Inside the Toolbox Plus
Live Sound’s resident measurement geek has found a way to lighten the tool bag load
At a gig or job site, do you carry a personal tool bag stuffed
with items you just can’t do without? The bag with the Maglite,
screwdrivers, dykes, needlenose pliers, Neutrik-sized Allen wrench, connector
adapters, etc.?
Then there are the bigger tools, like a signal generator, volt-ohm
meter (VOM), real-time analyzer (RTA), cable tester and so on, for
more specialized functions. And let’s not even discuss tools
that we just can’t afford, use sparingly or are just so fragile
that they shouldn’t leave the shop.
There are also times that I wish an oscilloscope were on site, or
that I could conveniently measure total harmonic distortion (THD),
or generate an impedance curve to determine if a compression driver
is bad or if the amplifier is loaded down. These types of things
sure add up to save a lot of on-site time.
I’ve recently been evaluating the new TerraSonde Audio Toolbox
Plus, and straight out, I can say it supplies the most versatile
and complete combination of specialized audio test functions available
in one product. There are a lot of other portable audio test tools
available, but none I know even come close to featuring the variety
of functions offered by this unit.
IF THE NAME FITS...
The first Audio Toolbox, housed in a black ABS chassis, was aptly named
due to the sheer number of functions available in one portable package.
Toolbox Plus represents the next logical step, but now it’s housed
in a rugged (and striking) anodized aluminum and steel chassis that’s
a marked improvement over the original.
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It also offers a larger LCD display
screen and rechargeable battery that is removable. |
The chassis of Toolbox Plus is not only attractive, but highly functional
and ergonomic. Output connectors, MIDI connectors, screen contrast adjustment,
measurement mic, and built-in loudspeaker are located on top, while input
connectors, power switch and battery door reside on the bottom. The LCD
screen and easy-to-use rotary encoder control wheel sit on the front panel.
But inside is where the real beauty happens, including 40 non-volatile
memories in which various test results can be stored.
In combination with the included software, the Audio Toolbox Plus offers
four primary function groups and a laundry list of useful individual functions:
FUNCTION 1: ACOUSTIC ANALYSIS
Sound Level Meter: Flat, A and C weighting, LEQ, and noise dosimeter
Real-Time Analyzer: 1/1 and 1/3 octave; flat, A and C weighting;
cinema X normalized
FFT Analyzer: 1/3, 1/6 and 1/12 octave; flat, A and C weighting;
cinema X curve normalized for a flat display
Energy-Time Graph: delay finder, 1/1 and 1/3 octave; flat, A, B
and C weighting; T- 10, -20, -30, -40, -50, -60
Reverb Decay Time: 1/1 and 1/3 octave; flat, A, B and C weighting
up to 11 seconds
Sound Study Graph: average LEQ and peak levels
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FUNCTION 2: TEST
Signal Generator: sine and square waves, pink and white noise,
polarity waveform, impedance meter, and wattage meter for 25, 50,
70, and 100-volt speaker lines
Electrical Level Meter/Frequency Counter: dBu, dBV; average,
RMS, and peak-to-peak voltage; frequency counter from 16 Hz to 50
kHz
Signal/Noise Ratio: incorrectly named, this is actually an
electrical dynamic range measurement calibrated in dBu
Sweeps: both ele-ctrical and acoustic amplitude response
and electrical impedance curves in either 1/3- or 1/12-octave steps
Distortion Meter: Total Harmonic Distortion (THD) plus noise
at octave centers from 63 Hz to 4000 Hz, accuracy to 0.01 percent
distortion
FUNCTION 3: SYSTEM TOOLS
Rapid Speech Transmission Index (RASTI): measures speech
intelligibility using the MTF (Modulation Transfer Function), 1.0
is perfect, 0.5 or above is considered acceptable intelligibility
%ALCONS: Articulation Loss of Consonants, an alternate method
to assess speech intelligibility. Uses RT-60 measurements and loudspeaker-tomeasurement
mic distances to compute ALCONS. Less than 15 percent is considered
acceptable intelligibility
Noise Criteria: ambient noise in nine one-octave bands; also
computes speech interference level via an average of four one-octave
bands from 500 Hz to 4000 Hz
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Polarity Tester: absolute polarity of mics, electronics,
and loudspeakers
Time Code Tools: reads fps (framesper- second) of SMPTE,
EBU, and FILM; has two simultaneous readers for left and right inputs
and will compute and display the offset between them in real time;
also displays the code’s format
Time Code Generator: reads one input and generates time code
simultaneously
Time Code Re-Generation: incoming time code can be regenerated
with an entered offset
Time Code Frame Rate: reads the running frame rate of time
code to three decimal places
Time Code Fault Detector: finds frames that are not the next
