Getting noises from the silencing function, track borders, and amplify/normalization functions

Audacity Help Forum Windows
1

Hi everyone.

For a long time, I have been getting unwanted noises from the use of Audacity’s silencing function and from other functions/aspects of the program, and it is sometimes (or even often!) ruining my recordings. When I silence a portion of a track, I get one “click” type noise at the exact point where the silenced portion starts AND one at the exact point where the silenced portion ends. Why is this happening, and what can I do to fix or overcome it? And, to complicate things further, the intensity or volume of these “clicks” varies from one application of the silencing function/effect to the next, even when NO changes are made to the track volume (including gain). And sometimes, the silencing of a portion of recorded material on a track produces NO unwanted noise whatsoever! So, what is going on?

Also, I get a very similar noise at both the beginning and ending borders of each recorded track. This is especially problematic when I record a short track (i.e. just a snippet of guitar, etc.) when I just want to record some very short piece so that I don’t have to wait through the entire recording to reach the particular spot that I wish to record the snippet it. Why does this happen, and what can I do about it (other than recording the snippet on a track that extends throughout the entire song/aup project)?

I also get these same types of noises when I apply Amplification, normalization, or potentially other functions/effects to a portion of a track (in other words, it Only seems to happen when they are applied to a PART of a track, and not when I apply them to an entire track after clicking on the track’s select button). Again, why is this happening, and what can I do to remedy it?

One last observation of this dilemma: These “click” type noises are often drowned out by the other tracks/instruments etc when the record levels for these other tracks are not particularly low. After Steve (I believe it was) explained to me a while back that the professional sound/music engineers DELIBERATELY set the track record levels very low (in order to ensure that they avoid clipping), I began setting my record levels much lower than I had previously (and stopped having problems with clipping), but have subsequently begun to have a bigger problem with these “clicking” type noises than I had before. So, clearly, the lower record levels are not enabling me to minimize (or totally drown out) these unwanted clicking noises, as the higher record levels were previously. One dilemma involved in this whole series of issues is how can I get high enough record levels so that I can avoid, or at least greatly minimize, this clicking problem when applying the silencing effect WHILE AT THE SAME TIME keeping the record levels low enough to avoid clipping? It seems to me that that is a VERY challenging balancing act. Does anyone have any thoughts on this and/or any of the other specific questions that I have raised in this post?


Thanks,

Dan

2

Sorry, but I forgot to mention that I have Audacity version 2.4.2, Windows 10.

Dan

3

When you select the region to be silenced or cut, specify zero-crossing-points, (press “z”),
then you are less likely to get a click at the join.
zero crossing points avoids clicks.gif
If you’re working with stereo tracks, zero crossing points on both tracks rarely coincide,
A solution then is a short (~20ms) fade or crossfade to avoid clicks.

4

Thanks Trebor, I was unaware of that particular function. If that works for me, it will be extremely useful. I haven’t had time yet to test it out, but I will today. However, I still don’t know what to do about the click or pop noise that you get at the end/edge of every track. I was thinking that, if the At Zero Crossing function works for me, then I could potentially use it to select a portion of the end of each track and then apply the “cut” function to them in order to both trim the ends AND do it in a way that will leave no click or pop sound. Do you think that this will work for that purpose or is there some other means of getting rid of the click/pop that always seems to occur at the end/edge of each track?

Dan

5

Certainly, trying to cut or do effects during loud sounds can get you into trouble, but there’s a plain hardware possibility, too.

A microphone is a device for turning plain battery voltage into moving sound signals. Sometimes, a little of the original battery voltage leaks in with the sound performance. When it does, you can get impossible editing jobs. Any time you cut between that microphone and anything else, you can get a tick or pop. The broken microphone is on the left.

It’s usually not that graphically obvious. There used to be a tool to get rid of that effect. Looking.

