Fixing limited audio

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MCLast
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Operating System: Windows 7

Fixing limited audio

Post by MCLast » Wed Aug 16, 2017 2:15 am

Alright, so this is an odd situation. I produce content for youtube, and recently tried to improve my audio by using an XLR mic with the current camera that I own. The camera, unfortunately only has a basic microphone jack. So, I acquired a converter cable that seemed to do the trick. I produced the video, it sounds good to me.. but some viewers are unable to hear the audio recorded with the camera and aforementioned XLR mic. I'm assuming that this is because certain audio channels are not being represented, and therefore on some devices the audio drops out.

I have attached a test file I did with the mic. I ripped the audio from the video file I produced, and converted it to MP3 format in Audacity. However, even when trying to fix it in audacity and putting it back over the top of the video.. the problem still comes up. Sadly, this is my best option until I can afford a camera with XLR audio in. But unfortunately, they are fairly expensive.

https://www.dropbox.com/s/smhcuu0zucmaksa/Test.mp3?dl=0

Above is the sample.

kozikowski
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Re: Fixing limited audio

Post by kozikowski » Wed Aug 16, 2017 3:09 am

You have a Devil's Adapter (I'm guessing).

http://forum.audacityteam.org/viewtopic ... 40&t=96664

You can continue to use it that way, particularly if everything sounds OK except for the audio vanishing here and there.

While you have your stereo voice track before you use it anywhere else, "flip over" the right track. Note in the first five seconds or so, the upper blue wave and bottom one are mirror images of each other? That's very wrong, but it can be fixed in post production.

Use the black arrow menu drop-down to the left of the blue waves.
Split Stereo Track.
Select the bottom one by clicking just above MUTE. Effect > Invert.
Top track pulldown > Make stereo track.


Done. The two tracks aren't mirror image any more.

Neither the microphone nor the camera is broken. It's just the wrong adapter for the job. The microphone naturally creates voice signals like that because that's how it lets you use 50 and 100 foot long microphone cables—assuming you're using a sound mixer or portable broadcast audio recorder.

You're not.

I used to have a list of cable adapters you could buy to do this......

As we go.

Koz

MCLast
Posts: 10
Joined: Wed Aug 16, 2017 2:07 am
Operating System: Windows 7

Re: Fixing limited audio

Post by MCLast » Wed Aug 16, 2017 4:15 am

Thank you so much for your quick reply! And I apologize for any stupid questions, because I'm just now learning audio editing.

But, the steps you provided will fix the audio loss?

MCLast
Posts: 10
Joined: Wed Aug 16, 2017 2:07 am
Operating System: Windows 7

Re: Fixing limited audio

Post by MCLast » Wed Aug 16, 2017 4:17 am

Also, I don't see an option for "Make Stereo Track" under the top track pulldown.

kozikowski
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Re: Fixing limited audio

Post by kozikowski » Wed Aug 16, 2017 4:40 am

I don't see an option for "Make Stereo Track"
You won't if you got the first step wrong.
Screen Shot 2017-08-15 at 21.30.09.png
Screen Shot 2017-08-15 at 21.30.09.png (23.12 KiB) Viewed 932 times
Note the two blue waves are clearly opposite each other. One goes up and one goes down.
After you split stereo track, you should have something like this.
Screen Shot 2017-08-15 at 21.31.27.png
Screen Shot 2017-08-15 at 21.31.27.png (26.92 KiB) Viewed 932 times
Now select the bottom wave by clicking just above MUTE. Then from the top toolbar, Effect > Invert.
Screen Shot 2017-08-15 at 21.33.31.png
Screen Shot 2017-08-15 at 21.33.31.png (29.41 KiB) Viewed 932 times
Note the two waves are going the same way now?

Then just jam them back together into a repaired stereo show with Make Stereo Track.
Screen Shot 2017-08-15 at 21.35.08.png
Screen Shot 2017-08-15 at 21.35.08.png (45.12 KiB) Viewed 932 times
Screen Shot 2017-08-15 at 21.35.22.png
Screen Shot 2017-08-15 at 21.35.22.png (23.74 KiB) Viewed 932 times
Let me know.

Koz

kozikowski
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Re: Fixing limited audio

Post by kozikowski » Wed Aug 16, 2017 4:45 am

I can unpack the magic, too. if you have a client, customer or posting that insists on a mono mix (one blue wave) rather than stereo (two blue waves), or is listening in mono, say on an iPhone speaker, your original track will drop dead (temporarily). Plug a full-on stereo headphone or earset into the bottom of the iPhone, and the show will come back to life.

It's really crazy-making. "How come about a third of my customers can't hear the show?"

They're not listening in stereo.

Koz

MCLast
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Joined: Wed Aug 16, 2017 2:07 am
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Re: Fixing limited audio

Post by MCLast » Thu Aug 17, 2017 3:13 am

Sorry about the late reply, but I was busy fixing everything in my video. Your advice worked, my video is now audible no matter where it is viewed.. and you have my thanks.

kozikowski
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Re: Fixing limited audio

Post by kozikowski » Thu Aug 17, 2017 3:34 am

Just to be crystal clear, you can continue to use your camera and microphone forever as long as you remember to do that little dance with the bottom audio track. The obsessive engineers are all jumping up and down about fixing it permanently, but I'm in favor of holding on tight if you find something that works.

Plus I can't think of a good, graceful, easy way to fix it permanently.

Koz

MCLast
Posts: 10
Joined: Wed Aug 16, 2017 2:07 am
Operating System: Windows 7

Re: Fixing limited audio

Post by MCLast » Thu Aug 17, 2017 4:55 pm

Oh, I completely understand that.

It'll be something that I will do until I can acquire a camera with an XLR port.

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