What is this noise and how to remove it?
 

Hi,

I have this specific "hum" and I can't figure out how to remove it. I have IzotopeRX, and the de-hum module doesn't do much. I can run spectral de-noise on it and get some of it removed. Obviously it affects the voice if I try to remove it completely. So, I'm hoping someone will be able to determine specifically, what it is and maybe tell me how to target just that noise.

https://www.dropbox.com/s/nbzyn4htea...Noise.wav?dl=0


Thank you
Kathy

Re: What is this noise and how to remove it?
 

If the file I downloaded is an accurate measure of the sample, it seems to be a very low level base noise that probably could be ignored, as -70 dB is pretty small. This kind of noise can be from normal electronic noise in the recording devices, background rumble in the venue of the recording, etc. My home, with even with a small and absorbent room, with everything electrical turned off, has a constant -52dB rumble much like this. Again, if the levels in the sample are the levels you are worried about, I don't think they are much of a problem. You are correct, de-hum is for a specific frequency and its harmonics; this is a broad-range random noise from near 0 to around 17khz, and that won't help. You could do a sample and remove using a regular noise removal tool if you feel it's necessary. The capture shows what looks to me like a typical random noise pattern that is, to some extent, always present in a recording.

Re: What is this noise and how to remove it?
 

The noise is broadband so a hum remover tool and would not work well in this scenario. 'Hum' removal tools typically work @ 50 or 60Hz and the pertinent harmonics.
The source file's noise is around -60dBFS, which should be inaudible for most playback situations, unless cranking the monitor volume to abnormal high levels or normalizing just the noise with no other content. The audio on the frequency spectrum graph was normalized to show the frequencies clearly.

Re: What is this noise and how to remove it?
 

So many tracks. What am I looking at here? I've got it in iZoRX10 Advanced and I can't figure out what I should be focussing on. Please explain.

https://www.dvinfo.net/forum/attachm...1&d=1671605502

Re: What is this noise and how to remove it?
 

OK, RX Spec Analyser giving -75, not bad at all. And now I "see" the other streams. Just what they are from your capture, like to know. But, it all depends on just what it is you're attempting to hunt down. Are you purely wanting to ascertain just where these low dbs are coming from? Curiosity? Is it impinging on your Project? Are you wanting something less than -75? Are you searching for what could be making this type of noise?

https://www.dvinfo.net/forum/attachm...1&d=1671606161

Nice project, but I need more of your premise for just what you are searching for - please?

Re: What is this noise and how to remove it?
 

We really need a sample of your problem audio in a file that also has the content you want to keep, not just the problem noise only. Too many unknowns with the file you have supplied.

Andrew

Re: What is this noise and how to remove it?
 

I used the AI-based process at audostudio.com for some problem tracks recently and it was pretty astonishingly good. You can process up to 20 minutes free as a sample. Very few settings but quite robust.

This was the test clip I did when first trying it out, where we weren't able to turn off the exceptionally noisy coolers behind a bar during a shoot. My post-production mixer couldn't match this with Izotope and has since used Audo on a number of projects, he says while it isn't always perfect, overall it is a huge time-saver.

https://www.dropbox.com/s/c22hdd03aq...t%202.mov?dl=0

Re: What is this noise and how to remove it?
 

Indeed.

It would be like me being given a Ball of Sheep’s wool, a Knitting Pattern and needles and then being told to make a pair of socks. But, in this instance, I’ve got the finished product and am now being told to come up with the knitting pattern.

I would dearly love the original file and just what it is that needs to be done. Hence my questions above and the motivation from Kathy just what it is she’s wanting. To produce nicer sounding audio, or, to determine what is making that noise.

Oh and BTW, I can’t knit.

.

Re: What is this noise and how to remove it?
 

Upload a full file with the voice. Very hard to ascertain anything from the download. Sure, a few of us would have a look at it for you.

Chris Young

Re: What is this noise and how to remove it?
 

