Combining audio files from multiple narrators requires normalization for consistency from slide to slide. Audacity and similar audio editors can normalize peaks but I've read that best results are obtained when the audio's RMS energy level is used for normalization, not the peaks.
What product(s) are eLearning developers using to normalize audio?
I give Levelator high marks for simplicity. It does a good job but more than one 3rd party reviewer has indicated volume levels are sometimes inconsistent. Interesting the complaints come from MAC/Safari or MAC/Chrome users.
Could be a MAC issue, but I suspect the RMS calculations of the Levelator could be better.
The problem with RMS is it may not identify the same average level on all files. Especially if you are mixing differents recorded sources. It may work well on longer files but in the end you might end up with 2 files RMS normalized with 2 differents global levels. I would go for peaking but look closely at peak levels close to zero; normalizing audio with peaks when you already have peaks to close to 0db might do nothing. Also, before doing a peak normalization, I would strongly suggest an expander (see it as a reverse compressor) which expand the levels of your wave to express it more throughout the entire db structure. When you normalize audio, it tends to bring the floor level higher thus making it more noizy if the background noise is audible.
I usually audio edit in Adobe Audition, which allows you to choose peak or RMS normalization (I usually use peak, though). Audition has a pretty good digital noise reduction feature as well.
We often use two narrators speaking to each other in our courses. I tried "normalization" and other standards methods but none of them really did a good job in leveling the volume.
I finally found Auphonic Leveler and always use it on all of my audio! Not only do I get consistent volume across slides, but also across all of my courses. It does a pretty good job in removing noise and hiss. You can try it free on their website.
I use Adobe Audition. I capture a noise print first from a "quiet" background part of the wave. Then run the noise reduction process (this ensures that when I compress the audio the low background noise is not boosted). Then I run the multiband compressor using the broadcast preset. Finally I normalise.
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Sam the BEST tool I've ever found is Levelator and it's free. http://www.conversationsnetwork.org/levelator
I give Levelator high marks for simplicity. It does a good job but more than one 3rd party reviewer has indicated volume levels are sometimes inconsistent. Interesting the complaints come from MAC/Safari or MAC/Chrome users.
Could be a MAC issue, but I suspect the RMS calculations of the Levelator could be better.
Sam
The problem with RMS is it may not identify the same average level on all files. Especially if you are mixing differents recorded sources. It may work well on longer files but in the end you might end up with 2 files RMS normalized with 2 differents global levels. I would go for peaking but look closely at peak levels close to zero; normalizing audio with peaks when you already have peaks to close to 0db might do nothing. Also, before doing a peak normalization, I would strongly suggest an expander (see it as a reverse compressor) which expand the levels of your wave to express it more throughout the entire db structure. When you normalize audio, it tends to bring the floor level higher thus making it more noizy if the background noise is audible.
Cheers!
Storyline 360 has a new Optimize Audio Volume option that normalizes audio across all slides: https://community.articulate.com/series/74/articles/articulate-storyline-360-user-guide-how-to-publish-a-course-for-web#step4
I usually audio edit in Adobe Audition, which allows you to choose peak or RMS normalization (I usually use peak, though). Audition has a pretty good digital noise reduction feature as well.
Cheers!
-Ray
Sam,
We often use two narrators speaking to each other in our courses. I tried "normalization" and other standards methods but none of them really did a good job in leveling the volume.
I finally found Auphonic Leveler and always use it on all of my audio! Not only do I get consistent volume across slides, but also across all of my courses. It does a pretty good job in removing noise and hiss. You can try it free on their website.
Russ
I use Adobe Audition. I capture a noise print first from a "quiet" background part of the wave. Then run the noise reduction process (this ensures that when I compress the audio the low background noise is not boosted). Then I run the multiband compressor using the broadcast preset. Finally I normalise.
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