Dayton WT3 - Manual (Page 38)

Using WT3 to Evaluate a Complete Speaker System
You can use WT3 to measure the impedance of complete multi-way loudspeaker systems. Based on
this impedance curve we can tell a number of things about the system, such as whether the woofer uses
a closed or vented enclosure. While a single peak in the low frequency range suggests a closed box, a
single peak would also be seen for a driver operating as a dipole on a large baffle. Twin resonance
peaks typically indicate a vented enclosure. The enclosure tuning frequency is the frequency between
the two peaks where the impedance is a minimum.
Before starting, make sure the WT3 unit has been calibrated and has stabilized for at least 90 seconds.
Measure the speaker system impedance as follows:
•
Launch the WT3 software and make sure the volume is at maximum.
• Make sure that the speaker system is not connected to any other equipment and then connect
the test leads of the WT3 unit to the speaker under test.
• Click the "Measure Free Air Parameters" button at the left side of the WT3 screen.
•
You should hear the sweep from the speaker, the impedance is plotted and the parameters are
displayed.
•
Save the system's impedance response to a memory for future reference.
• The DC resistance of the system is displayed in the R(e) field. Ignore all other parameters.
•
Repeat the measurement to confirm the result. Repeated measurements should be in good
agreement.