John
 
This is the best tip you have ever done. I really love your tips but here I learned something. 

Hi John - could you elaborate on why you feel this is the best tip I've ever done? I'd be happy to incorporate more of what made it seem that way in future tips if I know what aspect made it stand out. 

Week 139: The Reason Why You Don’t Want to Compress the Master Bus
 

 
The above is what you want to master...if you start with the below waveform, EQ will act very differently.
 
If you’re into mastering as part of the mixing process, then this tip doesn’t apply to you. But if like me
you treat mixing and mastering as separate processes (see Tip of the Week #135, “An Efficient Workflow for Pre-Masters”), this tip is important.
 
When it comes to dynamics, I’m not just talking about brickwall limiting; a lot of folks think “well I’ll add just a little ‘glue’ to the master bus so the tracks sit together better” but I even recommend against that. Here’s why.
 
For me, mastering is primarily about EQ and to a much lesser extent, dynamics. However EQ before dynamics or EQ afterward produces very different results. A good example is wanting to bring up a kick drum in an EDM song during the mastering process. If you insert EQ after limiting, the kick will sound big but the extra level is now above the limiting threshold. This restricts the amount of available headroom, so now you have to lower the overall level, or add a second stage of limiting to try and regain the additional level.
 
If the EQ is before limiting, then you’re “pushing” the kick into the limiter. While this doesn’t produce as much actual level as EQ after limiting, it gives the psycho-acoustic impact of more level because the kick “pushes” the rest of the audio out of the way to make room for the kick. The music sounds like it’s straining a little more, and has an added feeling of power.
 
Another consideration works in reverse. If a master needs to be brighter, I tend to add that after limiting. Brightness can lead to ear fatigue, so compression after EQ can bring up the brightness to an unnatural degree. But also note that boosting treble frequencies, unlike boosting a kick drum, doesn’t add a lot of energy to the master. So to maintain headroom, you may need to reduce the overall level by only a fraction of a dB or so.
 
The bottom line is the same recommendation I made in the tip for Week 135: Create pre-masters with headroom and no compression in the master bus, then apply the needed processing to master the song while keeping in mind the above considerations.

XLNT Craig, Thank You

Hmm. This is pretty contentious. I very rarely have anything on the master bus myself, but it's more a question of what school of thought you're in than of any "right" way to do things.
 
I'd disagree that using compression while mixing equates to mastering while mixing. At least, not necessarily. Mix bus compression can still be an up-stream pre-master step.

I'll put a compressor on the master while mixing, set very gently just to glue everything together, not to raise the level.
 
Dan

John T
Hmm. This is pretty contentious. I very rarely have anything on the master bus myself, but it's more a question of what school of thought you're in than of any "right" way to do things.
 
I'd disagree that using compression while mixing equates to mastering while mixing. At least, not necessarily. Mix bus compression can still be an up-stream pre-master step.

Yes, it can be. But anyone who does that needs to be aware of the implications if you decide you want to add EQ. Remember, I said this tip is for those who treat mixing and mastering as separate processes. If you do, why would you want to lock yourself into something during the mixing process that can limit your options while mastering?
 

dcumpian
I'll put a compressor on the master while mixing, set very gently just to glue everything together, not to raise the level.
 
Dan

Again, that's fine as long as you're aware that while mastering, if you want to add EQ, you can add EQ only to the compressed sound...which means the EQ will be more apparent on lower-level signals than it would be otherwise. If that's what you want, that's fine. But if that's not what you want, then your only option is to do another mix without compression, then add EQ > compression. So it makes more sense to me just to leave all that off of the mix, and then you can do whatever you want while mastering.
 
Maybe I'm just old school because I've mastered so many tracks, but to me the purpose of a mix is to get the optimum balance among instruments. Mastering is about processing designed to sweeten the overall mix. I guess the way I look at it is that mixes aren't supposed to sound "good," they're supposed to sound "right." Then mastering transforms that which sounds "right" into something that sounds awesomely great.
 
Also sometimes I do EQ before and after compression. I just finished mastering an album where some songs had spots where I needed to drop the lower mids a bit. Doing so post-compressor would have created more of a "hole" in the sound, whereas doing it before compression let the compressor interact more with the dynamics in the area with the reduced response. If compression had been "baked" into the audio, I wouldn't have been able to achieve the effect I wanted. Ditto for those songs where I boosted treble before compression, although in the instances where I boosted treble after compression (i.e., the more "powerful" songs), it wouldn't have mattered that the audio was already compressed.

I do a little limiting on the master buss. I don't do much compression at all on the master buss or EQ. You have given us something to think about. 

always a limiter on the master, not for extra loudness, just to protect the speakers!

^^ I do this
Only as protection.
All the best.