Its possible to reduce noise in this audio?

[Peter Berger]

Its possible to reduce noise in this audio?
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Thanks for any help or tips!

[Greg Miller]

The simplest solution is to apply a small amount (6dB) of noise reduction followed by an additional small amount (6dB) of hiss reduction. You can apply more reduction, but then you eventually produce objectionable audio artifacts.

[Peter Berger]

Wow! What software did you use?
I tried to use noise reduction in Sony Vegas, but there are still some kind of occasional screaking sounds.

[Greg Miller]

I used Cool Edit Pro, which has been replaced by Adobe Audition (unfortunately with a very large price increase).

Luckily, you included some significant intervals of just noise (I was careful to avoid breathing, mouth clicks, or anything else except the pure background noise). I combined a few of those together, sequentially, then used that whole assemblage to get a noise sample. And finally I applied that noise sample to the entire file. I used an NR amount of just -6dB, pretty gentle, so as to avoid "metallic" or "robotic" artifacts. Happily, this lowered the lower-frequency noise quite nicely.

Even after doing that, though, there was a bit more hiss remaining than I liked to hear. So then I used the Hiss Reduction tool, again using the same noise assemblage for a sample, and again using a very modest -6dB NR figure. That produced the file that I uploaded.

Of course there are more settings that I didn't mention within each tool... just giving you a simplified idea of what I did. But it certainly took very little fiddling and probably no more than 15 minutes of time, including converting the file to mono (hey, it's half as much data), and trying a few different settings before settling on my final processing.

CoolEdit / Audition is a good audio package, if you don't mind being held up by Adobe. Frankly, I'm glad I bought it when it was its own company, but that's no longer an option. And, admittedly, Audition has gone through a few versions and has added some features that would be nice to have.

There are a few other programs that attempt to have similar tools. One -- Audacity -- is open source freeware, and you might take a look at that. I gave it a short try a year or so ago, but quickly went back to Cool Edit. My feeling was that Audacity wasn't as good, but I am admittedly biased after using CE for over ten years, and I didn't really relish another learning curve for a program (Audacity) with no apparently advantages. But in your case, the cost (zero for Audacity) might be an incentive.

[Peter Berger]

Thanks for the help! My friend have Audition, so I will try to remove the noise from all my audios with it. I hope I will manage to do it as good as you did :)

[Greg Miller]

Of course it depends on the type of noise. If there is a very pronounced, steady hum (motor, power line hum, etc.) that is just one or two specific frequencies, I sometimes the parametric filter first, to notch out those frequencies. I like to have the hiss filter start with a file that is pretty clean, so I use the hiss filter last. Before that I use the noise filter, but it, too, should be presented with a reasonably clean file; that's why I would notch out steady tones first.

And listen closely at each step. Too much filtering will make voices sound artificial and "robotic" and will completely destroy music. So filter just the least amount that you can.

If your friends have experience using these filters, they can help you with the various settings. Good luck!

[Peter Berger]

Thanks. BTW, could you recommend me some book or DVD where you can learn all these things?

[Greg Miller]

Jay Rose has written a few good books about recording sound for video, and audio postproduction. I highly recommend them for general knowlege about audio.

As far as noise reduction tricks, I've acquired a basic knowledge by working with broadcast and other audio for the better part of 45 years, and then using Cool Edit in various versions over at least ten years.

(I've also used Diamond Cut Audio for some more difficult noise reduction work, but in general I find Cool Edit Pro quite adequate and much more intuitive to use... but, as I said, that may be a personal bias because CEP has become second nature to me.)

Of course by next summer I might be ready for a vacation in Czech Republic, if my friends don't convince me to visit Ukraine first. ;-)

(By the way, Peter, don't forget to give us an update about the low levels with your H1.)

[Peter Berger]

:-)
BTW, this recording was taken by H1 with Rode NTG2.... the speaker had to be really close to the mic (because of the low leves).

[Jim Andrada]

By the way, you might want to look into the Izotope package - I've had very good luck with it.