There may not be a more divisive topic in the mixing-monitors-from-front-of-house conversation than whether one should mix monitors pre- or post-EQ. I’ve read numerous discussions on forums and social media with engineers frantically arguing their side as the only valid approach. I thought it would be wise to deconstruct this topic and present positives for both sides as well as a workaround.
First, let’s briefly describe the technical difference between the two approaches. Mixing monitors pre-EQ means that the pickoff point for the auxiliary (aux) sends is taken before the EQ just after the preamp and the high-pass/low-pass filters. Some consoles don’t even include the filters, going straight from the preamp to the monitor sends and as a result, the signal in the monitors is completely raw and not influenced by EQ changes on the respective channels. This can also mean that the signal is likely not affected by any dynamics processing on the channel. Check your manual for specifics.
Alternatively, mixing monitors post-EQ takes the signal for the aux 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, it might also mean the inclusion of dynamics processing. Modern digital consoles offer various pickoff points for aux sends giving engineers various options of including or excluding signal processing modules before the signal feeds the monitor outputs. Study the console and decide which one suits your workflow better.
Pros & Cons
The pre-EQ approach allows the engineer to have complete freedom of possible EQ moves during the performance without altering the monitor mix, keeping the mix stable and reliable throughout the gig. The caveat, however, is that the engineer has no way of correcting the sound to the monitors on a signal level, placing most of the responsibility of providing a good signal on the shoulders of the performers.
It’s a valid point. As audio engineers, we strive to get the best possible sounding signal at the source. This means that if we want the drums to sound better, we tune the drums, change the heads, or have the drummer adjust the playing style. In other words, change the source material so that it sounds good before it hits the microphone or direct (DI) box.
The catch is that sometimes there’s absolutely nothing that can be done in terms of altering the input signal. How do singers change their voices? We can try changing their microphone, but does anyone really carry an arsenal of 20 different mics to find the best one for the job? (And can this be repeated four or more times for the backup singers?)
Engineers favoring this approach are – in my opinion – more FOH sound oriented, which is a valid strategy. However, 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.
The other side of the spectrum is almost a mirror image. Engineers who mix monitors post-EQ want to reflect their channel EQ changes in the monitor mix. The reasoning is simple: if there’s a problem in the signal, it has to be addressed in both directions: towards the audience and towards the performers. For example, a muddy vocal needs reduced low-midrange for all pickoff points, providing the option of fixing the sound in the monitors by fixing it for FOH.