Get Out There with Your Audio Analyzers and Measure What your Systems are Doing

March 6, 2014

Anthony Grimani (agrimani@pmiltd.com) is president of Performance Media Industries, with offices in San Francisco, Los Angeles, and Paris, France.
You’re probably familiar with the Denver Broncos’ story this year: future Hall of Fame QB, record-setting offense, expected to win the Super Bowl by most pundits. They made it to the big game as expected…and were promptly crushed by the Seattle Seahawks and their really loud fans. Imagine all of the hard work and expertise that went into the Broncos season, only to end in disappointment.

This sad story struck me as the perfect illustration of something that’s happening in our business. I’ve been involved in several recent projects–including trade show demos and residential installs–where the final audio calibration and tuning step was left to an automatic system. Each time, the system failed to deliver. All of those months of design and weeks of painstaking installation crashed and burned in minutes as the automatic system trashed the sound performance of great equipment and engineering. Like the Broncos, these projects got to the title game, but failed to deliver when it mattered most.

The people that created automatic systems Trinnov, Dirac Live, RoomPerfect, and MultEQ are all very smart and know a ton about physics, acoustics, and DSP. They’re also great guys. Unfortunately, their products simply don’t work well enough on large custom projects. They sometimes get little things wrong like when speaker distances are off by a few inches, or when speaker levels are up or down a dB or two. Sometimes they get a lot wrong, like when high frequencies are shelved down as much as 15dB, or when creating crossover frequencies that lead to overload and poor bass performance.

I recommend that you close the loop. Get out there with your analyzers and measure what your systems are doing; listen to circulating pink noise from something like the 5.1 Audio Toolkit and compare that to reference in-ear Etymotic transducers. I know you know what this stuff is supposed to sound like, so take matters into your own hands. Auto calibration may be OK for a $500 HTiB, but not custom high-end.

Rooms must be calibrated, and you must see that it’s done right. It’s not that hard to do right.
Rooms must be calibrated, and you must see that it’s done right. It’s not that hard to do right. You need about $500-$1,000 of equipment. Some test mics from Behringer or Audix, a USB mic preamp and multiplexer, and Room EQ Wizard from Home Theater Shack will get you started. A little education is required as well, but we’re not even talking two-year college-level stuff here. It gets heady if you want to go deep and be the best of the best, but that’s not necessary. A little knowledge with the right tools goes a long way. It will certainly produce better results than automatic systems. If you really don’t want the responsibility yourself, hire a third-party calibrator. There are a lot of guys around who are already great at it and will be an asset to your business.

Budget about $1,000-$2,000 for a good calibration. It will accomplish everything an automatic system can, plus detect issues with the installation that even the best automatic systems can’t. It takes a little more time than running an automated setup routine, but it’s worthwhile when you put it in perspective. In one of the aforementioned projects, I corrected what the automatic system messed up and manually tuned everything in less than two hours. It was a far cry better than what the automatic system did in 30 minutes. At the end of a months-long project, are you going to quibble over one-and-a-half hours?

Don’t get swayed by all the hype surrounding automatic audio calibration systems. Good tuning of a room is still about the human element. Get your analyzer and grab a copy of the 5.1 Audio Toolkit, along with some Etymotic ER4S headphones. Spend a few hours analyzing, correcting, listening, and comparing.

Take pride in your work. Check your work. Show it some love! Don’t be like the Broncos and take a safety on the first play, throw a pick six, and one hop the second half kickoff to Percy Harvin and let him score. Finish the season. Win the game.

Chase Walton contributed to this column.

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