on 11/2/02 11:50 AM, richpeet at wrote:
> Ok I tried this in cool edit. I took a Mono track, converted it to
> Stereo, inverted one track, and reconverted it to mono. Sure enough
> there was no signal left.
Rich and All,
I've just tried inverting a sound track in Peak, then mixing it with the
original. Same result as Rich - complete cancellation of the signal, very
dramatic! So I thought to make use of this effect by selecting just the lo=
w
noise out of a recording (using Q10), then inverting that noise, then mixin=
g
it back with the original. It has no effect at all. The fact that I had
passed the signal through the filter seemed to upset the process somehow.
If you wanted to use phase cancellation as a noise reduction method from th=
e
files in the computer, how would you do this? I guess it is easier to use
band pass filtering, but I'd still like to know how to use phase
cancellation for noise reduction on processed sounds. Anyone know?
Vicki Powys
Australia
on 11/2/02 11:50 AM, richpeet at wrote:
> Ok I tried this in cool edit. I took a Mono track, converted it to
> Stereo, inverted one track, and reconverted it to mono. Sure enough
> there was no signal left.
>
> Now I run a ME 67 long shotgun over my 32" dish. My original thought
> was to be able to aim my narrow 32" dish and cya when I overrun the
> preamp on a loud recording received by the dish. But I also see that
> I can pivot my shotgun because of the way I mounted it and will be
> able to point it at single source noise problems, invert and cancel.
>
> How far away can I have the diaphrams of the two mics before I can no
> longer use this technique? Is 24" to far?
>
> --- In Klas Strandberg <> wrote:
>> Using a mono parabol, you can have an extra omni outside of it and
> connect
>> it antiphase. By moving it, you can "tune" your filtering to the
> noise which
>> is present. The remaining noise is the noise which is reflected by
> the
>> parabol "only".
>>
>> Klas.
>>
>>
>>
>> At 14:21 2002-02-10 +0100, you wrote:
>>>> Date: Fri, 1 Feb 2002 09:39:46 EST
>>>> From:
>>>> Subject: Re: noise filtering 101
>>>>
>>>> Jeff,
>>>>
>>>> You audio sounds pretty good after being filtered. Here is a few
> things I do.
>>>> When I have recordings with car noise, I first use the FFT
> filter to do a
>>>> 85dB rumble cut for anything below 120Hz. That gets rid of wind
> noise too.
>>>> When I use noise reduction, I get the profile from the sample,
> manually
>>>> select a line just over the green noise signal, and reduce noise
> by 80dB. I
>>>> noticed your settings are at 40dB. I usually keep the noise
> reduction level
>>>> slider on the low side. Overdoing noise reduction ruins the
> quality of the
>>>> audio, so you might have to play around a little. Cool Edit Pro
> has a hiss
>>>> reduction plug-in that seems to work better than noise
> reduction. There are
>>>> other noise reduction programs available, such as Algorithmix
>>>> (http://www.algorithmix.com), that may work better than Cool
> Edit. I gave up
>>>> trying to get quality audio anywhere near highways, railroads,
> and airports,
>>>> but sometimes that is a luxury that can't be often found.
>>>>
>>>> The only thing you can do about faint recording is to either get
> closer to
>>>> your subject or get a preamp for your mic. For noisy
> environments, getting
>>>> close to your subject is critical for quality recordings. Did
> anyone ever
>>>> think of putting a mic with a long cable on a remote controlled,
> camouflaged
>>>> model boat? Sounds like it could work.
>>>>
>>>> Bruce
>>>>
>>>
>>> I experience a continuing growing problem with noise.
>>> Because of growing population there is always some kind of
>>> unwanted noise somewhere. You can name them all, plains,
>>> trains, highways, farmers with machines or a loud radio on
>>> some populair station. Is it the right way in using all
>>> kinds of systems afterwards? I experience the same problems
>>> with overdone or degrading the wanted sound too much by
>>> cutting too much. With computers today all kinds of
>>> unbelievable filters can be used. But with severe cutting
>>> you degrade the wanted sound often too much. I'm wondering
>>> if it might work when you use a hightech filter between the
>>> mic and the recorder or by using a shotgun with an out of
>>> phase random mic for noise canceling. I suppose its not an
>>> easy task because you have too set the equipment to a
>>> certain level so your ready for recording instantly. Whats
>>> your opinion about this?
>>>
>>> Joop Nijenhuis
>>>
>>>
>>>
>>> To unsubscribe from this group, send an email to:
>>>
>>>
>>>
>>>
>>> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>>>
>>>
>>>
>> This outgoing e-mail is scanned for viruses with Norton 2002
>>
>> Telinga Microphones, Botarbo,
>> S-748 96 Tobo, Sweden.
>> Phone & fax int + 295 310 01
>> email:
>>
>
>
>
> To unsubscribe from this group, send an email to:
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
________________________________________________________________________
________________________________________________________________________
|