Hi! I have a recorded file (wav) where the recorded signal is very weak. When I try to aplify the signal the signal is almost lost in all the noise (mostly high frequency) that also seems to be added from nowhere... maybe it is "white noise"? Are there any program (not expensive) that can can remove this unwanted noise from the file?
amplify without increase of noise
Started by ●February 14, 2007
Reply by ●February 14, 20072007-02-14
By 'amplify' do you mean to scale the numbers up before you play them out, or turn up an analog volume control? Dirk On Feb 14, 10:17 am, "StefanF" <stefan.fr...@passagen.se> wrote:> Hi! > I have a recorded file (wav) where the recorded signal is very weak. When > I try to aplify the signal the signal is almost lost in all the noise > (mostly high frequency) that also seems to be added from nowhere... maybe > it is "white noise"? Are there any program (not expensive) that can can > remove this unwanted noise from the file?
Reply by ●February 14, 20072007-02-14
Stefan, There is a consumer application called SoundSoap which may be suitable for you: http://www.bias-inc.com/products/soundsoap/ Answering the question of whether "is it white noise" may require some additional signal processing involving analysis of the signal spectrum. There are some MATLAB .m files available on the Internet and various algorithms which can be used to remove white noise. Nicholas In article <CKqdnYobXa6GtU7YnZ2dnUVZ_oSnnZ2d@giganews.com>, stefan.fritz@passagen.se says...> Hi! > I have a recorded file (wav) where the recorded signal is very weak. When > I try to aplify the signal the signal is almost lost in all the noise > (mostly high frequency) that also seems to be added from nowhere... maybe > it is "white noise"? Are there any program (not expensive) that can can > remove this unwanted noise from the file? > > > >
Reply by ●February 14, 20072007-02-14
On Feb 14, 11:09 am, "dbell" <bellda2...@cox.net> wrote:> By 'amplify' do you mean to scale the numbers up before you play them > out, or turn up an analog volume control? > > DirkAlso, how are your playing the data out? Dirk> > On Feb 14, 10:17 am, "StefanF" <stefan.fr...@passagen.se> wrote: > > > > > Hi! > > I have a recorded file (wav) where the recorded signal is very weak. When > > I try to aplify the signal the signal is almost lost in all the noise > > (mostly high frequency) that also seems to be added from nowhere... maybe > > it is "white noise"? Are there any program (not expensive) that can can > > remove this unwanted noise from the file?- Hide quoted text - > > - Show quoted text -
Reply by ●February 15, 20072007-02-15
>Stefan, > >There is a consumer application called SoundSoap which may be suitable >for you: > >http://www.bias-inc.com/products/soundsoap/ > >Answering the question of whether "is it white noise" may require some >additional signal processing involving analysis of the signal spectrum. > >There are some MATLAB .m files available on the Internet and various >algorithms which can be used to remove white noise. > >Nicholas > > >In article <CKqdnYobXa6GtU7YnZ2dnUVZ_oSnnZ2d@giganews.com>, >stefan.fritz@passagen.se says... >> Hi! >> I have a recorded file (wav) where the recorded signal is very weak.When>> I try to aplify the signal the signal is almost lost in all the noise >> (mostly high frequency) that also seems to be added from nowhere...maybe>> it is "white noise"? Are there any program (not expensive) that cancan>> remove this unwanted noise from the file? >> >> >> >> >Thanks for your replies! I looked at SoundSoap, and it looks interesting. But there doesn�t seem to be any trial version, and it would be nice to be able to see if it can do what I want before I buy the product. Dirk, what I want to do is to increase the volume since the actual sound I am interested in is quite silent, if you know what I mean. But when I do it with for example an equalizer, lots of "noise" is also added (or amplified). The sound is recorded with an mp3 player, so of course the quality is not so good to begin with. So the question is if it is possible to enhance the quality (reducing the "white noise) without totally destroying the target signal, which is quite weak.
Reply by ●February 15, 20072007-02-15
On Feb 15, 6:16 am, "StefanF" <stefan.fr...@passagen.se> wrote:> >Stefan, > > >There is a consumer application called SoundSoap which may be suitable > >for you: > > >http://www.bias-inc.com/products/soundsoap/ > > >Answering the question of whether "is it white noise" may require some > >additional signal processing involving analysis of the signal spectrum. > > >There are some MATLAB .m files available on the Internet and various > >algorithms which can be used to remove white noise. > > >Nicholas > > >In article <CKqdnYobXa6GtU7YnZ2dnUVZ_oSnn...@giganews.com>, > >stefan.fr...@passagen.se says... > >> Hi! > >> I have a recorded file (wav) where the recorded signal is very weak. > When > >> I try to aplify the signal the signal is almost lost in all the noise > >> (mostly high frequency) that also seems to be added from nowhere... > maybe > >> it is "white noise"? Are there any program (not expensive) that can > can > >> remove this unwanted noise from the file? > > Thanks for your replies! I looked at SoundSoap, and it looks interesting. > But there doesn't seem to be any trial version, and it would be nice to be > able to see if it can do what I want before I buy the product. > Dirk, what I want to do is to increase the volume since the actual sound I > am interested in is quite silent, if you know what I mean. But when I do it > with for example an equalizer, lots of "noise" is also added (or > amplified). The sound is recorded with an mp3 player, so of course the > quality is not so good to begin with. So the question is if it is possible > to enhance the quality (reducing the "white noise) without totally > destroying the target signal, which is quite weak.- Hide quoted text - > > - Show quoted text -Are you running the low-level signal through the equalizer, converting it to integer and then amplifying it, possibly converting it to integer again? Again, you didn't say how you were amplifying it and playing it out as a wave file? Playing it with what? Dirk
Reply by ●February 15, 20072007-02-15
Stefan, Is your signal bandlimited? Then you could simply attenuate the frequencies before amplifying the signal, which is equivalent to adjusting your eq levels. In order to determine the "whiteness" of your noise you would have to look at the power spectral density. White noise has a flat PSD, which means the noise signal is uncorrelated in time. Denoising is a large area of signal processing. Are you just looking for a prepackaged software solution, or do you have access to something like Matlab? What OS are you using? There are many open-source programs which can clean up your wave file. If you're a linux user try the Gnome Wave Cleaner http://gwc.sourceforge.net/ -Marc
Reply by ●February 19, 20072007-02-19
StefanF wrote:> Dirk, what I want to do is to increase the volume since the actual sound I > am interested in is quite silent, if you know what I mean. But when I do > it with for example an equalizer, lots of "noise" is also added (or > amplified). The sound is recorded with an mp3 player, so of course the > quality is not so good to begin with. So the question is if it is possible > to enhance the quality (reducing the "white noise) without totally > destroying the target signal, which is quite weak.You must amplify the signal before it is recorded. Use a high quality preamplifier (either standalone or in a mixing console) and chose the proper microphone (if we talk about audio). If you tell us what you want to record you can get more help. bye Andreas -- Andreas H�nnebeck | email: acmh@gmx.de ----- privat ---- | www : http://www.huennebeck-online.de Fax/Anrufbeantworter: 0721/151-284301 GPG-Key: http://www.huennebeck-online.de/public_keys/andreas.asc PGP-Key: http://www.huennebeck-online.de/public_keys/pgp_andreas.asc