KVR Audio

stevemej · Post by **stevemej** » Sun Aug 22, 2004 7:27 am

I live near a motorway and, In a nutshell I am planning to try and eliminate noise pollution by sampling the incoming noise, inverting the wave and firing it back to where it came from thus annihalating the noise .

Anyone suggest a starting point. ( I have looked briefly at Wavelab and seen a plugin called clone boy which seems to do something similar to this).

Am I barking up the wrong tree?

Karbon L. Forms · Post by **Karbon L. Forms** » Sun Aug 22, 2004 7:36 am

Just barking maybe.
Would you not need to apply delay compensation to the motorway? Otherwise your inverted wave will be out of sync surely. f**k knows eh?

Dr. Feelgood · Post by **Dr. Feelgood** » Sun Aug 22, 2004 7:46 am

seriously though.... wouldn't the processing have to take place on a device very close to the ear (like a hearing aid)? The inverted sound should be a inverted sound of what you hear, not the actual source. I think there a devices somewhat similar to this concept for patients with tinitus.

jens · Post by **jens** » Sun Aug 22, 2004 7:59 am

HELLO,

WITH MOST MICROPHONES NOISE FROM THE STREET ISN'T A BIG PROBLEM - JUST RECORD FROM THE OPPOSITE SIDE OF THE ROOM TO WHERE THE WINDOW IS.

THANKS

tee boy · Post by **tee boy** » Sun Aug 22, 2004 8:24 am

Steve,
Sorry mate but i really dont think this idea is at all feasible. I presume you intend to remove any recorded noise using phase cancellation? If so, then you need the EXACT same recording (minus your music ofcourse) for it to be effective. As this is totally impossible, so is the task at hand. You'd be much better off looking into ways to isolate your studio from any external noise.

If nothing else works, there are noise reduction plug ins that can analyse a short recording and build an according spectral filter. These can be effective but not the ideal.

stevemej · Post by **stevemej** » Sun Aug 22, 2004 8:38 am

jens wrote:HELLO,

Hi, firstly thanks for replying.
I'm not in the music game I simply want to eliminate noise pollution from my garden. I realise that I will never get rid of it all but i figured if i could have several mic/speaker combinations pointing towards the loudest sources then i might be able to reduce the noise by 50% (so I can drink beer in peace).

THANKS

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stevemej · Post by **stevemej** » Sun Aug 22, 2004 8:42 am

tee boy wrote:Steve,
Sorry mate but i really dont think this idea is at all feasible. I presume you intend to remove any recorded noise using phase cancellation? If so, then you need the EXACT same recording (minus your music ofcourse) for it to be effective. As this is totally impossible, so is the task at hand. You'd be much better off looking into ways to isolate your studio from any external noise.

If nothing else works, there are noise reduction plug ins that can analyse a short recording and build an according spectral filter. These can be effective but not the ideal.

As Mentioned above, I dont have a studio. I just want to reduce the noise in my garden from the motorway. I have thought about wether or not I would need a delay. However, surely it dousnt matter where the opposing waves meet (providing it is before it hits my ears) they should still cancel each other out.

I would be interested to hear what any sound technicians/scientists think

griels · Post by **griels** » Sun Aug 22, 2004 8:50 am

You could try noise cancelling headphones... I believe BOSE makes some. Probably there are in-ear inserts that serve the same purpose.. Not sure where you could get them though.

There was some 'sound beam' thing I heard about which focuses sound waves on a very specific spot. It might somehow be possible to monitor and cancel out the background noise within this spot. But don't quote me

Don't think you can do it for a whole room regardless, as the direction/phase of the soundwaves is non uniform. At least, not without umpteen speakers/mics.

Think your best bet is soundproofing and double glazing, or moving house

jens · Post by **jens** » Sun Aug 22, 2004 8:51 am

stevemej wrote:
Hi, firstly thanks for replying.
I'm not in the music game I simply want to eliminate noise pollution from my garden. I realise that I will never get rid of it all but i figured if i could have several mic/speaker combinations pointing towards the loudest sources then i might be able to reduce the noise by 50% (so I can drink beer in peace).

Hi Steve,

what I meant was the following:

Due to the uni-directional-character of typical studio-mics noise from the street isn't actually that big of a deal. If you have nonetheless very noisy recordings then try to change the miking placement.

I live on a street with heavy-traffic and the big windows (nearly the whole front-side of my flat is glas) aren't the best ones noise-preventing-wise.
Nonetheless I manage to get good recordings without serious noise issues.

