From WAV to MP3
David Shamah, The Jerusalem Post August 9, 2005
Audacity does much more than plain, simple recording, as you have probably figured out by now - and much of its abilities are due to its wide set of industry standard plugins used by music professionals for synthesized and computer generated music. We looked at the noise removal
plugin in some detail, but if you want to enhance your music, there are other plugins available.
Amplify, for example, increases or decreases the volume of a track . When you open the dialog box, Audacity automatically calculates the maximum amount you could amplify the selected audio without it being too loud. Bass boost will amplify the lower frequencies while leaving most of the other frequencies alone. It's most effective if you don't try to boost too much. And the wahwah effect makes your stereo music seem as if it's traveling from one speaker to the other.
One very cool feature will satisfy the curiosity of rock conspiracy theorists and members ofof the PMRC (Parental Music Rights Coalition). The Reverse effect plays a song from back to front, in reverse order - and if you play certain songs slowly, it is said, you can find out if Paul is dead, who killed Kennedy, and how rock music makes people worship th devil and such. You can also copy reverse sections and paste them into other songs, for interesting effects. Other useful effects include fade-in and fade out for tracks.
Among the aforementioned plug-ins that Audacity comes with are Freeverb, which gives you a reverb effect, Delay, which creates several echo effects, and tremolo, which makes music sound other-worldly. However, plug-ins (which appear on the bottom of the Effect menu, as well as on the Analyze menu), ar eall made by third parties. Audacity supports VST (Virtual Studio Technology), Ladspa, and Nyquist plug-ins, of which there are thousands available, both commercial and open source. However, the Audacity manual urges caution: "It is possible for a poorly written plug-in to crash Audacity, so always save your work before using a plug-in effect." After you've recorded a few songs and played with the Audacity effects and plug-ins, you'll figure out which ones work best on which types of songs.
As mentioned last week, labeling is a bit of a hassle, no matter what conversion method you use, because there are no digital labels or tags on analog recordings. You can label a song after it's been converted to an MP3, as mentioned - or you can label it during the editing stage, by using the Label Track commands on the Project menu. You can export these labels as text files and reimport them into other files. If you just want to call your files "track 1, track 2," etc., you can save a lot of time in labeling.
Then there is the question of saving into file formats and exporting. Audacity can save in a number of compressed and uncompressed formats, including WAV, MP3, AIFF (used mostly with Macs), and OGG Vorbis format, which offers more efficient compression than MP3, and is open source to boot. Audacity also has its own native file format, which you can't use for any music player (other than Audacity itself). However, if you plan to extensively edit a large file (like an album side), it makes sense to use the Audacity format, because the file will open much more quickly, and you'll be able to pick up the trail on whatever effects you are using, since they will not yet be integrated as permanent parts of the file. Audacity, by the way, has an unlimited level of undos per editing session, so you can always turn back the clock on whatever you have done.
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WAVs are uncompressed, so saving a file as a WAV is a simple procedure. MP3 compression is another, more complicated issue - you want to compress a song small enough so that it is easily transferable or downloadable, but not too low that the compression would negatively affect music quality (although with a compression scheme you always lose some quality in the final product. MP3 compression works by removing portions of the original signal which are determined to be essentially inaudible — a technique known as "perceptual coding." What has been lost cannot be restored in playback).
In the standard CD audio format, one minute of music takes up roughly 10 megabytes. When converted to MP3, that same minute of music takes up only about 1 megabyte. The main decision to make when exporting to MP3 is determining what bitrate to use - the higher the bitrate, the better the sound quality. As mentioned, Audacity uses the open source Lame MP3 encoder for encoding, so make sure the Lame files, especially Lame_enc.dll, are in the same folder as Audacity. You set up all the information for a file's MP3 compression rate, as well as sampling rate and all sorts of other things on the File > Preferences menu. Usually the samoling rate for a stereo music file is 44100 hz, and the bitrate is 128.
There are lots of ways to skin a cat, as the saying goes - and lots of ways to move music off tapes and records and into digital format, other than Audacity, which we covered last time. For example, if you own the Nero Suite - used for recording CDs - you can use Nero's various options to record files to a WAV CD format (which you can then convert to MP3 format using Audacity). If you don't mind shelling out $25, you can download Digitope's Media Digitalizer (http://www.digitope.com), which gives you more automatic options than Audacity (you can download a full free trial option to check it out). And Huelix's Audi Recorder is another useful all in one solution (http://www.huelix.com/audiorecorder). Personally, I thing it's investing the time to learn the free open-source Audacity - you already paid for your music at least once. And you know the old saying - "fool me twice, shame on me!"
ds@newzgeek.com