KI DOJO
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Articles and Interviews
Tango Music part 1: Lossless or lossy compression?
(by K.Zahariev and P.Müller)
As a teacher of argentine tango I teach of course not only tango technique but also about its music. Many students and dancers now
use computers to store their tango music and I ask my friend
Konstantin for help. Why?
Because like many things in life, also for the compression of our tango music we have to choose between quality
or quantity while using a computer for dj-ing or archiving our numerous Cd’s.
“Hi Patricia,
Sound files on a normal Cd (that you put in your Cd player) are very
large and they are not compressed for size in any way, normally known as Wav audio format. For each second of music we need 176400 bytes
of disk space, which is a LOT - it is more than 10 MegaBytes/minute!
So people devised clever compression algorithms to reduce the size of the sound files when they are recorded to a hard disk on your computer. This is how the "mp3" compression algorithm was created.
There are two types of compression algorithms - lossy, and lossless.
Mp3 is a lossy algorithm, meaning that it throws away some of the audio in order to compress the file more. Then if you try to put it back into a Cd Wav format to hear again your music, or into some other format (lossless or lossy), it is not the same anymore, it has lost sound quality because sound information was thrown out forever. The mp3 algorithm sacrifices sound quality for disk space, so it achieves a file size of only
10 percent of the original Cd Wav file size. This was very important a
few years ago when disk drives were small, between 5 and 10 GB (GigaBytes).
Any time you play a sound file, for you to hear it, it has to be de-compressed back to a Wav format. So when you listen to an mp3 file that you created, you are listening not to the way the file was originally on the Cd, but to the de-compressed mp3 file that has reduced sound quality.
Of course mp3 people argue that the algorithm throws away mostly only things your ear can't hear
anyway, unless you create the mp3 with a very high compression (less than 5% of original Cd Wav file size).”
“Excuse me, Konstantin, this means I cannot use mp3 if I want to create an archive of tango music with its original sound. So, what alternative do I have?”
”I chose to use a lossless compression algorithm, more or less a compression of 30-50 % of original file size on Cd. For most tangos, it is closer to 30% because they were all mono until late 1950s, and the two stereo channels on the Cd are more or less the same. Lossless compression does not throw any sound information away from the original file, so when you de-compress it back to hear the file, you are listening to exactly the same file that was on the original Cd - bit for bit identical.
With tango, we have enough sound quality problems with the original recordings, so I didn't want to reduce the quality more and I chose to use "monkey's audio" lossless compression (http://www.monkeysaudio.com/). with the 3-letter abbreviation "ape". There are also other (http://flac.sourceforge.net) or Lpac (www.nue.tu-berlin.de/wer/liebchen/lpac.html).
”What program can I combine the codec (which means CO-mpression/DEC-ompression) “ape” with ? And what size of drive space
do You use?”
“I use a free program called dBpowerAMP (http://www.dbpoweramp.com/ ). I use the dBpowerAMP Music Converter (dMC) to "rip" the tangos from the Cd (which means to read them from the Cd and convert them to "ape" format and save them on my hard drive). Then I use the dBpowerAMP Audio Player (dAP) to organize and sort the files. You can read more about audio formats,
and other things, in more detail at http://www.dbpoweramp.com/spoons-audio-guide.htm
If you want to use “ape” format on average, you will need 10
Megabytes of drive space per tango
song in ape format."
“This means for example if I have 2000 tangos, I will need roughly 20 GB (Giga bytes) hard disk, or if I have 3000 tangos, I will need 30 GB hard disk space, and so on, right?”
““Yes, that’s right. But if you have problems with drive space on your laptop, you would have to go with mp3, just keep your Cd’s because you need them for the original quality sound files. However if you have
30-60 GB drive space, you can try ape lossless audio or some other lossless format.
Good luck!”
“Thank You, Konstantin.”
