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Logic 9 Adding an insert effect into the audio recording signal path

Discussion in 'Logic 9' started by WrinklyD, Aug 18, 2011.

  1. WrinklyD

    WrinklyD Member

    Is it possible with Logic LE9 to add a gain insert effect into the signal path before recording (tracking not bouncing) to disk? I have a Saffire LE Audio Interface which unfortunately doesn't give enough gain (in my opinion) to give a decent s/n ratio when I record my PRS SE Custom (guitar) through a passive DI Box into Logic. From my experimentation I've come to the conclusion that the Audio Channel Strip Inserts are post the recording process so I wondered if there was a way to reroute stuff. By the way I know I could buy an outboard pre-amp but before I did that I wanted to know if it could be achieved via the software.
  3. slirak

    slirak Member

    You can (in the Environment), but it won't help you. You've got to get the gain up before the signal gets digitized - that is, before it enters you computer at all. Raising the gain the way you suggest would be no different than applying the gain plug after the track is recorded. Or simply cranking up the level in the mixer. So outboard it is.
  4. WrinklyD

    WrinklyD Member

    Many thanks,
    Okay outboard it is.

    By the way are there any audio signal routing diagrams for Logic 9 out there? I've got some for Logic 8 but I'm not sure how valid they are for L9 or how comprehensive they are. One or two of them seem to contradict each other as to whether the effect inserts are pre or post the original recorded audio. I've assumed they're post recorded audio as you can't hear the effects on any audio sample in the Bin or the Sample Editor.

    Thanks again.
  5. slirak

    slirak Member

    I don't know of any diagrams, but I haven't looked. The inserts are post though and that's at least the default behavior in any DAW. There's no setting to switch them to pre, but you can insert stuff pre recording in the Environment. However, even though most DAW's pretty much mimic an analogue set up, pre inserts aren't particularly useful in a DAW.

    There are a couple of reasons for this. First, you'll never run out of, say, compressors or gates in a DAW, as you probably would with an analogue setup. You still might need to "print" the effects just to save CPU, but a freeze function is a much more flexible way to do this, because you can always un-freeze the effects then, should you need to adjust a parameter.

    Also, in a sense, anything that's passed your audio interface is already sort of post. Sort of. Thing is, as soon as the sound gets digitized (and that happens in your audio interfaces hardware), your initial s/n ratio is set. You can always make it worse inside the DAW, like by over compressing, or mess with an expander which could make thing's better. But unlike analogue gear, the critical point in the signal flow is, in this respect, not when the sound gets recorded and not when it hits the mixer's pre amp, but when it gets digitized. This is also true when it comes to clipping. A signal that's clipping when it's digitized can't be saved by a software pre insert limiter or compressor, because the clipping has already occurred.

    There are special instances when printing an effect at recording time could be useful even in a DAW, but that's rare. Well, if you're doing layered live loops on stage, it's not that rare, but then you'd probably be using Ableton Live or a hardware looper anyway. :) (BTW, I actually don't think Ableton Live has any way to create pre inserts either, but it's easy to route one track to another in Live, thus printing any effects on track 1 to track 2.)

    But I digress.

    The bottom line is, when you're recording digitally, make sure you've got as good s/n ratio as possible and make sure there's no clipping - before the input of your audio interface.

    Incidentally, in your scenario, raising the signal level via a pre insert in an analogue setup wouldn't do the s/n ratio much good either, since the noise would be raised in level just as much as the guitar signal.

    The Saffire LE does have pretty weak (though very nice and clean sounding) input amps (I've owned one). So a separate pre-amp is a good choice if you decide to keep the Saffire.

    But if I were you, I'd look into what you could sell it for and add the cost of a pre-amp to that figure. You may well be able to find another audio interface for that money, that's better suited for your needs. It does have a bit too much latency too, for my taste.

    I did my math and ended up with an Apogee One instead. No need for a pre-amp or even a DI box with that one. Less latency too, even though it's USB. Very limited input and output wise though, so it might not fit your needs. But there are a lot of interfaces out there. I'm sure there's one for you too. :)
  6. WrinklyD

    WrinklyD Member

    Thanks again,
    That is very helpful information. Your point that the audio interface performs the a/d coversion hadn't occurred to me ( duh!). But once you realise that, it's clear the s/n has to be improved outside of the DAW and its interfaces. I'll also look into other audio interfaces. Thanks again for your time and the help.
  7. slirak

    slirak Member

    It's a very common misconception when you're used to the analogue world. Been there. Many of us have. :)
  8. jonperl

    jonperl Member

    All true stuff but to answer the original question, you _can_ record insert effects. On way is to use an "Input" channel strip and insert the effect there (these are not commonly used, so check the manual). Or you can use and Aux set to that physical input, insert the effect, output to a bus, and use a track with the input recording that bus.

  9. Gio

    Gio Member

    +1 on Jonathan's info.
    Aux listening to input, outputting to bus, and audio channel listening to that bus. Add Plugin to the aux channel.
    Good Luck
  10. Eli

    Eli Senior member

    +2 here. But I just use the Input object instead of an aux object outputting to a bus and then to a channel strip.

    PS: Jonathan - enjoyed your Omnisphere videos.....
  11. WrinklyD

    WrinklyD Member

    Thanks for your advice everyone. It's amazing how quickly you can learn something if you can just find the right people to ask!

    Dave :)

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