Mixing Monitors from FOH: Pre- or Post-EQ?
I don’t know if there is a more divisive topic in the mixing-monitors-from-FOH world than whether one should mix monitors pre- or post-EQ. I have stumbled upon numerous discussions on forums and social media with engineers frantically arguing their side as the only valid approach. So I thought it would be wise to deconstruct this discussion and provide arguments for both sides and also a workaround to this ongoing battle.
What does it actually mean?
Let me take a second and describe the technical difference between the two approaches. Mixing monitors Pre-EQ means that the pickoff point for the auxiliary sends is taken before the EQ, just after the preamp and the HPF and LPF filters. Some consoles don’t even include the filters, but go straight from the preamp section to the monitor sends. As a result, the signal in the monitors is completely raw and not influenced by EQ changes on the respective channels on the console. Usually (but not always), this can also mean that the signal is not affected by any dynamics processing on the channel. The musicians on stage receive the unaltered signals, with the engineer controlling only the level balance between the signals.
Alternatively, mixing monitors Post-EQ will take the signal for the auxiliary sends after the EQ module of the console. This means that all the EQ changes made by the engineer will influence the sound in the monitors as well. Depending on the console, this might also mean the inclusion of dynamics processing. Digital consoles nowadays offer various pickoff points for auxiliary sends, giving engineers various options of including or excluding signal processing modules before the signal feeds the monitor outputs, so it is very important to study your console and decide which one suits your workflow better.
Pre-EQ monitor mixing- pros and cons
The Pre-EQ philosophy of mixing monitors allows the engineer to have complete freedom of possible EQ moves during the performance without altering the monitor mix, keeping the monitor mix stable and reliable throughout the gig. The caveat here, however, is that the engineer has no way of correcting the sound on a signal level, placing most of the responsibility of providing a good signal on the shoulders of the performer. A valid point- we all strive to get the best possible sounding signal at the source. This means that if you want to make a drum sound better in the monitors, go and tune the drums, change drum heads, adjust your playing - in other words, change the source material so that it sounds good before it hits the microphone or DI box. The catch here is that sometimes there is absolutely nothing that can be done in terms of altering the input signal. How do singers change their voice? You could try changing the microphone, but do you really carry an arsenal of 20 different microphones to find the best one for the job? And can you repeat that 8 times for all the backup singers? Engineers that are in favor of this approach are in my opinion more FOH sound oriented, which is a valid strategy, but they remove one of the tools for shaping monitor sound from the equation, relying only on the monitor mix bus EQ to shape the sound on stage according to the artist’s wishes.
Post-EQ monitor mixing pros and cons
“As with most things in life, not only in audio, your approach is going to be your call. Just know that there is always more than one way of doing things and that there is usually never a clear right or wrong.”
The other side of this spectrum is almost a mirror image when it comes to arguments. Engineers that mix monitors Post-EQ want to reflect their channel EQ changes in the monitor mix. The reasoning is simple - if there is a problem in the signal, it will have to be addressed in both directions - towards the audience and towards the performers. A muddy vocal needs to have reduced low-mid range for all pickoff points. This gives the engineer the option to fix the sound in the monitors by fixing it for FOH sound. And here is the catch - the engineers will adjust channel EQs during the performance as well, changing the mix for the monitors. This makes the sound from the monitors more unstable, sometimes even causing feedback issues if those channel EQ moves are substantial. The engineers gain the ability to fix monitor sound on a per-channel basis, but lose the complete freedom to shape the sound for the audience as desired, because they are limited by the restrictions of the monitor world.
Is there a clear winner?
What approach should you then choose if you have to mix monitors from FOH? Well, that will be up to you. Weigh the pros and cons of both approaches and decide which works best for you and your act.
There is a way, however, to have your cake and eat it, too. In the day and age of digital consoles you can combine both approaches. My preferred way is to double the so called “money channels” - lead vocals, solo instruments, whatever you decide is your most valuable input - and duplicate them on the console. The first one is sent to your main bus for FOH sound, the second is sent exclusively to monitors. Voila, the best of both worlds at your fingertips. You have the freedom of shaping the sound for FOH to your liking without affecting the sound in the monitors, with the added bonus of now having the ability to have signal corrective EQ for your monitor mix as well.
But if for some reason I don’t have that luxury (maybe there are no spare channels on the console), I usually opt for mixing monitors Post-EQ. Having said that, here are some things I keep in mind.
This approach is way more effective when you do your homework on the input source side as well. Make sure that your microphone selection is the best possible one, that the mics are placed where they should be and that the sources are in their best possible shape.
You should also consider that you shouldn’t be correcting a bad sounding PA system on a channel level. When all system engineering principles are applied and your system is optimised on a system processing level, you reduce the need for channel corrective EQ.
If you decide that you will go this route, you have to be aware that your EQ moves influence the monitors as well. So boosting an EQ band and sweeping to find the frequency you need to cut is out of the question.
Cutting instead of boosting will be your friend, and you should train cutting as much as it is absolutely necessary, no more. Retaining as much of the signal as possible will ensure the monitoring will be more stable and will support your FOH sound as well.
As with most things in life, not only in audio, your approach is going to be your call. I hope that this article will make that decision slightly more informed. Just know that there is always more than one way of doing things and that there is usually never a clear right or wrong. If it makes your client happy and helps you create a great experience for the audience, then you did a good job. It never hurts, however, to try out things on your own and see if there is another workflow that can make you faster and more efficient.