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Waveform question

Posted: Sun May 02, 2010 6:33 pm
by Jim_B
Could you please tell me what the darker blue (waves) pattern entending over and under the center (gray waves) of the waveform represent? The volume of the mp3 prime track is too low and I need to amplify it. Since the outer (blue waves) extend to the +1.0 and -1.0 on the chart I cannot increase the volume (I need about +6 to + 7.5db) without noticeable clipping. Since this is not a Comparesonics type display I have no idea what frequency (or exactly what) the blue wave represents. I have tried playing with the FFT filter (-6db 10k to 20k) with no clipping improvement on then trying to amplify the filter applied track. The center (gray wave) pattern is very narrow. (normal for the low volume) Thank you for any help/education.

Re: Waveform question

Posted: Sun May 02, 2010 8:15 pm
by kozikowski
The blue waves represent the digital numbers that make up your show. As you noticed, once you exceed the maximum top and bottom, the show becomes damaged, sometimes permanently.

The darker blue in the middle of the waves is an illusion. If you magnify the waves sideways (to find an edit point) they go away.

You probably want to make the show more dense and forceful without making the peak numbers exceed the maximum. Chris's Compressor is a good choice for that assuming your show is voices chatting and music here and there. That's not a good choice if you're doing scientific experiments with specific volume levels.

Chris's Compressor
http://pdf23ds.net/software/dynamic-compressor/

Koz

Re: Waveform question

Posted: Sun May 02, 2010 9:00 pm
by Jim_B
kozikowski wrote:The blue waves represent the digital numbers that make up your show. As you noticed, once you exceed the maximum top and bottom, the show becomes damaged, sometimes permanently.

The darker blue in the middle of the waves is an illusion. If you magnify the waves sideways (to find an edit point) they go away.

You probably want to make the show more dense and forceful without making the peak numbers exceed the maximum. Chris's Compressor is a good choice for that assuming your show is voices chatting and music here and there. That's not a good choice if you're doing scientific experiments with specific volume levels.

Koz
Thank You for the prompt reply. If I understand you correctly if for whatever reason the blue waves are at the maximum top and bottom in order to get the sound level higher try the compressor you supplied the link to. I don't understand how the "digital numbers" got so high with such a low volume but that sounds like something I would have to learn what "digital numbers" actually are and their function in a mp3 audio track. This is a track given to me by someone else, I have never created a waveform that looks like this one in any of my recording methods. Since the track in question is 128kps 44mz music audio it doesn't sound like I'm going to have good results but I'll certainly try the compressor. Again, thanks for the quick reply.

Re: Waveform question

Posted: Sun May 02, 2010 9:22 pm
by kozikowski
So you have strike one and two before you even left home. Production in MP3 format is ripe for errors because Audacity doesn't edit MP3. It converts MP3 to an internal format and then makes a new MP3 when you're done. The show picks up damage -- sometimes significant damage -- each step. Do your work in WAV or another uncompressed format.

People are used to very highly processed and densely compressed modern music and they're shocked what "real" music sounds like when they just put a microphone in front of somebody and record them. "How come my guitar work doesn't sound like Nine Inch Nails." Because NIN music went through multi-thousand dollar post production and compression in a mixdown studio to sound like that.

You can do a lot of that in Audacity with the 1.3.12 tools over time, but there's no such thing as putting a microphone in front of somebody and walking away three minutes later with a Warner Brother's Records release.

Bruno, one of the forum helpers has been recording his live classical acoustic guitar and in that case, if he does everything perfectly correct, he has been getting release quality tracks. The goals are different. His work is anything but dense and loud.

You should be in Audacity 1.3.12 instead of 1.2. The 1.3.12 tools are much more polished and easy to use. Audacity 1.2 is very old.

http://audacityteam.org/download/

Koz