Denoise process

Forum|Forum|4 years ago
April 9, 2022
3 replies
336 views

I hope someone could please help me understand something when denoising a recorded audio clip

I have a ambient cell phone audio recording and there is a tremendous amout of heavy machinery and fans going which make it nearly impossible to hear anything else but when putting the recording through a denoising app and the speech is enhanced and most all of the loud noise is reduced there are voices that appear on the recording but very very distorted and echoey and underwater type sounding. My question is one are those voices being picked up from a far distance from the phone and when the noise is reduced the phone just so happened to pick it up In the distance? Cause when the recording is Denoised to full levels the voices become even more distorted and echoey. You are able to hear the phone being moved while its recording and from time to time hear the person holding the phone cough or say something which comes through as if there are closer than the voices that appear as in the distance .whar is the distance a ambient cell phone recording would be able to pick up also?

someone please help

This topic has been closed for replies.

A

Anonymous

Here is the clip without any editing

audiofile_raw(1).zip

SteveG_AudioMasters_

Community Expert

I've just listened to the start of this, and I have to say that it's not the sort of noise that an NR process will take out effectively because it's anything but constant. If that's going on behind the speech, then I'm afraid there's going to be very little you can do to improve it.

A

Anonymous

Thanks Steve I will try what you suggested but if you could maybe listen to the three two clips and maybe you'll see what I'm talking about the one clip is raw no editing at all as you'll hear a lot of noise and briefly you'll hear clear voices but the second clip is after running it through a denoising process and all of a sudden these voices appear but muffled and distorted kinda so do you recommend the same process to try and clean that up? And why in the second clip after denoising did these other voices appear? Thanks Steve

audiofile-#2_Denoised.zip

A

Anonymous

Raw clip

SteveG_AudioMasters_

Community Expert

There is only one clip in this thread (your last but one post), and it isn't the one I'd want to hear in order to work out whether anything could be salvaged out of it. But yes, the process is always the same, regardless. At each stage you have to experiment and listen closely to the result, and build the final result up in stages.

SteveG_AudioMasters_

Community Expert

Could we start from somewhere slightly different, perhaps?

The thing that's most important to understand about Audition's NR is that you really shouldn't try and do it in one go; we discovered years ago that there's an approach which leads to significantly better results. What you have to do is multiple passes, and take very little off at each pass. Also, it works better if you change the FFT size between the passes, too. With most NR, the highest setting is the one to start with, and you work your way down to the lowest size, and you resample at each pass. How much do you take off? I generally take no more than 3-4dB off. Generally the noise reduction slider stays at about 80% - this is generally a good figure for most applications. Also, if you want to reduce any bubbly noises, the Smoothing setting in Advanced (where you alter the FFT size) needs to be at a generally higher setting than the default - I leave it on 99 as a rule, and because I'm doing a lot of passes the broadband noise gets reduced anyway. Generally it's this that suffers with high Smoothing values, but the result generally sounds a lot better.

If you are really careful (and a little bit lucky) you can achieve pretty good results with NR - but only if you do it in stages - at least three. This applies to pretty much any NR app - not just Audition's. Even the Rolls-Royce of NR (iZotope's) benefits from this approach.

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