The latest revision of Rational Acoustics' Smaart is v7.1 which runs under Mac OSX (10.5 or 10.6) as well as Windows 7, XP, or Vista. Rational Acoustics recommends at least a 2 GHz dual-core processor and Smaart is compatible with CoreAudio, WAV or ASIO audio drivers. I ran Smaart on a MacBook 2 GHz Core 2 Duo/4 GB RAM with Digi 002R and MOTU Traveler interfaces. If you've never used Smaart, it's worthwhile reviewing the resources available from the Rational Acoustics web site, particularly the PowerPoint presentation and basic setup guide. Reading these documents while following along with your system can cut down the learning curve, and since there's a lot to learn about Smaart, this idea is... well... smart.
Smaart's primary modes (Real Time and Impulse Response) include time and frequency domain measurements, but first you need to set up your hardware in the audio dialogue. When Smaart recognizes your interface, it appears on a menu of available I/Os. You can then set sample rate, bit-depth (16 or 24) and apply your own names to the inputs and outputs (nice for managing multi-channel systems). Smaart played very well with my Digi 002R at sample rates of 44.1-, 48- and 96 kHz, though it does not support 88.2 kHz (which I don't see as a problem). I cannot say the same for my MOTU Traveler, which Smaart did not like very much. Sometimes Smaart would recognize the Traveler, and other times - typically after changing the sample rate - it would not.
Averaging and Weighting
One of the few gripes I have with Smaart is that weighting is neither displayed nor accessible from the Control Strip, though it is indicated in the trace area. Figure 1 shows the Smaart Spectrum (RTA) function. Note that the Control Strip on the right (detailed in figure 2) displays the averaging but not the weighting, which I consider essential [Editor's note: the numeric readout at the top of the Control Strip shows weighting for the dB meter, not the analysis tool]. The Spectrum display can show RTA, Spectrograph or both via split screen (figure 3). All of the screens look great and are easy to read, but one thing I did not like is that when you zoom in or out, the scale of the screen changes, but the resolution of the grid does not (i.e., you can zoom in as far as you want, but the grid is still divided into 6 dB steps). To select an area of a window for zoom, right-click and drag on it or, on a one-button mouse, hold <Control> + <Option> and click and drag.
At the top of the Control Strip is a numeric indicator that shows dBFS, dB SPL (Smaart provides calibration for SPL) or dBLEQ. dBLEQ is capable of long-term SPL monitoring over a user-defined period (we went as far as six hours), with user-defined increments. A "logging" feature creates a text file of these measurements showing minimum and maximum SPL as well as the actual SPL at a given date and time. It's a very useful tool, especially in venues where the neighbors make noise complaints.
Impulse Response measurement is always tricky, because if measurement parameters are not set carefully, data acquisition is inaccurate. The setting for Time Constant (TC) must be long enough to include the entire decay time of the system under test. When capturing the impulse response of a room with a decay time of 1.5 seconds, a TC of 682 mS yields inaccurate data, because Smaart is not given enough time to "hear" the entire decay. The solution is increased TC, which also increases the FFT (Fast Fourier Transform). Processing time increases with increased TC, so one benefit of using shorter TC is that you see the results faster. Smaart provides TC settings ranging from 2 and 10922 mS, with corresponding FFT sizes and averaging to improve reliability.
There are a couple of minor things that I'd like to see tightened up in Smaart. In addition to the aforementioned difficulty with the Traveler interface, there is an issue with using the MacBook's built-in I/O. Smaart recognizes the I/O, but at times, attempting to use it prompts a message stating "Failed to Start Device." The folks at Rational Acoustics are working on solutions to those issues.
Nit-picks aside, there's no doubt that Smaart is an extremely powerful software tool, in particular for touring sound companies and installers. It takes a bit of time to become familiar with all of the capabilities but should be considered essential for anyone requiring critical evaluation of audio system performance. It's also an excellent teaching tool, providing a means of illustrating a variety of acoustic phenomena. A new license for Smaart runs $895; upgrades from earlier versions range from $450 to $650.
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