I working on a sound file of a transfer from a spoken work broadcast dubbed
from a lacquer disc that was copied from a tape. I do not have access to the
tape.  It sounds ok except that there is a low frequency, relatively low but
audible level burble, a bubbly-rumbly noise.  It sounds like a tube about to
go microphonic, maybe.  It's from 1955.  


Any ideas of how to get rid of that noise without affecting the sound?   I
tried boosting it 4 octaves and trying spectrum repair in RX 5.  Returning
to pitch, the sound is still there and the voices are duller.  


It's irregular rather than periodic.  Filtering destroys the round tones of
the speakers.  


I can't send a sample- I have Verizon slow-speed and can't get Fios in my
county, through the surrounding ones have access to it.  Local politics.
For various reasons, can't use Comcast without it costing me another
$150-200 a month in overhead.  


Any ideas?


Steve Smolian