[TusharK]

An Israel-based firm called Silentium has developed active acoustics software that is claimed to remove 90% of unwanted cabin noise.

The active road noise cancellation system is said to filter out frequencies in the range of 20 Hz and 1 kHz. It works just like noise-cancelling headphones. The system uses 6 accelerometers that are mounted on the chassis at specific locations. These monitor unwanted road noise and send signals to an on-board control unit.

The control unit uses Silentium's software that plays an equivalent anti-noise signal through the car's speaker system. Both pressure waves reach your eardrums at exactly the same time and cancel each other out.

This technology could also help reduce the weight of the vehicle as carmakers would be able to reduce the amount of noise insulation materials used in cars.

The technology has been adopted by Jaguar Land Rover in the F-Pace and Velar.

https://www.youtube.com/watch?v=pUDu_pyaMtQ

Link to Team-BHP News

[shobhit.shri]

Awesome concept! How does it works against the "desirable" sounds, both from inside and out like ambulence horns and people talking in the cabin?

[QuadraticAmoeba]

This sounds like a very interesting technology with good potential. I own some noise-cancelling earphones, and they are very nice to use on busses and planes.

They do give me a headache after prolonged use. Based on this, I wonder what the downsides of this technology are? I'm sure one of the cons is cost, noise-cancellation technology is probably not very cheap.

[anumod]

Endeavour already has the same technology and it works very well . Is there any new tech addition in this news ? The only difference I can see is the higher frequency band in this tech (Endeavour has a range of 30 Hz to 180 Hz )

[Cessna182]

The graph has been zoomed in for visual impact, but it oscillates between 58 and 65 db. While this is a good demonstration of the technology, I don't think it will be very perceptible to the human ear. maybe if 10 db or more reduction was demonstrated, it would make it clearer if the human ear can discern this.

[Beelzebub]

Originally Posted by anumod

Endeavour already has the same technology and it works very well . Is there any new tech addition in this news ? The only difference I can see is the higher frequency band in this tech (Endeavour has a range of 30 Hz to 180 Hz )

Ford Endeavour's active noise cancellation works for narrow frequency band of 30 Hz to 180 Hz, which mainly cancel Engine Noise of lower frequency band. And since all 3 microphone are placed inside cabin, I don't think this tech works well for road noise or other traffic noise (which are in higher frequency band). As per Article (Source 1-Link given below) while the frequency range of interest (30 Hz to 180 Hz in Ford Endeavour), the system can reduce unwanted background noise anywhere between five and 15 decibels, however the system is capable of reducing overall noise by up to three decibels. Since this is not much effective in reducing road noise and traffic noise, hence not marketed by Ford as much as Jaguar and Land Rover.

As per study (Source 2),

A change of 3 dB is accepted as the smallest difference in level that is easily heard by most listeners listening to speech or music. It is a slight increase or decrease in volume.

On the other hand, the tech by Silentium works in broad band of frequencies – from 20Hz up to 1kHz and is able to reduce noise peaks by 10dB in this frequency range and overall noise levels by 3-4dB (Source 3).
The frequency of road noise is around 1 kHz (typically ranges from 700 Hz to 1,300 Hz) and frequency of traffic noise peaks around 1 kHz (source 4) hence theoretically this system works better in reducing road noise and traffic noise along with engine noise.

The noise levels and spectral content of highway traffic noise
are influenced by vehicle type, volume, and speed as well as
pavement type. The spectral content for passenger vehicles
typically peaks and is dominated by frequencies around
1,000 Hz. Spectral content for heavy trucks typically peaks
and is dominated by frequencies from 500 to 1,000 Hz.

Source 1: https://autotechreview.com/conversat...gy-explanation

Source 2: https://jlaudio.zendesk.com/hc/en-us...oubling-Output

Source 3: https://media.jaguarlandrover.com/en...driver-fatigue

Source 4: https://acousticstoday.org/wp-conten...hway-Noise.pdf

[IP_Man]

Originally Posted by shobhit.shri

Awesome concept! How does it works against the "desirable" sounds, both from inside and out like ambulence horns and people talking in the cabin?

It works on destructive sound wave interference. Out of phase sound waves, when they meet, cancel each other.

In a car, especially diesel, lot of low frequency noise infiltrate in the passenger cabin. Source of noise may be drone like sound from engine and rumble of noisy tyres. This tech has a microphones strategically placed in the cabin to measure low frequency noise to generate equal and out of phase sound waves through built in speaker to cancel noise.

It works effectively only on the low frequency sound waves so mid frequency sounds like outside honking, conversation, music won't gets affected.

I have personally checked, it works beautifully on Ford Endeavour.

[Zinda]

Useful Tech with immense potential. So, this new Tech can take care of Engine noise, Tyre noise and apparently of wind noise too

Will it cancel the rattling "noise" as well?

[frewper]

Originally Posted by Zinda

Useful Tech with immense potential. So, this new Tech can take care of Engine noise, Tyre noise and apparently of wind noise too

Will it cancel the rattling "noise" as well?

We definitely need this tech for Maruti, it can do wonders for them, iron out those nasty rattles.

I wonder how much all this tech is gonna cost though. Because noise cancellation is not even common in the lower end earphones (even 1k-2k range).

[ach1lles]

Since I have been introduced to and have understood the active noice cancellation tech, whenever I hear any unwanted sound in or around my place I immediately think of a time when this tech, and sensors would be generalised enough to be used everywhere: the washing machine, the mixer grinder, dish washer, the neighbours generator, the fan, the exhaust, the AC blower etc.

The tech is quite simple in its principle and has been around for sometime. It should be easier to implement for appliances too, because they'd be at one place and mostly noising in a set range of frequencies. Next billion dollar start-up idea right here

[vjbox]

I have always been curious about this tech. I although wonder how can one use the car's speakers to listen to music if the noise cancellation tech uses it instead to cancel the road noise ? So its got to be either listening to radio/music or noise cancellation, yes?

[v1p3r]

Originally Posted by vjbox

So its got to be either listening to radio/music or noise cancellation, yes?

Nope, both work together. Just like with NC earphones or headphones. Though the louder/more constant the main sound (voice/music) is, the less you will need or hear the NC effect.

[vjbox]

Originally Posted by v1p3r

Nope, both work together. Just like with NC earphones or headphones. Though the louder/more constant the main sound (voice/music) is, the less you will need or hear the NC effect.

Ah got it - that explains that. I am certainly very keen to get a first hand experience with this tech though.