I have about 100 LPs I've started transferring to audio
CD. I'm using SoundForge 6.0 together with Sonic Foundry's
Noise Reduction 2.0 plug-in to do the processing. My
process goes something like this...

1) thoroughly clean the LP (Nitty Gritty vacuum system)

2) capture each side of the LP as one, long file
(44.1kHz, 16 or 24 bit, stereo)

3) apply Sonic Foundry's click and crackle removal plug-in

4) split the big file into smaller files containing
individual tracks.

5) apply one or more rounds of Sonic Foundry's noise
reduction plug-in to each track using portions of the
surface noise in the gaps between songs as the noise
fingerprint (resampling the noiseprint between rounds
if multiple rounds are used)

6) carefully listen to the processed track through
headphones and try to manually fix any remaining
problems.

7) normalize the audio to some consistent sound level

8) burn the collection of processed tracks to CD


My trouble is with step number 6. I consistently run into
two audio problems: the stray click or pop and something
that I don't know how to describe other than "buzz". The
clicks are usually not hard to clean up but this "buzz" is
something else altogether. I would appreciate any advice on
how to get rid of it or ideas on what might be causing it.
Here's some more details...

I'm not sure how best to describe the "buzz" noise. It
sounds like a torn speaker or something sitting on top of
your speakers vibrating at a resonance. It doesn't appear
(or often appear) at very low signal levels but it most
certainly appears in areas with lots and lots of headroom
left so it's not distortion due to clipping or something I
wouldn't think (however this is consistent with the
resonance theory). It's worse on some LPs than on others.
In fact, some LPs produce no "buzz" at all. It typically
lasts 100 to 200 milliseconds and it typically appears in
only one channel at a time. It can appear in either the
left or right channel, and seems to do so with equal
frequency, but it doesn't usually appear in both channels at
once. For mono recordings I've had good success replacing
the "buzzy" bit with a snippet from the clean channel.
Unfortunately, for stereo recordings that trick doesn't work
so well.

I can't find a good way to get rid of it and I'm out of
ideas. Here's what I've tried so far...

* I tried just deleting the bad region but, although
short, the duration is usually long enough that it
can't be simply snipped out without hearing the edit
in the final audio.

* When I zoom in on the waveform of an area with "buzz"
I can usually see a small amplitude, high-frequency
signal superimposed on the top of the "good" signal.
For that reason I tried using the equalizer tools to
filter out high frequencies just over the affected
region. This can occasionally reduce the problem but
more often than not it just replaces the "buzz" with a
"thump".

* I've tried SoundForge's Tools--Repair--Replace
option, and that actually does a pretty good job
getting rid of the buzzing sound. Unfortunately, in
its place it leaves other audio artifacts that are
usually more annoying than the orignal buzz. In fact,
as near as I can tell, the "Replace" tool is about
worthless.

Initially I was worried that the buzz may be an artifact of
using the click and crackle removal and/or surface noise
reduction tools too aggressively. However, I've gone back
and listened to parts of the original audio captures before
any processing was applied and the buzz is there. That
means its either something real on the disc or it is being
caused by something in the equipment between the disc and
the computer. Like I said, it reminds me of a resonance
buzz so I could be made to believe it has something to do
with my turntable pickup. I just don't know how to fix it
if that's the case. Anyway, for the sake of completeness,
here's my equipment...

An Esoteric Sound Murray II turntable

A new Stanton D5100AL11 stylus (tone arm adjusted for
2.5g of tracking force)

A KAB EQS MK12 pre-amp/equalizer

Either an ESI Waveterminal U24 USB, 24-bit, low noise
digitizer or a Creative Labs Sound Blaster Audigy sound
card.

If anybody can offer any advice on what may be causing the
buzz or how I might be able to clean it up I would be most
greatful!


Thanks in advance,


Charlie Hubbard