Koz

6

The classic way to suppress DC noises is the High Pass Filter. DC has no “frequency” and so dies in most high pass filters. Unfortunately, starting DC and stopping DC both make actual sound (pop) and the filter will not remove those. Correct me, but this is one of the exact problems you have.

Someone generated a tool that worked a different way. It analyzed all the up data and all the down data in the performance waveform and then juggled the math until they came out even. That one did take care of DC problems during a performance as well as the beginning and ending pops. “Averaging out” any good sound performance will always come out zero.

That’s the one I can’t find. I’m going back into the older machines…

Of course, what you should really be doing is finding and getting rid of your broken microphone. Very few people have noise problems like this.

Koz

7

Getting there. Apparently, it used to be a formal tool.

DC can be removed with the DC offset remover pug-in

That was from 2014.

Koz

8

Got it.

This is from a very old forum posting.

https://forum.audacityteam.org/t/question-about-normalization-how-does-it-work-in-audacity/6447/1

At the bottom of this discussion is ESP_normalize which has the magic arithmetic processes. It’s still alive. I downloaded it.

This is the message:
https://forum.audacityteam.org/t/question-about-normalization-how-does-it-work-in-audacity/6447/17

And the actual code in zip compressed form.
ESP_normalize.ny.zip (2.07 KB)
The discussion travels around all the damage possibilities and how far gone the performance has to be before you’re forced to give up. Pretty far gone as it turns out.

Koz

9

You can still get into trouble if you try to edit between two loud sounds without paying attention to that Zero-Crossing thing. This only solves the problem of your broken microphone.

Koz

10

Oh, and there’s one note about using that tool. You have to do it to the work, tracks, and clips before you do your edits. It won’t clean up clicks, ticks, and pops after the fact. Its job is to prevent them.

Or you can get rid of most of these problems by fixing your microphone.

Koz

11

Thanks, Koz, for all the great insights and advice. It’s really interesting that you have zeroed in on the likelihood of a broken microphone, because I have been suspecting for a while that the Shure SM-57 that I have been using, though a very good brand and model, has a problem inside it and is therefore at least partly responsible for the variety of noises that I have been getting when recording. I borrowed it about a year and a half ago from a musician friend of mine who I was in bands with in the 80’s and 90’s. It is a very old mic (at least 25 years old), and has probably seen better days. And it has probably been stored in his basement for at least part of that time. But, unfortunately, I have not had much money to play around with for new equipment like that, so I resorted to borrowing a handful of old items. I will definitely look into getting a new mic, and hopefully that will remedy most, or even all, of my problems concerning noises.

The mic is likely the culprit here for at least a lot of the noise trouble, since I rarely get any such problems when I use my electric guitar, electric bass guitar, or my Casio keyboard, since all of these instruments are connected to my laptop/Audacity through an external USB soundcard. Similarly, my drum machine plugs directly into the external USB soundcard and it doesn’t generate the range or variety of noise problems that I get when using the mic for either vocals or recording my acoustic guitar. So, here’s hoping that a new Shure SM-57 will clear most of these matters up. However, I am still not sure what causes a click or pop at the end/edge of each recorded track (this happens regardless of the instruments I use or the way that I connect them to my external USB soundcard/Audacity). I have also been suspecting that my older (and refurbished) HP Elitebook laptop may be responsible for some of my noise difficulties, perhaps including this one with a click or pop at the end/edge of each track. Any thoughts on this possibility?

Many thanks for all the info. and guidance,

Dan

12

You mentioned that the clicks appeared when editing,
all those clicks are avoidable if you always use zero-crossing when making a selection.

If the clicks are at start & end were on the on the raw recording, before editing,
then what Koz said about DC offset.

13

The SM57 and SM58 series are notoriously hard to kill. They’re very simple microphones and very well made. By the way, the SM58 is the “rock band” vocal microphone, the SM57 is thought of as an instrument microphone (in front of the drums), but your mileage may vary, void where prohibited, consult your local listings. The SM58 has the better wind/breath blast and pop filtering (the big head).

