SMAART (short for Sound Measurement Acoustical Analysis Real Time) is a software application with a rich heritage, owing to early input from, and adoption by, some of the pioneers of audio measurement. It was the first dual-channel measurement platform made to work with nonproprietary computer and audio I/O hardware, effectively bringing these tools to the masses.

In its 15-years of existence, SMAART has been owned/licensed by two different loudspeaker manufacturers and an acoustics-consulting firm. In 2008, however, Jamie and Karen Anderson, Adam Black and Calvert Dayton founded Rational Acoustics, which acquired full ownership of SMAART the following year. Rational Acoustics is a company based out of Putnam, CT that’s all about the development, sales and support of SMAART and whose mission is to equip audio professionals with the right tools and skill set for effective sound-system optimization.

Being a frontrunner in the world of technology comes at a cost. When one pushes the envelope in software development, one uses the tools that are available at the time. SMAART 1.0 was released in 1996. SMAART 3 was released in 1999, and was the foundation on which versions 4 and 5 (released as SmaartLive) were built. As the program became more sophisticated and its popularity increased, the desire grew among advanced users to be able to do more with the data they gathered than just visualize it. Namely, they wanted to be able to extract it and then import it into external devices (i.e. to set EQ curves in system DSP’s).

By version 5, SMAART had developed into a highly sophisticated program with lots of features; however the entire platform was built on an antiquated code base. Extracting data required an excessive amount of effort, and the need to support multiple operating systems was becoming a bigger issue. It became evident to the developers that it was time for a complete overhaul. In 2006, after two years of programming, SMAART 6 was released. Though the feature set was not as extensive as the previous version, the system was completely rebuilt using modern programming techniques, capable of supporting multiple measurement channels, and now ran on multiple operating systems including Mac OSX.


In April of 2010, Rational Acoustics released SMAART version 7, which is more efficient still, and was built using object-oriented code architecture, meaning that the data gathering engines and display functions, for example, are now treated as separate modules. This allows for a tremendous increase in flexibility for setting up multichannel measurements; computer hardware is now the only factor limiting the number of measurements that can be run simultaneously. Users of previous versions of SMAART will immediately be able to see the potential for a new array of measurement possibilities just by looking at the setup dialogs for the various measurement modes.

I have had the opportunity to employ SMAART on tours, one-off concerts and corporate events, and in the alignment/commissioning of permanently installed systems. I’ve discovered that a number of people are familiar with the program and its RTA functionality but are ignorant of the transfer function and impulse-response measurement capabilities, despite the fact that this technology has been around for some time. Though this will be repetition for veteran users, it seems beneficial to outline the basic functions and the corresponding applications in addition to commenting on the changes in version 7.

The most widely known mode of SMAART is its spectral engine. Though the process for obtaining the data is very different, the same information is displayed as could be seen on a traditional real-time analyzer. The RTA screen is a graph that places frequency on the x-axis (“frequency domain”) and sound level on the y-axis, allowing the user to observe the relative level of the sound at various frequencies. The information can be viewed in either bar graph or line graph format (with linear or logarithmic frequency scaling), and at a number of different resolutions. Unlike traditional RTAs, SMAART can display multiple input sources on one screen, with a different colored line representing each source. The RTA display is a very useful tool for identifying a feedback frequency or visualizing the sound that an instrument is producing having a SMAART system tied in to the solo bus on the console is a great supplement to audio monitoring. SMAART 7 is capable of displaying real-time averages derived from multiple input sources on the RTA display, which was not possible in previous versions. Also part of SMAART’s spectral engine, the Spectrograph display shows RTA information over time. In this plot, frequency remains on the x-axis, but the y-axis is replaced by time, and SPL is indicated by color. This is a useful tool for viewing the spectral content of dynamic music, or identifying problem frequencies (in lavaliere microphones, for example).

The real power of SMAART and other two-channel measurement platforms, however, lies in the transfer function measurement mode. Whereas the real-time spectral displays (the RTA and spectrograph) are useful for visualizing the sound that one hears, the transfer function measurement mode is about measuring the changes that occur to the audio from one point in the signal chain to another. In the live sound context, one common practice is to use SMAART to compare the signal leaving the mixing console against a measurement microphone. This allows the system engineer to see the cumulative effect that the system processor, loudspeakers and acoustic space have on the response.

Like the RTA screen, the transfer function display also appears as a line graph with frequency on the x-axis and level on the y-axis. The difference, however, is that the line represents the effect that the “system under test” has on the signal. In other words, in the live sound example (comparing the sound leaving the console to the output of a measurement mic), a perfectly flat line would represent a perfectly flat system response, whereas a 6 dB bump at 400 Hz, for example, would indicate that the signal coming out of the console would be boosted by 6 dB at 400 Hz by the time the sound arrived at the measurement mic position (likely due to low mid buildup in the room). Because the transfer function measurement is the result of comparing two signals, the source material does not matter, provided that all of the frequencies of interest are present. This is extremely powerful in that it allows full bandwidth music to be used in place of pink noise for optimizing sound systems. It additionally allows system engineers to compensate for changes to the acoustical characteristics of a space (i.e., a venue filling up with people) in real time, using whatever program material is running through the PA. Also integral to the Transfer Function screen is the phase trace, which is critical for setting driver alignment delay and crossover parameters.

