Dear Walt,
As usual your answers are very informative and helpful. I have followed you=
r
comments with some questions and comments of my own. My comments are in CAP=
S
and please don't think that I am YELLING at you! Using CAPS is just a bette=
r
way to separate our comments.
1. "10 dB is, if I remember correct exactly how much the signal is reduced
by the portadisc if you use mono and only send the signal in one input."
I USED A Y CABLE AND HAD BOTH LINE INPUTS IN USE SO I SHOULD NOT HAVE
SUFFERED SIGNAL LOSE. I DID SOME RECORDING IN STEREO ( 2 1/2 HOURS) AND THE=
GAIN WAS THE SAME BECAUSE I SENT THE SIGNAL TO BOTH INPUTS.
2. "Note that the NIMH batteries now come in 1800 mah capacity from a coupl=
e
manufacturers".
THAT IS GOOD NEWS. DOES THE LIFE OF THE BATTERY INCREASE IN PROPORTION TO T=
HE
MAH CAPACITY..SO THAT 1800 IS 1800/1550 (16%) LONGER LIVED THAN THE 1550?
3. As we've discussed, the habit of setting the meter right up at the peg,
which was necessary with tape due to it's poorer dynamic range is
something to get away from for digital recording. With the portadisc you
have a dynamic range better than your mic, and should set the levels
down 10-20dB lower than you would for cassette. It will still get
everything your mic produces.
DOES THIS MEAN THAT SOMETHING RECORDED AT -30DB WILL LOOK THE SAME (AND MOR=
E
IMPORTANTLY, SOUND THE SAME) ONCE IT IS CONVERTED TO A WAVE FILE AND THE
AMPLITUDE INCREASED APPROPRIATELY? THERE MUST BE SOME LEVEL OF dB WHERE THE=
MACHINE IS UNABLE TO PRINT THE TOTAL SONG/CALL? THIS IS AN IMPORTANT QUESTI=
ON
FOR ME AS I WOULD DEARLY LOVE NOT TO USE THE SME-BA3 Hi Gain Booster.
4. "One thing that might help is to leave the phone level knob extended.
It's next to the power button and might fend things off a little.
GOOD IDEA! I'LL TRY IT.
5. "The sampling rate is exactly the same as audio CD's, so I assume you
mean the ATRAC compression.
YEP! THAT IS WHAT I MEAN.
6. "If you hook only to one input, then it adds that input to the signal fr=
om
the unconnectedinput and still attenuates. Try comparing the gain you get
with your mic
feeding a single channel of stereo vs the mono fed via a single channel."
AS I SAID ABOVE, THE MICROPHONE SIGNAL WENT TO BOTH MIC/LINE INPUTS SO THAT=
I
SEEMED TO HAVE THE SAME GAIN WHETHER THE MACHINE WAS SET TO STEREO OR MONO.=
DOES THIS SOUND CORRECT?
7. "Digital recording has considerable more dynamic range than cassette. I
suspect the noise you are seeing is either actually there in the
environment, or is the noise floor of your mic, most likely the latter.
In either case the cassette did not have the dynamic range to pick it up."
SO DOES THIS MEAN THAT DIGITAL RECORDINGS WILL USUALLY BE "NOISIER" THAN
CASSETTES? THE NOISE I AM TALKING ABOUT IS UNIFORMLY HIGHER THROUGH THE
ENTIRE RANGE OF dB. ON THE SPECTRAL ANALYSIS THE ENTIRE BACKGROUND IS
"DARKER" FOR THE MD RECORDING (EVEN WHEN THE SONG FROM THE CASSETTE AND MD=
ARE OF EQUAL LEVELS.
8. "ATRAC does, as has been noted leave out some of the dynamic range at th=
e
highest frequencies. Most of what it leaves out we probably don't want,
mic noise and such like. It's like it cuts the dynamic range keeping the
louder signals and dropping the quieter ones. This occurs above 16 or 17 kh=
z."
THIS SEEMS TO DESCRIBE EXACTLY WHAT I AM SEEING IN THE SPECTRAL ANALYSIS.
THIS IS A SLIGHT PROBLEM FOE THE HIGH PITCHED SINGERS..I GUESS FOR THE
SCIENTISTS?
THANKS SO MUCH FOR YOUR KNOWLEDGEABLE ANSWERS. WE ARE ALL LUCKY HAVE THE
EXPERTISE SHOWN IN THIS LIST SERVER.
My very best,
John
John V. Moore Nature recordings
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