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Low vocal input level using Bluebird and PreSonus Audiobox

1355 Views 9 Replies Latest reply: Feb 19, 2013 6:13 PM by kelvin15 RSS
kelvin15 Level 1 Level 1 (0 points)
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Nov 15, 2012 4:29 PM

I'm using a PreSonus AudioBox 22VSL and a Blue Bluebird condenser mic to record vocal tracks in GB.  The input level is very low and the waveform is almost a straight line.  I've already adjusted the input level on the vocal track with GB, the input level within the Preferences option in GB, the input level within my Macbook operating system, and the gain on the AudioBox.  Everything is set pretty high but the volume is very low.  If I turn it up any higher it distorts.


I just switched from a Shure SM58 plugged into a Blue Icicle into GB and had no issues. 


Any ideas why the input level would be so low?  I'm almost ready to return the Bluebird mic and the PreSonus AudioBox but I thought this would be a superior combination.  Thank you.

GarageBand (Mac) '11
  • isteveus Level 5 Level 5 (4,125 points)

    Did you turn on phantom power?

  • isteveus Level 5 Level 5 (4,125 points)

    The only level that makes a real difference is the gain on the interface. Once it leaves the interface it is digital. If you have a good signal to noise ratio at the interface you should be fine.


    I think I saw that the 22VSL has up to 35db of gain this should be more then enough gain for just about any mic. Have you tried it a full gain?  If you use your shure mic with the interface does it make a difference?

  • Edgar Level 3 Level 3 (990 points)

    When adjusting levels, always follow the signal flow and make sure that the different stages are properly leveled to maintain a good signal to noise ratio. For example, you don't want to compensate a level issue on the Fader if the problem is at the input Gain.


    Here is an example with the typical stages:


    1. When you connect your Mic to an external Audio Interface, you have to set the level right there first. Usually audio interfaces come with their own little software mixer where you can monitor the level that you send to your computer (enter your computer), or you can monitor the level with some LEDs on the front panel. If you don't get enough level from your microphone there, then there is no need to troubleshoot your OS or even GarageBand, your problem is at the Microphone+Interface stage.
    1. Once your level is correct at the interface, the next checkpoint is the System Preferences Audio. This is the stage where the signal enters you OS. Choose the input tab and monitor/adjust the incoming level there with the Input volume and Input level (if available for your input source).
    2. The third checkpoint is your application GarageBand. Please note that you don't have any input controls in GarageBand itself. Whatever signal comes into your computer (USB) and is set with the input level in the System Preferences, that is the level you are about to record in GarageBand. Yes, the Recording Level slider in the Track Info window let's you adjust the incoming signal, BUT this is just a remote slider for the actual "Input Volume" slider in the System Preferences window, they are linked. So technically, you are not setting a separate input gain in GarageBand, you are just setting the system input level from inside GarageBand. Here is a screenshot.





    Hope that helps



    Edgar Rothermich


    'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

  • isteveus Level 5 Level 5 (4,125 points)

    I believe it all depends on the interface. I have used several interfaces and neither the the sound preferences (step 3) or Audio/Midi setup utility can control input or output of interface.


    With the interfaces I have used the hardware (interface) or a software/driver control the i/o.

  • Edgar Level 3 Level 3 (990 points)

    It all comes down to the basic understand of Drivers. I spend quite some time in the advanced section of my GarageBand book to explain that. Here are just a few point.



    • On one side, you have the hardware device (Audio Interface, Built-in mic, built-in audio jack, etc) and n the other side, you have the software application (GarageBand, System, Logic)that want to use the Device
    • The most important piece in that scenario is the "interpreter" in the middle, the Driver.
    • The Driver is the gateway to the hardware device and decides what elements of the hardware device can be controlled by the software.
    • Any software application has to communicate with the Driver if it wants to control elements of the hardware (level, mute, sample rate. etc)
    • And here is the crucial part: Of all those software apps that can talk to the Driver, who is the Driver listening to? Who is in charge? There are two scenarios. All the apps can control the Driver (whatever was the latex setting), or an app takes exclusive control over the Driver (and therefor the Audio Device), so no other app can change its setting. (Please note that I'm talking about controlling the settings, not the use of the Device. Any app can still use the Audio Device)
    • For example the System Preferences Sound window and the Audio MIDI Setup utility lets you talk to the Drivers. They provide a different subsets of controls of a Driver they access. If you look at the "Recording Level" in GarageBand, this is a control that accesses the Driver directly to change the input level. The System Preferences Sound window has a slider that controls exactly the same component of the Driver (and therefore the Audio Device). The Audio MIDI Setup has also a slider that also controls exactly the same control. You get the idea. Everybody can access the input level and if you have those three window open at the same time, hen you can see that those sliders are linked. Whatever slider you change, the other one will follow.
    • The second scenario is when one app takes over the Driver exclusively and won't allow another app to control it. For example, if you select Device X in Logic, then switching the Sample Rate in Logic will switch the Device's Sample Rate Setting. You can't change that setting in the Audio MIDI Setup utility anymore, the Driver won't allow any other app to change it until you quit Logic and release its "stronghold".



    Here is a diagram from my GarageBand book that shows the elements that are involved.






    Here is another diagram that demonstrates who is controlling what





    As you can see, it can get a bit complex with different Devices, different Drivers and different Apps. However, if you have the understanding of the basic concept then troubleshooting gets much more easier and stuff is becoming to make much more sense.

    Luckily most of the time the situation is "plug-and-play" and the user doesn't have now all that. However if one piece of the puzzle is missing and stuff doesn't work, then you need that basic understanding, because everything turned into a "plug-and-pray" situation.



    Hope that helps



    Edgar Rothermich

    'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'


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