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Subject: Re: mp3 features
From: LoveLearn (LoveLearn_at_iw.net)
Date: 2003-09-11


The current automatic volume alteration discussion raised questions.
MusicMatch JukeBox includes a volume leveling option. Select which mp3
files to process. Processed files are replaced by slightly larger
volume leveled copies. On MusicMatch playback formerly frustratingly
quiet files seem normally loud. Is this processing equivelant or
identical to the volume leveling proposed RockBox?
MusicMatch volume leveling processing appears CPU intensive on PCs.
Similar processing might be very slow on Archos hardware.

I ran Peavey CS800 professional sound reinforcement amplifiers years ago
which included a quick acting volume peak limiting option. When driving
one of these 800 watt units to very high levels, audience members never
heard these spike reductions nor did they hear the recovery period
because it was so fast acting in both directions. When playing really
loudly, switching off this spike limiting circuitry instantly revealed
clearly recognizable clipping distortion while reducing apparent average
sound pressure level. After we discovered those two perceived
performance enhancements, we always left the spike reduction circuit
switched on.

I've played with RockBox "Auto Volume" spike limiting. I don't use it
because its shortest recovery time is distressingly long and obvious to
me. I've experienced volume spike limiting that functions so fast
audience members can't perceive it's occurring. Would it be possible to
duplicate that circuit's effects with RockBox software?



Page was last modified "Jan 10 2012" The Rockbox Crew
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