Speed Volume Compensation (SVC)

nikey22

Well-Known Member
33
4
Canada
Vehicle Model
LX-NAVI
Body Style
Sedan
in an LX (non-navi), how does the head unit know to adjust the volume based on speed?
I've checked the wiring on CONNECTOR A, and there is no blue vehicle speed pulse (VSP) wire on A23 for this TRIM. This only exists on the NAVI equipped cars.

Interesting...... any thoughts? Thanks.
 
in an LX (non-navi), how does the head unit know to adjust the volume based on speed?
I've checked the wiring on CONNECTOR A, and there is no blue vehicle speed pulse (VSP) wire on A23 for this TRIM. This only exists on the NAVI equipped cars.

Interesting...... any thoughts? Thanks.

I always thought it just picked up noise from the mic for Bluetooth calls. I do notice a difference in sound when it's turned onto any setting, versus when it's off.


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Thanks guys. Good points.
Also, looking into it further; I've noticed that the radio (even the base radio) has B-CAN lines; Its possible that these somehow send some data on speed to the head units.
The same principle applies for the sun light sensor. There is no DIRECT connection from the sunlight sensor to the NAVI unit; There are only 2 F-CAN bus lines and in the NAVI, there is F-CAN inputs, so that's probably how the NAVI knows to switch to night mode when its dark.

Webby, I'll look into the A12 input, but it looks like it is a security wire, possible it stores theft code info/activation information.
 
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