14
NOTE:
The DSP2B/BP will automatically start-up and read the SPL dBA
measurement on the
screen.
4. Check the SPL reading and measure the SPL to confirm that it meets the design
requirements Turn off your emergency message on your system.
5. Insert the STI-PA disk into the Talkbox CD player.
6. Connect the ¼ inch TEST TONE OUTPUT jack on the Talkbox to the LINE INPUT jack
on your system panel.
7. Set the VOLUME CONTROL on the Talkbox to 50% (12 noon).
8. Play the STI-PA tone through the Talkbox.
9. Go back to the same location that you made the previous SPL measurement with the
DSP2B/BP and check the SPL again.
10. Match the SPL level to your previous reading by either adjusting the Volume control on
the Talkbox or the channel input pot on your control panel.
NOTE:
Do not change the systems master volume as this is already set to code. Your test
procedure is now calibrated. To make an intelligibility test, place the analyzer
microphone in the location to be tested.
11. To make an intelligibility test, place the analyzer microphone in the location to be
tested.
12. On the analyzer, press the MODE SWITCH until the display reads STI or CIS
depending on your job specifications.
13. On the computer screen press the EMPTY BUTTON (without the STI-PA TONE
playing) and press MEASURE to collect the AMBIENT SOUND in the room.
14. On the Talkbox, start the CD player with the STI-PA TONE.
15. On the computer press the MEASURE BUTTON again to collect information with
the STI-PA TONE.
16. To save the information for the Empty room, refer to the section on (PROCESS OF
SAVING MEASUREMENTS FOR EMPTY ROOM) on page 15
17. The screen on the left of the computer screen will show you your MODULATION
TRANSFER FUNCTIONS and your MEASURED STI SCORE.
18. Return to the location that the EMPTY ROOM measurements were taken being
careful that the same locations for each test remain the same for the OCCUPIED ROOM
TEST.
NOTE:
You do not need the Talkbox for the OCCUPIED ROOM TEST
.
NOTE:
In the event of an STI failure, possible reasons may include; An unfurnished room under
test will produce a significantly lower STI value since the large flat reflective surfaces
will add echoes and the lack of absorptive materials will also increase RT60 times and
reduce the STI value further.
19. Open the file for the EMPTY ROOM for each location 1 at a time so the
OCCUPIED information is saved into the proper EMPTY ROOM file.
20. If not already connected, connect the analyzer to the computer and click on the
OCCUPIED BUTTON.
21. Click the MEASURE BUTTON.
22. To save the information for the Occupied room, refer to the section on (PROCESS
OF SAVING MEASUREMENTS FOR OCCUPIED ROOM) on page 16
The screen on the left of the computer screen will show you your MODULATION TRANSFER
FUNCTIONS and your MEASURED STI SCORE along with the ADJUSTED STI SCORE
