Questions about Clipping

Audacity Help Forum macOS
1

I have gotten into “Mojo” (akak "Mobile Journalism) using my iPhone and interviewing people out in the field.

I have a decent tripod, external shotgun microphone that mounts on my iPhone rig, lights, and so on.

I record audio from my shotgun mic into a Zoom H6.

From the tiny bit I know about recording Internet radio streams online - as per my other trhead - and then editing things in Audacity, clipping is supposed to be “evil”.

However, when I am interviewing people outside (or technically inside), I would like to know…

1.) Is it that big of a deal if I set the gain on my H6 so that occassionally things clip?

2.) Is it a big deal in post-production if I “amp things up” - not sure what the proper audio term is - so that there is occassional clipping?

Why would I want to allow clipping?

Well, if I record with a Gain=7 on my H6, it seems that the audio in my tests stays between -18dB and -12dB, but when I bring it into Audacity, the amplitude - not sure of the proper audi term - is pretty low.

If I record at Gain=8, things sound better, but there may occassiob=nally be clipping.

Likewise, if I record at Gain=7 and then I amp things up in Audacity - but purposely amp things up so that slight clipping occurs - then things sound much better than if I just use the suggested “Amplification” suggested by Audacity.

Hope that makes sense?

The first real-life interview I had a few weeks ago suffered because the audio was too low, and when I tried to amp it up, I got too much distortion.

That being said, i am tempted to turn up the Gain=8 so that I get a stronger singal to start with, and it seems to me that unless a person goes from whispering to shouting, an occassional clip isn’t a problem.

And when I tested out my new tripod and rig tonight at home, the few times I had clippinb (visually) in Audacity, there was no way you could hear that clipping, which is sorta what I am hinting at above - that is, maybe clipping is over-rated??

Thoughts so I can get better field recordings??

2

I don’t think your field recordings are the problem. The problem is post production editing where you need a way to increase the volume of the voice without damaging it.

Clipping represents a sound event where the recorder stopped following the show. It’s simple as that. You can’t “filter clipping out” because there is no show back there. It’s trash the recording system made up while it was losing its mind and blowing spit bubbles.

Does this sound like something you want in your show?

Do you have mono WAV versions of one of your low volume “clean” presentations? One blue wave? If so, cut a 20 second chunk of it, Export Selected Audio > WAV, and post it on the forum. Scroll down from a forum text window > Attachments > Add Files. If at all possible, include a place where they pause for a second without gasping or making noises.

Field recording is not for the easily frightened.

Koz

3

Not following you.

In my OP I mentioned two separate scenarios…

In one case, I don’t think I had the gain high enough, and when I amped up the recording in Audacity, it not only raised the speakers volume but amped up a lot of background sound and harmonic distortion (?) and make the new results louder, but sounding worse than the faint original.

In the second scenario, tonight I was testing out my new tripod and rig and when I did tests at various distances from the shotgun mic and at various gains, it seemed to me that it was better to run things maybe at Gain=8 than Gain=7, but I’m not sure if you are supposed to record LOW and then edit things up HIGH, or if you should record at a higher gain and then leave things as is in editing.

Follow me?


What do you mean?

What “show”?


Not following your use of the term “show”… There is “no show there”?


Huh? Why is the system “losing its mind”?


When I recorded tonight - and I forget if the gain was 7 or 8 - there was one small sliver in the Audacity file that went up to the top of the scale. But when I listened to my voice speaking, I couldn’t hear it - as opposed to if I turn up the volume too much on a radio show and I clip a whole bunch, then I can clearly hear that.

My point being that the human voice seems more prone to clipping for a nanosecond because of how we speak, and tonight that didn’t seem to cause much of an issue.

So if my 60 second recording was around 0.5 on the volume scale in Audacity - not sure what that is caleld - and I had a split second that was clipped at 1.0, then I would still like to amp things up to maybe 0.8 on the volume scaling in editing so you can hear 99% of the recording at a higher volume, understanding that that 1% clipped in recording and so that was lost anyways.

If I just try to increase the volume of the track, Audacity sees the split-second clipping going to 1.0, and so it want amp up the rest fo the track which is too low volume.

So how do you balance all of that?



Yes.


Yes.



Let me try and find a sample…



Well, this is for a startup business and it is my passion, so I’m up to the challenge if you gurus are will to teach me some!


Koz
[/quote]

4

We can’t help if there are too many problems at the same time. Sometimes the description in the post isn’t enough and it’s good to actually listen to the recording. That’s what we need now.

Koz

5

Any problematic interviews I have are actually .MOV files from my iPhone.

I did it once, but don’t recall how to properly separate the audio files from the video, and I head out tonight to go back out in the field.

As I shoot new video, let me see BOTH how to separate the audio from the video so I can post it here, AND of course I can just straight up post audio files from my Zoom H6 here as I start recording with that too - which is supposed to be my main audio source moving forward.

All I was asking in my OP is whether it is better to record out in the field with the gain possible a notch too low, and then amp it up later in Audacity, OR if it it better to possibly have the gain a notch too high out in the field - knowing you might occassionally clip - but ending up with an audio file where the volume is at a more usable level as-is, and is easier to massage in Audacity because you don’t have to crank up the volume a bunch.

