Understanding WAV, PCM audio, sampling rate, bit depth and preservation masters.
What is WAV?
WAV is a container/file format widely used to store digital audio, commonly containing linear PCM audio for professional recording and preservation.
What does PCM mean?
Pulse Code Modulation represents an analogue waveform as a sequence of digital samples. Sampling rate and bit depth determine important characteristics of that representation.
Why use WAV for preservation?
A straightforward uncompressed or appropriately lossless WAV workflow can retain the captured audio without the quality loss associated with lossy delivery formats such as MP3.
What is sampling rate?
Sampling rate describes how many samples are taken per second. IASA recommends at least 48 kHz for digitising analogue material and identifies 96 kHz as a useful higher sampling rate for many materials.
What is bit depth?
Bit depth relates to the available dynamic range of the digital representation. IASA recommends at least 24-bit capture for analogue materials.
Why create a WAV master and MP3 access copy?
The WAV master can retain high-quality audio for preservation while an MP3 can provide a smaller convenient file for everyday listening. The access copy should not replace the preservation master.
Frequently Asked Questions
Why is WAV used for archive audio?
WAV can contain uncompressed PCM audio and is widely supported by professional audio systems.
Is WAV better than MP3 for preservation?
For many preservation workflows, yes. MP3 is a lossy compressed format intended primarily for access or distribution.
What WAV specification should I use?
The appropriate specification depends on the source and project, but IASA recommends at least 48 kHz and 24-bit for digitising analogue material.
Further Reading
Oxford Duplication Centre — Practical Expertise
Audio preservation depends on the original carrier, compatible playback equipment, a controlled signal path and careful quality assurance. The preservation master should retain the best practical representation of the source, with access files created separately.
Need DAT tapes digitised?
Oxford Duplication Centre provides professional DAT digitisation for individual tapes and archive collections, with preservation and access outputs tailored to your requirements.
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