You know, I posted this to alt.audio.minidisc and to the MiniDiscussion
boards, but not yet here.
A lot of tracks on my CDs were mastered way too softly and peak in the -6 dB
to -3 dB range. I've an application that unfortunately involves copying to
audiocassette, so I need to set the levels on the MD to be as strong as pos-
sible without clipping.
My CD changer offers peak search, but the function is not of much use.
Someone explained to me that it is intended for analog copying, so it tries
to locate the passage that averages out the loudest over several seconds, not
necessarily the single loudest sample. Multiple runs of peak search over the
same track invariably result in its selecting different passages.
Further complicating the matter is that the VU-meters on the MD recorders,
as Grega Simenc has explained to me, show only about 100 or so samples per
second, not all 44,100, so a given input at a given gain might like the
"OVER" indicator on some plays but not on others, depending on whether the
clipped sample or samples were shown on the meter or not.
I've been resorting to the following procedure, which is so wearisome that I
haven't recorded anything from CD to MD in weeks:
1. I set the MD to monitor the digital signal from the CD changer.
2. If at any time in the following steps I lower the gain to +0.9 dB or
lower, I just set it to 0.0 and stop testing. After all, the correct
setting can't be negative in this situation.
3. I take a peak search and set the gain high enough for the passage to clip.
While the CD changer repeats it, I lower the gain until it can play three
times without lighting "OVER".
4. I take another peak search and, if at the gain level determined in step 3
it lights "OVER" on one try out of three, I lower the gain until it
doesn't.
5. I take a third peak search and do it again.
6. I play the track, watching for lighting of "OVER". Whenever it lights,
I pause the CD, lower the gain, rewind the CD player before the passage
that would have clipped, and resume play.
7. When I get all the way through the track, if I haven't broken out because
of step 2, I lower the gain another 0.2 dB just in case there were samples
that didn't make the VU-meter but which would have clipped.
It is very wearisome!
Now, I understand that if I had a working soundcard there are recording util-
ities that can scan a .wav file or such, spot the highest amplitude, and re-
port its value. But I don't have a working soundcard nor any other reason
to shell out for one, and my audio equipment is in another part of the house
from my computer, so computer-dependent solutions are not practicable for me.
When I asked on alt.audio.minidisc, Chris Knoche said something that made me
think of using the Peak Hold feature of my JE520 instead of the CD's peak
search facility to get the initial setting for step 6. But its meter is so
coarse that I don't know if it would help much.
When I asked on the MiniDiscussion boards, T. Huu and I started a correspon-
dence where T. (don't know which pronoun to use) suggested a voltage meter
with digital display and peak hold of its own. But I thought, first, I'd
need to get separate readings for the left and right channels, and they'd
need to be taken from the analog output, and second, I thought it would take
quite a few decimal places to get enough resolution to figure the gain within
a couple tenths of a decibel as I'd like, but the way the math works out when
I try it it takes about a 2.3% drop in voltage to correspond to a 0.1 dB drop
in amplitude, and that left me wondering whether I was calculating it right.
So, is there any resolution to this problem? Is there anything that improves
on my current method? A voltmeter with digital display and peak hold would
be rather expensive (not to mention dependent on the CD changer's DAC),
wouldn't it?
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