A new feature of SMAART 7 is the ability to display averages from multiple (transfer function) measurement groups. One obvious application would be to take the information from several different measurement microphones placed at different positions throughout the space, and display their average as a single line. Because the data acquisition module and display module are two separate functions, SMAART 7 is capable of comparing each mic input to the reference input with the necessary delay times and averaging them in real time.

Unlike the Spectral and Transfer Function measurements, the Impulse Response (IR) measurement mode is a time-domain measurement, displaying sound energy over time. IR measurements are useful in acoustical analysis, allowing for the visualization of reflections and signal-decay characteristics. SMAART7 is capable of displaying impulse response both in real time and from saved data.

An impulse-response measurement is the visualization of a file that is generated through a process called convolution. Convolution basically produces an audio clip representing what a momentary full bandwidth impulse would sound like decaying in the acoustical space in which the measurement was taken. As is the case with the transfer function, what is being measured is not the actual source material, but rather the cumulative effect that system under test (in this case, the acoustical space) has on the any given source material. In the captured impulse-response mode, the user can visualize the spectral characteristics of the decaying impulse on a frequency domain plot, simply by clicking anywhere along the IR window.

The user can also plot the signal decay on a spectrograph display. This is useful for visualizing the “sound of a room”. RT60 (the time it takes for a signal in an acoustic space to decay by 60 dB) is one well-known metric for quantifying the acoustical properties of a room; however it is blind to frequency. Visualizing acoustical decay using SMAART 7’s spectrograph on a captured IR allows the user to see which frequencies linger the longest, and which frequencies decay the fastest. A “harsh” room might have the exact same RT60 as a “boomy” room; however, one would certainly be able to see a large difference between the two rooms by viewing their respective IRs on the spectrograph display. SMAART 7’s IR measurement mode is a very powerful tool in acoustical analysis and for acoustical problem mitigation planning.

In Use

I had the privilege of attending SMAART training in Seattle, Washington, hosted by Advanced Broadcast Solutions. The class was three days long, and Jamie Anderson was the instructor. On the first day, we covered basic audio theory (very briefly), defined the objectives and context of system optimization, looked at SMAART’s three measurement modes, and then began to delve into data interpretation.

Early in the day, Jamie presented an example of a TF measurement where there was a 6 dB decrease in signal level from 3k up. He asked the class to interpret the measurement. Through a series of slides, he illustrated that one might correct the problem by boosting EQ, boosting the HF output of the processor, or boosting the HF amplifier, but that the problem was the result of a one-legged cable between the processor and HF amplifier. It was a powerful example of how the responsible system engineer should exercise common sense when diagnosing problems, rather than going straight for the EQ.

With anecdotes like, “Don’t ever let me witness you pointing at a computer screen and saying, ‘Look at how good this system sounds,’” Jamie rightly drilled it into our heads that SMAART is a tool, and cannot replace common sense and the use of one’s ears.

We spent most of the second day doing measurement exercises in the classroom setting using the same source material, with all of our measurement systems tied to Jamie’s audio distribution network. On the third day, we went into another room and practiced deploying a Nexo system in several different configurations. We additionally talked in detail about I/O devices and measurement mics, and tested several different mics.

I would highly recommend the class to anyone who wants to get a good working knowledge of SMAART, but would commend a Syn Aud Con class or a Meyer seminar as a good prerequisite to anyone who is not fairly comfortable with basic audio theory (specifically, understanding phase interaction).


SMAART 7 is an indispensible tool. It is very stable and includes a number of UI improvements over previous versions. The company recently released an API (application programming interface), which will pave the way for seamless real-time interaction between SMAART and other software programs. The folks at Rational Acoustics plan to continue adding both new functionally and all of the features that were present in version 5.

Additionally, they plan to add all of the functionality of SMAART acoustic tools (an IR-based companion program to SMAART 5 with extended capabilities) as part of the standard software package. I am told that the ability to produce a waterfall plot from IR data is also on the list, which is very exciting indeed. Rational Acoustics is clearly in it for the long haul. SMAART 7 is a fantastic program, and the training and support are superb.

Prices: $895 (new license, electronic delivery or hard-copy package); $450 (v.6 to v.7 upgrade, electronic delivery); $550 (v.5 to v.7 upgrade, electronic delivery); $650 (v.4 to v.7 upgrade, electronic delivery)

Contact: Rational Acoustics |

Ben Williams is owner/engineer of Essential Audio, a Nashville-based live sound reinforcement, system design and integration firm.