Saturday, April 29, 2006
Sound Editing
With Audacity you can either record analog audio from sources such as a microphone, tapes, or records or import sound files such as WAV, AIFF, AU, Ogg Vorbis, MP2 and MP3. Recording and editing can be done in 16-bit, 24-bit, and 32-bit floating point sampling rates at up to 96 KHz.
Using multi-channel hardware you can record up to 16 channels at once or using a dubbing technique you can dub over existing tracks to create multi-track recordings. A great mixing feature of Audacity is that tracks with different sample rates or formats will automatically be converted in real time. Once loaded you can then edit the sound with operations such as copy, cut, paste, splicing, fading, and mixing and can even undo or redo those operations an unlimited number of times.
Audacity also allows changing a sound recording's pitch without altering the tempo, and vice-versa. Also it is possible to remove unwanted qualities in the recording such as hiss, hum, or static. Frequency alteration with equalization, an FFT Filter, and Bass Boost effect are possible. Volume alteration can be accomplished with compressor, amplify, and normalize effects. Additional sound effects such as wahwah, phaser, echo and reverse are easily done as well. You can save the recording in formats such as Ogg Vorbis, MP3, AIFF, and WAV sound files.
You can also expand Audacity's capabilities with Plug-Ins from various sources such as LADSPA plug-ins, VST plug-ins and even create new effects with the built-in Nyguist programming language.
For those hard core Digital Signal Processing people, visualizing frequencies is available by using the Spectrogram mode and detailed frequency analysis can be accomplished by using the “Plot Spectrum” command.
Installing
The installation of Audacity for MacOS and Windows is simple since you get a .dmg, .sit, or .exe file depending on your OS. For Linux, I chose to download the source. But there are a few additional packages that are needed or recommended. wxGTK is required, libvorbis, libogg, lame, libmad, etc. are needed of you want .mp3, ogg vorbis encoding and decoding support support. See yesterday's (C.P.O.T.D.) for installation instructions for the needed extras.
This is how I installed Audacity on my Red Hat AS 4 box. There may be other packages needed for your installation. Remember there are wonderful resources to get these dependancies, such as up2date and yum. For instance, if you need the gtk development package, it is as easy as doing an up2date gtk-devel or yum -y gtk-devel. From the previous packages installed from past projects covered in C.P.O.T.D., you may not have to install any other packages, if you are lucky. Also, I am using paco for the package tracking (CPOTD post) but you need not utilize it. Just do a make install in place of the corresponding paco... "make install" line.
To utilize more functionality in Audacity, additional Codec libraries must be obtained: flac, libmad, libogg, libvorbis. To simplify the install I downloaded the libraries again since yesterday in the event you haven't gone through yesterday C.P.O.T.D. (go now and read it... its a great post!)
cd /tmp
wget http://superb-east.dl.sourceforge.net/sourceforge/audacity/audacity-src-1.2.4b.tar.gz
wget ftp://ftp.mars.org/pub/mpeg/libmad-0.15.1b.tar.gz
wget http://superb-east.dl.sourceforge.net/sourceforge/flac/flac-1.1.2.tar.gz
wget http://downloads.xiph.org/releases/ogg/libogg-1.1.3.tar.gz
wget http://downloads.xiph.org/releases/vorbis/libvorbis-1.1.2.tar.gz
wget ftp://ftp.mars.org/pub/mpeg/libid3tag-0.15.1b.tar.gz
wget http://easynews.dl.sourceforge.net/sourceforge/wxwindows/wxGTK-2.6.3.tar.gz
tar zxf wxGTK-2.6.3.tar.gz
cd wxGTK-2.6.3
./configure
make
paco -lp wxGTK-2.6.3 "make install"
ldconfig
cd /tmp
for file in audacity-src-1.2.4b.tar.gz flac-1.1.2.tar.gz libmad-0.15.1b.tar.gz libogg-1.1.3.tar.gz libvorbis-1.1.2.tar.gz libid3tag-0.15.1b.tar.gz
do
tar zxf ${file}
done
cd /tmp/audacity-src-1.2.4b/lib-src
mv ../../libid3tag-0.15.1b libid3tag
mv ../../flac-1.1.2 libflac
mv ../../libmad-0.15.1b libmad
mv ../../libvorbis-1.1.2 libvorbis
mv ../../libogg-1.1.3 libogg
cd ..
./configure --with-libmad --with-vorbis --with-libflac --with-libresample --with-portaudio --with-soudtouch --with-libid3tag
make
paco -lp audacity-1.2.4b "make install"
Running Audacity
To run audacity, just type
audacity
Conclusion
Audacity's interface is very clean and elegant, It is very simple to use and is quite intuitive but to get the most out of Audacity, you should look at the documentation, read the manual and go though the tutorials. The documentation is very well written and gives some great tips and techniques to maximize your effectiveness with your audio projects. Also a great resource is The Audacity Wiki which also contains tips, tricks, and documentation that even you can contribute to.
