ALL YOU EVER WANTED TO KNOW ABOUT CD RE-
... BUT WERE AFRAID TO ASK
by Chris Burmajster
This article was originally written for Toccata, the magazine of the Stokowski Society and published in the autumn 2000 edition
In the Autumn 2000 edition of TOCCATA, Richard Luce, writing about the Cala Bach / All American Youth Orchestra CD wondered "how it was possible, given the shortcomings of these 60-
Obviously, one must start with the source recordings, which in this case were on shellac 78 rpm discs. The 78s were transferred onto DAT (a professional digital audio format) and were transferred 'straight', which means exactly as they came off the discs -
I have been re-
The first thing to be done is to transfer the analogue source to a digital format, usually tape based, although that is slowly changing. Because the work will be done in a very sophisticated computer and the audio will have to be transferred from the tape into the computer at some point, you might as well put the original directly into the computer in the first place wherever practicable. Until recently this idea of putting the audio onto the computer itself was expensive, but the fall in the price of huge hard drives (which store the audio) has made it much more of a practical proposition.
In the old days. at Decca, we would transfer the analogue source to digital tape (either Decca's own IVC based system or Sony U-
On today's modern computers editing is nondestructive because the original audio on the hard disk is not altered in any way. When you edit, you tell the computer to play this bit of audio on the hard drive. and then that bit, and then another bit, all of which might be on different parts of the hard disc. So playback is accomplished by the computer jumping from one part of the disk to another (in accordance with your instructions) with such speed that it sounds to us like continuous audio. However, the original audio is not altered in any way and you can undo what you've done at the click of a mouse. Toys for the boys!
In the case of the All-
To give non-
Dynamic range is the difference between the loudest and the softest sounds. In real life, a large orchestra can manage over 100dB and only recently could any recording medium capture that without some sort of fiddling by the recording engineer. Ironically, capturing the full range of dynamics is not really desirable for most home listeners, because in the small space of the home, the quiet bits will be inaudible and the loud bits will blow you and your neighbours to kingdom come! However, this is not a problem with any 78 disc, as the dynamic range will have been severely compressed by the original recording engineer to fit the constraints of the medium. You might think that this would make life easy for the re-
So, once you've loaded the audio into the computer, the first thing is to edit the sides together to make the program run as desired. This presents the first problem, as 78s do not always run at exactly the same speed, thus giving problems of pitch and speed differences between the sides. There are sophisticated computer software programs (known as plug-
After the editing is done, the clicks and ticks need to be removed. There are two ways of doing this, depending on what kind of clicks they are, how frequently they come, and how loud they are. In a lot of cases, another of those clever computer plug-
One very important point about all these clever processes is that their success is to a large degree dependent on the way that they are used. For example, with a de-
Once the basic audio is clean. then comes the icing. There are two things that can be done here, equalization and adding artificial reverberation. Equalization (EQ for short) is just a technical name for treble, middle and bass adjustment, although it's a lot more sophisticated than on home replay equipment and -
Artificial reverberation can also be added. Again, good musical taste must dictate how much and of what type sounds right for the particular program you are working on. In the case of the Bach CD the originals were very dry and boxy, so 1 added a Royal Albert Hall type of reverb which gave more richness to the sound, together with the EQ which both Edward and myself thought Stokowski would have liked.
As always, you are guided by your ears and your musical sense of what sounds right and what doesn't. Whilst you can teach a monkey to operate the computer, you cannot teach what feels right musically speaking, or at least it's very difficult. Ironically, I personally have a horror of EQ and artificial reverb. certainly as far as more modern re-
© Innocent Ear 2002.