Telex DN9848 Loudspeaker Processor Monitoring the Input Signal, 5.2.5Compression Page

Input Channels

5.2.5Compression (Page 14)

Each input has an independent full-range compressor to improve the dynamics of the incoming signal levels. The compressors are variable ratio and can be set to a hard knee characteristic for a sharp gain reduction response at the compression threshold, or soft knee for a more ‘musical’ response.

To set the compressor parameters

1On the first compressor menu page, use the centre knob to select a threshold value in the range –10dB to +21dB, and the right-hand knob to set a ratio from 1:1 to 5:1.

2Turn the left-hand knob clockwise to access the first sub-menu page. Use the centre knob to select a hard or soft knee characteristic and the right-hand knob to set the bypass state to ‘No’ so that the compressor is included in the signal path.

3Turn the left-hand knob clockwise to access the second sub-menu page. Use the centre knob to set the compressor attack time (range of 40 s – 1ms in 20 s steps or 1ms to 100ms in 1ms steps). Use the right-hand knob to set the release time (10ms to 2s in 10ms steps).

To switch the compressor out of the circuit

Set the bypass state on the second compressor page to ‘Yes’. The other settings are held for future use.

5.3. Monitoring the Input Signal

Each of the four inputs has a 9-segment signal meter for monitoring the internal signal clipping and compressor headroom or gain reduction.

The top CLIP segment monitors the internal signal clipping. It operates independently of the rest of the meter, lighting when signal clipping is detected at any stage in the processing circuits, regardless of whether the input level is above or below the compressor and/or limiter thresholds. Hence, the audio engineer has full visibility of internal signal clipping that may result in audio distortion.

The 0 to - 40 signal meter monitors the input level on a relative scale, where the 0 segment is set at the specified compressor threshold. For example, if the threshold is set to +9dBu then the input signal meter 0 segment is set at 9dBu true value, and a signal of –3dBu registers as 12dBu below the threshold (below left). Thus, when the signal level is below the threshold, the meter indicates the headroom.

When the signal level reaches the threshold, i.e. the red 0 segment lights, the meter ‘flips’ and reads downwards to show the amount of gain reduction applied to the signal.

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