54
VSX-C300
Center SP
Sub-woofer
Front SP
Center SP
Surround SP
Subwoofer
Connected
Connected
low
low
low
ON
Connected
Not connected
high
low
low
OFF
Not connected
Connected
low
Not connected
low
ON
Not connected
Not connected
high
Not connected
low
OFF
7.1.4 Specifications of Speaker Detection
1. Purposes
Whether the speakers are connected or not is automatically detected, and settings appropriate for the detected speakers are made to allow you
to easily play surround-sound without making cumbersome speaker settings.
2. Method of detecting speakers
Whether a center speaker and/or subwoofer is connected or not is detected 600 ms after the power is turned on.
< Detection of the center speaker >
The microcomputer sends a detection signal and after 10 ms will read the logic of the responding signal to judge whether the speaker is
connected or not. The response signal will be read at A/D. A voltage of 3.5 V or more is judged as no speaker connected.
The response signals at A/D are read every 2 ms, and if the same results (less or more than 3.5 V) are obtained, the detection result is considered
correct. If a different result is obtained for the second detection, a third detection is carried out, and the two results that agree will outvote the
other. If detection fails three times, then it is judged that no center speaker is connected.
< Detection of the subwoofer >
The logic of the signal from the phono jack with a switch is read by the microcomputer to judge whether the speaker is connected or not. The
signals are read every 1 ms, and if the same results are obtained, the detection result is considered correct.
If a different result is obtained for the second detection, a third detection is carried out, and the two results that agree will outvote the other. If
detection fails three times, then it is judged that no subwoofer is connected.
3. Speaker settings
According to the results of the detection, speaker settings are made as follows:
Results of the Detections
Speaker Settings
4. User's settings
In Setup mode, more detailed speaker settings are available. Once the user's settings are made, those settings have priority.
However, if the configuration of connected speakers has changed, then the detection results become valid and have priority over the user's
settings until new user's settings are made.
5. Detection circuit for the center speaker
mute
More than
100 k
Ω
POWER AMP
Center Detection
Check signal from U-COM
Detection signal to U-COM
Mute
About 8
Ω