But neither of those microphones needs battery anywhere to work right. The preamp and digitizer is the place where DC Offset could happen. That’s where I would look for digitizing damage. So the actual microphone in that case should be safe.


The pramplifier and digitizer is the square black thing on the left by the coffee cup. Strictly speaking, this is fancier than your setup because that microphone takes phantom power battery from the preamp.




This is a well-used SM58 working into a Shure preamplifier and USB digitizer. As it turns out, this is not a terrifically good preamp because it’s too quiet. There is a volume control on the side but it’s purely decorative. You always use it cranked all the way up. I complained to Shure. I said I would give anything for a little more volume boost, and they said, “That’s the way it is.”

Koz

14

Thank you again, both Trebor and Koz, for additional help. It is difficult to determine exactly what thing or things are responsible for the noise problems that I’ve been having, but we may be narrowing it down now.

I have problems with both the editing stage and the actual raw recording. As for the former, I tend to get clicks when I select a portion of a recorded track for either silencing, amplification, normalization, or other functions/effects. I spent a while last night selecting unwanted areas of various tracks and silencing them (WITH the use of the “Z” button for the At Zero-Crossing function), and I had to do most of them more than once until the areas in question were silenced WITHOUT THE CLICKS BEING CREATED IN THE PROCESS. It didn’t take too long to accomplish this on most of the areas, but on one or two, I finally (after 10 or so attempts!) had to give up, because it would not do it without leaving a click on at least one of the two edges/borders of the selected region. So, for some reason, the At Zero-Crossing function is not working properly or consistently on my computer with Audacity. Is this indicative of a problem with my computer, or might it still be something else, like my external USB soundcard (or, possibly, both)?

Also, as mentioned, I get a pop or click at the end/edge/border of each recorded track, and, so far, the silencing function has not been able to successfully silence or remove them. And yes, this click/pop shows up on the raw recording (i.e. as soon as I record a track and then play it back to listen to it). Do you think that this also indicates a problem with my computer, or possibly my external USB soundcard (or, possibly, both)?

Koz, you wrote that since I am not using a battery powered microphone, it does not seem to indicate a problem with the mic I’m using, but, instead, a likely problem with the preamp and/or digitizer. Let me provide a little more detail on my set-up so that the whole picture might be even clearer to you. I run my SM-57 through an almost brand new Alesis 4-channel compact mixer. Then, I connect the mixer to my Startech external USB soundcard (via its line-in), and then it connects to one of the USB ports on my HP laptop. I use the mic for both recording my acoustic guitar and for singing. When I record my electric guitar, I go out of the line-out on my amplifier and connect it to one of the channels on my Alesis mixer, and then, again, into the soundcard/laptop. I use a similar set-up for the electric bass guitar, Casio keyboard, and drum machine. So, do some of these noise problems that I experience seem to point to a problem with the external USB soundcard? I believe that this soundcard is performing the same essential role that your digitizer is, and I also believe that my Alesis mixer is performing the same essential role as your pre-amp. Please correct me if I’m wrong. Therefore, based on what you wrote yesterday about some of the noise problems likely stemming from the pre-amp and/or digitizer, do you think that something is probably wrong with either my mixer or the soundcard, or both? Until about four months ago, I was using an old, Realistic brand mixer, and I got the same basic problems, so I doubt that the mixers (especially my new Alesis) are to blame. But, I have had some doubts before about the soundcard. I should probably get another one (from a different brand), and see if that helps to clear things up. What do you think?

Thanks again,

Dan

15

Did you try ESP_normalize from up the messages?

It’s almost certain you are creating damaged sound tracks. The “silence” on these tracks does not match dead silence in Audacity editing. When you cut between them there is a step up or step down.

Any abrupt change up or down like this has a sound. Tick or pop in this case.

There are three solutions.

