Tech Focus

Smaart SPL: Early Details On A New Sound Pressure Level Measurement Tool

Same feature set as Smaart v8.4 update offered for users looking to add SPL monitoring capability to additional computers without need to purchase additional installations of Smaart v8.
Screenshot of new Smaart SPL from Rational Acoustics.

Rational Acoustics, developer of Smaart sound system measurement and analysis software, recently released Smaart SPL, a new stand-alone SPL measurement and monitoring software program. It provides the complete SPL measurement feature set from the company’s flagship Smaart v8 program in a purpose-built package, with an interface designed for simplicity and speed.

The new software offers a full-featured solution for monitoring, metering, and logging SPL with a format and a price point more accessible to users who don’t require the FFT analysis functionality of v8.

“SPL monitoring in the live sound industry has become incredibly important from a performance standpoint, as well as for both health and safety and legal reasons,” says Rational Acoustics founder and president Jamie Anderson. “With the release of the Smaart v8.4 update in November 2019, we included a major expansion of Smaart’s SPL monitoring capabilities and it was a logical next step for us to make those features available to a wider audience as a separate, lower-cost stand-alone package.”

Under The Hood

Smaart SPL uses the same multi-device multi-input approach as v8, meaning that the number of simultaneously available calibrated inputs is not limited by the software in any way. Users can log data from as many microphones in as many locations as desired, as long as they have sufficient hardware.

When logging is enabled, the program displays a continuously updating SPL history timeline, where users can view the entirely of the logging/logged event as well as overlay multiple metrics and zoom in on specific time ranges for a closer look at the data. SPL data from each microphone is written to a logfile in real time, in a data format that can be easily exported into a spreadsheet program or loaded back into the program for later review.

The customizable SPL Meter Grid is a useful “heads-up display” during the show, with green/yellow/red “traffic light” color thresholds that can be configured independently for each metric to give instant visual feedback on levels. The meter grid can be resized and moved to an external display – it also makes a great SPL meter bridge for a mixing console (Figure 1 and Figure 2).

Figure 1
Figure 2


When it comes to evaluating the level of a song, set, or entire performance, the standard metrics found on most basic meters – SPL Fast and Slow – can fall short, giving only seconds of context when minutes are required. An Equivalent Continuous Sound Level (Leq) metric calculates a single-number dB equivalent over a given number of minutes, indicating an “average” level over time (or more accurately, a continuous level that would result in the same total sound energy over the period).

For the dynamic signals found in live sound reinforcement, a 10- or 15-minute Leq (Leq10 or Leq15) measurement becomes an important tool to evaluate compliance with noise ordinances and level limits. The longer time periods don’t suffer from the instability of an SPL Fast or Slow measurement, and they allow mix engineers freedom to craft a mix that has loud, exciting moments as well as quieter, intimate moments, while remaining within a compliant long-term level. Smaart SPL goes beyond the usual Leq1 and Leq10 metrics, allowing users to configure an unlimited number of Leq metrics, from 1 second up to 1,440 minutes (24 hours).

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Smaart SPL can also measure and compute NIOSH and OSHA exposure dosage in real time – a timely feature given the growing wave of consciousness about Noise-Induced Hearing Loss (NIHL) in the live sound reinforcement industry.

The Exposure N and Exposure O metrics display the measured noise dose in percentage, just like an industrial noise dosimeter. This allows users to determine whether show levels are safe without resorting to a data table or pulling out a calculator (Figure 3).

Figure 3

Remote Monitoring

Smaart SPL and v8 both offer an integrated SPL web viewer, which allows remote viewing of the history plot and meters via a standard web browser on any device connected to the network or, with proper network configuration, any internet-enabled device anywhere in the world. This feature allows a production trailer to keep tabs on levels across multiple stages at a large festival, for example (Figure 4).

Figure 4

Class Compliance

For general measurement purposes, Smaart SPL can be used with any user-supplied measurement microphone and audio interface, along with a microphone calibrator. In cases where class compliance is required – to comply with applicable standards, or if logfiles need to withstand legal scrutiny, the program has been designed to work with SG Audio’s 10EaZy hardware for a turnkey Class 1 or Class 2 calibrated solution.

Current Smaart v8 owners have access to the same feature set as Smaart SPL, as of the v8.4 update. However, users looking to add SPL monitoring capability to additional computers will find Smaart SPL an attractive option without the need to purchase additional installations of Smaart v8. For more information on Smaart SPL and to download a free demo, go to

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