Construction Kit File Formats
I have performed extensive research and testing towards providing the best balance of fidelity and file size in the production of construction kits (loops). I have determined that the best results are obtained from producing
- 24-bit sample depth
- 48 kHz resolution
- FLAC loops
- REX loops
and to package the final kits with ZIP.
perkXsoundlabs construction kits used to be distributed compressed with 7-zip. By popular demand, these kits are now compressed with the much simpler, ubiquitous and widely-supported ZIP format. The space saved by using 7-zip was minimal since the files were already compressed with FLAC and REX.
FLAC is the Free Lossless Audio Codec, a lossless compression algorithm developed as a free software project. It compresses audio files to 50 - 75% of the file's uncompressed size with absolutely no loss in fidelity. REX is a widely-supported loop format developed by the Swedish software company, Propellerhead. Not providing AIFF (Audio Interchange File Format) and WAV loops saves a lot of space. Also, to reduce the size of these kits, filter swept versions are not provided since this simple effect is trivial to achieve in even the most basic production environments.
Most Microsoft Windows, Apple Mac OS and Linux music production environments support FLAC loops and REX loops. For those that don't support FLAC, like Propellerhead Reason, the FLAC loops can easily be converted to WAV loops by a host of free applications; then again, Propellerhead invented REX loops, Reason supports them and they have many advantages over WAV loops—so you really needn't bother with the FLAC loops if you are using Propellerhead Reason.
For decompressing FLAC to WAV loops, I would suggest fre:ac, the free audio converter, which correctly preserves the 24-bit resolution.