Focusrite 18i20 and 18i8 issue

Dmac252

New member
Here is my situation. I am doing live recordings in a fixed location. I am using an 18i8 as my primary interface and an 18i20 as my ADAT unit linked via optic from the out of the 18i20 to the in of the 18i8 Connected via USB2 to a Toshiba L70 laptop running windows 8.1 my DAW is Pro Tools 11 latest version. All of my audio are direct outs from a Yamaha IM8-40 which are all pre-fader direct outs.

My issue is that I do not seem to have preamp control over the ADAT channels. Even if I turn the preamps all the way down I still get a hot signal on some of the channels in Pro Tools. In MixControl I have the analog inputs assigned to the individual ADAT outputs linked to the ADAT inputs on the 18i8.

Since there is no actual input control in Pro Tools on the armed channels themselves I continually wind up with clipped/distorted audio on some channels

Any suggestions, would be appreciated and entertained
 
I would like to know the answer to this also as I don't know what "db level" ADAT digital compares to if anything. I know if you feed one audio interface into another (my scarlett does this) you are probably going to overload the inputs because +4db pro line level is too hot for the scarlett pre's. But thats analog. I would be interested to know if the digital signal carries the same (db level?) considerations as analog connections do? Not to hijack your thread, sorry.
 
From what I understand, the ADAT signal is simply transferred "As-Is" and changes nothing in the signal. Therefore, it must be the signal coming in has to be too hot. The only other thing that could be happening is the primary interface (the one connected to the computer) could be increasing the signal during conversion. If you have the option, you might want to switch around which one is connected to the computer to see if there is some post processing going on. But the clipping is not happening in the ADAT-ADAT connection.

Edit: I got to thinking about this a bit more, I have to assume the computer connected interface does no conversion, just a pass through. Therefore, the ADAT connected interface has to be the one clipping. I will research a bit more, but once the signal is digital, it just gets sent to the computer in a digital data stream.

Check the ADAT source, has to be there.
 
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Hi guys,

This one is a bit odd!

So you've got your analog inputs going into your 18i20. These then leave over ADAT into the 18i8?


Do these signals clip on the meters of the 18i20?

Essentially, if the signal isn't clipping on the 18i20 sides of things, it shouldn't clip once it's been converted and made it's way into Pro Tools.


Best,

Miles
 
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