User`s guide

9) Click on the "Measure Free Air Parameters" button at the left of the WT3 window.
You should hear the sweep and then see the impedance response of the driver appear on the screen similar
to the screen below. The speaker’s free air parameters are displayed in the Parameters Bar at the right side
of the screen. At the left side you can set the upper impedance limit and the high and low frequency limits.
10) Measure the driver’s V(as).
Once you have measured the speaker’s free air parameters the "Measure V(as)" button becomes enabled.
Select one of the three methods to measure the V(as) at the upper right side of the WT3 screen. The three
V(as) measurement methods are:
Test Box Method - requires a suitable test box
Added Mass Method - requires you to add a known mass
Specified SPL Method - requires the SPL be known
Enter the required data and then press the “Measure V(as)” button to start the measurement procedure.
11) After measuring the speaker you can:
• Save the data to one of 20 project memories.
• Save a WT3 project file (file type .wt3) which includes your test setup and all 20 memories.
• Export the parameters and impedance data in either .txt or .zma formats.
• Overlay plots of various measured impedances from the 20 memories for detailed comparison.
• Print a report showing the impedance and parameters of the displayed memories.
12) Quit WT3.
Quit the WT3 application software by using “Ctrl+Q” from the keyboard or by selecting “Exit” under the
“File” menu. On exit the software saves your application settings for the next session.
13) Future sessions with WT3.
In the future when you want to use WT3 you only need to connect the WT3 hardware unit, raise the master
volume and then launch the WT3 software. If you happen to launch the software first you will then need to
select “Audio Device Selection…” under the “Edit” menu so that WT3 can scan for the hardware and select
it for use. The software will retain its calibration from session to session but it is still a good idea to verify
the calibration at the start of each session by sweeping the supplied calibration resistor or some other
resistor of known value.
Troubleshooting
If there is a problem, review the USB port setup in Step 3. Also, remember that the hardware unit requires a
full 90 seconds to stabilize after power up. During this time the sweep may not be heard and measurements
will not be valid.
Revised: 4Feb11