.-
Ron

Ron Miller
Director of Choral Activities
Lock Haven University of Pennsylvania
244 Sloan Hall
Lock Haven, PA 17745
(570) 893-2132
rmiller1(a)lhup.edu

It sounds like you have too much input level - and perhaps there is no input
level control on the recorder, so it is distorting

2 things to do:

Make sure you are using a decent mic - this one doesn't sound that great -
and 100 to 15000 isn't all that impressive

Use a small mixing board (such as Mackie 1202) to run the microphone through
- then you can adjust the levels and get an undistorted sound

Good luck

John Helgen
Minneapolis

You do not say what model the MD recorder is. If it is one of the small Net
MD recorder/players, such as MZ-N505, the input is for line level only and
not microphone level.
Sony has been misleading in advertisements of microphones it says are
compatible with certain Net MD players, which are only for line input.
If it is a deck or full size MD recorder, it may be another problem.
Also, I would use a more omni-directional mic for recording choir.

Best regards,
Bill Wood
First Presbyterian Church
Greenville NC
wmwood(a)greenvillenc.com

My suggestions is to not use a minidisc recorder. I have made a
CD with my mini disc, but there is too much compression so that
the results is not really that good.

Dale Voelker
dvoelker(a)judsoncollege.edu

Sounds like a bad mic, but try setting the mic back further from the chorus
(to avoid overloading the mic itself), and keeping an eye on the level meter
on the MD recorder. The meter must NOT go above 0db, even though there is
porbably some "headroom" available (level meters are usually deliberately
conservative). If these things don't clear up the distortion, you might have
an impediance mismatch between the mic and the recorder. A low impedance
microphone will not mate with a high impedence input (which is what you
probably have) and vice versa. Transformers are available from Radio Shack
to help correct this. If you can determine that your impedence matches and
the problem still exists, then either the mic is bad or there is an
overloading problem with the mini disc recorder. Try another mic first. If
no better results, a good electronic repair shop is in order for your
recorder.

Sorry it has to be so technical. Good luck - Fred Wygal

I use an AudioTechnica AT822 Microphone which is perfect for recording choirs. I have been using it for three years now with no problem. It costs about $350.00

Virginia Moravek
John P Stevens HS
Edison, NJ
I find that when I get distortion in my recordings using a minidisc it is
because the MD's record level has been set too high. It's not a problem
with the microphone in most cases.

----------------------------
Jason Shelton
I think it is highly likely that you simply have the recording gain set
too high. Just turn down the digital input recording gain and that will
probably do the trick.

Best wishes,
Terry Cordery.
Music teacher and bass songman at Selby Abbey, North Yorkshire, UK.

there are a number of things that might be contributing to this phenomenon. the MS907 is actually a stereo condenser mic, but i doubt that has anything to do with the problem you are having.
here are some things that you can try:
1. less likely--check the battery in the microphone. i don't know how long you have been using it, but the batteries do die in those microphones. when you turn the mic on a little red light should blink on for just a moment.
2. make sure that the mic is going into the right jack. many mini-disc recorders have both a line-in input and a microphone input. make sure you are plugged into the microphone input.
3. most likely--check your input level: you should be able to select the level at which the input is recorded onto the minidisk. what could be happening is that your level is set too high and it is "clipping" digital clipping makes a very distinctive pixellated garble (technical term of course). usually higher sounds are louder, especially in the human voice, hence it getting even more distorted with higher notes. check your manual as to how to turn down the input level, i think that'll probably do the trick

the microphone you have is fine. i use it myself and i find it to be a very good microphone, i've actually used it for some very nice audition recordings in conjunction with my minidisc recorder.

best of luck
alex Neumann
We at Mansfield University produced a CD while on tour in Europe this
summer using a mini disc recorder . Here are the specifications. We
experimented with two different microphones (at different times) with good
success.

Sony Digital Mega Bass Walkman MZ-R55

Electret Condenser Mic ECM-717 (recommended by Mark Recording)
(about $100)

Also used Sony ECM-MS908C in some venues (about $100)


We used an extension cord to make sure that the sounds of the MD player
would not be picked up. We used ordinary discs. (No Gold Discs, etc)

Hope this helps. Good luck!
Peggy Dettwiler
--
Peggy Dettwiler
452 N. Main St.
Mansfield, PA 16933
570-662-4721 W
570-662-1055 H
_____________________________________________________
Turn the input volume down until there is no distortion. If the input volume
from the Mic is to high it will clip and distort.

David Arivett
President
Songs Of David
www.songsofdavid.com

Worship www.songsofdavid.com/music.html
Choral www.songsofdavid.com/choral_page.htm
Jazz www.songsofdavid.com/music_jazz_film.htm





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