Audison ASP - AP BIT AUTOMATIC SPEAKER PRESENCE
In order to solve the problem associated with OEM amplifiers that feature signal interruption, shutting down when a proper speaker load is not present as often found in aftermarket integration, the Prima amplifiers feature ASP(Automatic Speaker Presence). Available as an optional plug-in accessory, this circuit provides the ability to simulate the OEM speakers presence during the short time frame the head unit performs the check after being turned on.
It is ASP is indispensable when installing AP8.9 bit with some OEM sources requiring, only at the initial turn-on instant, a resistive load impedance at the outputs to detect the speakers presence.
In case there is no load, the source disables the outputs, usually only for the Rear section.
Therefore, if during the calibration process you cannot adjust the input signal level due to lack of signal on some or all of the AP8.9 bit inputs, while installing the ASP module, when you turn on the AP8.9 bit a temporary load will be simulated; afterwards that load will automatically get disabled, fixing the issue.
Thanks to ASP, there is no need to mount fixed power resistors at the source outputs; the resistors would produce heat and, in addition to that, would make the source heat up unnecessarily. the RCA inputs or portable auxiliary sources using the 3.5 mm RCA/Jack adapter.