How to Add Bass Restoration to Your Factory Stereo

Quick answer

Add a dedicated bass restoration processor, like the AudioControl EPICENTER Micro PRO or EPICENTER PRO, between your factory source and amplifier to restore and enhance low frequencies lost in compressed audio or small speakers.

Installation steps

1. Disconnect the battery: Disconnect the negative battery terminal to prevent accidental shorts or power-on damage during installation. Always disconnect power before working on any car audio wiring.
2. Identify the line-level signal path: Locate the RCA or 3.5mm output from your factory source (e.g., head unit, phone, or Bluetooth receiver) that feeds your amplifier. If your factory stereo uses speaker-level outputs, you will need a line-output converter first. If you only have speaker-level outputs, add a line-output converter before the processor.
3. Connect the processor inline: Using RCA cables, connect the source output to the processor's input, then connect the processor's output to your amplifier's input. For the EPICENTER Micro PRO or EPICENTER PRO, use the balanced inputs if your source provides a balanced signal; otherwise, standard RCA works fine. Double-check that the input cable is fully seated to avoid intermittent bass dropouts.
4. Power the processor: Connect the processor's power wire to a 12V source (e.g., accessory tap or fuse box) and the ground wire to a clean metal chassis point. Use an inline fuse rated for the processor's current draw (typically 1A or less). Do not tap into the same circuit as critical safety systems like lights or brakes.
5. Set the subsonic filter and output voltage: On the processor, set the subsonic filter to match your subwoofer's tuning frequency (e.g., 25 Hz for a ported box tuned to 30 Hz). Then adjust the output voltage to match your amplifier's input sensitivity (typically 2V or 4V). Setting the subsonic filter too high will cut off usable bass; setting it too low risks damaging the subwoofer.
6. Tune the bass restoration effect: With music playing, slowly turn up the EPICENTER effect control until the bass sounds full but not boomy. Use the ACR-4 remote (included with the EPICENTER PRO) to make adjustments from the driver's seat. Less is often more; too much boost can cause distortion or amplifier clipping.
7. Secure and test: Mount the processor in a dry, ventilated location using double-sided tape or screws. Reconnect the battery and test with a variety of music to ensure consistent bass response. If bass sounds thin at low volume, check that the processor's input gain is not set too low.

What you need

• AudioControl EPICENTER Micro PRO Bass Restoration Processor: The EPICENTER Micro PRO includes balanced inputs with a built-in line driver, a switchable pfm subsonic filter, and selectable output voltage. These features let you integrate it cleanly into a factory system without extra adapters, and the subsonic filter prevents damage to your subwoofer by blocking ultra-low frequencies.

  

• AudioControl EPICENTER PRO Bass Restoration Processor: The EPICENTER PRO also offers balanced inputs, a built-in line driver, a switchable pfm subsonic filter, and selectable output voltage, plus the ACR-4 remote for easy control. The included remote lets you adjust the bass restoration effect on the fly, which is useful when switching between music genres or audio sources.