Active noise cancelling muffler question.

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The Artist formerly known as Turbo84
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I've always been amused by active noise cancelling systems, and would like to do some playing around with something like that on my Corvette, but I haven't seen much on what is available to use as the (possibly high temperature) speaker. The signal processing seems pretty straightforward, and it would be amusing to have the feedback signal cockpit adjustable to control the volume and tone of the exhaust depending on if you're cruising around, or at the track.

I'll have to do some digging around to see if there are any car enthusiast sites that are playing with this.
 
That is interesting. I have a set of noise cancelling headphones and they work by picking up ambient noise, processing it so that it's 180* out of phase and sending it back to the ear pieces. But remember, we;re talking about headphones too. How big would the thing have to be to cover up a BB with open headers at 6500 RPM?
 
About 20 years ago I was talking to a Walker Exhaust rep - we disscussed that Walker was working on a "Sound Cancelation System" where they would send a sound foreword from the tail pipe to cancel the exhaust sound
 
About 20 years ago I was talking to a Walker Exhaust rep - we disscussed that Walker was working on a "Sound Cancelation System" where they would send a sound foreword from the tail pipe to cancel the exhaust sound

:hissyfit::surrender: that makes no sense on the surface of it, how in hell you going to have flow if the pressure is canceled??
 
I think Lexus used this in the 80's for a short time. I think the issue is packaging. The source of the sound (the engine) and the source of the out of phase sound have to be the same path length to the chamber (muffler)where they are combined. Lexus did this with co-axial pipes. The problem with co-axial pipes is that the inner diameter carries exhaust gases but is restrictive due to it's smaller size.

I don't think anyone is using this technology anymore.
 
I've always been amused by active noise cancelling systems, and would like to do some playing around with something like that on my Corvette, but I haven't seen much on what is available to use as the (possibly high temperature) speaker. The signal processing seems pretty straightforward, and it would be amusing to have the feedback signal cockpit adjustable to control the volume and tone of the exhaust depending on if you're cruising around, or at the track.

Now, I have heard it all.:suicide:
 
About 20 years ago I was talking to a Walker Exhaust rep - we disscussed that Walker was working on a "Sound Cancelation System" where they would send a sound foreword from the tail pipe to cancel the exhaust sound

:hissyfit::surrender: that makes no sense on the surface of it, how in hell you going to have flow if the pressure is canceled??

Maybe read my post again ? :)
 
......The source of the sound (the engine) and the source of the out of phase sound have to be the same path length to the chamber (muffler)where they are combined.......

So, like, they need to be clocked? :rolleyes:


Intersting idea, but I don't see how it could be done passively and wouldn't the complicated technology ( and possibly the wieght of that as well) negate any gains? Except for the bling factor, I can't see it giving any practical improvement to the performance of the car. But hey it could fun to play with as an experiment......
 
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problem solved
 
There was a company that offered this for the C4 back in the late 80's I do believe it was Power Effects exhaust. They had a speaker on the side of the muffler and a on/off switch in the car. I remember hearing it at Bloomington Gold one year.
 
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