Follow me?

If so, can you offer some advice on that now so as I interview people I am gathering good and uable audio to later be edited in Auadacity??

(Of course I can post interviews here as I gather them in the field in this latest trip.)

6

the gain possible a notch too low, and then amp it up later in Audacity

Yes. But.

You’re juggling too many balls for quick, simple analysis. If you dig in the instructions for the H5, you may discover the built-in limiter/compressor which allows you to record denser and louder voices during the performance.

Audacity will open the sound portions of many video formats. You may not have to do any file management. You may need to install the FFMPEG add-on for this to work.

Please note Audacity will not put the completed sound file back into the video. You need a real video editor for that.

Koz

7

So where do I begin knowing that I will be out in the field starting on Monday? (Travelling for the next two days)

Do I just try things out, listen to the results, and trust my ears that if it sounds okay then it will likely be okay in Auadacity?


My Zoom H6 does have a -20 Pad (db??) on each of its four XLR ports…

Are you advicing me to turn that on and crank up the gain to 10?

I have experiemented with the “padding”, but it seems more geared toward noisy environments like Grand Central Station than just interviewing a person in a quiet neighborhood on their doorstep.

Since I am interview people about the upcoming elections, I have 2 weeks left to get this right after losing 3 weeks of work due to a bad iPhone mic. So anything you can offer right now for a quick crash-course would be a lifesvaer!!!

I have invested in this big ass tripod and boom arm, I have a regular tripod for my iPhone and so I can mount my shotgun mic on it, and I have a wireless lav kit that I am learning how to set up right now as we talk.

Hoepfully with my better audio related gear, I will have better luck, but any advice now would be priceless!!

8

When I get back from my video-shoot, I will be learning FInal Cut Pro and how to break off the audio, edit it in Audacity, and then merge it back into my video in FCP.

My goal now is it just mac sure my audio is “good enough” so I don’t end up like where I was after my first trip - which mostly got screwed up due to an unknown failing iPhone microphone.

Now that I will be trying to record people both on my iPhone and on my XLR shotgun mic, I hope that things get easier, but back to my OP, I could use some advice on the proper way to set the gain as I record people out in the field…

9

Zoom H6 does have a -20 Pad (db??)

That’s not for simple recording. That’s for recording a trumpet or other loud, close sounds. Using it when you don’t need it will increase the microphone internal or electronic noise.

Not Grand Central, but making a recording near one of the New York Central locomotives as it’s pulling out.

trust my ears that if it sounds okay then it will likely be okay in Auadacity?

That’s why sound recording people almost always wear good quality headphones during a shoot.

It’s not the worst idea to stop writing checks long enough to fool around with everything and see how it works.

Koz

10

I suspected that.


Okay.


I see a picture, but was there audio to go with it?


I bought a $300 Audio-Technica BPHS1 and paid to have the cable shorten from like 10 feet to 30 inches so I can use it comfortably out in the field with my H6.


So I see my H6 has both a “low cut filter” and the “compressor/limiter” you linked to.

Can you give me a quick crash course in what each feature does, and why I would (or would not) want to use them as I am interviewing people outdoors??


Yeah, I already broke the bank at B&H over the last few weeks, so I think I have all of the gear I need, now I just need to get better at using it!!

P.S. One thing I bought this week is a Saramonic wireless lav set. I just tested it out and I think that will really make getting decent audio easier, although lavs are a bit tricky during a pandemic…

11

Can you give me a quick crash course in what each feature does,

I’ve never used that collection and My lesser Zoom recorders don’t have that feature (that I know of). That’s worth a checkout over tea.

Basically, as the sound gets louder than a set volume, an electronic guy turns down the recording volume and then lets go when the sound gets quieter. That’s the compressor. The limiter comes along behind and swats down abrupt, sharp sounds that are too fast for the compressor. There’s a version of these tools in the Audacity Audiobook Mastering Suite, and almost all broadcast radio transmitters have them.

The trick is setting them. They have magic controls labeled Attack Time, Release Time, Slope, and Threshold. Books are written about how to do that.

You can get into trouble with those tools. They permanently modify the voice and if you don’t like what they did, that’s just tough. It’s burned into the show. You can’t take the effect out later.

If you’re sure you will always be recording voices, the High Pass Filter can be a good thing. That’s the rumble filter. Also called Low Cut. It can take out some microphone handling noises and wind. The trick is to remove bass notes without screwing up male voices. It can help with P-Popping.

This is the switch if you’re going to have one. Up is low cut. Down is no effect.

Screen Shot 2020-10-17 at 14.01.16.png
The generic Hollywood filter is about 100Hz. That’s also the value we used in the audiobook process.

Koz

12

although lavs are a bit tricky during a pandemic…

Here, let me jam my hand up your shirt…from six feet away.

There’s a trick here, too. Somebody is making a lavalier that records in two different volumes at the same time. It makes setting volume much less tricky. I wrote that down here…somewhere.

Koz

13

THanks for the thoughts.

I am heading out on the road soon…

Will be in touch with you (and Steve) as soon as I can!