What are the circumstances of the recording? That sounds more like mechanically generated noise than electronic noise? What are we actually listneing to? The sound of your preamp when nothing is plugged in? The sound of an empty room, via a mic .... or what? As everyone has said, it's extremely low, but then we've all normalised it to an annoying sound, but that's probably unrealistic? what are we listening to, recorded on what?

Re: What is this noise and how to remove it?
 

Kathy, I should have mentioned in my reply that if you are worried about the effect on your voice content from removing this very small signal, it should have no practical effect. It is a fairly even signal across the entire vocal range, so removing it would just, at most, reduce the amplitude of the content by a tiny amount. An ordinary noise-removal effect (sample and remove) would do the trick. Simple answer, try it and see. You are correct that noise removal can affect content --- if it is a significant part of the signal, and particularly if over a narrow frequency range; removing a spike like that leaves a "hole." But this is a different animal.

Re: What is this noise and how to remove it?
 

Whatever the noise is, it's a combination of things.

Track #1 has two channels, both left and right tracks, which appear to be dual mono and appear to be identical to each other.

Track #2 is showing on both channels, but appears to be summed mono.

Tracks 3 & 4 are purely White Noise. Track #3 showing on both left and right channels, and track #4 only on the left channel.

If I had the job of processing this "audio" I would totally lose tracks #3 and #4 as they are purely "noise". I would ditch Track #2 as it appears to be a summed mono version of what is on Track #1.

Finally, looking at Track #1's two channels, I could clean this up very quickly with Sound Soap, I think? Not having the associated audio with this 'noise' makes it hard to come to a definitive conclusion, but I have cleaned up this sort of noise quite successfully in the past.

Chris Young

Re: What is this noise and how to remove it?
 

Hi All,

Thanks for all the replies. I think I'm obsessing over nothing. I think this is the room noise that I'm hearing (the hum of the fluorescent bulbs, perhaps). I know you asked me for details but in the interest of everyone's time, I don't think it's worth discussing it, as I can't hear it when I don't listen on my monitoring headphones.
It actually turns out that I won't be using any of this recording. I'm not happy with the content.

Thank you everyone who jumped it to help.

Kathy

Re: What is this noise and how to remove it?
 

Kathy - lots of people spent time on this for you, and you don't think it's worth discussing? That's a little rough, if you don't mind me saying so.

The thing to remember is that you haven't fixed it, diagnosed it, or done anything to prevent it happening on a track that IS important.

We tried.

For what it's worth - the audio format you recorded it in is very unusual? All thos summed and empty tracks? Maybe you are recording on something a bit strange? If the noise worried you enough to join a forum and post - the worry will still be there?

Happy Christmas

Re: What is this noise and how to remove it?
 

C'est la vie, as they say.

Anyway... have a happy holiday season everyone.

Chris Young

Re: What is this noise and how to remove it?
 

This post has a low SN Ratio.

Re: What is this noise and how to remove it?
 

This post and the low SN ratio is what I've experienced with previous Kathy posts. Marginal audio (understandably as it's a legit cause for posting about a problem), not enough of it to really work with, and it feels like everything is secret squirrel. You wouldn't even know what it was about / what the project was in the end. At least she has a copy of Izotope RX these days, to give credit where due.

Kathy, we're always happy to help if you're open to it. Just be real with us and it's all good. We're all very friendly over here (as you will have noticed).

Andrew

Re: What is this noise and how to remove it?
 

FWIW: Listening with headphones (especially tightly coupler over the ear) will generally make any background noise/hiss/hum much more noticeable.
and
Background noise tends to intrude more when gain is increased to compensate for mic placement that is increasingly distant from the talent/desired source.

Re: What is this noise and how to remove it?
 

Thanks for the tip about Audostudio. I tried varied recordings and I found that it's amazingly good for speech. Apparently the AI recognizes what is speech, and gates it ON. That's as opposed to recognizing unwanted noise and gating it OFF.

