Pre/Post Faders?

StarMan

Member
My apologies if this is a stupid question but what is meant by Pre-faders and post-faders?

To illustrate, I have routed a group of guitar tracks to a "group" bus. That "group" bus has been sent to a "Fx channel" which means all the guitars in the group channel are now having the "FX" being added to them, so far correct am I? Ok now I notice that in the group channel it has a switch that allows you to turn on or off the "pre-fader, what is this and what happens to the effect? I have read up about pre-faders and post faders but am as confused as ever...Please explain.
 
Pre Fade/Post Fade
Refers to functions that happen either before (Pre Fade) or after (Post Fade) the main fader of a channel in a mixing board. For example, the Pre Fade Listen (PFL) is taken before (pre) the fader by definition. In certain situations it can be advantageous to monitor or take signals out of the board before or after the signal has passed through the fader. When driving headphone mixes or stage monitors, for example, it is common to use a pre fade aux send, so that the levels can be set independently of the fader position. It's like having two separate mixes at the same time. Plus, you avoid unexpected levels being sent to the artists because you made a change for the main mix. On the other hand, it is customary to use a post fader signal to drive effects units such as reverbs, where it can be advantageous for mix of the signal sent to the reverb to be the same as the overall mix. Pull down a particular part in the main mix, and you also pull down its signal going to the reverb unit. Most of this is a matter of individual preference based on different circumstances. There are a number of other functions in a mixing board that may take place pre or post fade (inserts, EQ, dynamics, etc.) depending upon the board in question.

Hope this helps.
 
Is there someway this can outlined in a simple diagram? I appreciate the explanation, but still don't get it. My apologies. Sometimes I find seeing a diagram explains it quicker and easier than the written word...I feel ashamed about something that is obviously simple to understand yet don't get it :(
 
I can't do a diagram, but try this:

A post-fade setting on your group bus sends everything within that group to the FX channel at the level that the group fader is set. This is most likely what you want. As you raise or lower the fader, you raise or lower the amount going to the FX channel.

A pre-fade setting on the group sends everything within that group to the FX channel at its initial level and unaffected by the group fader. Raising or lowering the group fader doesn't change the amount going to the FX channel. This is most likely what you don't want.
 
things that happen before the fader (pre) like your monitor sends on a live board mix - if you turn the fader up so will your monitor feed/volume.
Things after fader (post) like your effects sends on a live mix - if you turn up the fader nothing happens to the feed/volume.

I'm I getting this backwards? Dang I just don't think about it or try to explain it I just do it.


SORRY.
 
things that happen before the fader (pre) like your monitor sends on a live board mix - if you turn the fader up so will your monitor feed/volume.
Things after fader (post) like your effects sends on a live mix - if you turn up the fader nothing happens to the feed/volume.

I'm I getting this backwards? Dang I just don't think about it or try to explain it I just do it.

You think too much! Monitor sends are (usually) prefade (for me): turning up the main channel fader doesn't effect the monitor level. FX sends (eg reverb) I do post-fade: changing the fader changes the amount going to reverb.
 
Ok, what may be confusing you (because it confused me too) is that the whole "pre/post" thing seems backwards but it's not. Remember that the aux track with the reverb is its own seperate entity with its own volume fader. Try this: Route your guitar group to and aux track and name that aux track reverb. Insert a reverb plugin on the aux track and make sure to turn the wet/dry mix all the way up. Now leave it post fader. Set both the guitar group and reverb aux track's faders to 0dB. Automate a fade out on the guitar group. Listen and watch the faders. You'll see the guitar volume fader slider down but the reverb aux's fader stays at 0dB. Why does the reverb get quiter then? Because being post fader the guitar track is dictating how much signal reaches the reverb aux track. 0db > -20dB >-40dB, ect. Now click the "pre" button on the aux track. Now listen and watch the faders. The guitar group's volume fader slides down but the reverb's stays at 0db. Being pre fader the aux track still recieves 0db of guitar (because that's the volume you have the aux fader at) whether or not the guitar volume changes. This can be a really neat effect to make it sound like an instrument is fading into the distance instead of just fading in volume. Hope this helped.
 
StarMan...

What you are asking about is called a 'Signal Path'. It describes the path a signal takes thru a mixer. If you seek a diagram, google 'signal path mixer diagram'. The Mackie mixer books are good in explaining it.
 
I feel ashamed about something that is obviously simple to understand yet don't get it :(
Don't be. You're in good company. For the last couple of years, I've been going through the manual of my DAW and the tutorials that AKAI forum members have written on recording the effects, for example, {seek out Dogbreath or Treeline ~ they'll confirm how complicated it is at first on a DPS 12} and I'm still at a loss as to the ins and outs of pre and post fader ! One day before I die, I will get it !
 
I sometimes get overwhelmed because I'll see people write about something I don't understand, then I'll get stressed and try to figure it out. Lately I've been thinking, keep it simple. I'll learn a little here, a little there, and each mix will be a little better. Until one day I'll realize, "hey, I know a lot"!

So, if you don't understand it, ask some questions, experiment. If you still don't get it, move on and keep working with what you do know. For example I used to hear people talk about New York compression and didn't know what it meant. Then I just recently learned and realized it was something I was already doing!

In summary, don't sweat the details, learn as much as you can, and practice whatever limited skills you have (mine are super limited, but growing daily). I think you'll be surprised how much more recording gets done, and how nice it can sound with a simpler approach.

Oh, and just so I don't get accused of not addressing the question, I do mostly post-fader for recording and for effects (compression, reverb, eq etc). When i doubt in a recording situation, I stick with post-fader.
 
If you turn your fader all the way down, but still hear reverb on the channels, then the reverb is pre-fader.
 
Yeah, that was backwards, but you had the right explanations, just...backwards.

If your monitors are pre-fader, moving the fader won't affect the monitor volume.

If you turn your fader all the way down, but still hear reverb on the channels, then the reverb is pre-fader.

Thanks RAMI :) like I said, I just do it and when it comes to explaining it ................. :confused:
 
This is why experience mixing on an actual, physical console is helpful when trying to understand the basics of signal routing.
 
i'm new to mixing - i can read schematics for (and have built) electronic gear but the diagram for my yamaha mg166cx is "connection heavy" (16 inputs, 6 buses) and "function starved" (relative to a premplifier, say). so it's TOUGH on the eyes - plus, i haven't been able to draw direct connect between every switch on the board and every one in the diagram - yet. gettin closer tho.

and yeah - since the keyboard guy has the space HE has the mixer (and most of the instruments) - and i don't get to go back-and-forth between diagram and mixer.

sometimes, a mind is a terrible thing . . . .
 

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i'm new to mixing - i can read schematics for (and have built) electronic gear but the diagram for my yamaha mg166cx is "connection heavy" (16 inputs, 6 buses) and "function starved" (relative to a premplifier, say). so it's TOUGH on the eyes - plus, i haven't been able to draw direct connect between every switch on the board and every one in the diagram - yet. gettin closer tho.

and yeah - since the keyboard guy has the space HE has the mixer (and most of the instruments) - and i don't get to go back-and-forth between diagram and mixer.

sometimes, a mind is a terrible thing . . . .
The block dia and the zoom tool is your friend for mixers like that. That and a few prints and a highlighter perhaps to trace through a few the various path and pet trick options!
:)
 
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