2 Jun
2010
2 Jun
'10
1:13 a.m.
Hi,
what sparked (pun intended) my interest in audio initially (which must
have been about 7 years ago) was a bad recording of a song
(called "Sparks").
The goal was to:
a) improve the recording by any means necessary to make it more
enjoyable
b) get the knowledge and skills to maybe someday record it properly
I got a bit sidetracked to say the least. My knowledge about audio
certainly has increased significantly, but I'm hardly closer to my goal
than I was 7 years ago.
I didn't manage to improve this particular recording, nor did I try for
a long time.
And while I'm more able to re-record the song I have no contact with the
composer and interpret.
It would be nice if I could at least improve the recording, but I don't
quite know how to start.
My only 'source' file is a single mp3.
The major problems of the recording are:
1) quite a lot too much bass of the acoustic guitar - this is easy to
correct
2) a very loud noise, possibly from some part of a laptop. To my
knowledge the recording was made in two takes, guitar and voice, on a
laptop with a cheap mic of some sort. The noise seems to be located
mainly somewhere around 12kHz, a region which seems to be important for
the clarity of the voice. Any attempts to just pull down with an eq
(4-band parametric for example is what I tried today) had a significant
impact on the voice.
3) a constant level of noise, probably from some part of the cheap
equipment used. Due to the two takes it's 'doubled' for the most part of
the song.
To tip it all off, I can't even make out all lyrics. It might be that
some significant hints are simply masked by the noise, or they simply
are hard to make out.
I'd really love to somehow get this recording to an enjoyable state,
no matter how involving it is. Given the source it seems next to
impossible, but it has to be possible to make at least some
improvements.
Thanks in advance for any advise.
--
Regards,
Philipp
--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen
offen." Bertolt Brecht, Der gute Mensch von Sezuan
2 Jun
2 Jun
1:59 a.m.
On 2 June 2010 at 0:10, Philipp <hollunder(a)lavabit.com> wrote:
It would be nice if I could at least improve the
recording, but
I don't quite know how to start. My only 'source' file is a
single mp3.
Bummer. But, ya can still learn.
The major problems of the recording are: 1) quite a
lot too
much bass of the acoustic guitar - this is easy to correct
2) a very loud noise, possibly from some part of a laptop. To
my knowledge the recording was made in two takes, guitar and
voice, on a laptop with a cheap mic of some sort. The noise
seems to be located mainly somewhere around 12kHz, a region
which seems to be important for the clarity of the voice. Any
attempts to just pull down with an eq (4-band parametric for
example is what I tried today) had a significant impact on the
voice.
3) a constant level of noise, probably from some part of the
cheap equipment used. Due to the two takes it's 'doubled' for
the most part of the song.
Is there any part of the sound file that has only the noise
present, without the music playing? The more the better; 5-10
seconds would be good, and 1-2 seconds might be adequate. If
so, then you could try the noise removal effect in Audacity.
I use it often and I'm quite happy with it. I would try the
noise removal first, before compounding the recording with other
effects.
Audacity at version 1.3.11 (probably before then, but certainly
after 1.3.0) has a good graphic equalizer in it.
Parametric EQ might help to really "zoom in" on some things.
To tip it all off, I can't even make out all
lyrics. It might
be that some significant hints are simply masked by the noise,
or they simply are hard to make out.
After the noise reduction, then you might try compression or
expansion to isolate various sounds. Frequency sensitive
compression or expansion might also help, but is more difficult
to use.
I'd really love to somehow get this recording to
an enjoyable
state, no matter how involving it is. Given the source it seems
next to impossible, but it has to be possible to make at least
some improvements.
One thing you might try, which I haven't tried, is to make
several passes at the file. On each pass you try to isolate one
instrument or vocal, making that sound as good as you can, while
trying to eliminate all the other sounds. Saving a collection
of those kinds of sound files might allow you to mix those
intermediate files back together to produce something useful.
Is this recording stereo, with things panned somewhat left and
other things panned somewhat right, and yet other things panned
to center? If so, then you might be able to get at yet more
aspects of the recording by subtracting right from left, or visa
versa.
Hmm, you might also websearch for "audio forensics" or "audio
restoration" or similar topics as I'm sure there are folks who've
been farther down this path.
Please report back on how it goes. I'll look for your report in 7
years. ;-)
Good luck!
--
Kevin
2:13 a.m.
Excerpts from Kevin Cosgrove's message of 2010-06-02 01:59:30 +0200:
This is certainly a thing worth trying, thanks. I'm not sure thought
that I can isolate it well enough to make this work.
On 2 June 2010 at 0:10, Philipp <hollunder(a)lavabit.com> wrote:
Thanks for your reply Kevin. Audacity and its noise removal facilities
was the first thing I tried, about 7 years ago, back then on windows. I
may have tried it another time in between. Maybe it's time to give it
another shot.
