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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. INPUT LEVEL indicators 17 INPUT LEVEL indicators 17 Unlike analog tape recorders, digital audio recorders are very unforgiving when it comes to excessive signal levels. Digital audio signal clipping normally produces unpleasant distortion, pops, and clicks that can be impossible to remove without the use of highly sophisticated editing equipment. So great care must be taken when setting the recording level. With a digital audio recorder such as the CBX-D3, noise and hiss produced by setting the recording level too low are not a problem. But setting the level too low reduces the effective dynamic range of the recording. In general, you want to use as much of the 96dB* dynamic range as possible. Basically, the recording level should set so that the loudest signals light the –24 and –6 LEDs, but never the CLIP LEDs. When recording with microphones, where sudden signal surges are possible, it may be worth having a “dry run” before you hit the record button. 8 Playback Sampling Frequency for Playback Although digital audio devices generally use the same sampling frequency for both recording and playback, the CBX-D3 includes a sampling frequency converter (SFC) that allows playback at a different frequency from that used to record. This feature makes it possible to replay multiple files at the same frequency, regardless of the frequencies originally used for recording. Specifically, the CBX-D3 can replay sound files using any of four sampling frequencies (44.1, 48, 32, or 22.05kHz). The frequency is selected through the controlling software, usually so as to match the sampling frequency of the device (such as digital mixer or DAT, MD, or DCC recorder) to which digital sound is being sent. The SAMPLING FREQ indicator on the CBX-D3 indicates the selected frequency. The sampling frequency used for recording determines the maximum sound quality obtainable from the file; use of higher frequencies at time of playback will not improve the quality. If you recorded a file at a 44.1kHz sampling frequency, it will not sound any different when replayed at 48kHz. But you should also note that a sound file recorded at 48kHz will generally suffer no noticeable quality loss when replayed at 44.1kHz. OUTPUT MONITOR indicators The four OUTPUT MONITOR indicators show the current output level of each channel. Each indicator consists of a single LED which gets gradually brighter as the channel’s output level increases. Output levels can be controlled by software. * 96dB is the...