E.g. check this recording:

http://zone-x-music.com/mp3/sag_mir-master.mp3

It can be a big pain in the arse if you strieve to record the room's ambience though of course.

jens · Post by **jens** » Sun Aug 22, 2004 8:55 am

stevemej wrote:
tee boy wrote:Steve,
Sorry mate but i really dont think this idea is at all feasible. I presume you intend to remove any recorded noise using phase cancellation? If so, then you need the EXACT same recording (minus your music ofcourse) for it to be effective. As this is totally impossible, so is the task at hand. You'd be much better off looking into ways to isolate your studio from any external noise.

If nothing else works, there are noise reduction plug ins that can analyse a short recording and build an according spectral filter. These can be effective but not the ideal.
As Mentioned above, I dont have a studio. I just want to reduce the noise in my garden from the motorway. I have thought about wether or not I would need a delay. However, surely it dousnt matter where the opposing waves meet (providing it is before it hits my ears) they should still cancel each other out.

I would be interested to hear what any sound technicians/scientists think

- I completely misunderstood you

my bad - sorry

Karbon L. Forms · Post by **Karbon L. Forms** » Sun Aug 22, 2004 8:59 am

http://www.nctgroupinc.com/noisebuster.htm

Svante · Post by **Svante** » Sun Aug 22, 2004 9:09 am

stevemej wrote: I realise that I will never get rid of it all but i figured if i could have several mic/speaker combinations pointing towards the loudest sources then i might be able to reduce the noise by 50% (so I can drink beer in peace).

This is a common technique, a lot of airlines use it in their cabins. The problem is this: if you get destructive interference in one place (cancellation, total silence), you're bound to get constructive interference in another place, which will actually quadruple the acoustic power.

I also live next to a highway, but my windows have triple glazing, and when I shut them ... complete silence. aaahh. Another good thing is acoustic absorbants - textiles, furniture, all soft things - stop the sound waves from bouncing around and thus reduce the sound level dramatically.

stevemej · Post by **stevemej** » Sun Aug 22, 2004 10:54 am

jens wrote:
stevemej wrote:
tee boy wrote:Steve,
Sorry mate but i really dont think this idea is at all feasible. I presume you intend to remove any recorded noise using phase cancellation? If so, then you need the EXACT same recording (minus your music ofcourse) for it to be effective. As this is totally impossible, so is the task at hand. You'd be much better off looking into ways to isolate your studio from any external noise.

If nothing else works, there are noise reduction plug ins that can analyse a short recording and build an according spectral filter. These can be effective but not the ideal.
As Mentioned above, I dont have a studio. I just want to reduce the noise in my garden from the motorway. I have thought about wether or not I would need a delay. However, surely it dousnt matter where the opposing waves meet (providing it is before it hits my ears) they should still cancel each other out.

I would be interested to hear what any sound technicians/scientists think
- I completely misunderstood you

my bad - sorry

Its OK, I am posting in a forum where most people are into music and its quite reasonable to assume this is where I'm coming from.

HAS ANYBODY TRIED REALTIME PROCESSING OF SOUND. WHICH PROGRAMS DID YOU USE ETC?

stevemej · Post by **stevemej** » Sun Aug 22, 2004 11:00 am

stevemej wrote:
I live near a motorway and, In a nutshell I am planning to try and eliminate noise pollution by sampling the incoming noise, inverting the wave and firing it back to where it came from thus annihalating the noise .

Anyone suggest a starting point. ( I have looked briefly at Wavelab and seen a plugin called clone boy which seems to do something similar to this).

Am I barking up the wrong tree?

SEE THIS LINK: http://www.newscientist.com/news/news.jsp?id=ns99992094
ITS WHERE I GOT THE IDEA. UNFORTUNATELY I HAVE BEEN UNABLE TO TRACK DOWN SELWYN WRIGHT SO AM GOING TO HAVE A GO MYSELF>

Also a bit of technical info. I found;
For the technically inclined, this facility measures 6m x 6m x 5m; the eight channel system is based on a Texas instruments tms320c32 processor using a two tap filter and a circular buffer technique to implement the delayed version of the update algorithm. This allows easy algorithm implementation in software and significantly reduces computation time for a large number of channels a 16 - input, 8 - output. PC 16108 provides a 12-bit interface with the external equipment. This board contains three selectable levels of gain: 1,10,100.

stevemej · Post by **stevemej** » Tue Aug 24, 2004 6:42 am

Anybody know of a vst plug-in which inverts the sound wave?

REALTIME SOUND PROCESSING QUERY