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Input trim question


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Trying to understand more about the input trim issues.

 

1.  If I use Auto Trim to trim an input and it shows something like -3db I would then expect that if I go to look at the trim manually it would say -3db when in fact it shows something totally different.

 

It appears to me that the auto trim only shows the change that it will make to current trim setting.  Is this correct?

 

 

 

2.  If I want to set trim levels manually, what is the procedure that you would do equivalent to a manual board?  It appears to me that Auto Trim sets input levels much lower than I would get using what I think is the correct method.

 

 

3.  If I turn off Auto Trim and Trim Tracking and set a unrealistically high input gain setting (lets say 50db) that should definitely cause clipping and distortion, then I turn Trim Tracking on and start playing why don't I see my trim settings change?  Trim tracking seems to be changing the input trim but I can find no evidence of it other than my ears.  As we all know, our ears are very unreliable sometimes.  Is there somewhere I should see the effects of trim tracking?

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I set mine manually. At the top left of the screen beside the "Setups" box, there is a green "level" button. Press it and you can change it to "trim" (I think it is trim....going on memory here...but I know it is red). Then, your encoder knobs will set the gain. You can set the gain with all levels completely off. Just like an old analog board.

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Right, except an old analog board would have a red light that would show you when you were clipping the input.  The old method being that you would try to take the highest level of gain that wouldn't clip the input.

 

(Manual trim is also available on the Performance page in slider view, or also available on the tweak page for the input)

 

How do I know when I'm clipping?  If I drive the manual trim up high enough for the signal to hit the top of the linear guage then I usually end up with some unrealistically high gain settings.  Much much higher than Auto Trim would have set.

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It has better than a red light. It has a meter! Shows exactly where you are. Set it so it is just bouncing around the "0db" mark Try it! Sounds like you have already done it. In fader view, you can also set it to be one of the meters you can constantly view (I set level as the main, with inout gain at the bottom). I knew it was in the other modes too, just didn't know you did so I started with one way. I think you know what to do. Don't set it to hit the top (or side) as the clip. But wherever the setting ends up, as long as it is not clipping, then you are good right? It goes from nothing to a distorted clip. You will find it. Like I said, I set mine to line that would be the "0db" mark. I have lots of level, and a lot of headroom with the levels. I then set trim tracking to on, so I know I won't clip during the night. Works awesome.

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The meter (input trim and level) will turn red if is clipping. When auto trim adjusts the input is looks at the levels and sets it slightly over 0dB. This is the same thing that you would do manually when setting a trim. We leave about 15dB of headroom whicj is pretty standard for digital desks.

When auto trim adjusts the analog gain for clipping the gain is made up digitally after the converter so that the level does not change. That is why we do not show a gain reduction.

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Thanks so far for the responses.  Still have some questions.

 

I'm sitting here with my HD500x plugged in and am driving the input pretty hard.  With Auto Trim selected and no Trim Tracking on with a std lead tone I get a setting of around 14db.  Yet I can go to manual trim with tracking off and drive it up to about 32db the meter is pegged but nothing changes color.  I can drive it all the way to 60db, the meter never wavers because it's already pegged but nothing changes color.  Obviously I should be clipping long before this...and it sounds like it's clipping but not near as much as I would think.

 

The "background" of the meter is red, but it's always red with trim selected as the control.

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OK.  Answering my own question here.  My HD500 just doesn't seem to get hot enough output under normal circumstances to drive the meter to turn red.  Tried a stronger input source and I was able to drive the meter red no problem.

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Question for the genius's:  If I have an input that is running with Trim Tracking on and later on I turn it off, what happens to the post input delta's that were applied while it was on?  Do they remain in place but unchanging?  Are they immediately discarded?  Or do I not understand what is going on ....  again?

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You're going to have to bear with me here as I haven't got my head round how to set trim manually despite all the good advice here. The following is what happens when I put a guitar with a signal from an amp head through a load box line out directly into a line input on the M20D.  If I set the red trim low and then go to the green level and set that reasonably high I get a distorted clipping sound.  If I set the red trim high - even full up - and go to the green level and set that anywhere from low to full on I get no distortion whatsoever.  So is the best way to do things manually to set the trim level as high as you can and do what my ears tell me or am I going about this the wrong way?

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Thanks - I understand the principle of setting it at zero.  What I don't get is why there is less distortion when I set the input trim higher than when I set it lower.  It seems counter-intuitive to me and that it should be the other way around?

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