SP395 SoundPro Audio Integrator
Form7492
Operation Manual
70
TechBench Menu
The TechBench menu contains test functions which are primarily oriented towards audio
equipment testing and calibration. The TechBench menu includes the following tests:
Level/Freq. Meter
Signal Generator
Amplitude Sweep
Distortion Meter
Phase Meter
Crosstalk Meter
The TechBench menu showing the available test functions.
The SP395 assumes that tests of audio equipment involve standard line level audio inputs.
Therefore, while the same left and right inputs are used on the right side panel of the instrument,
line level audio is expected.
The SPL, Acoustics, TDA and Noise Tools functions, are designed for microphone inputs. These
functions use the microphone SPL calibration stored within the SP395. Electrical functions,
such as the TechBench, Speaker, Utilities functions expect line level source inputs. These
functions use a dBu calibration within the SP395. Keep this in mind to prevent potential
confusion over measurement results. For example, if a 0 dBu electrical signal is plugged into the
Sound Level Meter, you may see results like +150 dB SPL, depending on the sensitivity
calibration that is stored. Conversely, if you are using a microphone with the Amplitude Sweep
function, you will see very low results, perhaps in the –70 to –60 dBu range.
When performing TechBench measurements of audio signals you typically would not be using a
microphone. Therefore, remove phantom power to the SP395 inputs by changing both the left
and right phantom voltage from 48V to 0V as indicated in the top toolbar.
Use the auto-gain input feature of the SP395 as it provides the optimum range from most
measurements. To select auto gain, change the M to an A in the top toolbar on the left and/or
right channel.
All functions that display level data allow you to select the display units as dBu (0 dBu = 0.775
V rms, or the equivalent voltage level to dBm, referenced to a 600mw power level), dBV (where
0dBV is referenced to 0.0 Volts RMS), Volts average, Volts RMS or Volts Peak-to-Peak.
