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Resonator vs. Muffler – and what you need to know if you change your exhaust


There are plenty of technical terms in the automotive world, few are misunderstood more than a resonator. Ask ten people and nine of them won’t get it right. In fact a resonator, which is NOT a muffler, does an important job in exhaust system. After all, just think of the amount of time invested by the factory to insert this device in most modern vehicles. They wouldn’t do anything unless there is a solid tech reason that warrants such a move.

To begin our discussion, it is critical to understand what a muffler does. As most would agree, a muffler quiets exhaust noise. Regardless of the muffler’s internal design (i.e. chambered, glass pack, turbo, etc.) it must reduce the sound of the exhaust system. If it does not, it might be a resonator – but more on that later.

Take for example a chambered muffler. The hot exhaust air enters the muffler, is directed by the internal deflectors causing cancellation of the some of the more negative frequency sound. A glass pack muffler uses a fiberglass packing to REDUCE SOUND. They both have one thing in common – sound reduction.

A resonator, by its exterior shape, can commonly be confused with a glass pack muffler due to its narrow casing. Like mufflers, resonators come in different styles but commonly use a tube, inside a larger tube along with packing materials. But as opposed to a muffler, a resonator simply TUNES the EXHAUST. It does not necessarily reduce sound and though some do to a much lesser extent than mufflers.

On occasion, when installing a new Legato Performance Exhaust system, owners will remove the resonators thinking that it will increase flow and improve sound. That is far from the case. Often when removing the resonator from a new vehicle, such as a Camaro or a Mustang, the sound will increase slightly but the trade off will be the introduction of drone and/or loss of that cool exhaust note will result. For that reason, we do not recommend removal of the resonator on cars that will be driven on the street at a constant rpm rate below 2500. For racecars, obviously, knock yourself out.

A Note on Flow

Both resonators and mufflers are placed in the tubing that directs the exhaust from the engine our to a safe point outside the vehicle. Most popular mufflers do not restrict exhaust flow dramatically – and that includes chambered mufflers that are often wrongly accused of inhibiting exhaust flow and decreasing potential horsepower. A well-designed muffler, such as those offered by Legato, will increase flow by scavenging exhaust from the combustion chamber. That’s how we make power.


The Factory does a very good job of making the exhaust systems they offer perfect for the average buyer. Legato offers systems that deliver the sound and power that enthusiasts love. But key to that enhancement is not removing parts needlessly. If we offered catback instead of axle back systems for Mustangs and Camaros, we would include a resonator to avoid drone.

Resonators – the key to “tuning” your exhaust system.


*Customer satisfaction with purchased Legato Exhaust Systems can only be guaranteed if the stock system has not been otherwise modified. Note that removal of factory resonators will always result in excessive drone. Use of H-pipes or X-pipes may result in unsatisfactory sound compared to what Legato Performance supplies on an otherwise stock system.