Are the Mbox 3 Pro line inputs too hot?

[bcent15]

Here's my issue: I have an API lunchbox with a 512c preamp installed connected into a line input of my Mbox 3 pro via a single XLR female to 1/4" TRS cable (Lunchbox to Mbox respectively). The line input is set to +4 on the Mbox. When my input signal on the preamp reads 0VU, the input level on the Mbox and in Pro Tools 10 reads about -6dBfs. That's too hot, it should read about -18dBfs, correct? Depending on the system, 0VU should be at least somewhere between -20dBfs and -15dBfs. This is frustrating because this setup won't allow me to open up my preamp as much as I 'd like to. According to the Mbox technology guide, the line inputs of the Mbox 3 do indeed bypass the internal preamps: http://www.avid.com/static/resources...logy_Guide.pdf

Does anyone know what is up with this level mismatch?

[bcent15]

bump

[Ben Jenssen]

I never used a series 3 mbox, but can't you adjust its input in the control panel?

[DMB13KOS]

I've had trouble getting a hot enough signal from a guitar amp line out into the Mbox line in.

[bcent15]

I never used a series 3 mbox, but can't you adjust its input in the control panel?

That only works for monitoring purposes, it doesn't actually attenuate the signal at the line input. Even if I was mistaken and the fader on the control panel is all the way up to zero, there still shouldn't be so much of a mismatch between what the preamp is putting out and what the mbox is seeing.

[Pinball Wizard]

Yes, this is a problem. If you put +4 into the line inputs it comes out as -10 in Pro Tools. That's waaaaay too hot. I'm not sure what they had in mind here. Even if you are using a console insert point that runs at -2, you still hit PT at -16 which is a little too hot for my tastes. I built up two 8 dB resistive pads in barrels to use with the line inputs.

No, the front panel faders do not control the line input gains.

Related notes:

This is not a problem at all with the Eleven rack....+4 in gives -18 in PT just like it should be.

Also with the Mbox 3 pro & Mbox 3, the microphone inputs are just the opposite....they are low in gain. See

http://duc.avid.com/showthread.php?t=319700


btw, I packaged an old API 312 card onto a 500 rack panel & edge connector. I run it into the line input of the mbox 3 pro. I only use one of the secondary windings in this case & it works extremely well. IMO you should be able to obtain excellent results with what you have when you get the level issues straightened out.