For example, a recording w/ speech + bg noise is processed very well. A recording with singing and noise is not processed correctly, apparently because singing does not have the same sound pattern as speech, so a lot of the singing is partially removed. A recording w/ speech, desired SFX, and continuous background noise (e.g. from the storage medium) is not processed correctly ... the speech is retained OK, but the SFX is mostly removed, along with the background noise.

Bottom line: for working with dialog stems this is probably great. But for restoring mixed recordings (what I'm working on lately) this is the wrong tool. Certainly overkill for Kathy's current super-secret project.

Re: What is this noise and how to remove it?
 

I'm sorry. I'm recording on Sound Devices mixpre-3. I set it up so I can record each channel separately. That's why have all of these channels when I open the file. I just delete all of them leaving just the one that has the voice in the Center channel.
I don't have any issues with this set up. When the room noise is low the recording is pretty clean to my ear.

Here is a snippet of the recording with the voice:
https://www.dropbox.com/s/dx5lzzmb8otaf5a/Clip.wav?dl=0

Thank you, and again apologies for dropping this topic without any further input from me and not appreciating the time an effort everyone put into trying to help and solve this for ME.

Kathy

Re: What is this noise and how to remove it?
 

No worries from me, glad to see you back here and to have that snippet to analyze. I now understand the multi-track scenarios - it did throw me a bit. Now if my approach is incorrect and happy to be corrected.

My initial thoughts are that the low dB for the voice will kind of "mask" any noise floor that's there. I'd say that your MAX recorded VO is 50% of what you are presenting here:
https://www.dvinfo.net/forum/attachm...1&d=1672207190

Once I GAINED your clip to -10dB I could clearly "hear" the noise floor. I don't think you've got enough to hear that rumbling noise with your cans. This is what I can achieve by adding +6dB GAIN:

https://www.dvinfo.net/forum/attachm...1&d=1672207932

And now with adding a further +6dB GAIN - ie +12dB over the original:

https://www.dvinfo.net/forum/attachm...1&d=1672207932

And now clearly reveals rumbling at -45dB:

https://www.dvinfo.net/forum/attachm...1&d=1672207932

So, to recap, your sample does have some room noise rumbling, I've lived with less-than-perfect Audio - oh yes! But, if my attempts to analyze your sample has any useful response on your initial question, that you're looking for noise, then I would have to suggest it sounds like room noise. You're not hearing over your cans as a result of this masked by the initial low recording dB.

HTH!

Re: What is this noise and how to remove it?
 

OK, I've now used Noise reduction on that rumbling. I've now got a cleaner Signal and a Noise floor of -85dB! I like this:

https://www.dvinfo.net/forum/attachm...1&d=1672209565

Here's my DropBox link:

https://www.dropbox.com/s/qf1yzgp80j...%201a.mp4?dl=0

Re: What is this noise and how to remove it?
 

OK…. I’ve now listened and re listened comparing yours and mine. I’m more than convinced that the noise is coming from PC fans and being amplified by your room and surroundings. Reducing this by 50%, from -45dB to -85dB allows your Signal to win the day, and smother the noise floor. If I’m wrong about your PC fans then you’d have to look deeper and maybe consider removing any electrical forces impinging on your recording.

Re: What is this noise and how to remove it?
 

As Zappa said: "Sometimes yah just gotta walk away from a project!" - I'm done . . .

Further treatment was to remove clipping > Post-treatment Analogue Audio Warmth > Light touch of reverb.

Here's that treatment:

https://www.dropbox.com/s/dkqgvbcwsl...ugs1a.wav?dl=0

I'm done!

Re: What is this noise and how to remove it?
 

O...K...

One last thought, in any way, is your connection to your pc being used via the System Audio? Or are you set up using the drivers for that Pre3? What are the drivers for it?

Re: What is this noise and how to remove it?
 

Graham, what do mean by "cans'? I'm not connected to PC at all. What drivers are you talking about?

