BIRMINGHAM, MI – The relentless pursuit to limit or lessen noise in vehicle interiors extends to items you might think would be overlooked, including the unassuming door latch.

While its noise is heard briefly when entering and exiting the vehicle, automakers nevertheless are taking issue with an overly audible latch.

“As vehicle cabins got quieter, people started hearing more things, good or bad,” Mike Hietbrink, general manager-Kiekert USA, tells media here at the 2016 Tech Crawl event featuring suppliers.

Hietbrink later tells WardsAuto the majority of the 60 brands Kiekert supplies, armed with data from consumer surveys, are asking it to manage latch noise to create a perception of luxury in their vehicles.

There’s no way to create a noiseless latch, but noise can be dampened to create the desired low-frequency sound most OEMs favor, says Hector Verde, director-product development of the Americas for Kiekert USA.

“A lot of customers are looking for a low-frequency sound – that’s what everybody prefers, not a high (-pitched) metallic sound,” Verde tells WardsAuto. Low-frequency sound is associated with luxury thanks to the plentiful door seals found on most luxury models.

“Maybe (certain cars) really don’t have them, but the perception would be low-frequency sound, that you’re sealing the car very nice,” Verde says.

The three areas of noise in a normal latch include opening noise, actuator noise during locking and unlocking and closing noise.

Of the closing noise, “You want it to be as close to refrigerator (-like) as possible – just a thud,” Verde says, adding customers don’t want to hear the mechanical components inside the latch, but want to know the door has closed.

For the power lock/unlock actuator, Kiekert aims for a very short actuation sound, but at a deep frequency.

The German supplier does not use decibels as the primary measurement of noise, because measuring in decibels is not subjective and high-frequency sound at a low dB is possible.

Says Verde, “Then what you have is people saying, ‘Ah, I don’t like the way that sounds,’ even though maybe they can’t hear it so well.”