Sample workflow for LP digitization
Basic workflow: Cleaning; recording level tests; artefact removal; trimming and labelling; volume adjustment; export.
It is not the only way of working - there are many alternatives. Like any recipe it can be adapted to suit your personal needs. Most of the clean-up steps are optional and need only be applied if your particular recording requires them.
You can work in AIFF rather than WAV if required.
UNDER CONSTRUCTION
Please note that this page is currently under construction - please bear with me for a few days while I work on it.
Overview
All of the processing in this tutorial is carried out with Audacity. Some users may prefer to use alternative software for specific sub-tasks like noise removal and the removal of clicks and pops (current Audacity Click Removal may not give as good results as other software).
Work with Audacity set to a Project Rate of 44100 Hz and Default Sample Format of 32-bit float (the Audacity defaults). You can use 16-bit if you prefer; it will give smaller working file-sizes but you may lose a little quality in some of the processes. Export WAV files at 44100 Hz 16-bit PCM stereo. That is the standard required for burning CDs and it will produce WAVs that are accepted for import by iTunes (and other music player software).
Note that this workflow does not at any stage necessitate the saving of an Audacity project (though you may wish to do that if you need to interrupt your work). It relies on the export of WAV files.
Workflow
Clean the LP
Cleaning the LP carefully and thoroughly before recording it will reduce the number of clicks and pops and will improve the quality of your recording.
Placeholder: mention of cleaning methods (manual/automatic/dry/wet) and possibly links to a few generally recommendable cleaning machines.
Recording levels
Check the levels: play portions of the LP, or even the whole side of the LP, to check the recording levels so that you avoid any clipping during the recording. Try to aim for a maximum peak of around –6 dB (or 0.5 if you have your meters set to linear rather than dB}. Tip: enlarging the Meter Toolbar by clicking and dragging helps with this task.
Capture
Record both sides into the project prior to doing the processing. You may find it helpful to zoom out so as to show the whole side of the LP in the Audacity window. You can if you wish work with single sides of an LP as it gives a smaller working set.
Place-holders for song labels
Mark the approximate label points while recording: place your cursor at the approximate point required and click CTRL+B – alternatively you can mark the current recording point, while recording, between tracks by using CTRL+M.
Raw master
Export a single WAV for this side of the LP at 32-bit float (not 16-bit). Retain this WAV file as a maximum quality "raw-capture" file that you can import back in to Audacity later for any future re-editing (or to start over with editing if you damage the project while working on it).
Remove DC-offset
Placeholder: Use Audacity's Normalization effect - with no Normalization
Remove subsonic rumble and low frequency noise
Apply Audacity's High Pass Filter (available from the Effect menu), using a setting of 24 db/octave roll-off, and a cut-off frequency of 20 - 30 Hz to rid of sub-sonic garbage frequencies. It's amazing that the waveform can show these sub-sonic frequencies, usually deficiencies in the cutting lathe during the original recording session.
Whether you need to or not will depend on the quality and alignment of your turntable, arm and cartridge.
Remove clicks and pops
Placeholder:' Audacity Click Removal, Draw Tool (or Hard Limiter)??
Remove hiss and high frequency noise
Get a noise sample from the lead-in groove before the music starts. Apply the Noise Removal effect with Noise Reduction set to no more than 12 dB (9 dB is a good guideline) Frequency smoothing 300 Hz, Attack/decay time 0.25 seconds.
Noise reduction is always a compromise, because on the one hand you can have all the music and a lot of noise, and on the other hand, no noise and only some of the music. Try lower settings on the "Noise Reduction (dB)" slider until you get the best compromise.
Whether you need to or not will depend on the quality of your LPs and your stylus and cartridge.
Clean the inter-track gaps
These are rarely truly silent so replace them with silence by selecting the gap and using CTRL+L. Shorten the inter-track gap to around a maximum of 2 seconds, though you may wish to use a shorter gap or even no gap at all for some recordings.
- Peter 19Mar10: that's because I much prefer to control the intertrack gaps myself - sometimes shorter sometimes longer and sometimes no gap. I don't want my CD burning s/w "helpfully" adding a 2-second gap - even if that is the Red Book standard. I don't think George Martin worried about the Red Book gap with Sgt Pepper, nor Pink Floyd with their concept albums :-)>
- Peter: also I import a lot of the WAVs into iTunes for conversion into AAC - for this I need to control the run-out and run-in lengths.
Adjust label positions
If you are using a 2-second gap, leave a silent tail of say 1.5 seconds and a run-in on the next track of 0.5 seconds.
Fade-ins/outs
You may wish to more cleanly fade out the track ends and fade in the track beginnings (normally fadeouts should be longer and fade-ins, if required, quite short).
As an alternative: you may find it easier to do: fade-out, silence gap, fade-in, shorten gap, adjust label position – in that order, one track at a time.
Track names
Edit the labels for song-names: we suggest using 01 <song-name_1>, 02 <song-name_2>, and so on as this helps keep them in the right order for CD production or loading into iTunes. You may find that changing the zoom level will help you with this task - or you can advance to the next label by ensuring that the focus is in the current label then using the <Tab> key.
Amplitude adjustment
Adjust the amplitude of the recording. Use Effect > Amplify as the last editing step to bring the amplitude up to around -1 dB. Use Amplify rather than Normalize as Audacity’s Normalize effect operates on each stereo channel independently and can thus change the stereo balance. If your equipment is not balanced you may prefer to use the Normalize effect.
Compression
Placeholder: Use Audacity's compressor
Export a set of WAVs
Use Export Multiple to produce a set of WAVs for each track on the LP at 44.1kHz 16-bit PCM stereo. Audacity will down-sample on export from 32-bit to 16-bit. Shaped dither will be applied by default to cover any clicky noise that may result from the sample size conversion. You may prefer to change this to triangular dithering in Preferences. See this article in the Audacity Wiki for more explanation.
- Peter 19Mar10: actually this is really at the very boundary my technology. I merely have mine set this way after a long forum/email discussion with SteveTheFiddle - it was the setting he advised for the way I was working. BTW: What is the Audacity default? I can't remember as it a long time since I've had a clean install.
Backup
Backup your WAV files: you don't want to lose all that valuable work and do it all over again, do you? Use two separate external 1 TB USB disks to hold the WAVs - each LP can be stored in its own named folder by artist (or composer for classical) to make retrieval easier.
Alternative software you may wish to consider using
Placeholder
Low Frequency removal
Clicks & pops
Process this file through the ClickRepair software: I change the ClickRepair defaults to: De-click 30, Crackle off ,Pitch Protection on, Method wavelet - select Reverse for particularly precussive recordings. ClickRepair will returns a 32-bit float WAV file with “-cr” appended to its file name for example: side<n> -cr.WAV
Hiss & noise removal
Compression
Links
|< Tutorial - Copying tapes, LPs or minidiscs to CD
> See also tutorial on: Recording 78rpm records
Placeholder: link to GoldWave
Brian Davies's ClickRepair software can be accessed from here: http://www.clickrepair.net/
Link to: Chris's Dynamic Compressor
