T-44/48 Series Amplifier
Operation Manual
T-44/48 Series | rev.
firm. 1.258 and above
32
On Tecnare Loudspeaker Preset this protection is calibrated by Tecnare and cannot be
modified. Please in case of used power amplifier different to advice of Tecnare refer to our
support department for limiter setting.
4.3.7.3
Xmax Excursion Limiter
The Excursion Limiter protects the driver against excessive linear movement of the
cone and voice-coil which could otherwise cause mechanical damage. Since this movement
(excursion) is related to the inverse of the signal frequency, drivers are prone to being damaged
by very low frequencies. This limiter is progressively more sensitive at lower frequencies and,
rather than varying the gain to provide the limiting action, it uses a sliding high-pass filter to
progressively curtail the low-frequency response, effectively limiting the linear excursion to
below the X-max specification of the driver.
To set the limiter up, it is necessary to know the shape of the family of Excursion vs.
Frequency curves of the driver for various drive voltage levels. A curve should then be chosen
where the slope is high where it passes though the specified X-Max value for the driver. The
peak voltage and frequency of this point should then be noted.
The Xmax limiter is then set up using just two parameters:
Threshold
– the peak voltage of the point arrived at above. This is calibrated at the output of
the amplifier. The Excursion Limiter can be defeated by setting Threshold to the maximum “Off”
value.
Frequency
– The frequency at which the above threshold voltage is appropriate for.
A further parameter “
Min
” may also be available for more advanced applications. This
allows the increasing limiting action at lower frequencies to level-off below a certain frequency.
In most application, this would be left set to its default value of 5Hz.
On Tecnare Loudspeaker Preset this protection is calibrated by Tecnare and cannot be
modified. Please in case of used power amplifier different to advice of Tecnare refer to our
support department for Xmax Excursion Limiter setting.
4.3.8
Bridge
When an amplifier pair is set to Bridge Mode, it uses two amplifier channels to drive one
loudspeaker with greater power. In this mode, only one set of Output controls is active per pair
of amplifier channels since both of the amplifiers in the pair are driven with the same signals, as
determined by the channel 1 (or channel 3) controls. Bridge settings should be set up
before
recalling Drive Module Presets. Module Preset Recall will see a bridged pair of outputs as a
single channel.
Bridge Mode is enabled or disabled in the AMP page for a given odd numbered Output.
When enabled, the Bridge indicator will be illuminated between the bridged channels.
4.3.9 Routing
Outputs can be driven from any DSP input. This routing is the fundamental means by
which Drive Modules are created.
Routing should always consume outputs consecutively alphabetically and numerically.
However, non-consecutive Drive Modules may be created using manual routing and
Recalling
Components
. See the
section of this user manual for more information.
4.3.10 Driver
The optimal drive level may be adjusted for a given driver impedance using the
Load
parameter.
See Load Matching
.
