ARC Audio SRI lead

Many new vehicles come with various features such as OnStar or navigation systems that make headunit replacement difficult and not your best option. If you have been struggling for an inexpensive solution to interface an aftermarket audio system to your car’s OEM system, your struggles are over. From the clever folks at Arc Audio comes the SRI, an OEM integration device that is specifically designed to level match and sum two- and three-way OEM systems to a full range output. With a host of other OEM integration related features, at a very affordable $279 USD, the SRI will likely be a popular choice.

ARC Audio SRI OEM chart


The Arc Audio SRI is a six-channel Signal Restoration and Integration module, capable of summing three separate stereo inputs to a single pair of stereo outputs. Included in the SRI circuitry is a signal sensing turn-on circuit for use with OEM systems that do not have a separate 12-volt trigger lead. In addition to the six channels of high-level input, the SRI features an auxiliary input for easy interfacing with a different source, like your personal music player or gaming console. The included wired remote control provides main aux switching control, as well as level control of the aux source.

Connections to the high-level inputs are made using removable four-wire connectors, and they are clearly marked for channel and polarity. Summing of OEM signals is accomplished via simple summing switches. To correct for the occasional OEM signal that is intentionally wired out of polarity from the factory, a pair of 0-180 “phase” switches are also provided.

ARC Audio SRI IMAG01354

The SRI is a flexible product and provides several different system configuration possibilities. It can be configured to take three different input signals and convert them to a single full-range output, or you can choose to have a full-range output and a non-summed subwoofer, or a summed woofer and full-range output with rear fill, or just use it as a level control for three-way output with no summing. If your OEM system does not have a remote turn-on wire, you have a couple options. You can simply connect the SRI’s remote on terminal to a switched source of 12 volts at the fuse box, or you can take advantage of the auto detect function. Robert Zeff’s patented bridge mode detection circuit will turn the unit on and off by sensing the signal directly from the OEM head unit. Note that this signal must be applied to the left channel of input three to function properly. Once connected, the SRI can provide a 12-volt trigger for your amplifiers using the dedicated remote output connection.

Setting up the SRI is pretty straightforward thanks in part to the logical and well-labeled controls, as well as the included setup CD. Simply play the CD and turn up the radio volume until the level indicating LEDs turn orange. If you reach full volume on the radio with all green LEDs, then you increase the gain by adjusting the three gain pots on the top of the SRI. Once you see a flashing orange LED, you know you have matched your radio to the SRI.

ARC Audio SRI IMAG01353

Should you experience any sort of noise issues, the SRI has a three-position ground isolation switch allowing selection of the appropriate setting to eliminate the noise. The RCA inputs and outputs are gold plated for corrosion resistance and a pair of RJ-45 connections provide balanced outputs for use with the Arc Audio SE series amplifiers.

ARC Audio SRI OEM 01 Max Flat frequency responseARC Audio SRI OEM 02 Aux Input max flat frequency responseARC Audio SRI OEM 03 Separation or crosstalk vs frequency


The SRI shows the pedigree typical of Arc Audio components. Audio performance is excellent, with very low THD and an extremely flat frequency response. Signal-to-noise performance and stereo separation are also very good. The unit simply works exactly as intended. The output impedance, a critical specification in this sort of device, is among the best I have ever measured at a very low 22 ohms.

From a sonic perspective, the SRI is completely transparent. In my listening tests, I cannot detect any hint of its presence in the system, which is precisely the goal. The perfect amplifier was once described as a straight piece of wire with gain. Well, the SRI comes close to that description as a level matching and summing device instead of an amplifier. When properly set up, it’s not even there.


If you find yourself in a situation where you need or simply want to retain your OEM radio, but you really want to improve the system’s amplification and loudspeakers, the Arc Audio SRI interface device should be high on your list of possible solutions. It’s easy to install, sounds great and won’t break the bank. For more information on the SRI and all the other Arc Audio products, you can visit them online at

ARC Audio SRI IMAG01344

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