Tim Gillett wrote:> My guess is the lassoo technique can
> work with a simple patterned noise such as the audience member whistle  
> but not so sure it would work onĀ  swish or hiss which is essentially random

To find out, you need to try it yourself. I have done it (seen no 
T-shirt, though)
and got some of the distraction of the swishes reduced. Did it for a 
shortish period
in the beginning of one song and my customer was happy with the result.

As you point out, it is more difficult to define the area to be attenuated
in a noise-type swish than it is with a tonal distracting sound. A 
whistle sound
appears rather sharp edged in the spectrogram and often you can use even the
RX Magic Wand selection tool for that.

In a record swish the frequency content and the gain change smoothly and 
it doesn't
have any sharp borders.

That's why you need to advance with small moves, like an archaelogist 
with a soft
brush. You draw kind of "height curves" with the lasso tool around what 
seems to be
the most distracting area at the moment. It takes time and you need to 
be patient.

I guess that such an algorithm wouldn't be impossible for the developers 
to build,
they have done more complex things,  but it is possible that the demand 
for swish
detection in a restauration program is not large enough, so that they 
would start
developing it.


Eero Aro
Audio Restoration Tonfiks