Making mistakes while mixing is the human component of live sound production, and we all are guilty. However, with a little more attention to details, these minor blunders can be averted. This installment of Theory and Practice will recap common mixing mistakes as a reminder to avoid them in the future.
Now, we are not talking about gain structure issues, but having good gain structure habits being taken for granted. This means that zero dBu is more than a good suggestion for average signal levels. Keep it in the green and out of the reds. Double Assigns
Of all the blunders I see, double-assigning or double-routing input channels to both master and subgroups is the most common. In rare occasions, intentional double-assigning can boost signal levels when all other means are exhausted. But in most cases, you have unintentionally violated rule number one in mixing: "turning something up can be done by turning everything else down."
So check before and during your show for channel double assigns. I typically run into this problem via two ways. One is "fat fingers" resting on the faders and accidentally toggling the assign buttons. The other is previous console operators, when some have shied away from subgroups and assigned everything to the masters.
It pays to always "zero" up the console, even if you were the last person to use it. And if your assign switches also need the pan control to select subgroups, it is worth the half-minute to run through all the input strips and verify that the channels are routed correctly.
Mutes
Rule number two in mixing is "If it does not sound right, it is likely that something is wrong." This happens especially when accidentally having channels muted, and something just does not seem right. For example, I was at a club watching the house tech mix the opening act, and watching beside him at FOH before mixing the headliner. All the while he had most of the guitars and keyboards muted during the second set–but he was happily adjusting the muted channel faders and tweaking the channel strip EQs, and using his "ears" to adjust to taste. All I could do was smile and try to not deflate the house guy's ego.
When dealing with mutes and mute groups, get into the habit of not seeing red mute LEDs on active channels during the show. In essence, why not let a fader be all the way off instead of a mute indication? Yes, there are pre-fader auxiliary issues to be aware of, but you can just mute out unused channels to keep you sane. Do not shy away from using a cue wedge or headphones to periodically check subgroups and the main mixes. Everything has got to be in those mixes to be in the mains speakers. After all, mixing with the stage wash is a lot less frustrating with all the channels unmuted.
Counter-Equalizing
This is another common blunder I see, especially with the headphone-agnostic console operators. The classic case is the tech making a minor "hack" on the FOH graphic equalizer, and then proceeding to run through every input channel source on the console and remove the "hack" from the strips. Not only does this appear asinine from the outside observer's perspective, but it takes away precious attention from the performance to run down the channels, knob-twisting away.
I watched "an old soundman" go through this counter-equalization ritual for the better part of the first set. Meanwhile, he was missing every show cue to bump up solos and keep the lead vocal from being buried in the mix. It took every ounce of restraint to not reach in for the faders to hit the cues, while the soundman was busy trimming the EQ strips. It was much like a father teaching his teenager to drive and hitting the phantom brake pedal on the passenger side of the car.
The cure for the counter-equalization habit is to recognize it and focus on the one or couple input sources that need equalization. Don't commit to a global equalization change unless it is well thought through. Channel strip equalization can be done quickly just tossing on the headphones and PFL-ing the channel of interest. But do not spend significant time on this and lose track of the performance.
Polarity Sanity
On low frequency sources like kick drum and bass guitar, take a quick moment to run through both options on channel strip polarity and stick with the loudest result. Many sound persons fail to at least do the checks and just rely on the previous operator's opinion on polarity. Especially with different bass amp direct outs or DI boxes, bass instrument polarity can change from act to act. Do not accidentally fight the phase onstage; work with it.
Subgroup Assigns
Much like the channel assigns, run through the subgroups and note both the assignment to the masters and to which master mixes they have been assigned. Some previous operators will hard-pan pairs of subgroups, and your technique of mono-panned multi-subgroup categories will sound awkward if pushed to one side of the stacks. So do not forget those sub-group pan controls in the zeroing checklist. It is much easier to start mono on every subgroup before forming stereo positioned subgroups.
Inserts are Not Inputs
This has been my own mea culpa of late in that effects returns and break music playback have been accidentally routed into TRS insert jacks instead of the TRS line inputs on the channel inputs. There is nothing worse than getting the "Where is the signal?" or "Where is that 'verb?" when firing up the system before the show. Or worse yet, having no effects in a time-constrained changeover, and diving into the doghouse to check the patching when no signal shows up on the effects returns.
Zero Thy Comps and Thy Gates
In the time crunch that always happens getting a guest console ready for your act, the insert compressors and gates are likely to get ignored until the show is underway. Suddenly the previous act's "squash the lead vocal like hell" settings become apparent in the mix. The blunder here is that you did not take the precious seconds to reset the comps and gates, or at least bypass them until you have
the spare moment to set them up to match your signal gain structure. If you have to pull inserts on the fly, strongly
consider dropping channel gain before pulling or bypassing the insert. Nothing says "dumbs@#$" worse than a sudden increase in vocal loudness when pulling an insert.
Final Notes
Always zero up the console if you have the time to do so. I make it a habit to arrive early to get the consoles taped, channel-assigned and zeroed, if I am the first act of the night. Even minor things like flattening up EQ strips before the show can pay big dividends later on when a head-scratching feedback tone arises. Blunders are going to happen, but you can minimize them by thinking ahead. Even if you are a follow-on act, spending some precious time checking out the previous sound person's settings will give you the foresight in the triage of setting changes at changeover.
