Audio: Analysis Tools, Part II

In our last issue, I began an examination of how useful audio products for the live-event market are developed and evolve.

The focus of that column was the compact handheld analyzer called Audio Toolbox, developed by TerraSonde of Boulder, Colo. With its dedicated hardware approach, Audio Toolbox has gained a solid following in the industry, and it appears that other manufacturers will soon be offering their own dedicated hardware for audio analysis.

However, one company has chosen a purely software-based approach to the development of audio analyzer tools — SIA Software of Whitinsville, Mass. Founded in 1995, SIA has developed software for sound system measurement, acoustic analysis, and realtime control.

While the “bring your own hardware” approach requires initial hand-holding to navigate users through computer issues, the cost-effectiveness and flexibility of hardware independence, coupled with the increase in laptop processing power since the '90s, have more than compensated for support issues SIA has faced. In fact, SIA's flagship product, SmaartLive 5, has become one of the most popular tools for professional audio analysis.

For this column, I spoke with Jamie Anderson, SIA product/market manager, and live-sound engineer Robert Scovill. Scovill is a longtime SmaartLive 5 user who has seen the evolution of the product from its humble beginnings to an industry standard. In particular, I wanted to get a flavor for the trends in audio analysis software development.

Audio analyzers

First, a little background on audio analyzer technology and SmaartLive.

“Actually, our industry didn't come up with using FFT (Fast Fourier Transforms), which is essentially a way of taking time-domain data and transforming it into frequency-domain data,” explains Anderson. “This came out of research from the military-industrial complex for hunting submarines. By the early 1980s, the first commercial FFT-based analyzers began to appear.

“The primary companies providing these were Hewlett-Packard and Brüel & Kjaer. These were capable of running only very tiny FFTs in comparison to what we use today, and they cost a ton of money.”

In the mid-'80s, industry engineers started experimenting with dual-channel measurement techniques using FFT analyzers to measure the responses of loudspeakers and sound systems. These engineers included John Meyer, Don Pearson, Ken DeLoria, and future SIA co-founder Alexander Yuill-Thornton II.

They all used off-the-shelf HP and B&K analyzers that looked at frequency information on a linear scale. Because processors were power-challenged, people ended up having to run multiple measurements just to get one useful full audio bandwidth measurement.

In 1991, John Meyer introduced his answer to this measurement resolution problem with his SIM System II, which incorporated multiple FFT-analyzers working in parallel. This purpose-built analyzer revolutionized dual-channel FFT use in audio system engineering.

By the mid-1990s, digital signal processor chips (DSPs) began appearing on high-end computer sound cards. It was at about this time that Sam Berkow and Alexander Yuill-Thornton II decided to try building their own dual-port, FFT-based analysis system using off-the-shelf computer hardware as its DSP engine.

Their first step was to mockup DSP functions to run on the host computer's CPU to test the code that would run on the outboard DSP. Upon doing this, however, they discovered that fast 486s and early Pentium PCs had sufficient power to run FFTs in realtime without a DSP co-processor, which would increase the flexibility of the system.

Robert Scovill remembers one of his first meetings with Berkow during this period. “At a gig once in Chicago, Sam came down to see me and I didn't know him from Adam at the time,” says Scovill. “We were doing Tom Petty and Heartbreakers at the United Center in Chicago. He walked up and said, ‘Hey, can I borrow your P.A. for a few minutes?’ It was so off-the-wall that I said, ‘Sure, why not?’ He set up a very early version — probably a Beta version. I saw it and thought, ‘They're going to have this on a laptop soon and it's going to be good.’”

A prototype of the Smaart software was introduced at AES in 1995. The next year, SIA negotiated a license agreement with JBL to be its only distributor of Smaart. In 1998, as SIA's agreement with JBL was about to expire, SIA was sold to Eastern Acoustic Works. As a subsidiary of EAW, SIA continued to produce Smaart upgrades and new versions. In 2000, the version 4 release was dubbed SmaartLive, and production has continued, with SmaartLive 5 now available and SmaartLive 6 due out later this year.

Pros and cons

Having all the power of a modern PC at their disposal has given SIA users unparalleled flexibility, and it has put a friendly face on the underlying power of SmaartLive's dual-port transfer function measurement capability.

SmaartLive's intuitive interface makes it easy to use. As a result, SIA's diverse user base includes everyone from sound engineers and high-end sound contractors to home theater installers and musicians.

The shift in working habits for live-sound engineers has been significant. Tools such as SmaartLive combine the listening and looking mechanism to isolate, for example, where an EQ filter wants to go quickly and precisely.

However, Scovill explains, “Remember that the thing can give you bad info, as well. You have to know and expect a result — no different than any test instrument. It's just a way of confirming what you may or may not believe. The software won't solve anything. You're in charge of solving it.”

Knowing the pitfalls of being at the mercy of computer operating system issues, Anderson says he's a big fan of dedicated hardware. In fact, he says later this year SIA plans to release a stripped-down version of SmaartLive (yet to be named) based on a dedicated input device. It will feature SPL monitoring, an RTA, a spectrograph, device control, and the ability to perform delay and reverberation time measurements. It will be a single-channel system, with no transfer functions or impulse response measurement capabilities, Anderson says.

He also notes another development. “We are also starting to let other people's hardware import our data,” he says. “Our interfacing with third-party devices has been very successful, such as being able to share the EQ traces and overlay measurement. We're starting to see systems become more sophisticated where, if you look not too far into the future, you'll see every element having its own amplifier and DSP.

“With that, we'll have given ourselves the power to make our systems do incredible things, or to be so complicated they are virtually unusable. Coherent control will be the name of the game — integrating system control and measurement into one user-friendly environment, empowering not entangling the engineer.”

Emerging trends

With such powerful tools now available to help to precisely tune a space and isolate anomalies, new expectations are on the horizon. Scovill notes one development that should keep live-sound engineers on their toes for a long time.

“We have that concept of linear transfer in the world of the recording studios where the speaker system reacts very much like the audio coming off the desk,” he explains. “In the coming months, that is going to become so apparently necessary in the live-sound world, it's not even funny, because … the concept of being able to do mobile mastering and disc releases at a live concert is in play. What that means is that the front-of-house mix better be together, since it's going to be added with ambience and released to the public at the end of the show.

“If your sound system is way out of whack in terms of linear transfer — for example, the sound system is weighted heavily in the bottom end — the mix you present for CD duplication is going to be very light of bottom end. Try to get that without some sort of FFT analysis tool. Forget about it.”

As for SmaartLive 6, due out this year, Anderson says the key word is “multi.”

“We're building the new version of Smaart from the ground up to allow us to accept input devices that are multi-input devices via ASIO, where you can have eight inputs instead of just two,” Anderson says.

“Yes, its heart is a dual-channel analyzer — that's not going to change — but we want to run multiple analyzers off those multiple inputs. We want to run multiple transfer functions. Say I put three mics in a room and adjust the speakers, and look at those three transfer functions change as I'm making my changes. This will all be workable within a multi-platform (Windows, MacOS) environment, with multi-threading it so that it can be easily controlled externally.”


Alex Artaud is a musician and engineer living in Oakland. Email him at [email protected]