1GA16_1L.DOC ROHDE & SCHWARZ14
5 5 MeasurementsMeasurements
The SPEAKER application software covers a variety of loudspeaker measurements which are displayed
in the softkey line (softkey level 1).
• IMPEDANC for measuring all relevant impedance values and corresponding frequencies and for
determining associated parameters.
• PHASE for measuring phase linearity and detecting polarity reversal.
• SOUND for measuring sound pressure characteristics and loudspeaker sensitivity.
• THD for measurement and display of THD+N, THD total, d2, d3, or similar
Pressing the START softkey (F12) triggers the selected measurement and the described measurement
procedure.
55.1 .1 Impedance and Associated ParametersImpedance and Associated Parameters
The impedance curve of a loudspeaker chassis or system gives information on important parameters
which sufficiently characterize the response at low frequencies. The parameters include the quality factor
Q
t
, resonance frequency f
r
and equivalent volume V
eq
. Equations used in this Application Note are in line
with DIN IEC 268, part 5.
Since UPD and UPL comprise a DC generator and a DC measurement function, the DC impedance can
be measured without any additional equipment being required.
The impedance measurement is selected with the IMPEDANC softkey (F6).
5.1.1 Test Setup
For measuring the magnitude of the (complex) impedance of a loudspeaker array or system, the latter is
connected to the XLR output Channel 2 of the generator (+ and -) and the voltage drop V1 is measured at
the generator output (via GEN coupling).
FIG 5 Test setup for impedance measurement
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