As technology changes it opens up a whole world of posibilities with various format issues. This is no more evident than when you are creating a CD master for your next audio CD project. Whether it be a bands latest CD or EP or an educational product there are some important considerations to take in to account when making your final production master.
So how do your know which format to supply for manufacture of your discs? CD Audio? Aiff? Mp3? Flac? .Wav? and what should the parameters be?
The first question that has to be asked is where do expect customers to play the CD? If your answer is "at the least a regular cd audio player, portable CD walkman or car player" then your only reliable and highest quality option is .cda or CD audio format.
CD Audio format is: Stereo, 16bit and 44.1Khz sampling rate. No other format can be directly used to make your CD copies apart from a DDP image. (This is usually done by higher end Mastering Engineers for replicated discs). Find out the difference between Replicated and Duplicated CDs here
If you supply other formats such as a disc with Mp3, Wav files, Aiff, Itunes M4a files or upload/download of files via our FTP server or on a thumb drive, this will require time to make a new master and also need to be approved before the production process begins.
The CD audio master can then be analysed by us prior to sending to production to ensure it meets quality standards.
As mentioned previously some audio masters are now provided by Mastering houses in DDP format. Often these are uploaded to our server as an image file with a MD5 Checksum file. This checksum is used to double check the integrity of the file when your audio discs are replicated.
When your engineer is sending DDP files you should request a normal CD master made from the same image to verify and check for errors prior to production. Currently we cannot analyse DDP images for quality issues as they are not strictly an audio disc. It is therefore important for you to know what you are sending to production is ok and is your responsibility.
DDP images are generally not used for production of duplicated discs, that is, runs typically under 500 copies.
There are many compressed audio file types available now and these should not be used for your audio masters. They do not represent the hours of work that you have done in the studio and are best used for streaming audio playback or portable digital devices such as computers, Ipods and Mp3 Players.
Files that are not suitable for high quality CD masters include MP3 (of any sample rate) Ogg Vorbis, WMA, Flac, .Wav files, AIFF, M4a and Mp4s. Although often a CD master will be made directly from Wav files, this format itself (a MS computer based audio file) is not directly suitable for a replicated or duplicated run of CDs.
It is possible to re-master these compressed audio formats to a CD master suitable for production, For example if the original masters have been lost. However there will be losses of quality compared to the original recordings and the results will depend on the time taken in the re mastering process. We can create new production masters in our editing suite from a variety of different formats. More information on CD Mastering is available here
If you are producing talking books or educational programmes then often both CD Audio and Mp3 versions are created. Mp3 versions will save multiple discs being used in the production process as you will be able to put considerably more audio on a disc than and normal audio CD. The number of discs used will be determined by the amount of compression used on the audio files. Playback of the Mp3 discs will require a player that can play that specific format, such as in a computer, laptop, some newer portable players and car players.
Finally using high quality discs and mastering at the lowest practical speed will provide higher quality masters, We have a free mastering pack available with tips and master grade discs here:
If you are unsure if your master disc is the correct format for producing your next CD project give us a call on 08 9375 3902 or 1300 4 PROCOPY and we'll advise you on it's suitability.