how to filter ambient background noise from a recorded speech signal?

Hello everybody, I have a .wav file containing a conversation between two persons and there is a lot of noisy sound around them (classical music and trickling water). Is there an efficient method that keeps this conversation noiseless.

Would you please help me?

Thanks in advance.

[Shadi Ayyad]

Is there an efficient bandpass filter that keeps only speech in a .wav signal?

[Walter Roberson]

No there is not.

Answer 1

[Walter Roberson]

No, there is no efficient way.

However, you can filter the speech with a band pass filter from about 330 Hz to 4000 Hz and that will provide a start.

http://www.eetimes.com/author.asp?section_id=36&doc_id=1328589

[Shadi Ayyad]

thanks I will try this

[Shadi Ayyad]

I have tried a band pass filter in the range [330-4000Hz] in this piece of code:

[f,fs]=audioread('segment.wav');
n=10;
beginFreq=330/(fs/2);
endFreq=4000/(fs/2);
[b,a](n,[beginFreq,endFreq],'bandPass');
fout=filter(b,a,f);
audiowrite('out.wav',fout,fs);

but the filtered wav signal does not contain any sound at all..

do u have an idea about it?

[Walter Roberson]

What is that line

[b,a](n,[beginFreq,endFreq],'bandPass');

[Shadi Ayyad]

sorry, it is [b,a]=butter(n,[beginFreq,endFreq],'bandPass');

[Walter Roberson]

That would still be invalid syntax. Are you sure you do not have a function name in there, such as butter() ?

[Shadi Ayyad]

yes i have corrected it already it is:

[b,a]=butter(n,[beginFreq,endFreq],'bandPass');

[Shadi Ayyad]

so the range u gave me [330-4000Hz] does not work.. is there any thing to try.. I will send you a figure concerning the spectrum of the wav signal that I have.

[Shadi Ayyad]

the figure i not available.