An independent engineer has reverse-engineered Honda's proprietary factory audio signal. The device, called Pure from startup S2iAudio, plugs into the factory wiring harness in place of the stock amplifier and hands an unprocessed digital signal to an aftermarket DSP — no factory wires cut, and the car returns to stock by simply unplugging it.
Founder Ash Shabudin started the project after buying a 2025 Acura Integra Type S and deciding he didn't want to sum the factory analog outputs, since there's no way to know what processing is already baked into them. Cracking it meant identifying a proprietary RS485 control stream — carrying volume, bass, and EQ commands — running alongside the audio, on a connector that doesn't even appear in Honda's parts catalogs.
Pure decodes that control signal and manages the digital audio feed to the DSP. The shipping Gen1 ($350) mimics the analog remote-level input found on DSPs from brands like Helix and Arc Audio, while the just-finished Gen2 ($400) handles volume attenuation on the device itself and works with any amp or DSP with a TOSLink input. Compatibility covers popular Honda and Acura models from roughly 2016 onward, including the Civic, Civic Type R, Accord, CR-V, Pilot, Odyssey, Ridgeline, and Integra with premium or Bose factory systems.
Why it matters for tuning: starting from an unprocessed digital signal means your DSP is working with a flat, known input instead of fighting hidden factory EQ that changes with volume. If you've measured a summed factory signal before, you've likely seen response curves that shift as you turn the knob — a clean digital feed removes that variable, so your measurement and your correction actually stay valid at every listening level.
One install note from the maker: if you want to keep factory features like navigation prompts and voice calls, pick a DSP that supports signal ducking so those sources still take priority. Pure is available now direct from S2iAudio.
