To date, I've only just copied CD's straight, with Nero and have not attempted any plain or fancy frigging with the music. I have now begun to mount my extensive music collection onto my HDD with great success but all the programs I've used have a 'Normalise' option. I'm presently in love with CDEX for ripping to MP3. Would someone please explain how to use this feature and more importantly, explain what it does?
In 16bit audio sample values can be between -32768 and + 32767. Normalising to "xx %" scans a track for the biggest sample value "s_max" and multiplies all sample values with "normalisation_factor" = 32767 * xx % / s_max".
Example:
Normalise a low volume track with peak sample value = 10000 to 95%:
normalisation_factor = 3.112865
The peak sample value of 10000 becomes 31129 = 95% of 32767, a sample value of -1000 becomes -3113 etc.
Problem with normalising: Peak values don't tell you much about how loud a song is perceived. Because of this there's replaygain (and similar wavgain, mp3gain, vorbisgain etc.) that use knowledge about sound perception to adjust perceived volume. Read more about it here: http://replaygain.hydrogenaudio.org
BTW: Thread moved to audio as it belongs there. :)
tigre,
Thank you very much for the link and explanation of normalisation. MP3Gain has now become a permanent member of my arsenal. I've had great interest in reading all of the threads in the 'Audio' area and I'm about to embark on my next project. I have 200+ vinyl albums and as many cassette tapes to be .wav'd and MP3'd but I'll start a new thread. Thanks again.
Jon
I would definitely advise against normalization. It does not increase the percieved volume of the track, but as Tigre says, raises the peak values to the one you specify. Most of the time, this is not what you want to do. The figure you are looking to change is the RMS (or average) volume instead.
In all honesty, it's best left alone as it is seriously easy to actually degrade your audio if not careful.
wilkes,
I hear you loud and clear. All I did was run my complete MP3 folder through MP3Gain and it did its thing. My 56 year old ears don't percieve any degradation of the music, so I'm happy. I really wanted to do this as I become tired of having to fiddle with the volume slider alla time. I care for my 82 yo Mother and she has ears like a bat, goes to bed at 7.30 pm every night and she can hear a flattulent fly at 500 yards. Waking her is not to be toyed with. There is nothing more horrifying at 3.00am to be confronted by a very old, irate woman who's not wearing her upper or lower teeth.
