Looking for app or ZST plugin to remove unwanted noise

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Does anyone know of an application or ZST plugin that can remove sound from an audio sample of a certain frequency? Specifically, I have an audio file in which during a quiet song mobile phone interference cuts in. The sound is of a very specific frequency and given the right software I think it would be possible to remove or minimise the volume of the offending noise.

You might be able to notch it out with parametric EQ.

You can try Audacity. There's a built in noise removal plugin that supports noise profile. Reaper's built in FIR plugin should also give ok result.

I've head good words of iZotope RX, but it's very expensive. May be you can use it in trial mode and record the result.

Look for compressors (musical, not air.... They function to do what you're asking for. You can set them to cut off or include sounds above a certain level. At least that's what analog ones do, it's one reason commercials are so dang loud...

As mentioned earlier, there are some noise reduction plugins, but any method of reducing noise will have an impact on the overall sound at that point. The key is to use the plugin only on the section with the noise. If it's a higher frequency, sort of like tape hiss, you may be able to low pass filter the frequency with minimal damage to the part you want to hear.

A compressor will not work for this purpose. A compressor is used to reduce the dynamics of a recording (and is frequently abused in current music recordings to increase volume levels--google loudness wars for more). This is done by reducing volume when it goes over the threshold. A compressor will make the noise more prominent.

well, in that case you need a filter; high pass, low pass, or band pass. Graphic equalizers will help with specific frequencies.

Compressors can set a noise floor that will get rid of some of it. It depends on the overall effect you're going for. Eventually if you process a signal enough, it sounds that way. For the most part, you can only get rid of things that are there. It's hard to add something that isn't there to begin with.

No reason you can't use both.

Howdy, audio restoration engineer here.

If you have access to Adobe Audition (any version), it has a notch filter that will do exactly what you want. You can view the waveform in spectral mode and see the frequencies (fundamental and harmonic) as yellow lines; highlight the section with the offending frequencies, open the Frequency Analyzer, scan the selection, note the frequencies that appear as peaks on the graph, write them down. Open the Notch Filter, enter the numbers in the boxes, specify how many dB to attenuate them, hit OK, and poof! gone.

As if that were not enough, Audition 3 has what is called a Healing Brush. Again, in spectral, zoom on the section, click on the Healing Brush, and draw a line over the frequency with the cursor. It disappears. I love technology!

I've used this procedure to remove the sound of a squeaky bass drum pedal in some old records. It works like a charm.

As mentioned, compression won't do it for you, and noise reduction will affect all the other adjacent audio, besides, you couldn't isolate the frequency with NR. Notching or healing will remove the offending sound, while leaving everything else around it intact.

I will look into getting Adobe Audition, it sounds like the right tool for the job.

No, notch filtering will not remove vocal tracks. The only way this is achieved is subject to an absolute: the vocal must be panned dead center in the stereo image. Then the stereo image is OOPSed (turned 180 degrees out of phase), and the vocal disappears due to phase cancellations. But so does everything else that was panned dead center, like the bass, some of the drums, particularly the kick, and any other instrument not panned anywhere left or right. If your vocal is mono but has stereo reverb or echo, you'll still hear the reverb or echo. If you have double-tracked vocals panned slightly left and slightly right, you'll still hear them.

I believe there is some karaoke equipment that has enhancements of some kind on this technology, but I don't know anything about it. If you want to hear a music track without the vocal, you've pretty much got to have the master multitracks, and mute that channel. Otherwise, forget it!

Anecdotally, on The Beatles' White Album, the tracks "Birthday" and "Ob-La-Di Ob-La-Da" have all of the music in mono, panned dead center, and all of the vocals in stereo. If you OOPS the track, the music disappears, and you can hear them singing acapella, and cracking each other up during the take. These little asides are hilarious, but totally buried in the stereo mix.