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Chapter 7 : Recording
Chapter 7 : Recording
Chapter 7 : Recording
7 Recording
Sampling frequency
The CBX-D3 can record at any one of four sampling frequencies:
48kHz, 44.1kHz, 32kHz, or 22.05kHz. These sampling frequencies are commonly used
for digital audio, and each has its own specific applications. The sampling frequency
determines the audio quality (bandwidth), with higher frequencies producing better
quality.
The sampling frequency can be set by the controlling software. The SAMPLING FREQ
indicators on the CBX-D3 front panel will show the selected frequency.
48kHz
At 48kHz an audio bandwidth of about 22kHz is possible. Consumer DAT and DCC
recorders can record at 48kHz only. Professional equipment also supports this frequency.
44.1kHz
With this sampling frequency an audio bandwidth of about 20kHz is possible. This
frequency is used for all prerecorded CDs, DATs, and DCC cassettes. Although 48kHz
provides a higher audio bandwidth, 44.1kHz is considered good enough for most
applications, and most professional digital audio engineers use this sampling frequency.
32kHz
At this sampling frequency an audio bandwidth of about 15kHz is possible. This frequency
is widely used for broadcast applications where a 15kHz audio bandwidth, roughly that of
FM radio, is acceptable. Many DSB (Direct Satellite Broadcasting) transmissions use this
frequency, although some may also use 48kHz.
22.05kHz
At this frequency an audio bandwidth of about 10kHz is available. This frequency is
widely used in multimedia applications. It might not seem very useful for your audio
applications, but if you are limited by hard disk space or the audio material you are
recording already has a limited bandwidth it may be useful.
Which sampling frequency for recording?
Since the CBX-D3 contains a sampling frequency converter, it is possible to play back a
sound file at a different frequency than it was recorded at. However, playing back a sound
file at a higher sampling frequency will not improve the audio quality, as the audio
frequency bandwidth is limited by the sampling frequency used for recording.
This leaves you with two deciding factors for choosing a sampling frequency. First, what
audio bandwidth (audio quality) do you want to use, and second, how much free disk space
is available? See "Hard disk size" on page 10 for a listing of recording times that are
available at each sampling frequency for a given size of hard disk (free disk space).
Setting the analog input level
Use the INPUT LEVEL control dials to adjust the recording level for analog input. You
can set the level independently for each channel. You can also use these controls to balance
the left and right channels of a stereo source connected to the analog inputs.
The input level automatically switches to accommodate line or microphone input. The
nominal input level for line input is –20dBm; the nominal level for microphone input is
–60dBm. Refer to the INPUT LEVEL indicators when adjusting the level.
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