I love doing “advanced application” stuff where people don’t expect it. It’s not that I’m into complexity for complexity’s sake, but I do like to exceed expectations when possible. So, when The Floyd Show wanted to take things to the next level by having quadrophonic sound available, I was pretty thrilled.

I was so thrilled that, the second time we did a show that way, I went a little too crazy. I put a bunch of channels through reverb and delay, and pushed all that through the rear speakers. Loud. I wanted to hear it!

About a third of the way through the show, one of the club’s security humans came up to me.

“Dude, you’ve REALLY got to turn those down.”

Oops.

What went wrong? Was I tearing people’s heads off?

No, as I found out later. What was happening was that some people were getting an overpowering “FX to dry” ratio – and it was all because they were really close to the rear loudspeakers.

The Correct Solution Over Here Is Wrong Over There

In small-venue sound, there’s a bit of truth that’s hugely relevant…and yet rarely discussed:

A mix “solution” that is the result of both acoustical sources and PA reinforcement is spatially dependent. A listener at a different point in space is not necessarily receiving a solution of the same validity as people at other points in space.

In other words, what sounds perfect in one spot may not sound all that perfect when you’re on the other side of the room, especially if a listener gets (proportionally) very close to part of the PA.

Why?

SPL (Sound Pressure Level) increases as distance to a source decreases. Not everybody knows the math involved for modeling this reality with physics, but I’m pretty sure that almost everybody has an intuitive grasp of the idea. (The math actually isn’t that hard, by the way.) The reason this matters so much for small-venue audio humans is as follows:

If the sound reinforcement system is only responsible for a portion of a mix “solution,” a listener that is in close proximity to the system is likely to be experiencing a mix which is overbalanced in favor of the PA.

(Yes, this is essentially a restatement of the first point.)

A Common Example

To look at this in familiar terms, let’s consider a PA system that’s only reproducing vocals. The PA is located just in front of the band, with about twenty feet between the stacks. Everything else in the room is coming from the band’s instruments on stage. An audio human, situated 30 feet from the stage, in the center of the audience area, creates a mix solution that they like. This mix solution is, of course, a blend of the PA plus everything else. The validity of the solution depends on the blend’s proportionality remaining the same.

For many points in the room, the proportionality does indeed remain relatively stable. It remains stable because the DIFFERENCE in distance from the listener to either the PA or the band doesn’t change too wildly. In fact, as listeners get farther away, the proportion between the distance to the PA versus the distance to the band is reduced – that is, the proportion gets closer and closer to being 1:1. If you’re somewhere behind the sound operator, your chances of getting basically the same mix solution are pretty good – even if you’re off to one side.

(Of course, that mix solution may be highly colored by room reflections – that is, reverb – but the fact remains that what you’re hearing is the “correct” solution plus reverb. Then again, to be fair, very strong and/ or unpleasant reverberation can result in a total acoustical sound that’s utterly terrible…)

Anyway.

Where problems start to happen is in the area in front of the FOH (Front Of House) engineer. The closer that a listener gets to the front of the room, the more the proportionality between the sound sources diverges from 1:1. In this particular example, a person standing dead center, four feet from the stage is almost three times closer to the stage than they are to the PA. It’s quite likely that, for that listener, the stagewash is overpowering the vocals-only PA to some degree. (The issue is probably compounded by the listener being out of the throw patterns of the PA speakers, although that’s beyond the scope of this article.) On the other hand, a person that’s down front and off to one side could be getting four times as much PA as stagewash, if not more. For them, the vocals might be a bit too “hot.”

Some Things Can Be Fixed. Other Things…

The bottom line here is that if the PA (or even just some part of the PA) isn’t the whole mix, then you have to be mindful of where and how your mix solution can change. In my case, what I failed to consider was that the people in the back of the room were getting an overdose of FX from the surrounds. I pulled the rear speakers down, and everybody was a lot happier. The folks in front probably weren’t getting much from the rear boxes anyway, so it wasn’t a big loss to them.

You can’t fix everything, though.

In small venues, people can listen from all kinds of places, and you probably won’t have the gear available to cover all of those places. Big shows can fix their problem areas with fills and delay stacks of all kinds, but little shows just have to “shoot for the average.” In my personal opinion, if 75% or more of the audience seems to be getting basically the same mix, then you’ve done your duty. Of course, trying for 100% is usually praiseworthy, but completely overcoming the problem of inconsistent distance in a small venue is expensive, time consuming, and chews up a lot of space. In fact, 100% coverage might not even be what you want – in small rooms, it can be very nice for people to be able to “get away” from the full-blast of the show.

(You also have to consider other psychology that’s involved. For some folks, an “off” mix is a tiny price to pay for being able to be nose to nose with their favorite band. A happy audience is a happy audience, any way you slice it.)