First, have a look at the file
When you are ready to start processing the
recording, I would suggest first having a look at its general condition. Of
course, you would have got a pretty good idea of the quality during the process
of recording, especially if you had taken the trouble of jotting down notes on
the time points at which problems occurred: maybe a long initial empty stretch
before the needle hit the groove, or a stuck groove, or some breaks which you
re-recorded in another file, or certain very noisy portions. Here’s a suggested
work flow to deal with it all.
Next, trim the empty bits
First things first: you need to trim off
the leading empty stretch (the leader), taking care to leave a few seconds
before the actual recording starts, so that you have a good stretch to capture
background ‘noise’ if needed (like the ‘hiss’ in a tape). Believe me, if you’re
doing a Beethoven, you will need it, as he is particularly challenging to
record with alternating stretches of very loud and very soft sound. If the
scratching noise in the quiet stretches is too obvious, you may have to try
subtracting the noise at least in these quiet stretches (the background noise
will usually not be noticeable in the loud bits).
To trim the leader in Audacity, you first
load the .wav file you have previously saved (menu File/Open), and move your
cursor position to the start (click on fast rewind, the double left arrow <<
in the control bar, just like any audio player).
Then position your cursor at the end of the
stretch you wish to delete, hold down Shift and click. The stretch between the
start and the current cursor position will go dark grey, in token of being
Selected; then you click on the Cut button (scissors icon, but Ctrl-x and Del key also work) to
delete that portion. There is another way to Select a stretch, in the
Edit/Select menu: you can Select a stretch from Start to Cursor, or from Cursor
to End, and do your stuff. The latter option is useful if you need to trim off
any ending empty stretch in a similar fashion. Of course, you have to first
position your cursor at the point in the recording that you want to work from
(or to).
If the rest of the recording is good,
that’s all you need to do, and you can
save the whole file using File/Export as a .wav file, giving it a suitable name
that gives the composer, genre etc. (the original file can have the tag
–raw.wav, the modified can have the tag –fixed.wav, as suggested in a previous
post).
Break the file into (2-minute) bits using
Snap-To
If, as is more likely, you would like to
improve the recording, one of the most helpful things you could do would be to
break up the file into little bits; I like two-minute sections. There are many
advantages in doing this, and dealing with each section separately. One is that
loading, processing, saving the files become much faster, so that you can
achieve some progress even in a short sitting. Secondly, if you goof up somehow
(deleting the file, for instance), or the computer hangs, you will only loose
the current two-minute bit, rather than the entire work. In fact, if you load
and try to work on a long file, chances are that the system will hang or crash;
so dividing it into small bits is helpful even if you have all the time (and
patience!) in the world.
There is a very nifty feature in Audacity
called Snap-To (on the Edit menu), that is enormously helpful in doing the
`slicing’ precisely. By turning Snap-To On, the cursor goes precisely to a full
number on the time line (minutes or seconds, depending on how zoomed in you
are). You may have to experiment a bit with zoom levels to ensure Snap-To to
goes to a full number of minutes, such as 2:00, 4:00, and so on. First, load
the whole file (with trimmed beginning and end, as described above), turn on
Snap-To, position the cursor near 2:00 (miniutes), which should pull it exactly
to 2:00, then on the Edit menu choose Select /Start to cursor, then File/Export
Selection to save this portion as a separate file. Next, Select from 2:00 to
4:00, go through this cycle repeatedly till the whole file is done. You will
name the files name-01.wav, name-02.wav, etc.
Now you can load each section separately
and do whatever processing you need, and Save the corrected files as name-01-fixed.wav,
etc. To put them all back together, you will have to File/Open the first one,
move the cursor to the end (click on the button for Fast Forward >> as
usual), then Open the second file in a second window (use File/Open), then
select the whole of this second section by Edit/Select All, then Copy the
selection (the usual Ctrl-c works!), switch back to the first file, Paste
(Ctrl-v works), then move the cursor to the end of the appended bit (Fast
Forward >> again!), add in the third file, and so on repeatedly. The only
thing to look out for is not to miss any file in the sequence, and to do it
carefully and systematically. Finally save the whole thing with a
name-fixed.wav filename. Of course, it will be advisable to save the interim
file after each step!
What processing to do on each bit (click
removal, noise removal, etc.) will be discussed in the next post.
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