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GarageBand with a M-Audio MobilePre problem...

Discussion in 'Digital Audio' started by BurtonCCC, May 29, 2005.

  1. macrumors 65816


    Just a question... when I have my MobilePre plugged into my PowerBook, using GarageBand, and my condenser mic plugged into the MobilePre, I do my recording, but as always, the sound only comes out of the left ear. When we use the MobilePre on my friend's copy of bootleg Windows-based recording software, he then just processes the channel, then copies it to the other side, in essence, creating a stereo track from a recording that was only in one ear. In GarageBand, I can't find out how to do this, so I've been using mono lately. My questions:

    1. Is there a way to process the channels so it comes out both ears when I record using the "channels 1 & 2 (stereo)" option in GarageBand?
    2. If not, I'm assuming this feature is in Logic Express?
    3. What are the drawbacks on me recording in mono right now? It comes out both ears, so am I losing quality? I thought I understoof the difference between mono and stereo until GarageBand started playing mono out both ears and stereo out only one. Can somebody clarify what the difference is?

    Any responses are greatly appreciated.

  2. macrumors 65816


    Hi Daniel. I am not a Garageband user, but here are some comments that may help.

    #1) If garageband is set-up to record on Ch1/2 it needs two inputs. From your orig description it sounds like you are only using one condenser mic (my apologies if you are using a stereo cond. mic), therefore you are only recording a mono signal, that is unless your hardware interface allows you to split the live input to channels 1/2. If you split the live input or use two mics then you can get stereo.

    If you just want sound out of both Ch1/2 you could mirror the mono file on track 1 onto track 2, then add a little reverb or the like to track 2 to make a slight difference in the two channels.

    #2) Yes Logic Exp should do this fine, but then again, you should be able to use GB to do it, although you might need to do a workaround to get it to work. If you have Logic Exp already give it a shot (that is if you are using 2 mics or a stereo mic).

    #3) I am kind of confused by your last sentence. Maybe GB is using Interleaved playback? I dont know. Any more detail you could give me on #3 would be great.

    Hope i made sense.... :)

  3. macrumors 65816


    Can I suggest that you dont copy the audio to another channel to allow stereo playback. The reason i say this is it will be detrimental for your mix when you do come to mix down.

    Instead try using the pan function of the Garageband to move the track to the centre of the mix. Really you should be recording in Mono as you are only using one track. If you just have something on input 1 of a stereo track, it'll only come out the left speaker/headphone. So just set your software to record in mono and all should be good!

    :EDIT: sorry if the beginning of this post sounded harsh! I had a mobile pre for a couple of months and I only ever recorded 1 track at a time (my guitar) so you can definately do it. But its just a case of telling the software to do this. Theres really no point creating a stereo track of a mono recording as this just wastes space in addition to the other problems it introduces.
  4. macrumors 65816


    Why do you consider copying the audio down to be detrimental to the mix? I do this all of the time to create strange layering effects that i can not achieve any other way. Then again in my work i am more concerned with creating a more abstract final product that most users are. When i played with GB (verson 1. i think, and it might have been a beta, it was on a friends computer a while ago...) i didnt think it allowed changes in panning assignment on mono tracks. Maybe they fixed this with version 2., or maybe i just overlooked it. :)

    The reason i like copying the audio down is to add an effect on either the left or right channel. Just a little reverb on either left or right channels just makes the mix sound a lot better to me, that is when working with a mono track originally. However if the OP is going to being doing lots of automation changes such as volume, etc then just changing the panning assignment on the mono track would be the best, and easiest bet.
  5. macrumors 65816


    If you are processing each channel independantly, then you probably wont run into problems. You get problems with phase when using an identical track panned hard left and hard right. If you have to sum the two chanels together for mono playpack the two signals add together and double the overall volume.

    If you do wish to go down that route, its necessary to lower the volume for both of your indentical tracks by -3dB to give an overall difference of -6dB..

    Thats probably the worst explaination anyones ever given, but I'm a year out of Uni and starting to go a bit rusty!

    BurtonCCC - when you go to record your condenser - go to new track as you would normally, but choose Channel 1 (Mono) in the Input menu instead of Channel 1 & 2 (Stereo). Then you should be able to pan the Mic centrally and hear it out both speakers! Good luck and enjoy!

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