– Don’t cut between tracks. It’s the abrupt change that causes the noise. Instead fade or dissolve between the two. The abrupt change goes away and so does the noise. This can take a lot of work and can turn simple editing into a retirement project.

– Apply software such as ESP_normalize to the damaged tracks. This software “knows” when a track is damaged and lowers or raises the wave. I believe it has no effect on undamaged tracks, so you can apply it to everything. Again, I need to be perfectly clear you need to do this to the tracks before editing.

– Stop making the damaged tracks. The damage could be created anywhere, but most likely the mixer or the USB digitizer—or a combination of the two.

The signal falling out of the bottom of your SM57 is tiny. Really tiny. The mixer has to boost the volume of your voice up to a thousand times for it to become useful. That’s not easy to do gracefully and if the mixer is going to make mistakes, that’s the place to do it. So lets say the mixer is including a little of its battery in with the voice (DC Offset). Nobody is shocked that it might do that by accident.

Now on to the digitizer. It’s a safe bet that your digitizer is going to convert everything presented to it to digital—including the battery. Now you have a digital sound whose no-sound “silence” doesn’t match the one in Audacity. Cut between them and it makes noise.


Let’s say instead the mixer is working perfectly well and is delivering your voice in perfect order. Let’s say the USB Digitizer isn’t feeling well and is adding a little bit of its battery to the sound before it converts the show to digits. Same effect. Your performance silence doesn’t match the silence in Audacity but this time the converter is at fault.

There’s no good way without test instruments or equipment substitution to tell what’s happening.

Koz

16

Suzy Sunshine insists on pointing out that you can also have zero crossing errors and noise.

Koz

17

I believe it has no effect on undamaged tracks, so you can apply it to everything.

A note on that software. I believe it’s pretty simple-minded and only makes up one correction. So if you have a track like my illustration on the left with a slightly negative bias, the software will create a small positive bump and we’re done.

However, if you apply it to two different tracks and one has an up error and the other down, it’s possible the software will average out the error and not correct anything. It’s not Artificial Intelligence here. It’s a simple Nyquist program.

Koz

18

It seems as if I’ve got my work cut out for me. I have to both repair the damage done through DC offset on several recordings that I’ve already done AND find out which components of my system are causing the noises, and then replace them. I guess, then, that I have just two things I need cleared up:

(1) Can I make a copy of an original track that has suffered damage from DC offset and then use the normalize effect on either it OR the original in order to try to fix the noises (I would want to do this so that I would be sure to protect either the original or the copy just in case something were to go wrong with the application of normalization on the other)?;

(2) When I get another external USB soundcard (to see if that will solve the noise problem), will I have to un-install the driver(s) for the one I am currently using, or will I be able to keep that installed while simultaneously installing the driver(s) for the new soundcard?

Thank you for all the assistance,

Dan

19

will I have to un-install the driver(s) for the one I am currently using

I’ve never had to install drivers for any simple soundcard or USB interface. You might need custom driver software if you expected the soundcard to perform fancy tricks such as multi-channel (over 2) or managing mono recording. But just plugging an interface in and performing a simple stereo transfer should happen right out of the box.

Remember, you’re installing the interface and letting it settle a bit and then open Audacity.

I’m fuzzier on this one, but I think you get to choose which software driver you apply and you can install more than one.


(1) Can I make a copy…

Yes, and work with the copy. You don’t have to go immediately into industrial patching and conversion. Do one short track and see if it works. Cut between Audacity silence and a quiet part of the performance and see if it pops, clicks, or ticks.

There is another simpler, legacy way out of this, but it does come with rules. You can apply Effect > High Pass Filter to each damaged track.

Screen Shot 2022-10-21 at 07.11.40.png
The catch is it doesn’t affect the very beginning and the very end of the track. So you would apply the filter and then cut off the first and last about half-second should do it. The advantage of ESP_normalize is that it corrects the whole track as if there was never any damage there at all.

Koz