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FiX™ 82: OEM Input Connections

FiX 82 Input Connections

The FiX™ 82 accepts up to eight channels (four stereo pairs) of full-range or band-limited output from an OEM audio source (250 mV – 30V RMS). Connections are made via four plugs located on the side of the unit labeled “OEM Analog Inputs”. Each 4-pin plug accepts two channels of audio input, separated in pairs (Left and Right). Engineered to combat induced cable noise, the input architecture is set up in a differential-balanced configuration, making these inputs compatible with virtually any analog audio signal.

The inputs for the FiX™ 82 are labeled as 1/2, 3/4, 5/6 (not channel specific) and 7/8 (sub only).  It is highly recommended that input channels 1/2 always be connected to a midrange signal.  These channels are monitored as part of the auto turn-on circuity and need a solid signal for it to function properly.  

Channels 7/8 must be connected to the factory subwoofer signal as it contains a needed Low-Pass Filter. Often times when the OEM system has a dedicated subwoofer amplifier, the amplifier will have some noise well above the range of the subwoofer. This is normally not an issue since the subwoofer can not reproduce the higher frequencies anyway. The only time this becomes a concern is when you want to sum the subwoofer signal with the midrange and high frequency channels to have a full range signal. The noise that would otherwise only go to the subwoofer and remain inaudible will now be added to the main speakers and will be plainly audible. These dedicated channels have built in low pass crossovers that help to eliminate the higher frequency noise before it is summed together with the other signals. This helps to ensure that the resulting full range signal is clean and noise free.

Depending on the specific architecture of your OEM system, you will need to locate suitable connection points to provide appropriate input signals to the FiX™ 82, while maintaining OEM functionality. It is recommended to obtain a service manual for the vehicle you are working on to locate and identify the correct OEM wires.  Read the article on Finding and Testing OEM Wires for more information.

The FiX™ 82 utilizes high impedance inputs, in some applications the factory amplifier will mute if it doesn't see a low impedance load (such as a speaker).  In this scenario you will need to install a FiX-LSA-4, so the amplifier sees that lower impedance.  To learn more, read our article on When to Use the FiX-LSA-4.

Refer to the table below when making connections with your OEM audio source.


It is vital to observe the correct electrical polarity of each channel’s input signal. Failure to do so can result in improper calibration, loss of signal and poor performance.

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