Does Your PA Need a Tune-Up?

by | Audio, Audio Connections, Production

Not long ago, I had a conversation with a young church Tech Director. He said their auditorium had some audio issues, mostly dead spots in the coverage, so they scheduled a contractor to re-tune the PA and remedy the issue. This brief discussion reminded me that there are still widespread misconceptions of what “PA tuning” is and what it is not

When I worked in AV integration it wasn’t uncommon to get a call from a client 6 or 8 months after completion asking us to re-tune the PA, because, “it just doesn’t sound as good as it did when you were here”. Almost without fail, it would turn out to be a people problem, rather than an equipment problem. The solution typically involved undoing well-intentioned, but poorly executed mixing techniques. And the PA tuning itself was fine. 

In the “If I had a dollar for every time… category, a recurring one is; the newly hired church tech director is certain the PA that has sounded great for the last 5 years, must now be re-tuned.  

What is PA tuning? 

In its simplest form, modern PA tuning is programmed into a Digital Signal Processor (DSP). Some systems have amplification built into the speakers or arrays. Others consist of a rack(s) of amplification that supply the speakers/arrays. Whether the DSP is a standalone unit or integrated in the network of amplification, it is the brain of the audio system between your mixing console and the speaker system. The DSP, consisting of multiple inputs and outputs, assigns and distributes the signal between subs and the main system. It controls the equalization or voicing for each amp/speaker. It also controls stereo and mono imaging and time alignment of the overall system. Modern DSPs are very sophisticated and can be quite complex. When a large system is installed in a church the systems engineer will program or tune the DSP, using reference microphones and software. In most cases the system designer or engineer has also used software to predict how the various speakers will function in the space, and tuning the DSP is the final step in turning the design into reality. 

A good AV company will train staff and volunteers on the audio mixing console, with little to no restrictions for the console user. But the DSP is typically password protected and only accessible via network connection with a computer. This is intentional. When a PA system is tuned properly, there should be no reason to access the DSP on a day-to-day basis. I try to avoid terms like “leave it to the professionals” but in this case, DSP access should be limited to someone with a thorough knowledge of your system, that can be trusted.

What PA tuning can’t do.

Early in my career, I was working with a church and coordinating with the AV integration company. When I brought up the topic of acoustic treatment, the AV rep said, “We’re not concerned about acoustics, it’s amazing what can be done electronically these days”. If you’ve read much of my content, you know that I could probably fill a coffee table book with the dumb stuff I’ve heard AV salespeople say over the years. A poorly-designed room, and rooms without acoustic treatment cannot be fixed with PA tuning. 

The young church TD I mentioned above, found out that re-tuning the PA cannot improve coverage. In fairness, if re-tuning a PA system adds some previously  missing clarity, there may be a perception of improvement. But actual dead spots in an auditorium, where the audio is noticeably different than other sections, cannot be remedied electronically. It requires physically re-positioning or adding more speakers.

PA tuning cannot fool-proof your mix. You can have a perfectly tuned PA and still experience substandard audio if your engineer is having a bad day. As a general rule I am skeptical of an audio engineer who immediately blames the PA tuning for a less than desirable mix. I’m far more likely to be open to the discussion with someone who has mixed in the environment multiple times and can pinpoint audible issues. 

When I am asked to mix as a guest engineer, I’m usually invited to help re-establish a base level mixing standard and train a team of audio people. That time must be dedicated to the team, not to stake a claim as some kind of master audio guru. In fact, unless I find something glaringly wrong that is obviously the result of a tuning issue, I simply focus on what I can do to help the team. 

I have commissioned many new systems which necessitate a level of tuning knowledge. In that capacity, I work alongside engineers whom I have a history with and trust, but I am not a systems engineer and I don’t tune PA systems. I know many mixing engineers who, like me, prefer to stay in their lane when it comes to PA tuning. 

How often should I get a tune-up?

This is another misconception.

Not every time you hire a new Tech Director! If your DSP crashes or gets damaged from an external event, of course you may need to replace it, reload a file or re-tune. In my career I’ve learned it’s much more common that a DSP gets struck by meddling hands than by lightning. 

If you install acoustic panels for the first time, then you should have your system re-tuned. If you install a new mixing console, it might be worth opening your DSP to make sure the output levels from the new desk are configured properly. Similarly, when replacing any blown or damaged speakers, it’s worth checking under the DSP hood. 

Otherwise, if your system sounds right, and you trust the team that tuned it, there should be no reason to re-tune the PA regularly. 

Is it Art or Science?

As you may have guessed, it is both. I have seen the best and the worst examples of leaning too far in either extreme. 

I worked with a church once that had a new system installed consisting of great equipment by a well-respected AV integration firm. As is typical, I had multiple conversations with the church over a period of weeks before I arrived onsite. They expressed concern over the PA tuning. They were surprised that such great equipment, designed, installed, and tuned by a well-known, highly-regarded company, could sound so bad. Being the skeptic I am, I expected to find issues on their mixing console, fix them, and not have to worry about the tuning. But they were right. It sounded really bad. They wanted my unbiased opinion, and were very happy to know they weren’t crazy after all. We brought in an independent systems engineer and we worked together to re-tune the system. And it’s been great ever since.

When it comes to tuning a newly installed PA system, I think the process gets rushed sometimes. On our most successful projects, we perform the PA tuning while there is still a crew on site available to adjust speaker positioning if needed. The “tuning window” should remain open when the worship band does their first rehearsal(s). It’s important to get a real-world sense of how the system will perform. 

A system can technically be tuned to all the correct specifications, which checks the science box. But my favorite systems-engineers are able to tune musically as well, which checks the art box. 

I have found that in addition to the use of some reliable diagnostic tools, a trustworthy guest engineer, scheduled to observe and mix a few services, can help you determine when and if your system needs a tune-up. There are some great ones out there who don’t forget to listen

As always, I hope this content has been helpful and I look forward to hearing from you. You can contact me at rchochran@worshipfacility.com. And don’t forget to listen!

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