Compressing Aux / Hard Limit Channel in the 4800

[junomat]

Two part question:

1. Can you compress an aux?

2. Can you hard/brickwall an input channel to avoid overs?

Thanks.

 

[captdan]

Question #2: Yes.

The limiting has to be done before the ADC - in otherwords - using an outboard compressor/limiter. Best way to do that: using a TRS cable into the preamp's insert jack. Output from the preamp is sent to the limiter, then output from the limiter is sent back to the DM's insert and onto the mixer's ADC. This way overs and clips are attenuated before the analog signal is digitally converted.

Question #1: Yes. However, in this scenario the return channel is treated, not the aux send. To do this on the DM, choose one of the full featured channels (with default EQ/Dynamic capabilities) for the aux's return. Then apply compression accordingly.

CaptDan

 

[TascMan]

When I read question 2, I think the OP means limiting within the board, before the AD conversion. In which case the answer is no. Like Dan said, you have to treat your inputs with a limiter externally before the board converts to the signal to digital, to prevent digital overs, prior to going to the board's input channel. This is why there is an insert jack at each channel input. The incoming signal is still analog at this point and doesn't convert until after the insert jack's return. After this point, it's up to you to check your input signal gain.

 

[captdan]

I think the OP means limiting within the board, before the AD conversion. In which case the answer is no.

You're probably right.

There's often confusion between limiting/compressing input going into the mixer and applying compression after the fact. The DM's channel dynamics are strictly for artistic 'sculpting' and mix balance volume control; they do nothing for hot input sources. If a signal is clipped at the ADC - and after the preamp - it's permanently damaged. That's why input gain staging - whether it's done with preamp settings, inserted outboard limiting, or both - is so important.

The other side of the coin is also true: a lower input volume can be compensated for in the mixer - using channel Trim, Dynamics, faders, DAW plugins, etc. 24 bit provides extensive dynamic range with extremely small noise floor.

CaptDan