Normalise Bug in Chain?[SOLVED]

[Shaky]

Spurred on by my earlier post I have been looking at a chain to convert my library of wav files into normalised flac files.

However, I have come across some strange behaviour in the preliminary test on 3 files.

Of these two performed as expected, but the third (actually the first in the series) that initially had fairly low levels were further reduced on the normalise pass.

At the same time applying normalise with the same parameters on the standalone file produced the expected behaviour.

I can supply the file if anybody is interested, a 46mb wav file.

Any ideas?

[steve]

To what level are you normalizing the tracks?

[Shaky]

To what level are you normalizing the tracks?

-2db

[steve]

Import the normalised "low level" file into a fresh Audacity Project.
Select the entire track, then select the "Amplify" effect.
The Amplify effect should offer to amplify by +2 dB.
Apply the effect, then look carefully at the waveform. I suspect that somewhere in the track there is a small spike that has an unusually high amplitude (note that "spikes" may be up or down).

[Shaky]

Import the normalised "low level" file into a fresh Audacity Project.
Select the entire track, then select the "Amplify" effect.
The Amplify effect should offer to amplify by +2 dB.

Nope, Amplify is proposing 9.8db.

There are no spikes, and no clipping warning when I amplify by 9.8db.

Would it help if I try to post the file?

[steve]

Nope, Amplify is proposing 9.8db.

Try applying Normalize to the file on its own (not in a chain). Does it normalize correctly?

[Shaky]

That works.

[steve]

Could you see if you are able to reproduce the problem? - perhaps generate some short tones from the Generate menu so that you know exactly what there peak amplitude is and export them as files. If you are able to reproduce the problem, please give step by step details of what you are doing.

[Shaky]

Could you see if you are able to reproduce the problem? - perhaps generate some short tones from the Generate menu so that you know exactly what there peak amplitude is and export them as files. If you are able to reproduce the problem, please give step by step details of what you are doing.

OK, I have had a go at this and am unable to reproduce the error on a test file with a generated tone.

However, the original file I detected this issue on has consistently failed to produce the correct results via the Chain, on perhaps on 3-4 attempts.

Perhaps if I send you the file via dropbox?

[steve]

Yes if you can upload the file somewhere and post a link I'll take a look. Thanks.