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Old August 18th, 2012, 06:57 PM   #1
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Help with audio decision

I shot a video of a student music performance and recorded the sound using two different systems. I cannot decide which audio to use in the final product. Any help and comments will be appreciated.

AudioTest-A:
http://dl.dropbox.com/u/86774786/AudioTest-A.m4a

AudioTest-B:
http://dl.dropbox.com/u/86774786/AudioTest-B.m4a
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Old August 18th, 2012, 11:17 PM   #2
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Re: Help with audio decision

Just my two cents: Recording "B" is recorded at a lower level, peaking mostly around -12 db which is fine; the last 15 seconds gets up close to maxing out. On recording "A," peaks are mostly around -6, but the last 15 seconds goes up into distortion territory. The applause on both tracks is way over 0 db, but on "B" it is somewhat better. Also, track "A" loses some of the first notes of the piano.

You can normalize B to whatever your standard is for your purpose, but it keeps the most detail overall, according to the waveforms. Problem is the last 15 seconds, which will throw the normalization off, as they are pretty hot. This part needs to balance better with the envelope of the rest of the piece.

I wanted to attach a .wav file of a test I did selecting out the last two chords, and adding some compression to hold them to -4dB, and the applause as well, to -3dB That works pretty well. The file, unfortunately, is too big to insert here....but you might have a look at that possibility. If you want to raise the level by normalizing, you may want to compress just those last few "hot" seconds to balance them a little without losing the emphasis that they provide.

EDIT: here's a link to the file on Dropbox, an example in the last few bars of what you might think about doing: https://www.dropbox.com/s/j5zr3shrnn...udioTest-B.wav

Last edited by Battle Vaughan; August 19th, 2012 at 12:03 AM. Reason: addendum
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Old August 19th, 2012, 09:19 AM   #3
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Re: Help with audio decision

I like "A" better, the violin was miked closer and has more detail than "B." Apply a limiting filter to the file to prevent over peaking during the applause, and I think you're good to go.
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Old August 19th, 2012, 07:39 PM   #4
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Re: Help with audio decision

Thank you for your help and comments. I listened to the improved wav file of "B", it sounds better with the loud section compressed. I will try to apply the same to "A".

"A" was AT825 stereo microphone connected directly to D5MKII via 5-pin XLR to stereo mini-plug.

"B" was Sony ECM-MS957 stereo microphone connected to Zoom H4N via 5-pin to dual 3-pin XLR.

Both microphones were side by side, "A" attached to the camera and "B" attached to the gear. I set up the "B" system with the expectation that I would get better quality audio with Zoom recorder and XLR connection. But when I listened to them, somehow "A" sounded better to me (clarity, tonal quality), hence I couldn't decide which one to use.
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Old August 19th, 2012, 10:04 PM   #5
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Re: Help with audio decision

Hi --- "a" may sound "better" because it's louder. Otherwise the wave forms are pretty much identical.

You can compress the problem parts on "b" as I outlined and raise the output by normalizing to whatever level you want. It has the cleaner waveform in the problem areas. Just a suggestion.

-12 is sort of a normal level for video, the A track at -6 is pretty hot and leads to clipping at the end. Clipping the applause probably isn't too noticeable, however, if you bring it's level down to something reasonable most people won't notice. Subjectively, the louder track --- barring gross distortion-- will always sound "better". Best wishes for success with your project!
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Old August 22nd, 2012, 08:00 PM   #6
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Re: Help with audio decision

After equalizing the loudness of "A" and "B" and considering your valuable comments, I decided to use "B" for the video. There were 17 students and total of 23 performances that day, so I have more work to do, basically compressing loud parts (mostly applause) and syncing to video. Thanks again for your suggestions.
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Old August 26th, 2012, 10:10 PM   #7
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Re: Help with audio decision

Thanks for the input Allan. Before going any further, anyone coming along and reading this please don't reply to this thread because I will start another one. Actually, I've got a minimum of two in the "Audio" area.

Hmmm, cutting and pasting someone else's applause? Now that's an idea! For a group of 2 to 300 people that shouldn't change too much.

"But go and see where and what the hall or room sounds like first:" Ans: I'm kinda late for that because I've already done it. However, now I have some good material to work on for next year as this is an annual "Girls Choir Summer Camp."

One of the problems with stringing a wire across the floor is all the girls not in the particular choir group (there are about five choir groups and a couple speciality groups) sit on the floor in front of the stage and they sort of take turns going up on the stage to be in their groups so they would trample my delicate XLR cable if it went to a mic in front of the group. But maybe I can work on it. Have almost 12 months to meditate.

Let me go to work on a couple new audio posts.
Sound recorder: I don't have one suitable for this use. I do have an old 10.5" reel to reel Pioneer deck though, it's just not portable. I do have an M-Audio box that I've never used which is designed for the purpose of putting the audio on another device. Currently I'm just recording the audio along with the video.
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