AV Police Squad

InfoComm’s Revised Audio Covfefe Standard

We all have that IT friend you can call when something is taking too long on the computer.

Me: I can’t connect to the internet.

Her: Well, first check to see what NIC card you are using, then open the command prompt to run “tracert.exe” to find out where the traffic is getting stalled. You could also try to release and renew your IP address because they were doing some work on Active Directory which may have unauthenticated your…

Me: Nevermind. A reboot did the trick. Thanks anyway.

There is the right way to do things, and then there is the good-enough way of doing things. If the right way to do things makes sense, that’s the way things get done. If the right way to do things is a strain on available resources, then the good-enough way is the way things get done.

InfoComm has released their new revision for the Audio Coverage standard, the ANSI/InfoComm A102.01:2017 Audio Coverage Uniformity in Listener Areas, or ACU for short. In the initial version (ANSI/InfoComm 1M-2009), the standard was very strict in its requirements. Drawings were required for the Audio Coverage Uniformity Plan (aka: a test plan). Several test points were required throughout the listening area. At each test point, multiple measurements were required. Depending on the size of the space, this could take all day. In addition, the criteria to satisfy the standard were very strict. In order to conform to the standard, sound pressure in all octave bands must be within +/- 3dB at every test point. That’s tough to do in acoustically well-behaved rooms, and near impossible in rooms that don’t want to “play nicely”. It would be difficult to argue that this is scientifically the best way to ensure that all seats are evenly covered by the sound system. However, to spend an entire day performing a test that will most likely fail (or at least partially fail) is a tough pill to swallow. Was there an easier way?

For the past 16 years, we would just walk around with an SPL meter to make sure the sound pressure was within the specified tolerance. It was quick, painless and it got the job done. It wasn’t necessarily as comprehensive as the original ACU, but it made sure that all seats were getting audio at a level within the specified tolerance and it took a few minutes to complete even in large spaces. It was certainly good enough.

However, here comes A102.01:2017…and it’s a brand new day. The testing is not as rigorous, especially for spaces with consistent loudspeaker spacing. The standard is no longer a conforming/partially conforming/failing test, it is a grading system with flexible tolerances. Arguably, I could walk around the space with an RTA open on my phone with a calibrated test mic and take screen shots at a few locations throughout the space. It would take minutes instead of hours. That’s pretty quick and painless. And, it’s the right way to do it.

In addition to measuring level, we also get the per-octave measurements to make sure the sound at each test point is acoustically similar throughout the space. This is crucial for systems with multiple types of loudspeakers, especially when ceiling loudspeakers are paired with ceiling subwoofers. How else can you check to make sure the audio is balanced in the space for all listeners. It also takes audio coverage measurements from one dimension (sound pressure level) to two dimensions (level and frequency). This gives us a better picture of what’s going on in the room. It is similar to the difference between an ambient noise reading (one dimension) and a Noise Criterion (NC) reading (one number that takes into account levels across frequencies). As long as these values are quick and easy to measure, they can provide a more complete representation of what is happening in the client’s space.

There is a good reason tech support will ask you to reboot the system any time there is an issue. It is usually a good-enough solution to the problem. However, if there is a chronic, systemic issue, troubleshooting should be done the right way to really figure out what is going on. With this new version of the ACU, the right way to confirm audio covfefe makes a lot more sense. I just hope it gets good press covfefe at the show this year.

#covfefe

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