Here is another with a strange call after 10 minutes.
Same place today.
--- In wrote:
> It is interesting how you get different aspects pointed out from differen=
> What I heard was enharmonic distortion (but not a lot) and I confirmed th=
> by listening at quarter speed and 1/16 speed, with audiograms and with an=
> without frequency filtering. Enharmonic distortion is at frequencies not=
> related to the original signal and is much more audible at low levels tha=
> harmonic distortion. On a single note, several percent of harmonic
> distortion is often inaudible. What we complain about is enharmonic
> distortion when less than 1% can be unpleasant.
> The peak distortion near the end is slight and in practice inaudible as i=
> appears to be less than 1dB overload. When this happened, (before or afte=
> digitisation) I don't know, but with many recorders, levels like this
> trigger an automatic volume control giving a "hole" after the peak which =
> a much more audible defect than a simple peak distortion.
> The answer, as ever, is to record low. I would advise aiming at peaks com=
> in at -10dB or -12dB below 100%. We are long past the era when you have t=
> cram everything on as high as possible to overcome tape hiss, but the hab=
> sometimes lingers on. Plenty of headroom is essential with nature recordi=
> where peaks cannot be predicted. Out of doors, natural noise will almost=
> always swamp out any digital noise you will hear after lifting the playba=
> level to peak to -3dB or -6dB.
> Note about Blumlein recording (and ORTF etc). Any rig using spaced mics w=
> introduce phase shifts between left and right. This sometimes enhances th=
> stereo effect on headphones, but with open speakers, the image you hear i=
> very dependant on the room acoustics. The is why most studio mixes use le=
> stereo using pan pots rather than phase stereo to give a more predictable=
> stereo image.
> David Brinicombe