Crest Audio NEXSYS - VERSION 3.0, Software Manual

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Crest Audio Inc. NexSys v. 3.0
Other parameters that can be set include the Grid Scale and Limit Offset. These are adjust-
ed by clicking on the up and down arrows as appropriate.
Once Load Monitoring parameters are setup, these parameters can be copied to
other amplifiers by selecting an amplifier from a group or Plan window and
dragging it onto the open Load Monitor window which has the desired test val-
ues.
Pass/Fail Limits
Load monitor pass/fail limits automatically set to ± 10%. These limits are adjustable by
selecting Limit/Offset. Click on the up arrow to loosen tolerances or on the down arrow to
tighten. Always leave room for deviation in your reference for normal changes to the load.
For example, drivers that are well exercised may have a slightly different response from a
new driver out of the box. Both may be within the manufactures acceptable tolerances yet
they may not test exactly the same. Test tolerances that are set too tight may indicate failure
when in reality there is none. Passive crossover networks, long drive lines, wind loading on
a transducer and distributed line transformers (to name a few items) will also effect the test.
Bear in mind that a NexSys Load Monitor test measures the entire load that is connected to
the amplifier- so any changes that occur which cause the test sweep to indicate failed may
be attributable to influences other than transducer breakdown or failure. Load monitoring
indicates change- not the cause of change.
Once a good sweep is
made, the reference
sweep is stored by press-
ing the Save button.
Curve Limits - Further
Manipulation
Further manipulation of
the limits of a reference
curve is available by using
the right mouse button.
For example, wider toler-
ances may be required
around the resonant fre-
quency of a passive cabi-
net while tighter tolerances may be required in the upper frequency
range. To custom draw reference limits run a reference curve and
when the curve is complete double click the right mouse button on the response graph. The
arrow cursor will change to a cross hair cursor and the title bar in the Load Monitor window
will indicate "edit upper limit." While in this mode you can "draw" the limit by holding the
left mouse button down and dragging a new upper reference. Release the left mouse button
when you are finished editing the upper limit. Double click on the right mouse button to edit
the lower limit using the same procedure. Double click on the right mouse button a third
time and the cross hair cursor will return to the arrow indicating that you are out of the edit
mode. Once properly edited save the curve as the reference and it will be your base line for
all subsequent tests.
Software Manual Page 15.3
Load Monitor Window