[umvue]

I have some poor quality tape recording mp3s. They have background noise that makes them hard to hear clearly about the recorded conversation. 
 
I notice many music player software has equalizer feature that can modify sound. Is it possible to use it to filter out noise? If it is possible, how to do that? If not, is there something else I can try?
 
Thanks a lot in advance

 

[ab initio]

You might try rolling off high frequency hiss if the noise is white, albeit at tge expence of rolling off high frequency.

In short, no, i dont think you should think of an eq as a noise filter. Unless the noise has some very unique frequency content that you can selectively remove, the noise and the signal un a recording are inseparable. This is why it is important to prevent noise entering in the first place.

Cheers

 

[SilverEars]

Just a question related to this.  When they remaster old recordings, how to they get rid of the hiss?

 

[bigshot]

Yes, but it's pretty sophisticated. They use pattern matching broadband noise reduction. The way it works is they take a section of silence... the lead in groove in a record, or the space between songs in a tape... and analyze the noise in it using a computer plugin. It determines the frequencies where the noise exists and the proportion from one frequency to another. Then it gives you a slider control where you can dial in more or less noise reduction. This can also be applied dynamically, more noise reduction in quiet passages where hiss would be intrusive, and less in loud passages where the hiss is buried under the signal. If the settings are carefully judged, it works very well. If you want to try it, there is a VST plugin called Sound Soap that does this.
 
If the recording is band limited and doesn't have a lot of information above 6 or 7kHz, the engineer usually leaves a small bed of even hiss in the track. Having some higher frequencies, even if they're just noise, tricks the ear into thinking it has treble that doesn't really exist in the music. It's a psychoacoustic trick.

 

[umvue]

Thanks everyone for the input.
 
Suppose the noise is only a few narrow bumps around certain frequencies, is it possible to filter them out using some software?

 

[bigshot]

The narrower the frequency range, the easier it is. However, tape hiss is a pretty broad range. The best way to fix that is a dynamic broadband filter.