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  • Kwackman
    Posts: 35
    Joined: Sep 30th, 2007, 07:41
    Signal flow in Logic
    Hi, I'm sure I've seen a drawing for this somewhere, either in the tutorials or somewhere on line, but I can't locate it now. I know on the mixer page that the signal flows from the top insert point downwards to the lower insert points, but where does the fader come into the flow? Is it after the inserts or before? Or, if I put a compressor in a channel, is the fader after the compressor (and therefore is behaving as a make up gain control) or is the fader before the compressor (and the fader is almost acting like a threshold control) Hope this makes sense?! Cheers, Davy
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  • steveH
    Posts: 857
    Joined: Oct 17th, 2006, 05:19
    Re: Signal flow in Logic
    Inserts then Fader
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  • Kwackman
    Posts: 35
    Joined: Sep 30th, 2007, 07:41
    Re: Signal flow in Logic
    Many thanks Steve. Recently I was mixing a track with a vocal in it. I usually do instrumental, so this was sort of new for more. The singer was pretty good, but to keep here level constant, I went through and moved the fader to get a reasonably constant level. If I now insert a compressor, have I kind of undone my work in that the compressor is getting the unmixed track? Does that make sense or have I missed something?! Cheers, Kwackman
    Reply
  • Rounik Admin
    Posts: 8713
    Joined: Dec 16th, 2006, 08:13
    Re: Signal flow in Logic
    Do you mean you wrote volume automation to the track? Is that what you mean by 'moved the fader to a reasonably constant level' - I assume you didn't just place the fader at a static value? If you've written volume track automation then you can A-B the effect of a compressor by turning automation mode on that track to OFF (from Automation parameters menu in Track header). Cheers R
    Reply
  • Kwackman
    Posts: 35
    Joined: Sep 30th, 2007, 07:41
    Re: Signal flow in Logic
    Thanks for the reply Rounik. I didn't explain very clearly! Yes, I moved the fader through the song recording the fader moves with the automation. I've been thinking more about this, and I think my work flow may be a bit old fashioned- I'm from a time when plug in meant poking a brass plug into a jack field and the only digits were the ones at the end of your arm! My thinking was not to have a compressor in, and smooth the levels out by automation. Then I was going to use a very mild compression to give a bit of weight to the vocal. But, if the compressor goes in before the fader moves then it is dealing with a wider dynamic range than it would be if it was after the fader. So, I might play with doing the fader moves first, then sending the output of the channel to a new buss and insert the compressor in the new channel. That means the compressor settings are dealing with a more controlled signal and hopefully the "effect" of the compressor will be more constant too?
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  • Rounik Admin
    Posts: 8713
    Joined: Dec 16th, 2006, 08:13
    Re: Signal flow in Logic
    Hi Kwackman, I hadn't thought of this way... I tend to place light compression setting on the channel and then automate levels in any places if needed. But, you know, a lot of pro's prefer to use volume automation over a track instead of compression (depending on the material) - as a compressor can color the sound. Others, will always use a compressor on everything(!) And I'm sure there are plenty of the above who use both volume automation and a compressor. At the end of the day I'd trust your ears... well, not your ears in particular, but you get what I mean ;-) The Compressor has a lookahead function - so it should be able to see what's coming... but you can test this out by bouncing in place the audio track with volume automation (and no compressor). Then A-B a section where you're making the compressor work and you have a large rise/fall in level automation... Hope that helps R
    Reply
  • Kyjocuy
    Posts: 32
    Joined: Sep 18th, 2007, 06:13
    Re: Signal flow in Logic
    Hi Kwack, my two cents: I like to ride the faders when I'm recording. I'm also long in the tooth, and have digital hands. In the dark old days of tape, moving the fader meant changing the recorded level. Logic is different. Moving the faders alters the playback volume, even during record. To ride the recording level, you need to get your hands on the signal as it leaves your pre-amp, on the way into the computer. It takes a bit of practice of course, as every song is different, but that's the way to optimise levels whether you use dynamics on the way in or go direct. In the quiet passages you can add a couple of dB to maximise S/N and avoid meltdown by dropping the gain during the louder bits. While 24 bit recording is more forgiving of cooler levels than 16 bit, it still pays to get a strong signal just so you have a few volts to play with, and to keep that signal above the noise. This helps any downstream processors such as compressors. Think about it: if your signal level is all over the place, you may need to set an aggressive compression ratio to grab a hold of it. If you ride the mic, so you add a couple dB when soft, and cut a couple when loud, you can set a sexy light compressor and just add that magic "something". What you are really doing is giving your work a wider dynamic range than it is actually capable of in any other way...no compressor can be as transparent as your hands, er, your DIGITAL processors!!! Try it! Steve F
    Reply
  • Kyjocuy
    Posts: 32
    Joined: Sep 18th, 2007, 06:13
    Re: Signal flow in Logic
    Hey Kwackperson, part two... I kind of misread your first post, thinking you were wanting to level the level during record. Now I see you were talking about mixdown. My other post still holds true, and is the best way to get consistent level, which is a different thing to what we normally get a compressor to do. We are talking microdynamics versus macrodynamics. Usually we use compressors for control of microdynamics, that is, we want to control a sudden peak on one word or note or beat, that sort of thing. That is why we use fairly fast settings, like peak detection and fast release, so the unit is quickly ready to work on the next sudden peak. What you were talking about sounds more like macrodynamic control, where you are after consistent levels over time. For this you need much longer settings, release in particular, but also RMS detection rather than peak so that average levels are looked at and adjusted. The "classic" Teletronix LA-2A Levelling Amplifier is a case in point. We think of it as a compressor, which it is, but because it uses optical circuitry it doesn't react very quickly. Driven conservatively it gives a smooth ride, especially with more pad-like sounds. If you are more aggressive with it, the slow attack will let the "pick" of a note through and squash the body. Anyway, back to your mix. Use the compressor to catch the short, microdynamic peaks that jump out at you, then write automation to govern the more broad-brush level changes. Whatever methods you employ, make sure to let some random movement remain, otherwise your tracks will lose their interest, kind of like this long winded post........... I hope I'm making some sense. Steve_Awesome_Wells
    Reply
  • Kwackman
    Posts: 35
    Joined: Sep 30th, 2007, 07:41
    Re: Signal flow in Logic
    Thaks Rounik and Steve, Steve, My query was more about the position of the compressor relative to the fader. If it was post fader, then the fader was effectively a sort of threshold control for the compressor. But as I have now learnt from Steve H, the compressor is pre fader, so the fader is acting as a gain make up control of the compressor. I wanted to get clear in my mind what the fader was doing, and now I know!
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