Digital Audio Recording Procedures; Procedure - ACS Compact flash User Manual

Digital Audio Recording Procedures

Initially make all recordings (either music or voice) with a sample rate of at least 22KHz and 16bit.
This high quality, first-generation recording will later provide the greatest bandwidth and produce the best
sounding final audio.

Procedure

1. Record any audio clip of your choosing @ 22KHz, 16 bit Mono. Make sure that your samples do not
clip (go above or below the sample window). The peaks of your audio clip, should, however, fill verti-
cally at least 90% of the sample window. If they do not, you will need to boost your input signal by us-
ing a pre-amp or by some other means.
2. Edit the clip until satisfied. You can use a sound editor or filter program, such as Cool Edit to normal-
ize the amplitude of the sample. Use this command cautiously though, since it also tends to amplify
noise levels. It is always preferable to re-record your sound clip at a higher level to achieve better fidel-
ity.
3. After your editing is complete and you are ready to make a file for the Compact FLASH Digital Au-
dio System, use Cool Edit or a similar program to convert or down sample it to a 16KHz, 8 bit monau-
ral clip.
It is imperative that all initial editing and filtering be done to the audio clip while it is formatted at 16
bit and 22KHz or greater. Another important thing to remember when recording sound is that the back-
ground noise is amplified 256 times when down converting from 16 bit to 8 bit. It is, therefore, critical to
the quality of your final sound that there is no background noise while you are recording your clips or sam-
ples. The quiet noise of the fan on a PC for example, when amplified 256 times, can produce a very notice-
able hiss or static sound in the recorded clips or samples. Please be certain that your recording environment
is absolutely quiet.
Also remember that digital play-out devices do not introduce any static of their own other than quanti-
zation noise. They only play back exactly what was recorded. If there is excessive static in the audio clip or
sample, then there was probably static in it originally.
Compact FLASH Digital Audio System
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