SP395 SoundPro Audio Integrator
Form7492
Operation Manual
58
The ALCONS Speech Intelligibility test display screen.
The ALCONS test screen & control fields:
1.
Test Function –
Identifies the current test function as ALCONs.
2.
Distance Units – Speaker Distance (Units)
– selects the unit of measurement used to set
speaker distance from speaker to listener (microphone) in either feet (ft) or meters (m). To
set the speaker distance units, turn the control knob to highlight the Distance Units field,
and click to select
m
(meters) or
ft
(feet).
3.
Octave Band –
Selects 500 Hz, 1 kHz or 2 kHz octave band
.
Selects the audio octave
band in which the ALCONS test is performed. The audio output from the generator
matches the band selected.
4.
Testing Control/Steps –
Increments the test function through 4 positions or steps
including Hold (HLD), Min, Max and Run to complete the ALCONS test.
HLD:
Stop the test & holds the test results for analysis
.
Min
:
Sets Minimum Room Noise – Highlight the Test Control field and select "Min."
The SP395 reads the average background noise level in the room during this step. If this
level is greater than 50 dB, you should attempt to decrease the ambient noise for best test
results and better room acoustics.
Max:
Sets maximum room sound level using pink noise
–
This is the maximum sound
energy in the room with the octave pink noise test signal applied. Adjust the amplifier's
volume and/or SP395 generator output to increase the sound level to 80 – 90 dB. It is
desirable to get the noise level considerably higher than the Min room level dB for
improved decay range and test accuracy. This can be challenging as low frequency room
noise tends to limit the decay range in the lower bands. You may want to wear ear plugs to
enable higher noise settings. To store the Max Noise level, set the Test Control field to
"
Max
" and click the Test Control field to “Run”
Run: Click the Test Control field to display "Run".
The pink noise generator will
cycle on and off as readings are taken. The “Decay Time” field displays the actual time in
milliseconds for the sound field to decay by the Decay range amount. The RT60 time field
shows the extrapolated time for the sound to decay in the room, if a full 60dB decay range
were available.
5.
Minimum Room Noise Level –
The ambient room noise level. The minimum room noise
level must be at least 30 dB lower (indicated by a number display in the Decay Range