Testing: LP/tape transcription

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Revision as of 19:48, 3 May 2018 by PeterSampson (talk | contribs) (cut-off becomes hyphenated for 2.3.0 (so Connie says))
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  • Peter 01Apr15: Ready for review and "merciless editing".
    • Gale 02Apr15: Are these timing tests or just to see if the functions work? I suggested adding some of these actions to Testing: timing tests.
      • Peter 03Apr15: This is specifically not a timing test it is a functionality walkthrough based on a common Audacity use-case.
  • Peter 01Apr15:I deliberately decided not to embed this in a table as some of tests have text that would probably be too long for this, thoughts?
    • Gale 02Apr15: Perhaps the number of each section would be sufficient for a table.
      • Peter 03Apr15: I'll look into that, it could be a useful reporting mechanism.

This test is designed to cover the steps used to transcribe an LP or tape - or more details of the steps involved in this test workflow please see this page in the Manual.
Warning icon Work with Audacity set to a project rate of 44100 Hz and 32-bit sample format. these are the default quality settings, but use Edit Preferences to check and reset if necessary.

1. Recording levels

Use monitoring to adjust and set your recording levels - aim for a peak of -6 dB or 0.5 on the waveform.

2. Capture

Record one side of an LP/tape or 30-45 minutes of FM broadcast.

3. Raw master backup

Export a WAV for this recording at 32-bit float (not 16-bit).

4. Remove DC offset

Use Effect > Normalize to remove any DC offset. Use no amplitude adjustment at this stage.

5. Reduce subsonic rumble and low frequency noise

Use Effect > High Pass Filter... with a setting of 24 dB per octave roll-off, and a cut-off frequency of 20 - 30 Hz.

6. Remove clicks and pops

  • First use Audacity's Repair effect on up to 128 samples]]. Ideally this will be on an identifiable click - but actually you are just testing the operation of the Repair function.
  • Then select the entire project and use Effect > Click Removal.

7. Reduce hiss and high frequency noise

  • Use Effect > Noise Reduction's Get Noise Profile to obtain a noise sample.
  • Then use Effect > Noise Reduction on the entire project with the default settings:
    1. Noise reduction - 12 dB
    2. Sensitivity - 6
    3. Frequency (smoothing bands) 0

8. Place the song labels

Mark the approximate label points by eye/ear.

9. Silence the inter-track gaps

Use the shortcut CTRL + L or add silence with Generate Silence to edit the inter-track gap to around 2 seconds.

10. Fade Ins/Outs

  • Use Effect > Fade In and Effect > Fade Out at the beginning and end of the songs. Normally fade outs should be longer (typically a few seconds), and fade ins, if required, quite short (typically a fraction of a second).
  • Also use Effect > Studio Fade Out to fade the end of some songs.

11. Adjust label positions

Adjust the label positions to be 0.5 seconds before the start of the each track. To move the label, drag it by its center circle.

12. Track names

Edit the labels for the song names.

13. Amplitude adjustment

Normalize the amplitude of the recording using Effect > Normalize with Remove DC offset un-checked i.e. "off"

  • initial run with Normalize stereo channels independently checked "on" and with maximum amplitude set to -3dB
  • second run with Normalize stereo channels independently checked "off" and with maximum amplitude set to -2dB
  • now use Effect > Amplify with a New Peak Amplitude setting of -1dB

14. Compression

UseEffect > Compressor, with default settings, on the entire project.

15. Export a set of WAVs

Use File > Export Multiple to produce a set of WAVs for each song at 44100 Hz 16-bit PCM stereo. Dithering should be set to the default Shaped in Preferences.

16. Export a label file

Use File > Export Labels... to produce a text file of the labels.

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