Mazda goes all out on Mazda3 NVH improvements

MAZDA has made significant strides to improve noise, vibration and harshness (NVH) levels on its all-new Mazda3 small sedan and hatch range, as part of a push to give its best-selling model a more upmarket feel.

Speaking to GoAuto in February, Mazda Australia engineering and compliance manager Wayne Watson described poor NVH as the “Achilles heel” of the previous-generation version, resulting in Mazda engineers making a total of 49 changes specifically designed to improve refinement.

One of the ways in which in-cabin noise was reduced in the new Mazda3 was through reducing the vibration energy through the car, which has been achieved in part by using damping ‘nodes’ that sit inside the car’s steel panels – at the top of the B-pillar, under the car’s floor and at the rear.

The nodes are complemented by larger damping bonds that run along the width of the car’s structural panels and help to absorb thermal energy.

Additional insulation was included on the headliner and floormats designed specifically to process high-frequency sound without having it reverberate around the cabin, which helps to reduce the sharp change in noise levels by up to 7-8dB when transitioning from smooth to rough road surfaces.

Mazda has also designed a brand-new tyre for the Mazda3, with the new Toyo rubber made to better absorb and distribute the impact of bumps on the road thanks to an optimised vertical spring action.

One of the biggest points of focus for Mazda was reducing the number of holes in the vehicle’s parts to reduce the amount of noise entering the cabin, as an aperture of just one millimetre in diameter can reduce noise prevention by up to 30 per cent.

Ways in which Mazda have improved this include reducing the number of holes used in the production and assembly process, plugging holes such as around the transmission lever, moving the holes for the door speaker to the cowl of the footwell, and reducing the number of air extraction holes.

Other changes to sound insulation include the inclusion of sound absorption around the engine and wheelarches, new seals and glass, changes to suspension damping, and the use of better materials in the cabin to prevent noise from bouncing around.

Mazda has also worked hard on developing an overhauled sound system – either an eight-speaker in-house unit or 12-speaker Bose system on higher grades – that reduces the amount of buzz in the cabin and repositions the speakers to point towards the driver.

The new system is designed to let users listen to music at any volume they like while delivering ideal noise frequencies and recreating accurate hi-fi sound quality.

Overall, the noise level of the new Mazda3 is comparable to the CX-5 medium SUV.

Mazda Australia managing director Vinesh Bhindi said the focus on improved refinement will continue across Mazda’s range as new products are revealed and put on sale.

“This is the new direction for Mazda in terms of product development,” he said.

“The improvement that you see in the Mazda3 I think is a new start or a big step forward, and I suspect the engineers at Mazda Corporation will continue to do that as time goes on.

“So, what that looks like, how far forward from current, I think you’ll have to wait until the next products come out.”