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Logic 8 Presonus Firebox line in signal barely registering in logic

Discussion in 'Logic 8' started by beaker, Feb 2, 2010.

  1. beaker

    beaker New Member

    Hi...this is probably something quite simple, but i'm new to logic, and need help. I found that the pre's on my firebox weren't loud enough for mic recording, so I got a small ART Tube preamp, which I'm told creates a line level signal, and should then be plugged into the 'line in' on the back of the firebox. I've plugged my condenser into the preamp, preamp into a line in on the firebox, and record-enabled a track in logic, but i'm getting next to nothing registering on the channel strip, even with the preamp up pretty high. Tried the same in Garageband, with the same frustrating result. In my system prefs, i've set the audio input and output to the firebox, and get a nice bold signal on the mic input meter there. I've done the same on the logic preferences, but still getting nothing. Wondering if anyone can help....
  3. paulnajar

    paulnajar Senior member

    The FireBox Pre's are nothing flash but they should have enough gain for your condenser microphone.

    The following might seem like stupid questions but I have to ask. Do you have phantom power enabled? Have you turned up the input gain for the FireBox Mic channel?
  4. Peter Ostry

    Peter Ostry Administrator Staff Member

    Sounds as if the signal enters your computer but not the channelstrip where you expect it.

    Forget the ART preamp for now.
    The blue Firewire light at the right on the Firebox is on, yes? YES?
    Turn the volume of your speakers or headphones fully down (important!).
    Plug the microphone into the left input on the frontside of the Firebox.
    Turn on Phantom power. The button is labelled "48V".
    While you speak closely into the mic, turn up the gain knob labelled "1" until the "Clip" light goes on.
    Then turn the gain knob back a bit.
    In Logic, set the channelstrip of an audio channel to Input 1.
    Click on the record button of the channel strip.
    You should see a strong signal in the channel strip's level meter.
    Then everything is ok and you could record.

    If the above works, we'll go to the next stage. But try this first and report what happened.
  5. beaker

    beaker New Member

    Thanks Peter. I did the things you said to do, and yes I'm getting a decent signal in the logic channel strip. However, I had to speak really closely into the condenser and turn the gain all the way up on the firebox pre to get it to clip. So I'm getting sound into logic via the mic pre, although it's not ideal cos it's so low. What I want to do now is to be able to get a signal from the ART preamp through the line-in on the back of the firebox, and registering in a logic channel strip. I've got a short balanced cable (single xlr at preamp end and single trs at firebox end) to connect the preamp to the firebox, but little or nothing registering in logic channel strip when I try to use it. Don't know if you can suggest anything here.....
  6. beaker

    beaker New Member

    I've just worked it out....I had the input on the the channel strip set to 1, which is for the mic pre on the firebox. I just set it to 3 (line in) and immediately got a good signal. Doooooohh! Sorry to have wasted your time.
  7. Peter Ostry

    Peter Ostry Administrator Staff Member

    Yeah, that's why I suggested to use the mic input of the Firebox for the test, instead of the preamp. Just to make sure you select the correct input in Logic. Port 1 is port 1, there is no way to choose the wrong one.

    The audio inputs in Logic represent the ports of the interface. Mic 1 is input 1, mic 2 is input 2, and the first line input is number 3, that's where you are with your external preamp at the moment. You can rename the inputs in the I/O label section in Logic's audio menu, makes it easier to identify them.

    What you recorded with the wrong input selection is the channel crosstalk. At least you know now that such a thing exists and it is not as little as one may think. Theoretically you should not hear anything on another channel but your experience proves that there is a remarkable "wrong" signal because of channel crosstalk in the interface.
  8. beaker

    beaker New Member

    Many thanks.

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