CLIOwin 7 PCI User's Manual - Audiomatica

12.6 MEASURING AND REPRESENTING LOUDSPEAKER POLAR DATA
Now suppose we want to measure and give a graphical representation of the polar
response of the same two ways loudspeaker analyzed in 12.4.
We need to measure its anechoic frequency response, at various angles and save the
files following the rules given in 12.5.1.
We will use a PC controlled turntable (Outline ET/ST), under CLIOwin's control, and the
automation possible within the MLS control panel using the Autosave and naming rules.
12.6.1 PREPARING AUTOSAVE AND THE MLS CONTROL PANEL
For this test we would like to measure the speaker from -180° to +180° (in intervals
of 5°) relative to its front baffle.
The MLS measurement should be set in a particular way in order to automatically acquire
the responses at various horizontal angles. To do this we will use the autosave
function, the loop mode and the link to the turntable control.
Let's start with setting the autosave function. Pressing Alt-F2 we recall the Autosave
Setting dialog (fig.12.11); here we input the desired filename ('rogerslogchirp'), start
(-180) increment (5) and total (73) values.
Figure 12.11
The MLS menu is now ready to start taking measurements; we only need to properly
set the turntable and its control.
12.6.2 PREPARING THE TURNTABLE
We assume that the Outline turntable is properly connected to your PC (refer to 4.5.2
for details). To prepare for this measurement session you need to:
1) Manually set the front selector labelled 'Deg Step' to 5°.
2) Rotate the turntable counterclockwise until you reach the desired start position: as
we want to start from -180° position it at 180°.
3) Recall the turntable control dialog (Fig.12.12), set Resolution at 5°, Speed at 0.75
RPM and press Link To Measurement
152 Chapter 12 - Waterfall and Directivity