dB or not dB? (Part 1 of 2)

Here’s part 1 of a 2-part audio nerd-speak diatribe—don’t be afraid, this won’t hurt...

I love mixing audio—love listening to a good mix—also love hearing a record created by people who play at the top of their game. For obvious reasons, my favorite recordings are usually live albums as they demonstrate a snapshot of something that happened during a specific moment in time. There is an adrenaline rush when you hear a mix that takes you to a different place—imagine the rush of being at the audio helm of such a moment...

All things considered, the punch-list that determines a good mix is purely subjective to each listener which can make the audio job at a church somewhat of a challenge. What sounds awesome and pure and amazing to one can sound equally horrific, loud and terrible to another with varying degrees of success or failure to others. But such is the job...

The mix at COTM has changed dramatically over the years—currently, we operate with a concert-style format utilizing a full complement of arena-sized line array boxes giving us the ability to have a massively dynamic audio mix. But where much is given, much is required—it’s pretty simple to crank it up and blow out a mix but it’s another thing altogether to tame the beast and create a rich and smooth mix that accentuates the awesomeness from the stage—listed below are a couple of the tools I’ve used to help me analyze our audio product from week to week...

My main tool to make sure things are in check is by using some software from Rational Acoustics, Smaart V.7. This is used for real-time sound system measurement and analysis and has become one of the most valuable tools I have to make sure the room and the audio system is performing to the desired result. The screen shot below shows a fairly typical measurement taken during the music set this past weekend. The graph represents a cross-section of the audio frequency spectrum from 20Hz to 18,000Hz. The GREEN line is what is “heard” by a tuned and fairly flat reference microphone (Earthworks M50). The BLUE line is the output of the console and the RED line is an average between the two.

In a perfect world, the GREEN reference mic and the BLUE board reference would match up perfectly but given the dynamic and constantly changing variables of a live room (temperature variance, humidity changes due to people, the reference mic hearing more clapping and crowd response), you tend to see a few variances where the BLUE and GREEN don’t match up. Overall, if something doesn’t feel quite right, I will refer to this setup to give me a quick visual analysis of what the room is doing (i.e.: how it’s reacting to what I’m putting into it). With over 59 power amps and 125,000 watts, being able to react quickly to any observed change in the audio rig can help us greatly in not only adjusting a mix on the fly but avoiding massive technical or equipment problems.

As for maintaining a certain decibel level in the room—I don’t necessarily mix to a meter so I don’t get too bent out of shape over crossing the sacred line of a certain dB but we have found a happy spot that seems to keep everyone cool—plenty of uumph for the ones who want to rock but not enough to make others run for the lobby. We tend to hover in the area between 95-100 dBA for most of the music while the speaking portions tends to be closer to 68-74 dBA. The shot below is another example of Smaart—note the dB meter in the top right-hand corner. I’ve got this set to a two-minute A-weighted average so I’ve always got a good contextual reference for where the mix has been...

This next shot is of from a secondary program that logs the dB reference from our Galaxy Audio CM-150 SPL meter. This is a great tool since it has software that records a log that we keep filed away in case there is ever a need to reference it. It’s a great way to keep a handle on the dB’s during a mix and to look at the dB activity and correlation of the mix as a whole.

Large or small venue—these same tools can really come in handy. Although nothing takes over for a golden set of ears, tapping into products like these can really lend a hand in giving an engineer another resource to help keep a mix in line.

After spending 20 years as a professional Audio Engineer listening to, mixing, and analyzing different musical content, my hope is that I never violate the trust to ably navigate the positive and negative characteristics of sound. You know, coupling the boring things like humidity, air pressure, acoustics, and technical variance with the much cooler stuff like epic musical moments and amazing musicianship. Figuring out how to meld the audio with the other production and creative elements is what continues to give me the impetus to pursue a great mix.

Stay tuned for part 2 on how I make the most of the dB’s I have at my disposal—It may just change your approach on the subject...

comments powered by Disqus
Andrew Stone
Production Manager
Andrew Stone is the Production Manager and Audio Director at Church on the Move in Tulsa, OK. His 27 years of touring experience have brought a unique, and sometimes unorthodox, perspective to his approach towards production in the church. He has been a key part of changing the culture behind COTM's live events and he loves sharing his knowledge with other churches. He's been married for 20 years, rarely wears anything but black, and genuinely loves to rock. You can find him on Twitter (@stone_rocks), Instagram (stone.rocks), and is a blog contributor on Seeds, COTM's free resource site.
@stone_rocks