Re: What is this noise and how to remove it?
 

“Cans” is a slang term for headphones.

Your second part of your feedback is related to the Pre3. You record to it and then you upload it to your PC? Yes?

I’ve noted you’ve made no comment on my analysis nor my treatment and my methodology.

Re: What is this noise and how to remove it?
 

“Cans” is a slang term for headphones.

I have not heard that much since the 70's.

Re: What is this noise and how to remove it?
 

Old habits . . .

Re: What is this noise and how to remove it?
 

Graham, I'm in transit so I can't listen to anything

Re: What is this noise and how to remove it?
 

I'm pretty sure I heard it somewhere (most likely a regional radio station) in the 90s. Can anyone better that?

Andrew

Re: What is this noise and how to remove it?
 

Try this shop: https://theradioshop.co.uk/collections/headsets-cans

Thanks for reminding me of my age and my aging Sennies! Ah, nostalgia, it’s not what it used to be.

Re: What is this noise and how to remove it?
 

Nostalgia was so much better in the old days!

Andrew

Re: What is this noise and how to remove it?
 

https://playbutton.co/why-are-headphones-called-cans/

When a kid we played with the tin-can-and-string-telephones.

Re: What is this noise and how to remove it?
 

Cans is still very common in the UK - more now for 'headsets with mics'. In theatre it's ettiquette to say "off cans" when you take them off so people know you're gone and won't respond any more.

Re: What is this noise and how to remove it?
 

In the studios as far back as I can remember, we always used the one syllable word “Cans” quicker and cooler than ‘Headphones.’

Cheers.

Re: What is this noise and how to remove it?
 

A quick clean-up attempt. With a bit more time, could be improved. Download from here:

Chris Young

https://www.sendspace.com/pro/dl/w3k5s5

Re: What is this noise and how to remove it?
 

Chris, nice job. I took the liberty of running your sample through RX Waveform stats. What do you think?:


https://www.dvinfo.net/forum/attachm...1&d=1672467470

Re: What is this noise and how to remove it?
 

Yes Graham. I like that yours has more bottom end and sounds fuller. I found when I first tried giving it a bit more bottom end, it muffled the recording somewhat. Your recording made me revisit my first attempt.

To get to the result of version #1 that I uploaded, I just duplicated track #1 with the file on it to another track, track #2. I ran noise reduction on track #1. I then ran noise reduction on track #2.

Then I inverted the phase on track #2. This gave me 100% signal cancellation with track #1. No sound audible as the two tracks cancelled one another out. I then offset track #2 by three (3) samples to the right. This brought my tracks back to being audible. Obviously, though, sounding thin due to the opposing phase cancellation of track #2 vs track #1. On the master bus, I then added a DeEsser at 5506Hz with a -30dB threshold.

On this #02 version upload, again on the master bus, I added a +7.5dB boost @ 167Hz plus boosted the overall gain to peak at about -3dB. In other words, to levels I'm more than likely to use during an edit. All of it done 100% in Vegas Pro 17.

The inverted phase cancellation with offset method is something I've used for years when having to try to extract reasonable audio out of noisy ambient room mics for example.

Chris Young

Version #2 can be found here:
https://www.sendspace.com/pro/dl/6ejypm

Re: What is this noise and how to remove it?
 

Well, thank you for saying. I always add gain to start with. A bit like in video seeing how much Gain I can add without video noise. So, I add GAIN in stages until I got a well-represented fuller SN ratio that I could use, then off to the Races with iZoRX10 Adv.

Yes, I cut my Audio teeth within the VP and SoundForge packages. Using much the same approach as yours. Dupe Tracks; Inversions and the NR package. However . . . . iZotopeRX came along and I haven't done any Audio correction within VP or SF for the last 5 to 10 years, only iZo - It is pure VooDoo!

Again I captured the Waveform statistics in iZo and produced this graphic for comparison:

https://www.dvinfo.net/forum/attachm...1&d=1672486153