Our story yesterday on the fake sounds that surround us every day provoked plenty of comment, lots of debate and an avalanche of suggestions about other artificial noises we should have included. So by popular demand, here are five more sounds that exist purely by design.

The tick tock of a car indicator

In older cars, the click of the indicator was a useful side-effect of the mechanical relay that made the lights blink. That’s not the case anymore. New cars use silent electrical relays, so car makers have to actively engineer the sound the indicator makes.

While at first listen it can seem like all indicator clicks are the same, sound designers at car companies obsessively tweak the noise produced. At Ford’s Advanced Engineering Centre, they have a checklist that includes cadence, attack and decay rates, loudness and frequency.

So while the tick tock of the indicator is there to remind you that it’s working, manufacturers see the sound, just like the clunk of a car door, as a way to indicate the character of the vehicle. Ford has experimented with the sound of crickets chirping, bird song and a golf ball being struck by a club.

The digital camera shutter click

The most frequently mentioned artificial sound that we didn’t include in yesterday’s list was the shutter snap of digital cameras.

While some parts of the world (notably Japan) have made the sound a legal requirement in an attempt to stop covert photography and unseemly practice of upskirting, its mainly there to provide feedback.

Adding a shutter click and the sound of film advancing though neither is necessary is a camera designer’s way of making you sure you got your snap. Though the sound can alert others that your taking photos, most phones with cameras, compacts and DSLRs make it simple to switch it off entirely.

The music of the Segway

The Segway is one of the oddest modes of transport going and some seriously careful thought is put into its construction. That goes as far as structuring the gearbox to get the most melodious gear change sound possible.

The two-stage transmission inside the Segway uses a helical gear assembly which mesh more smoothly and quietly than traditional spur gears. But its designers went even further, carefully configuring the meshes to produce a sound exactly two octaves apart.

The “Harley sound”

The distinctive rumble of a Harley-Davidson engine – which the company itself describes as sounding like “potato-potato-potato” – originally came about thanks to its patented 45° V-twin engines. The design allowed the motorcycle maker to fit a high-torque engine into a small space but caused the cylinders to fire at uneven internals producing the “Harley Sound”.

Changes in regulations and motorcycle design over the years have put the Harley Sound at risk but the company’s noise, vibration and harshness (NVD) department helps maintain it. Its manager, Alex Bozmoski, explained the process in a paper written to celebrate Harley Davidson’s 100th anniversary: “We engineer the sound into the machine: sculpting the noise to produce the right balance of tone, pitch and beat from the intake, exhaust, engine and drivetrain.”

The sound of Harley bikes is tested in anechoic chambers at the Willie G. Davidson Product Development Centre in Wauwatosa, Wisconsin and assessed by a jury of experts from across the company. However, despite Harley’s extreme efforts to engineer the perfect motorcycle noise, it failed to trademark the sound, giving up a long running legal fight back in 2000.

The casino’s disembodied coins

Most casinos have replaced their coin-guzzling slot machines with models that distribute tickets if you win. That’s brought improved security for owners who no longer have to deal with large amounts of cash stashed on the gaming floor but it also promised a loss of the ambiance gamblers expect.

That’s where audio engineers come in. Head to almost any casino and you’ll still hear the sound of cascading coins, specifically structured to tweak the expectations of customers. In Digital Gambling: The Confidence Of Desire And Design by Natasha Dow Schull, an anonymous engineer explains: “We mix several recordings of coins falling on a metal tray and then fatten up the sound”.

International Gaming Technology, a Nevada-based gaming machine maker, boasts that it encodes each of its games with an average of 400 unique sounds to encourage players to stay at the screen. Ultimately, the tinkle of ghost coins is just a small part of a patchwork of fake sounds surrounding gamblers.

Liked this? Try these:

5 fake sounds designed to help humans
Is your photocopier spying on you?
Meet the robot arm that draws your portrait

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  • unity

    ow man, great article!
    One time I heard that the Harleys sound was design to simulate the sound of a horse walk. Do you know something about this?

  • Casas04

    Fact is, lot of noises are added just for feedback: the sound of the keyboard on touchscreens, the bells on elevators, and so on.

  • http://profiles.google.com/colintron Colin Walmsley

    Good fun, but what’s up with the spelling today?

  • guest

    DSLRs have physical shutters; so no, you can’t switch that off.

  • Sanit

    Have to agree that DSLRs have physical shutters, so the sound is real. Also all my cars I have ever owned (newest is 2005) has real relays that click loudly. There really is no such thing as quiet relay, it is either a relay or a power handling device like a TRIAC, MOSFET or high current transistor if it is silent. Relays click…

  • Courtsand

    The Harley ‘sound’ is from the use of a single connection of both cylinders connecting rods to the crankshaft. This is called a single pin crankshaft. Others have copied it, but most opt for more and smoother power from a staggered pin design.
    BTW, the picture ironically is not of a Harley.

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