Sencore's SoundPro series, the successor to the TerraSonde Audio Toolbox family of test instruments, offers self-contained, multi-function test capability for audio measurement. The SoundPro SP495 Audio Consultant provides a full swath of core and optional test functionality focused on acoustic and audio analysis. The standards-compliant test capabilities of the SP495, while applicable to, say, an FOH engineer, the "Consultant" part of its name also suggests where the test set is most likely to find its broadest embrace — with audio consultants working in installed sound, including house of worship, corporate, home theater, theme park, public address, distributed sound, and industrial sound analysis.
The SP495 is a 5 1/2" x 12 1/2" x 2 1/4" device (a portion of the length being an integral handle), weighing a bit over 2 1/4 lbs. It comes with a "line lump" DC power supply but can also operate from an internal (user replaceable) Li-Ion battery pack for as much as 5 1/2 hours (on a 6-hour full charge), depending on application. It also comes with a test microphone and padded soft case.
Top: The SP495 offers input via balanced Neutrik combo connectors. Bottom: The SP495 offers digital I/O, analog output options, and a handy reference speaker. Core Functionality
I have dabbled with the SP495's predecessors, so it was easy to figure out how get basic functions running. The front panel of the metal case is uncluttered, with just a rotary dial encoder and a backlit color LCD screen. Spinning the dial and clicking it selects menu items and parameters for adjustment for all SP495 functions. You'll spin the dial a lot, based on the number of control elements on the test screens and the flexibility of the unit (for some functions, like the fullrange generator frequency control, the interface would benefit from an increased parameter step size based on dialing speed). The bottom-panel sports combo 1/4-inch/XLR ins and an SD memory card slot, the toppanel analog and S/PDIF/TOSlink digital outputs and bidirectional USB I/O. I confess to reverting to the extensive manual (provided in PDF on disc) after a short time of familiarization — getting the most out of the SP495's capabilities and flexibility demands a more intimate knowledge of the device.
With the SP495 in tow, I met up with SR pro Ben Williams at a church where he recently finished a sound system overhaul. The SoundCore base software gives a range of, well, core functionality that we ran through first, beginning with simple SPL measurement (a range of 25-105 dBA SPL measurable with the supplied ANSI Type 2 microphone — an optional Type 1 microphone extends the range to 146 dBA). Though sound level is a simple test, the Sound Level Measurement screen serves to familiarize the user with a lot of SP495's flexible controls — speed of averaging/ response, automatic or manual mic pre gain, flat, A- or C-weighting, theater X-curve, relative measurement and peak hold, bargraph and direct numeric read out, speaker/headphone monitoring of input/output or USB I/O signals and generator level and signal controls (on/off, Pink/White noise, USB, sine and square waves — stepping by 1-2 Hz/octave/1/3 octave for tones). Settings like output level and mic gain are maintained from test to test while the unit is powered on.
For an install like a church or for testing environmental noise sources, it can be useful to know what levels are produced over time, facilitated in the SP495 by Leq averaged reading over a user-defined timeframe and by Dosimeter readings, measuring SPL over a defined time and correlating measurements to sound pressure exposure standards. There's also an automatable SPL chart recorder function that can log measurements over time, useful in part for evaluating environmental noise in a given locale, including elements like HVAC systems and external traffic noise sources.
RTA analysis of the room plotted the instantaneous frequency performance on a 1/3-octave scale, and with FFT measurement for up to 1/30 octave resolution (though with a slower refresh for the three-cascaded 1024-point FFTs). The plots could be frozen for deeper analysis, including cursor control to sweep to individual frequencies/peaks, and data can be stored for later use or use in a "difference" mode for before/after comparison. We also learned details on aspects of the room itself that Ben had already "intuited" during his system tweaks. RT60 measurements were facilitated with ease by the SP495, as well as a graphical display of energy decay vs. time, useful for mapping acoustic delays in a system and the incidence of reflection arrivals.
Additional core tests include speaker polarity (which can be performed up to 100 feet from the speaker...nice), actual speaker impedance measurement and a cable-tester function.
Giving You Options
The SP495 can be tricked out with a number of add-on firmware options, and the review unit was fully loaded. The SoundPro TechBench option adds tests like electrical signal level, frequency count, sweeps of frequency response and impedance, distortion (THD+N and IMD) measurement, phase and crosstalk. The resolution on these tests is decent for a handheld device, and might just save a tech carrying an additional test instrument into the field. Included is an oscilloscope emulation for rudimentary waveform visualization.
A major concern for many in the install market is speech intelligibility, and the SP495 can be upgraded to include industrystandard ALCONS (a numerical prediction of consonant loss based on RT60 and level measurement), RaSTI and STI-PA analysis (these last two tests are based on the system resolution of bandwidth limited pink noise modulated by sine waves. The test signals are provided on CD). Various standard noise curves can be plotted across a user's SPL vs. frequency test data with the Noise Curves firmware module. The Time Delay Analysis firmware graphs frequency response independent of room reflective energy (and includes "3D" waterfall graphs). This function can be handy in helping determine whether poor room acoustics are negatively impacting a sound reproduction system that is, in and of itself, performing as conceived. RT60 measurements can be enhanced with the Multi-Band Decay Analysis module, computing decay time simultaneously across seven individual octave bands for further identifying problem areas. The final firmware module uses the mic input with the headphone outputs to form an Audio Stethoscope for gremlin chasing.
The SP495 can be interfaced with Mac and Windows computers via RS232. I used an USB to RS232 serial port adapter to successfully interface the SP495 with both a MacBook and a Windows XP laptop. For Windows, the TerraLink software module provides a "follow-me" type of functionality for test functions, and, with the SP495 in a PC-link mode, recall and display of stored test data. For Mac, there's a SoundPro module for similar computer display. There's also an optional Windows report software module for link to a customized Excel spreadsheet.
In addition to using the SP495 in the sound reinforcement environment in Ben's church install, I used the SP495 for home theater evaluation. While the SP495 is equipped with the measurement capability for level and delay settings, and can be informative about room reflections and decay with its extended functionality, automated home theater testing for up to 6.1 systems (DTS and Dolby test signal generation) is facilitated by pairing the SP495 with Sencore's DAG5161 SurroundPro Digital Audio Generator (not tested). The SD card interface can be used for transfer to computer of impulse response, and the SP495 can also function as a stereo recorder, with the SD card used to "sneaker net" such data (as well as RTA, FFT and other data stores).
The SP495 is not inexpensive. Many FOH engineers may opt for a laptop and one of the available software sound analysis packages as a less expensive and more function specific choice for their needs. For the sound consultant set, needing an evaluation tool that provides data more traceable to relevant standards, and who is not simply dealing with the venue du jour but evaluating the space itself as well as sound system performance, the Sencore SoundPro SP495 Audio Consultant competently provides a comprehensive range of tools in a single portable package. For that class of user, simply reading through the feature set is likely to inspire gear lust.
Frank Wells, formerly a radio broadcast and recording studio technician, is the editor of Pro Sound News and the editorial director of Pro Audio Review.