On the MSN homepage today are some brief details of research apparently underway to cut down the noise from future airliners.
Does anyone else remember research that was publicised 20 – 30 years ago.
IIRC the idea was that microphones took in the noise from the engines and sent the noise back out on ‘loudspeakers’ at the opposite frequency(?) – the two cancelling each other out resulting in silence!
I think experiments were proposed with a BAC 1-11(?) – did they take place??
Roger Smith.
By: MarkG - 6th May 2008 at 14:28
But it is interesting to hear of a system applied to inside – anyone know if the technology for that is anything like I described?
Yes, there’s nothing new about the basic principle, it’s been around for years and is very effective – it’s what’s used in ‘noise cancelling’ headphones.
Put simply, microphones on the headphones ‘record’ the ambient sound in the room/aircraft cabin. That signal is inverted then mixed back in to the sound being played through the headset. The inverted signal then cancels out the ambient noise in the cabin due to ‘destructive interference’ and the end result is that the music, or whatever it is you WANT to hear, is still audible, but the ambient noise is eliminated.
By: RPSmith - 6th May 2008 at 13:38
Yes, I was thinking of external noise.
But it is interesting to hear of a system applied to inside – anyone know if the technology for that is anything like I described?
Roger Smith.
By: WG-13 - 6th May 2008 at 13:38
The technology certainly exists, and has been used effectively in a military application in recent times.
(Other than that, I’m not at liberty to say.);)
By: zoot horn rollo - 6th May 2008 at 13:27
I presume that you are thinking here of external noise? I know that similar work has been done internally for various prop driven airliners to cut down cabin noise and very effective it is too.
By: daniel-k - 6th May 2008 at 13:25
This technology is known to have been used in the Saab 2000 – in the cabin, that is. But for the outside noise… I guess it’s a bit more tricky?
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May 6, 2008 at 11:55 am