DSP
EAKER
S
ERVO
300
2.3 Errors and Warnings
The speaker will monitor constantly it's input level, positional feedback of the woofer cone,
currents of the amplifiers, operating temperature, status of the DSP and microphone input in
calibration. The speaker can maintain safe operation in many different situations, but might
inform the user about these. If electromagnetic pulse disorients the DSP, a special integrated
“watchdog” will turn the power off instantly to prevent permanent damage or misbehaviour. If
the temperature becomes dangerously high, the speaker will go into stand by mode and
wake up only after it has cooled down to safe range. If an external force is pressing the
woofer cone for too long, the speaker will flash the status led red, and eventually shut itself
down if the external force persists.
2.3.1 Blinking Red Status LED
In normal operation, the blinking status led simply tells the user that the A/D saturation
threshold is reached. This does not necessarily require any actions from the user, as there is
still about 4 dB headroom until the level is too high and the A/D converter saturates.
However, if the sound occasionally starts to distort, it is adviceable to adjust the input gain
control down to lower the input voltage and prevent distortion.
2.3.2 Status LED is Lit Red
When the speaker is in standby mode, the status led is red. If the status led turns to red in
the middle of the normal operation (with input audio present), there might be failure due to
several reasons. The speaker will automatically shut down if it detects any failure in its
operation or in the sensor data. For example, if external force is pressing the woofer cone,
the speaker will detect inconsistence between sensor and input A/D, leading eventually to
shut down in order to prevent damage to voice coil. After failures the speaker will restart next
time in safe mode and make some checks to return to normal operation safely. After safety
checks, the speaker will restore normal status.
2.3.3 Thermal Shutdown
The Servo 300 speaker are also equipped with thermal sensors. If the operating temperature
increases too much inside the speaker, it will shut down automatically. After the temperature
is back to safe levels, the speaker will return to normal function.
Rev. 1.6
21.06.2010
Page 10 (16)
