Forums

Source Separation

Started by dbormpou February 27, 2008
Hello 

I am a biologist and i am trying to eliminate 
certain sounds from a stereo recording eg the sound of 
cars from the recording of a park, without loosing a
lot in audio quality.

I have some experience in audio and computers
though i am not familiar with programming

I need suggestions on some programms i can use
for this purpose

Thanks
Dimitris    


On Feb 28, 2:02 pm, "dbormpou" <dborm...@bio.auth.gr> wrote:
> Hello > > I am a biologist and i am trying to eliminate > certain sounds from a stereo recording eg the sound of > cars from the recording of a park, without loosing a > lot in audio quality. > > I have some experience in audio and computers > though i am not familiar with programming > > I need suggestions on some programms i can use > for this purpose > > Thanks > Dimitris
Forget it. Unless the sounds differ in frequency content it is a bit like mixing paint and then trying to un-mix it. Are you trying to get rid of cars parking over the sounds of say birds singing? You could get rid of some of the lower frequencies for sure. Hardy
HardySpicer wrote:
> On Feb 28, 2:02 pm, "dbormpou" <dborm...@bio.auth.gr> wrote: >> Hello >> >> I am a biologist and i am trying to eliminate >> certain sounds from a stereo recording eg the sound of >> cars from the recording of a park, without loosing a >> lot in audio quality. >> >> I have some experience in audio and computers >> though i am not familiar with programming >> >> I need suggestions on some programms i can use >> for this purpose >> >> Thanks >> Dimitris > > Forget it. Unless the sounds differ in frequency content it is a bit > like mixing paint and then > trying to un-mix it. Are you trying to get rid of cars parking over > the sounds of say birds singing? > You could get rid of some of the lower frequencies for sure.
The spectrum of bird song is very different from the spectrum of a car. Whilst there are no magic cures that can completely eliminate the interference from a recording, spectral subtraction techniques can often help a bit. They tend to cause a lot of artifacts. They can make the audio sound downright spooky on some occasions. However, that may or may not be a show-stopper. It depends on the user's goals - identification good, the next great natural history program for BBC Bristol bad. Steve
>On Feb 28, 2:02 pm, "dbormpou" <dborm...@bio.auth.gr> wrote: >> Hello >> >> I am a biologist and i am trying to eliminate >> certain sounds from a stereo recording eg the sound of >> cars from the recording of a park, without loosing a >> lot in audio quality. >> >> I have some experience in audio and computers >> though i am not familiar with programming >> >> I need suggestions on some programms i can use >> for this purpose >> >> Thanks >> Dimitris > >Forget it. Unless the sounds differ in frequency content it is a bit >like mixing paint and then >trying to un-mix it. Are you trying to get rid of cars parking over >the sounds of say birds singing? >You could get rid of some of the lower frequencies for sure. > >Hardy >
Well i was kind of aware of that but i have heard samples of source separation algorithms and i was impressed. They have pretty clearly separated eg the guitar sounds from the rest a song, and i think that would be the way to go for me. Any help? D.
This may work for a studio recording, where the stereo is composed of 
mono signals in a very defined way. If you have a recording with just a 
stereo mic, I see no way...

dbormpou wrote:
>> On Feb 28, 2:02 pm, "dbormpou" <dborm...@bio.auth.gr> wrote: >>> Hello >>> >>> I am a biologist and i am trying to eliminate >>> certain sounds from a stereo recording eg the sound of >>> cars from the recording of a park, without loosing a >>> lot in audio quality. >>> >>> I have some experience in audio and computers >>> though i am not familiar with programming >>> >>> I need suggestions on some programms i can use >>> for this purpose >>> >>> Thanks >>> Dimitris >> Forget it. Unless the sounds differ in frequency content it is a bit >> like mixing paint and then >> trying to un-mix it. Are you trying to get rid of cars parking over >> the sounds of say birds singing? >> You could get rid of some of the lower frequencies for sure. >> >> Hardy >> > > Well i was kind of aware of that but i have heard samples of source > separation algorithms and i was impressed. They have pretty clearly > separated eg the guitar sounds from the rest a song, and i think > that would be the way to go for me. Any help? > > D.
On Feb 27, 8:02&#2013266080;pm, "dbormpou" <dborm...@bio.auth.gr> wrote:
> Hello > > I am a biologist and i am trying to eliminate > certain sounds from a stereo recording eg the sound of > cars from the recording of a park, without loosing a > lot in audio quality. > > I have some experience in audio and computers > though i am not familiar with programming > > I need suggestions on some programms i can use > for this purpose > > Thanks > Dimitris &#2013266080; &#2013266080;
If you can use a directional microphone, so you only get the bird's sounds. Clay
>On Feb 27, 8:02=A0pm, "dbormpou" <dborm...@bio.auth.gr> wrote: >> Hello >> >> I am a biologist and i am trying to eliminate >> certain sounds from a stereo recording eg the sound of >> cars from the recording of a park, without loosing a >> lot in audio quality. >> >> I have some experience in audio and computers >> though i am not familiar with programming >> >> I need suggestions on some programms i can use >> for this purpose >> >> Thanks >> Dimitris =A0 =A0 > >If you can use a directional microphone, so you only get the bird's >sounds. > >Clay > >*******************************************
Hello Dimitris, what exactly is your goal? what kind is the sound that you want to isolate? Is it indeed birds? Is it the sound of a specific species, or generaly you want to study the overall sound of the park? Manolis
dbormpou wrote:
> Hello > > I am a biologist and i am trying to eliminate > certain sounds from a stereo recording eg the sound of > cars from the recording of a park, without loosing a > lot in audio quality. > > I have some experience in audio and computers > though i am not familiar with programming > > I need suggestions on some programms i can use > for this purpose
This isn't hopeless. It's not only difficult, it's best described as magic. There are no programs that pop out the result, but an experienced manipulator with a variety of techniques at his disposal might be able to effect a remarkable isolation. (Don't be taken in by the crime-lab shows. They're fiction, after all.) One hears about the few successes, not about the majority; the useless attempts. Can you isolate the sounds you want before recording them? A highly directional microphone is one way; a radio microphone close to the source is another. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
On 28 Feb, 02:02, "dbormpou" <dborm...@bio.auth.gr> wrote:
> Hello > > I am a biologist and i am trying to eliminate > certain sounds from a stereo recording eg the sound of > cars from the recording of a park, without loosing a > lot in audio quality.
The simplest problems to handle are those that never occur. The best, by far, method is to try and plan the recordings such that you use highly directional mics and position yourself such that you can point them at the source of interest with as little noise from the background as possible. Assuming you want to record sounds of birds, this means that you get as close as possible under the tree where a bird sits, and point the mic at it with the sky as background. Or you point the mic at the ducks swimming in the pond making sure that the garden shed and shrubbery act as acoustic screens with respect to the street traffic behind. Of course, that's of little help with respect to the recordings that already have been made... Rune
On Feb 28, 3:48 am, "dbormpou" <dborm...@bio.auth.gr> wrote:

> >... > Well i was kind of aware of that but i have heard samples of source > separation algorithms and i was impressed. They have pretty clearly > separated eg the guitar sounds from the rest a song, and i think > that would be the way to go for me. Any help? > > D.
Source separation algorithms require knowledge of some kind of difference between sources such as frequency, duration, direction, coherence or distribution. You have given no description of the signals or their differences for us to work with. So, you have gotten answers about collecting better recordings. Algorithm help will require more information from you. Your example may have separated coherent tones (guitar) from modulated noise (voice). What do you need to do? Dale B. Dalrymple htp://dbdimages.com