BB: How do we correct that, and ensure that audio systems are doing what they claim to do?
JM: Good testing procedures are a place to start. For example, back in the late 40s or early 50s, Altec Lansing was having problems with other companies selling amplifiers to movie theaters claiming low distortion, but they discovered that wasn’t true. The amplifiers were claiming 100 watts but in reality they were producing 10 or 20 watts of useful power. That reflected poorly on Altec, because people would blame the Altec speakers.
Well, Altec came up with a two-tone analyzer for amplifiers, which was then licensed to test equipment makers so they could measure these amplifiers on the test bench. That way they had to prove that what they were offering was equivalent to Altec’s own amps. And that revolutionized the game. Now an amplifier had to deliver 100 watts with one percent distortion.
We need to expand on this approach, so that we have more results-oriented measurements of the systems in use, and specific standards that truly reflect the acoustic performance.
BB: Do we need new tools for that, or just a willingness to use those we have?
JM: It’s a combination of both. To a great extent, it’s developing new methods and procedures for using tools we already have, and teaching more people to optimize these tools. For example, there are useful algorithms for coherence and signal-to-noise that work dynamically. And there’s a recent proposal for measuring multi-band articulation. A number of new tools have been developed in acoustical research labs that haven’t been pushed to the PA world, and we’re now working on that.
BB: What’s the answer in live sound? Is this what you referred to earlier as “results-oriented procedures?”
JM: When technicians install a new projector, the first thing they do is put up a resolution chart to make sure everything is working properly and in focus. We need to apply the best practices in articulation tests, along with other measurements for the coherence and intelligibility of systems. For example, you can measure the effect of compressed signals, and how they limit the dynamic range. These are measurable quantities, but too often they aren’t applied outside the lab.
All relevant measurable quantities need to be factored into the system. We need to make sure that consultants have tools that they can use across the board, so they can be sure what they specify will work in the end. And consultants will welcome this if they know it’s going to be applied uniformly across the industry.
BB: What are Meyer Sound’s immediate plans to address the situation?
JM: We’re already starting to develop a systemic, result-oriented approach across the board to guarantee the results of an installation. And we’re working closely with our education team so that more professionals get more accustomed to looking at sound holistically.
In addition, we need to develop and refine tools that deal with audio resolution so we can optimize what we might call the sonic image. But a lot of things affect that, including room reverberation, the system itself, and the bit rate of the input signal. So we want to come up with a complete set of measurements that systems can be tested against.
Cinema sound is well ahead in this regard. Just a few years ago, we developed a special complex tone generator in partnership with NTi [test instrument company] for making sure cinema systems are working properly. Now we want to bring that philosophy into the PA world.
The challenge is how to test in a fluid, fast-paced environment. Cinema is a one-time installation so you have time to set it up. But a touring PA system is constantly moving. So the process is completely different, and speed is of greater importance. The tools need to be refined for PA, because it’s not just intelligibility but other parameters that translate into musical characteristics.
BB: How do you expect this new approach will benefit the industry?
JM: It gives consultants and integrators an objective way to evaluate and show the results of their hard work, and allows end users to better understand the performance of their system. It adds to the accountability and ultimately delivers a better listening experience to the audience.
We have to remember that it is not about theory. If you want a venue to be successful, a lot of things have to be done right, every time.
BB: Is the audience really interested in high-resolution sound reinforcement? Will listeners hear and appreciate the difference?
JM: It’s true that high-quality music is not as accessible as it used to be. We have a generation of listeners who have grown up listening to compressed music through ear buds connected to a phone. All they know is crunched, low-bit-rate audio. It’s like a whole generation has been eating nothing but fast food, and doesn’t even know what a freshly cooked meal tastes like.
Fortunately, we’re seeing signs of change and a hunger for good sound, such as the vinyl resurgence and the rise of high-resolution FLAC files.
We need to keep encouraging that. We need to acclimate the listeners, arouse their curiosity, and help them appreciate the benefits of listening to music in its full dynamic range.
Bruce Borgerson has been a freelance journalist and audio industry communications consultant since the 1980s.He has written numerous feature articles for Mix, Pro Sound News, Sound & Video Contractor and Church Production as well as for ProSoundWeb.