expected frame value
Time Code Calculator: adds and subtracts time code numbers
in various formats
Sample Scope: digital oscilloscope with a 48 kHz sample rate
resulting in a 24 kHz high-frequency limit (Nyquist frequency);
useful for checking proper waveform reproduction; XY/ Phase Display
Mode is useful for analog audio tape head azimuth alignment and
L/R phase coherency
FUNCTION 4: UTILITIES
Monitor Amplifier: stereo amplifier with mic preamps that
provides a line out, monosummed output to the built-in speaker,
and a stereo output to the headphone jack; signal is a digitized
16-bit, 48 kHz sampled signal with the expected limits of a digitally
processed signal
Cable Tester: tests XLR, balanced and unbalanced 1/4-inch,
and RCA-connected cables
Power Tester: tests phantom power on the male output XLR
for pins 2 and 3; battery power test indicates the battery type,
DC voltage present, and remaining operational time for the unit’s
internal battery
Computer Interface: computer access to the 40 memories in
the Audio Toolbox for analysis, hard drive storage and printing
via the serial adapter cable and MIDI ports using the proper computer
application program
Set Up and Calibration: recalibration of the following items:
user defaults, backlight on time, burn-in status, factory calibration
status, restore factory calibration values, input and output levels,
dB SPL level, frequency counter, phantom power, and battery voltage
About: lists TerraSonde tech support phone numbers, web site
URL, and current firmware version
WELL, NO ONE’S PERFECT
By now you may have gotten the idea that I really like this unit,
and you would be correct! However, there are a couple of shortcomings.
First, although the display screen is larger than found on the earlier
version, it’s still less than optimum in terms of readability.
However, TerraLink software enables the screen of a computer to
be used for a much larger display.
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The second shortcoming, albeit minor, is that the unit can stand flush on a flat surface only on its back and not on its top or bottom sides. |
Although designed with recessed connectors on both the input and output sides, the mic BNC connector on the top/output side and the battery-door screw and XLR release tabs on the bottom/input side protrude out from the recessed panels. Expanding the outside case size slightly would protect these protrusions and enable the Toolbox to stand flush.
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With such a well-done and attractive ergonomic design, it seems a pity that this was overlooked. |
From a contractor or live sound perspective, the unbalanced calibrated mic with BNC connector and almost useless six-foot cable is the only glaring mistake the product designers have made. There’s an optional low-noise precision mic with a balanced XLR connection available with an outboard pre-amp. However, the user shouldn’t have to pay extra money and carry around an extra box just to be able to remote the mic and use standard mic cables. The standard calibrated mic that comes with the unit should be upgraded to a balanced version, using the industry standard XLR connector. BNC connectors might be fine for the laboratory, but not in the field where this product is used.
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A “Pelican” type
lockable travel case would be a nice option if the Toolbox
needed to be checked as luggage or more durably or securely
enclosed. And the only other test that this product should
perform is the generation of a signal between audio ground
and chassis ground - the infamous “Pin 1” problem
test. Seems to me that the Toolbox could easily be programmed
to perform this test. |
THE WRAP
The TerraSonde Audio Toolbox Plus is perhaps the most versatile and easy-to-use
audio test and measurement device available, and well befits its name.
Most of its inboard filters and many tests meet or exceed ANSI standards.
With the exception of the very high-resolution and phase measuring capability
found in the Gold Line TEF- 20, Meyer SIM and SIA SMAART, there is very
little this box can’t do for practical audio measurements. It’s
practically the only device needed for most all of your audio test needs.
Use this Toolbox, and your other tool bags will lighten considerably.
The Audio Toolbox Plus carries a current U.S. list price of $1,799. For
more info, go to www.terrasonde.com.
Editor’s Note: John informed us at press time that he
received word that the next revision of the Audio Toolbox Plus will incorporate
a balanced calibrated microphone with an XLR connector. They are listening!
Live Sound Technical Editor John Murray is a 26-year industry veteran,
working for EV, MediaMatrix and TOA. He has presented two AES papers,
chaired three Syn-Aud-Con workshops and is a member of the TEF Advisory
Committee and ICIA adjunct faculty. We encourage you to send technical
questions to John at jmurray@livesoundint.com.