It would be nice if I could at least improve the
recording, but
I don't quite know how to start. My only 'source' file is a
single mp3.
Bummer. But, ya can still learn.
The major problems of the recording are: 1)
quite a lot too
much bass of the acoustic guitar - this is easy to correct
2) a very loud noise, possibly from some part of a laptop. To
my knowledge the recording was made in two takes, guitar and
voice, on a laptop with a cheap mic of some sort. The noise
seems to be located mainly somewhere around 12kHz, a region
which seems to be important for the clarity of the voice. Any
attempts to just pull down with an eq (4-band parametric for
example is what I tried today) had a significant impact on the
voice.
3) a constant level of noise, probably from some part of the
cheap equipment used. Due to the two takes it's 'doubled' for
the most part of the song.
Is there any part of the sound file that has only the noise
present, without the music playing? The more the better; 5-10
seconds would be good, and 1-2 seconds might be adequate. If
so, then you could try the noise removal effect in Audacity.
I use it often and I'm quite happy with it. I would try the
noise removal first, before compounding the recording with other
effects. Audacity at version 1.3.11 (probably before then, but
certainly
after 1.3.0) has a good graphic equalizer in it.
Parametric EQ might help to really "zoom in" on some things.
I've seen some calf sideband compressor, maybe it will help with that,
thanks for the idea.
To tip it all off, I can't even make out all
lyrics. It might
be that some significant hints are simply masked by the noise,
or they simply are hard to make out.
After the noise reduction, then you might try compression or
expansion to isolate various sounds. Frequency sensitive
compression or expansion might also help, but is more difficult
to use. I'd really
love to somehow get this recording to an enjoyable
state, no matter how involving it is. Given the source it seems
next to impossible, but it has to be possible to make at least
some improvements.
One thing you might try, which I haven't tried, is to make
several passes at the file. On each pass you try to isolate one
instrument or vocal, making that sound as good as you can, while
trying to eliminate all the other sounds. Saving a collection
of those kinds of sound files might allow you to mix those
intermediate files back together to produce something useful. Is this recording stereo, with things panned somewhat
left and
other things panned somewhat right, and yet other things panned
to center? If so, then you might be able to get at yet more
aspects of the recording by subtracting right from left, or visa
versa.
From what I gathered today the mp3 is stereo, but it
was recorded in two
passes with a single mic afaik, and I'm reasonably sure that
there's no
panning whatsoever. I'll check, but I think there's nothing to be
gained in this way.
Hmm, you might also websearch for "audio
forensics" or "audio
restoration" or similar topics as I'm sure there are folks who've
been farther down this path.
Thanks for the search hints.
Please report back on how it goes. I'll look for
your report in 7
years. ;-)
Good luck!
I hope it won't take another 7 years, but who knows...
--
Regards,
Philipp
--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen
offen." Bertolt Brecht, Der gute Mensch von Sezuan
12 Jun
12 Jun
1:59 a.m.
On 06/02/2010 12:10 AM, Philipp wrote:
2) a very loud noise, possibly from some part of a
laptop. To my
knowledge the recording was made in two takes, guitar and voice, on a
laptop with a cheap mic of some sort. The noise seems to be located
mainly somewhere around 12kHz, a region which seems to be important for
the clarity of the voice. Any attempts to just pull down with an eq
(4-band parametric for example is what I tried today) had a significant
impact on the voice.
have not tried on mp3s, but i think it would work on .wavs, assuming the
voice is dead center mono, no important instruments are dead center
mono, and the noise is uncorrelated, i.e. different on both channels.
convert the L/R signal into an M/S signal: M = L + R, S = L - R. plus
here means "mix", minus means "invert the phase of R and mix".
with luck, you will have voice and not much else in M, and the rest in
S. if the noise crept in after the voice recording, chances are it's
"stereo noise". if the original voice track was noisy, you lose.
if it indeed is "stereo noise", try to kill it in the side channel only
with aggressive notch filtering. the clarity of the voice should be
mostly unaffected, since it resides in M.
now reconvert back to L/R: L = M + S, R = M - S.
while you're at it, you can also play with the base width, by changing
the M:S ratio before converting back.
how well this trick works on mp3 depends largely on how well the stereo
information is preserved in the mp3 (joint stereo, discrete, or even
mono)...
this method is how naive karaoke filters work: eliminate center content.
another good way to accomplish this is to plug a stereo jack (that
carries unbalanced stereo) into a balanced line input. frequently seen
in the wild, usually unintended :-D
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3 comments
4 participants
participants (4)
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Jörn Nettingsmeier -
Kevin Cosgrove -
Philipp -
Philipp Überbacher