Buzzing Audio

[cwood11]

I am recording, from wav files, simultaneous audio on the two Video Studio 9 audio tracks.

One track is a propeller-style aircraft engine.

The other track is a pure sine-wave series of Dashes at 1020 Hz.

With just the Morse recorded, all is well.

But when playing back the rendered WMV video with both the engine sounds and Morse occuring simulataneously, the Morse is Verrrry Raspy/Buzzy.

No problem like this on ArcSoft, with the identical wav files before moving up to Ulead.

Anyone have a clue what I am doing wrong, and how to get around this?

I can Email a 10 sec WMV clip, 640x480, and only 300 kB, if that would be helpful.

Thanks very much.

Charlie

[DVDDoug]

You're mixing the audio, right? I mean, you don't have one sound on the left channel, and the other on the right. right?

Try reducing the volume of each track by 50%. Assuming that both tracks are at 0dB (the digital maximum), the level is increased by 6dB (doubled) when the two signals are mixed. But, since digital cannot go to +6db, you have distortion.

A good software mixer would "clip" (flat-topped waves) if you try to force it over 0dB. (Clipping is the same distortion you get when you overdrive an analog amplifier.)

Your distortion seems worse than clipping. A poor software mixer will "roll-over", like the odometer in your car rolling over from 999999. When a big number gets turned into a small number... that's severe distortion!

[cwood11]

Hi Doug,

Thanks for the reply and apologies for my slow response. I lost the location of my post, couldn't find it, searched my name, Wood, and searched "Buzz," and neither found my post. I probably set a record with my inability to find my post. Oh well, everybody has to be good at something.

OK, am I putting one sound on the left channel and one on the right channel? I don't think so, but I will tell you wnat I am doing.

1) Each signal, the Morse tones and the engine sounds, are mono mixed signals. Audacity is my audio editor and only one track appears while recording or playback.

2) On the timeline, I opened the "audio view" and see two sound tracks; one with a microphone to the left and below it one with a Musical Note to the left.

3) In the "microphone" track I pasted the engine sounds.

4) In the "Musical Note" track I have pasted the Morse tones.

If there is some visible display on the timeline of the level of the audio signals, I don't know how to invoke it.

I understand your suggestion of reducing each signal by 50 pct and I will give that a try. It does make sense.

Thanks again for taking the time to reply and I will post my results shortly after that experiment.

Charles Wood

[Black Lab]

If you click on the microphone or musical note it will open to display your level meters where you can make said adjustments.

Edit: You click on the speaker icon (underneath the storyboard and timeline icons) to open the level meters. You then click on the appropriate icon (video track, overlay track, voice track or music track) to see that particular audio level.

[cwood11]

Thank you DVD Doug and Black Lab for your help. I have made very good progress on the buzzing audio problem.

Charles Wood