Sound Symposer Delete: What It Is and Should You Do It?

What Is the Sound Symposer?

The sound symposer is an acoustic device that channels engine intake and exhaust sounds into the cabin through a tuned membrane and tube system. It's designed to enhance the perceived exhaust note at low speeds and light throttle — making the car sound more exciting when the actual exhaust is barely audible.

On the V8 Challenger, the symposer routes intake/exhaust resonance through a tube from the engine bay to the firewall, where a membrane vibrates to transmit the sound into the cabin.

Why People Delete It

On a stock or mildly modified Challenger, the symposer provides some additional sound engagement. But once you've installed an aftermarket exhaust:

1. The car is already loud — the artificial enhancement is unnecessary
2. The frequencies clash — the natural exhaust note and the symposer-transmitted frequency can create an odd combined sound
3. The symposer sound is not authentic — it's a frequency-filtered version of the intake sound, not the exhaust. Enthusiasts often find it annoying once they know what it is.

Common complaint: at low speeds (under 30 mph), an aftermarket exhaust Challenger has a strange, slightly artificial tone because the symposer is blending with the real exhaust note.

How to Delete It

The lazy method (free): Open the hood, locate the symposer valve (a black plastic housing with a vacuum line and a resonance tube, typically near the throttle body area). Unplug the vacuum line and plug it with a cap. The symposer valve stays open (no vacuum) and passes sound, but you've at least disconnected it from vacuum control.

The proper delete:

1. Locate the symposer valve and resonance hose in the engine bay
2. Remove the resonance tube that runs through the firewall
3. Install a cap or plug on the firewall port
4. Remove or cap the symphony valve itself

Cost: Free (just plugs and caps you likely have) to $30–$50 for proper cap fittings.

Does it trigger a check engine light? No — the symposer is a passive acoustic device, not a sensor-monitored component.

After the Delete

The cabin sound signature changes — the low-speed burble is gone, replaced by purely what the exhaust is producing. On a stock exhaust, the cabin gets noticeably quieter at light throttle. On an aftermarket cat-back, the sound becomes cleaner and more authentic.

Many owners with quality exhaust systems (Corsa, Borla) delete the symposer and report the sound is significantly more pleasing without the artificial frequencies layered on top.