When Things Go Wrong: Correcting For Flaws in Your PA

When Things Go Wrong: Correcting For Flaws in Your PA

How do you respond, though, when the trusted advice of an expert causes more trouble than it solves? Or when some small changes have unexpected consequences?

Designing a sound system for your room is an involved process. It takes planning, research, and finances. It takes a knowledge of technology, acoustics, and construction. It also helps to reach out to colleagues or hire an expert.

We did everything we could to do it right, but chaos interrupted anyways.

How do you respond, though, when the trusted advice of an expert causes more trouble than it solves? Or when some small changes have unexpected consequences? How does your mix change when things go wrong?

I thought we were doing it right.

We had a fantastic audio partner. We selected a nationally acclaimed integrator. We read the right books and made the right phone calls.

There was one stubborn detail, though, that just refused to go away.

Our building is a solid steel frame, and instead of sturdy joists spanning the massive beams, there are purlins, or wooden horizontal beams. On the first day of construction, my friend who was working as our project foreman asked me, "How are they rigging the sound system on the ceiling? They won't be able to hang any weight on those purlins." So I called our installation team and asked them myself. We sent over the structural drawings and had the lead designer come out. As she stood under the ceiling deck, the foreman and I asked about the rigging and we were reassured there was a plan.

Of course, soon after came the day when the riggers arrived with the equipment. They took their scissor lift up to the rafters, came right back down, and simply said, "We can't rig this design. We won't be able to hang this weight on these purlins." The foreman and I both looked at each other and said nothing.

It was two weeks to our grand opening.

We had to open the new church building, so we got back to work.

What else could we do?

The plan drawn up over those next few days was not as elegant as the original plan. And the result, unfortunately, left us with certain deficiencies; dead spots, hot spots, and the wrong type of speakers for the actual hanging points available.

Find the Problems

To discover how the improvised design performed, each engineer listened to their favorite albums through the PA as we sat in different seats in the room. We all choose music we listened too since high school. We heard this music though every stereo system, pair of headphones, and car speakers for years. We know how these songs are supposed to sound intimately and can tell when something isn't right. (If you're more of an expert than a volunteer, you might employ white noise or pink noise instead.)

During rehearsal, we did a similar thing with the band performing. We moved around and learned what each section sounded like. Then we'd adjust the vocals and go back through the hall making notes on the differences.

And as we found things we didn't like, we made changes along the way. We learned most of the room had a muddy quality, due to a combination of acoustics and speaker placement that wasn't obvious at the mixer. Then we tuned the system around the audience experience and worked around the issue.

Learn Your Options

But more than how to work around it, what we needed were real long-term solutions. Ultimately for us, that included altering our speakers again. Before I spell out what was done, here's a few concepts that might help you:

Line Arrays: In a nutshell, this style of main speaker aligns several of the same type of speaker in a column. They can be flown, but as they can be quite heavy, they can also be ground stacked. They also have great potential to provide the audience an even frequency response. When arrayed vertically, they provide great coverage for deep auditoriums.

Point Source Speakers: This other popular style of system mains works better for venues that are significantly wider than deep. While they are smaller and less powerful than a line array, that helps create more options for placement.

You can also combine point source speakers with line arrays to compensate for sections of the audience outside of the array. For example:

Delays: This point source speaker application delivers sound to distant or obstructed parts of the hall too far out of the range of your mains. As the name implies, processing is added to delay the audio signal by milliseconds. If a sound system is not delayed, the result might sound like speakers at an old bus station: The echoes of each speaker all reach you at different times, resulting in a muddy smear of echoes. In addition to helping the back of the hall hear more direct sound, properly delayed speakers also clean up and organize a lot of messy ambient noise.

Front fill: Depending on how your system is designed, there is usually a gap between the row of seats the main speakers can be heard and the edge of the stage. Fill speakers, generally low profile in design, sit at the edge of the stage and aim directly at the people in the pit or first rows. These output less power than the mains since they only support the main sound for the first several feet, instead of throwing to the back of the auditorium.

Equip Your Solutions

With that background in place, let's pick up our story.

The original design was to hang a horizontal array in the center of the room, but when we lost the ability to hang it safely, we changed the design to point source. This let us spread the speakers out to safe points while still addressing all 150 feet of our wide room. We also had to adjust the angles of the speakers a few times to achieve adequate coverage.

In addition, some additional truss work was added in the middle of our room, along with delays that were incorporated to reach the farthest sections from the mains. This really cleaned up the back of the room, and it was for a long time my personal favorite part of the room to sit.

We also had a significant gap of 10 to 15 feet between the edge of our stage and the first few rows of seats. As a Pentecostal church, altar calls are part of who we are. As a result, the area where no one was supposed to sit became one of the biggest needs. To fix this, we installed fill speakers to the sides of the stage. We may still add more.

Trust Your Calling

We did everything we could to do it right, but chaos interrupted anyways. Though we like to declare war on the way we do things, we also face ambushes that are beyond our control.

Be sure of your calling. If you work unto the Lord, the time is worthwhile, even if the PA is not. But so is the call to finish what you started. Listen to your PA and identify what needs to be fixed.

Research the different tech options, maybe hire another (better) expert. Do what you can to make the best of it while waiting for your answer. Then pursue the solution with all your passion. Even this can be worship.

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