GG CBC Records

["Megan, Ken and Anne" <smithqa@nexicom.net>]

Dear John and fellow F Minors,

The CBC people were indeed working from acetate.  They didn't say that the
'noise' they were trying to remove was humming.  (That was merely my
assumption  -- obviously wrong.)  Still, it seems to me that there is less
on the two CDs that I have.  These recordings were made from live
performances when Glenn Gould was very young.  Perhaps he didn't hum as
loudly then.  Like you,  I would not want to remove the humming .

Anne


>Sonic Solutions is a DAW (digital audio workstation) used for editing and
>mastering of material for CD release.  The fact that they reduced "surface
>noise"
>suggests that they were working from a vinyl disc (or acetate) as the
analog
>master
>format before converting to digital.  These noise reduction algorithms are
very
>
>powerful and can substantially lower the noise floor of older master
formats
>like analog tape (without noise reduction) or other older formats.   They
can
>also
>assist with newer recordings by removing what we call "room tone", which is
>the noise signature of a room picked up when working in large auditoria or
>churches.  This is quite useful in lowering the noise floor of an acoustic
>recording, particularly "classical" music, which tends to have very quiet
>sections
>and lots of dynamic range.
>
>These algorithms do not, however, do anything by way of removing humming.
>You normally feed in a sample of one second's worth of the noise you wish
to
>remove and this sample needs to be a fairly "steady-state" noise.  Since
>humming
>tends to be extremely time- and frequency-variant, the algorithm would have
>a pretty hard time discriminating it from other artifacts within the music
or
>the
>music itself.
>
>But hey, I'd leave it in even if I *could* take it out.
>
>cheers,
>jh
>