Mags wrote:Be seeing the musician on Thursday .. will strangle her for starting all this fuss ..
No need for that - As koz said in his inimitable way: "It's live recording's version of catnip."
I've just got home from work, made myself a nice cup of tea, and logged in to catch up with the latest developments with this issue. (252 views of this topic so far, so I think a few people must be following this particular story

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Mags wrote:exported this as an MP3 and increased to 85db
That is a
huge amount of amplification, and it still peaks below -10dB. If I understand correctly what you are saying. then the original peak amplitude of the recording will have been around -95 dB.
In case the above sentence sounds like technical mumbo-jumbo, I'll try and explain in layman's language:
With digital recording, there is a maximum level (loudness) that the recording can be. If you attempt to record louder than this, then the recording will distort rather than getting louder.
In Audacity, the recording shows up as a blue shape along the track, or if you zoom in on it, a blue wiggly line. This is the "waveform" of your recording.
Here we can see the waveform of the words "drumbeat fire":
(Click on the image to expand and remove the scroll bar)

- the words "drumbeat fire"
- drumbeat.png (3.06 KiB) Viewed 2073 times
And here I have zoomed in on the first part of the word "drumbeat":

- "dr" from the word "drumbeat"
- dr.png (8.13 KiB) Viewed 2073 times
Looking at the first picture you can see the vertical scale that goes from +1.0 to minus 1.0. This represents the maximum vertical height (loudness) that the recording can go.
In Audacity, the maximum is (somewhat confusingly) +1 to -1, which is equivalent to 0 dB (zero dB).
Signals (waveforms) are usually measured in dB, with reference to 0dB as the maximum. Any sound that is quieter than this is said to be so many dB's below zero - that is, a signal will have a negative number to represent the size (amplitude) of the signal. Total silence will show up in Audacity as a horizontal line at a level of 0.0, and this es equivalent to "minus infinity dB".
Here is a section of one of your recordings, where I have changed the view to show a "dB" scale:

- dB.png (3.66 KiB) Viewed 2076 times
You will notice in the above picture, all of the audio is in the range from about -70dB (the quietest parts) to about -10 dB (the loudest parts).
Ideally, your
original recording should go up to a maximum level that is close to zero dB. In practice, you must leave a bit of "headroom", so a maximum peak somewhere around -6dB is generally good. However, it seems that your original recordings had a maximum peak of only -85dB which is very quiet indeed.
Here is a picture of a recording from my computer when it is recording "silence". Again I have selected the "dB" scale and stretched the track so that you can see the measurement in dB.

- silence - or - "the noise floor"
- silence.png (4.52 KiB) Viewed 2072 times
You can see that even though I was attempting to record silence, there is random electrical "noise" at around -65dB". This is (as mentioned by alatham) what is called the "noise floor". Anything and everything that I record will have this noise added to it.
If I record my voice, and my original recording goes up to near the 0dB level, then this noise is almost insignificant and will just sound like a very, very quiet background hiss.
However, if my voice is only registering up to say -50dB, then the noise floor is relatively much higher, and when I turn up the volume, or amplify the signal to be able to hear it clearly, then I also turn up this background hiss.
In order to get a louder recording, and thus keep the noise floor relatively low, you need to get closer to the microphone, and you may also need to turn up the recording volume.
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I think that even when we have a good volume level in the recording, there may still be a certain amount of sibilance, but it will be very much less of a problem.