> I've posted an similar section from that recording with noise
> reduction done in Izotope RX2. I used a short section of hiss which
> had -- as far as I could hear -- only hiss as the base sample for
> the noise reduction, and have left the settings at defaults.
> Providing you can get a clean section of baseline noise RX2 can
> work wonders.
Paul,
The RX2 NR sounds splendid. Using Audacity, I had to split off the
bass as it modulates the HF noise reduction. I did also push the NR to
the limits.
> The original recording being used suffers a little as the Oade mod
> on the HDP2 exposes some very low level, non-steady state, system
> noise which can't be removed by this process. Fortunately it is only
> really apparent in very quiet recordings played back at high gain.
I looked at the quietest bass bits remote from the emu booms, and got
an approx 50Hz pattern with harmonics which give a hollowness to the
bass b/g. I've done a spectrum plot:
http://www.stowford.org/sounds/predawn-nr-for-db.gif
taken from a quiet point remote from the "booms". The spectrum shows a
50Hz fundamental with a string of harmonics and could originate at any
point from acoustic, mic, system, onwards. The booms have a similar
structure based on about 75Hz but are quite distinct.
I'm not familiar with the Oade mod but I looked it up and it promises
an extra bit, that's all. On my own rig, the MKH mic noise peaks at 4
to 5 bits, at 16 bit sampling, so you're not going to notice an extra
bit at the bottom end. With 24 bit recording you certainly don't need
extra gain as you have a range of 144dB. What does the noise profile
with a dummy 150 ohm load look like?
> I think if you were able to use a "bunker" sample of mic/preamp
> system noise as a baseline sample for RX2 the results could be very
> good indeed.
My anechoic chamber simulation was a pile of bedclothesw which works
at HF, but the central heating pump came through loud and clear. Do
you have any caves whic could give a low LF background level?
After all the above, I'm not sure if the original isn't the most
atmospheric, hiss and all. I hear a vivid soundscape with scattered
wild sounds in a silent landscape.
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
|
