Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
References: <firstname.lastname@example.org> <$cHaBGAC4uC+Ew2G@jmwa.demon.co.uk>
Subject: Re: Sound cancellation technology?
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Thu, 26 Dec 2002 22:20:17 -0000
NNTP-Posting-Date: Thu, 26 Dec 2002 22:20:21 GMT
John Woodgate wrote:
> I read in sci.electronics.design that Phil Allison
> wrote (in ) about 'Sound
> cancellation technology?', on Thu, 26 Dec 2002:
>> "John Woodgate" wrote in message
>>> I read in sci.electronics.design that Lady Liberty
>>> wrote (in
>>> ) about 'Sound
>>> cancellation technology?', on Wed, 25 Dec 2002:
>>>> Fine but not my question. Could someone please answer the actual
>>> OK, it is almost certainly possible, but would be very costly, not
>>> necessarily in terms of equipment but in the custom DSP software
>> ** Really ?
>> How do you cancell by a factor of 60 dB *any* noise that
>> intrudes into a bedroom ? This may include barking dogs next to
>> the window, road traffic noise of all sorts at close range, aircraft
>> noise, neighbours activity impacting the floor/ceiling interface
>> with deep, powerfull sub sonics etc, etc.
>> These create sudden and disturbing noise in the room at almost
>> any frequency 60 dB or more above ambient with attendant internal
>> reverberation and varying phase at any point and arriving from any
>> of dozens of sources and directions ??
> Well, your 60 dB appeared out of the woodwork, and such an extreme
> level of cancellation may not be necessary. The answer, anyway, is,
> with great difficulty and at great cost, as I said.
I generally solve this by the masking theorem. I turn up my 1000W and
1400W amplifiers to mark 11.
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.