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Toyota introduces noise-canceling tech on Crown hybrid
Toyota's Crown Hybrid gets brownie points for good gas mileage, but it's apparently a troublemaker in the motor noise department. Instead of merely adding insulation to the bulkhead, Toyota engineered an Active Noise Control system to reduce engine noise inside the cabin.
The contraption uses three microphones on the interior of the car to detect engine noise. Based on the frequencies they detect, one speaker in each of the front doors and a woofer on the rear shelf create antiphase signals to cancel out the noise. The canceling is set up to occur at passenger head level, and does not interfere with the music system or your own talking.
The Crown Hybrid, released this year in Japan, uses a slightly modified version of the hybrid system from the Lexus GS. Active Noise Control reduces cabin noise from the engine by about five to eight dB, and is permanently on. It's probably not out of the question that the Active Noise Control will make the jump to other Toyota products, and perhaps even Lexus models once they figure out how to put solid gold connectors on it.
[Source: Gizmag]
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Reader Comments (Page 1 of 2)
Vintage 10:03AM (7/18/2008)
This idea has been around a very very long time.
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EVan 11:28AM (7/18/2008)
+1
This technology has been around for quite a while. It's plagued with problems though and doesn't play nice with aftermarket audio.
Yar 10:14AM (7/18/2008)
"Get out of the vehicle, now!"
"Officer, I swear, I didn't hear..."
"Stop resisting!"
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XcRuNk 10:15AM (7/18/2008)
That's clever.
Now is there a switch to make the hybrid engine sound like a V12 or a 426 Hemi?
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Vintage 10:21AM (7/18/2008)
Actually, that's existed a very long time too. Back when the Discovery Channel had that "Beyond 2000" show on TV (1990-1996 or so?) they had a british small car outfitted with noise cancelling technology, a rpm sensor, and a computer that could emulate the noise of many different engines. You could make it sound like a ferrari, v8, whatever you wanted. It was pretty cool. :)
tankd0g 10:18AM (7/18/2008)
I certainly wouldn't pay for that if it was an option.
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FordFreak 10:58AM (7/18/2008)
me too, I'd never PAY for that- I'm sure there's more worthwhile options avalible...
FordFreak 10:23AM (7/18/2008)
I assume this is far more complex than the system Honda uses in the 2008 Accord. Anyone know?
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robu 10:39AM (7/18/2008)
It looks like it's the same. Since it is reading the engine RPM it looks like it is only trying to cancel the main combustion noise. For an 6 cyl at 6000 RPM, that equates to a frequency of 300 Hz. This is a much easier thing to accomplish that trying to cancel broadband noise.
Ken 10:42AM (7/18/2008)
Yes its more complex than the system on the Accord. The Accord's system is used to cancel the NVH from the variable cylinder mode. Low frequency rumbling is canceled only.
The '09 Acura RL has a much higher tech setup, cancelling many noises over a wider audio spectrum. At low RPM's it engages completely. The higher the RPM's, the less noise is canceled for a more "sporty" drive.
How it compares to the Toyota system is beyond my scope.
Clinton 10:23AM (7/18/2008)
I think this technology is a great way to reduce the weight of sound deadening materials. Lighter vehicles are good, yes?
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FordFreak 10:29AM (7/18/2008)
Saving weight is good for MPG and acceleration, obviously. But I'm curious as to the long term reliability of it. If it suddenly gets louder inside, clue-less elderly people may think something's gone terribly wrong. That is if they acctually HEAR the difference...
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dejal 10:40AM (7/18/2008)
As opposed to clueless ford freaks?
Shipey 10:55AM (7/18/2008)
@dejal
He didn't even say anything remotely inflammatory. Why the negativity?
@FordFreak
Toyota parts never fail, remember?
Seriously though, this is a useful technology and I'm surprised it took this long to find its way into vehicles. It's been around in stereo headphones for quite a while. If the sound could be generated from the regular stereo speakers, this could be a good way to cut down on weight, as others suggested.
dejal 1:26PM (7/18/2008)
"Clue-less eldery".
Why?
Just insulting for insultings sake.
His (hers,its) premis is that if you are old you are stupid.
Really? So, when you get old, are you planning to off yourself so you won't be clueless? Why wait.
Blake 8:58PM (7/18/2008)
@dejal:
""Clue-less eldery".
Why?
Just insulting for insultings sake.
His (hers,its) premis is that if you are old you are stupid."
I didn't get the impression that he meant that at all. I think you just took it that way.
rob 10:45AM (7/18/2008)
It's probably not going to save that much weight. The system will work best on the tonal noise generated by the powertrain in a very limited frequency range. It will not do too well with the broadband noise generated by the tires and wind that get into the interior. The passive noise control treatments will do a much better job than an active system in general.
There is a pretty significant amount of noise that is passed into the interior through the glass (approximately 4000 Hz). The number of sensors and speakers required to cancel this noise would be cost/complexity prohibitive.
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FordFreak 10:45AM (7/18/2008)
Yes as opposed to "clueless" ford freaks :) !!!
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rob 10:52AM (7/18/2008)
A number of years back Nissan had a noise control system in one of their vehicle. As I recall, during the second model year they added an on/off button so that people could actually tell that it was working.
Keep in mind that it takes roughly a 10 dB drop in sound pressure to appear to be half the loudness. So the 5 dB drop noted above is not that big of a change. And since it is likely to be affecting the combustion noise only, it's perceived effectiveness is probably not that good. At 60 kph and above, much of the noise you hear in your vehicle is from the tires, which are fairly broadband noise sources.
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s13hybrid 11:23AM (7/18/2008)
This is true. Most new cars' engines are so quiet they are hardly the problem. Most of the noise is coming from wind passing by the car, and depending on the tires a lot of noise will come from that.
I for one would rather be able to hear my car so I can be aware of problems.