1. Features of MP3, MIDI, wave, audio and file types including suffixes. By Georgina Honeysett PGCE ICT

2. WAVE WAVE means storing a pattern of music signals in digital wave form on computer. This means that any sound can be stored. However, these sound files are huge and process over 160KB per second. These files can be seen with a suffix of.wav (e.g. Fred.wav)

3. MP3 MP3, or MPEG level 3 indicates a type of sound file found on computers. MP3 is designed to store music at CD quality but using approximately 1/12th of the space. This compression method is PERCEPTIVE ENCODING. This means that approximately 90% of the music which the human ear does not respond to (I.e. duplicate notes, quieter sounds etc.) is removed.

4. Changing filename suffixes from fred.wav to fred.mp3 By changing a sound file filename from.wav to.mp3 only the name is being changed not the actual contents of the sound file. This is like ‘calling’ a CD an audio tape. The fact is that it is still a CD whatever you choose to call it! CDAUDIO TAPE

5. Converting files from MP3 to WAV to CD Audio To take some music from CD you use a programme called a RIPPER which copies the music and stores it as a.mp3 or.wav file depending on the software you are using. If you need a sound file to be in a particular audio format (.wav or.mp3) in order to run on your specified software, then your sound files need to be converted. To convert a file from.mp3 to.wav a program such as XING can be used. This converts.wav files to.mp3 files and vice versa. CD Audio is sound stored as a.wav file on a CD. A computer can report this as a.wav file or a.cda file depending on how the computer is set up.

6. Summary so far WAVE and MP3 store sound as a signal (a wave - digital representation of the sound). MIDI stores the notation to generate the sound (like an orchestral score.) to CONVERT a file from.wav or.mp3 use a program such as XING. CD Audio is sound stored as a.wav file on a CD.

7. MIDI MIDI stands for Musical Instrument Digital Interface and is used with computers. Where a CD stores sound music, MIDI is the manuscript version. It also involves hardware within the computer (including cables, keyboard, computer sequencers, synthesisers, instruments etc) It stores the pitch, volume and which instrument is being played.(channel) MIDI comes from the notation side of music and is best thought of in terms of an orchestral score where lots of different instruments can be put together in one entity.

8. FILE TYPES and suffixes Sound and music files can be found in several formats. Some of these have been explained already, but here is a list of others to be aware of..wav (WAVE).mp3 (MPEG 3).cda (CD AUDIO).wma (Windows media audio - Microsoft’s rival to mp3).mid (MIDI)

9. Identifying ‘good’ music sites. There are MP3 sites springing up everywhere. The simplest way to identify a ‘good’ music site is to do an Internet search for a keyword such as MIDI on a search engine such as Yahoo or monster crawler. E.g. MIDI AND Church music Bugs Bunny wav Some useful web addresses are: www.mp3.com mp3.lycos.com www.peoplesound.com www.vitaminic.com www.riffage.com

10. Downloading files, graphics and MP3 When downloading graphic files, right click on the graphic you wish to save to your computer and select ‘save target as’ from the menu. The file will be saved in your specified location. Double clicking on a music file sound automatically give you the option to save them. Otherwise proceed as for graphic files.

11. WRITING TO A CD. To record music on a CD, you need to use a CD writer to transfer the sound files onto a CD R (Recordable). This is the only type of recordable CD that can be read on all types of CD player equipment whether hi-fi or computer etc.

12. Easy CD Creator  To transfer sound files, a programme such as Easy CD creator can be used.  “Adaptec Easy CD creator lets you create your own data, audio and multimedia CDs from within Windows 95 or Windows NT. You can back up important files to CD, and read them back on standard CD - ROM drives.” (Adaptec,Inc.)