M20D and Auto Trim

[slammy69]

Hey all!

 

Not sure how the auto trim functionality works exactly. When I use it, it appears to have set the input levels correctly according to the meters, keeping them from clipping etc., but hardly any sound is coming out. I have the faders set to unity, and the main volume set to -30.

 

When I go and check the input levels in deep tweak, they are set super low. I have to crank the input levels back up manually, and then the sound comes out as I would expect. However, the input level meters are pegging out, as if it's clipping, but the sound is clear.

 

With my old Mackie board, gain controls set to unity, faders set to unity, and main volume set to -30, there was plenty of sound coming out.

 

Any input?

 

Thanks!

Slam

[SiWatts69]

If it helps...

 

Taking an SM58 as an example, for either me or our lead singer, auto trim typically sets the trim level at about 27dB

With a Beta58 it drops in at around 23dB (3-4dB less as the Beta58 has a higher signal level than an SM58)

We used to have a female singer using a Beta58 and due to her voice being somewhat weaker and her mic technique auto-trim typically set her Beta58 at around the 28dB mark.

 

Trim is the amount of gain being applied to the input to get it to a nominal unity level.

 

Auto-trim is trying to detect the highest peak in the signal and set a gain that is appropriate to handle those peaks without clipping occurring for anything other than quick peaks.

 

At -30db on your masters, you are effectively amplifying excessively at the start of the chain and then taking off that amplification at the end of the chain.

 

Ideally, you'd have trim set according to auto-trim (or close to it), then adjust the lead vocals to be around the unity mark (leaving a fair bit of headroom for in-gig adjustment) and set the other channel levels to get the mix from your lead vox channel. Then, bring up your masters to set an appropriate volume for the room. I can't remember ever running my masters as low as -30, having them typically sitting somewhere between -10 and 0

 

Remember, your mixer is only there to "shape" the sound.

 

When using auto trim, each performer needs to perform at performance level for about 20 seconds and then you need to accept the changes suggested for it to kick in. We tend to auto trim the drum kit mic by mic. Vocals we tend to do as a group. Bass and my sax and (when we had them) keys typically don't need adjusting much from one gig to the next as they're all DI style.

 

 

So;

TRIM is an amount of gain applied to the channel to bring the signal level/strength roughly to unity 0db and thus into line with all other inputs

Channel Fade is the relative amount of that channel's level fed to the main output mix

Master fade is the summed level of all channels

 

 

Too much trim will increase the risk of feedback.