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[Gordon Waugh]

The Mackie DL1608 digital mixer does not have recallable preamps. You have to turn the physical knob on the mixer to adjust the preamp gain. You cannot adjust the gain from the iPad. However, in the recently-released Master Fader 3.0 app includes a "trim" control.

The trim adjustment must be happening after the preamp gain stage. I am guessing it, in effect, works in combination with your fader. Thus, if a performer is louder or softer during the performance than during sound check, your can set the trim so your fader level for that channel can still be within a normal range (e.g., near unity gain)--and that's the only benefit of the trim control. In other words, if the preamp is clipping, reducing the trim will not stop it from clipping. Similarly, increasing the trim will not increase the signal-to-noise ratio.

Is that correct?


I suppose, if you are going to mix entirely from the iPad, the best strategy is still to set the gain with a fair bit of headroom. That's because lowering the trim won't stop the preamp from clipping.

Is that correct?

[Jeff Carter]

The trim adjustment must be happening after the preamp gain stage. I am guessing it, in effect, works in combination with your fader. Thus, if a performer is louder or softer during the performance than during sound check, your can set the trim so your fader level for that channel can still be within a normal range (e.g., near unity gain)--and that's the only benefit of the trim control. In other words, if the preamp is clipping, reducing the trim will not stop it from clipping. Similarly, increasing the trim will not increase the signal-to-noise ratio.

Is that correct?

Mostly. I haven't looked at the block diagram but digital trim usually happens right after the A/D conversion. So trim acts pretty much like the gain knob--it will affect send levels to pre-fade auxes, unlike the fader. You're correct that trim adjustments don't do anything to preamp clip or signal/noise.

Assuming the trim is recallable in snapshots (unlike the preamps), it could be useful in those situations where you use snapshots to store settings for multiple sources on the same channel, as long as the levels aren't too vastly different.

I suppose, if you are going to mix entirely from the iPad, the best strategy is still to set the gain with a fair bit of headroom. That's because lowering the trim won't stop the preamp from clipping.

Is that correct?

Yeah, in that situation I'd probably make sure I have a little extra headroom compared to having the preamp knobs within arms reach. Again, though, since the trim will affect the send to any pre-fade (i.e., monitor) sends this is, like the gain knob, something you don't really want to be adjusting after sound check unless you're getting some really frantic hand signals from the stage.

[ProSoundWeb Community]