Sound difference between adjacent audio clips

GregP wrote on 7/19/2015, 5:45 AM

I'm using SMS to create narrated slide presentations. I record the audio for each slide individually to simplify updates etc. When I play multiple consecutive audio clips, I can here ever-so-slight noise between the clips, even though there is no indication of noise in the wave form. Can someone help explain what causes this subtle but perceptible difference and recommend a way to "fix" it.

Comments

Steve Grisetti wrote on 7/19/2015, 8:35 AM

First, I'd determine whether it is an actual sound on your clip or not. Does the waveform for your audio indicate this noise? Do you hear it when you preview the audio clip in the Project Media panel? In other words, was it created when you recorded the audio or is it otherwise an actual part of your audio clip?

If so, you can certainly add a very brief fade at the beginning and/or end of each clip to hide it.

But if you find that this is just a sound that Movie Studio makes as it goes from one event to the next -- then you've got a problem. Movie Studio should not and usually does not do that.

You might want to try doing a test output to see if this sound is actually on the soundtrack or if you only hear it during your timeline playback.

GregP wrote on 7/19/2015, 8:52 AM

Newbie mistake. You could see noise if you made the wave form big/wide enough. I discovered this by inspecting the audio in Audacity.

UKharrie wrote on 7/20/2015, 2:53 PM

Ideally you'll be using the "Suite" version of SMS - then you can make a Copy in Sound Forge - where you can turn-up the volume " Process / Volume " - or turn down ( if you delete, then sync can be lost ).
However, SMS v12 has some useful audio tools ( other version no-doubt similar ).
Put the audio on its own track and turn up the gain - LH Track header.
Then: Insert Audio Volume will produce a blue line on the track, this represents the middle volume (i.e. no change, other than the Track controls). If you turn up the blue line ( Shift Left click / drag).

Just as this will increase the Audio-levels, the opposite is also possible ( Although Sound-Forge creates another file, so this is "probably" the best solution.).

It's easy enough to drop the Audio-level between scenes ( or to supress an individual noise ), However, I find it more-rewarding to use normal audio-tracks whenever possible. So, using the blue "Vol." line is reserved for those parts where I need to fix "troublesome" audio - for example where two speakers are at different levels, due to poor technique / wrong Mic-gains, etc.

However, a "silent" passage can be disconcerting for the audience, so you may need to combine some other "background noises" - to cover-up any otherwise silent passages.... recording a "Wild-track" is often a good idea, even if it isn't needed - at least it's there should you need it.
Fortunately SMS has the ability to give you many extra Audio tracks - and giving them a Text-title is useful should you need to revisit the .vf files some months later.

Good luck.

PS Wild-tracks should be recorded on a solid-state recorder ( Sony does some ). at "Actual-level" and again with "raised-gain" as this reduces the effects of amplifier / conversion noise. You'll be lucky if you can get a clean recording of 1min - normally I will voice the File name/ file-type and the Title ( ie Purpose). This makes Editing so much easier later-on.

musicvid10 wrote on 7/20/2015, 3:38 PM

Use the auto crossfades or cut ONLY at zero-crossings.
For "some" ambient noise reduction, copy the clip, invert and apply 6:1 compression, reduce the noise portion to half the ambient level, and paste-mix in Sound Forge. Experiment until the reduction sounds natural.