I'll start the ball rolling with this offering. It starts off a bit techi but eases up as I got bored and my head cold worsens.
.cda Files – compact digital audio
Data in the CD digital audio format is encoded by starting with a source sound file, and sampling it to convert it to digital format. CD-DA audio uses a sample rate of 44.1 kHz,.) Each sample is 16 bits in size, and the sampling is done in stereo. Therefore, each second of sound takes (44,100 * 2 * 2) bytes of data, which is 176,400 bytes.
Audio data is stored on the disk in blocks. Each block holds 2,352 bytes of data, with an additional number of bytes used for error detection and correction, as well as control structures. Therefore, 75 blocks are required for each second of sound. On a standard 74-minute CD then, the total amount of storage is (2,352 * 75 * 74 * 60), which is 783,216,000 bytes or about 747 MB. From this derives the handy rule of thumb that a minute of CD audio takes about 10 MB, uncompressed.
Using special software (e.g. windows media player), it is possible to actually read the digitally-encoded audio data directly from the CD itself, and store it in a computer sound format such as a .wav file.
To get a track from a CD onto your computer you need to extract the (xxxx.cda) file with the help of a “ripper” such as Audiograbber (www.audiograbber.com-us.net); this is very easy to use programme which will grab the file to your hard drive either as a .wav file or a .mp3 file
.wav Files
.wav files are uncompressed and consequently you’ll need about 10 mb of hard disk space per minute of music. Files are encoded and the standard is 16 bits at 44.1 kHz (i.e. CD quality) and has no “loss”. This is the best format to manipulate the audio files. You will need a sound editing programme to manipulate a track and this is the real expense come in. Top end software like Sonic Foundry Sound Forge, Steinberg WaveLab and Cool Edit Pro all cost quite big bucks. However, there are some free ones about like Audacity (www.audacity.sourceforge.net) & Exact Audio Copy (www.exactaudiocopy.de) There are also free demos kicking around the net too .
With theses programmes you will be able to trim the noise from the beginning and end of tracks, amplify, fade in and out and with some remove noise, hiss, click and pops.
Because .wav files are so big, it is necessary to compress track in order to save space and allow files to be emailed and streamed over the internet. Compressing can be lossy or lossless. Lossless encoding doesn’t save much and so it’s not really much use in these days of large hard drives. Lossy compression is the most widely used such as .mp3 and real audio files .ra. Basically, bits of a tune can be removed because some parts of the audio can not be heard by the human ear (so why the hell it there, I do not know)
.mp3 Files
Many of the editing software packages will allow you to convert an audio file to a different file format. There are also many free ones that can be downloaded from the net. My favourite is dbPowerAmp Convertor (www.dbpoweramp.com). Once you have installed the software, you can simply right-click on a .wav file in windows explorer and convert it to a .mp3, and you can choose the encoding to reduce the size of the file. You can also convert mp3 (and rar files with a plug in) to wav files to clean up and burn to CD.
.rar Files
Rar files are produced by Real audio software and tend to be used to “stream” audio over the internet such as radio shows. The basic programme is at https://www.realnetworks.com/products/producer/basic.html . The software to play them is free. I think that Sound quality depends on the file size and / or the speed of the server and your internet connection.
Recording to a PC
If you have got a sound card, you should be able you find a line-in socket around the back of the PC somewhere, it’s usually takes a 3.5 mm jack plug and an arrow pointing in +/- a blue ring (they’ll be a headphone (green) and microphone (pink) socket too) . To record onto your hard drive you will need a programme; a free one can be found at https://audacity.sourceforge.net/
To record from a tape deck you just need to have the appropriate cable with connection to the tape out put socket (usually phono) and a 3.5mm jack on the other end. However to record from a turntable you will need to amplify the signal somewhere along the way:
1) connect your amp ‘out’ to your sound card in
2) connect you headphone socket to your sound card in
3) connect the turntable lead to a pre-amp which you then connect to your sound card in. (These can be bought separately and cost around £40 - £50)
4) Buy a package like Steinberg Clean Plus that is software to clean up .wav files and contain a pre-amp too
You will need to check on that your sound card’s line channel is active; look for a speaker next to the clock in the bottom right corner of your screen and double click on it (if you can’t see it open Control panel from the start menu, click on Sound and Audio Devices and tick the box next to” place volume icon in the taskbar’. I would set the line in level to about half way and check the mute box is not ticked.
Usually, by default, your recording will be an uncompressed .wav file 16bit , 44.1kHz on the hard drive
You can now edit the files, convert it to .mp3 or .rar, and finally burn a CD to swap with other Soul Source anoraks like me!