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Wave File Compression Codecs Compared

Audio Compression Manager

This is a reference to compare the audio quality and compression bitrates of the different wave compression codecs available for ".wav" and ".dct" files using the audio compression manager including PCM, GSM, ADPCM, CELP, SBC, TrueSpeech and MPEG Layer-3. Note: The Audio Compression Manager (ACM) is used for recording to .wav (wave) or .dct (dictation) files. For other file formats, please start with the Sound File Formats page.

The ACM is used by:

The audio file compression formats listed on this page are low bitrate speech formats. Higher bitrate music and broadcast voice formats are not listed.

You can listen to samples of each audio format by clicking on the "Sample" link.



1 min =


11,025Hz 16bit PCM176.4kbs1292k11k16bitpcm.wav
8000Hz 16bit PCM128kbs937.5k8k16bitpcm.wav
11,025Hz 8bit PCM88.2kbs646k11k8bitpcm.wav
11,025Hz u-Law88.2kbs646k11kulaw.wav
8,000Hz 8bit PCM64kbs468.8k8k8bitpcm.wav
8,000Hz u-Law
* toll quality telephone
11,025Hz 4bit ADPCM44.1kbs323k11kadpcm.wav
8000Hz 4bit ADPCM32kbs234.4k8kadpcm.wav
11,025Hz GSM6.1018kbs131.8k11kgsm.wav
8000Hz Mp3 16k16kbs117k8kmp316.wav
8,000Hz GSM6.10
* cell phone quality
8000Hz Lernout & Hauspie SBC 12k12.0kbs87.9k8ksbc12.wav
8,000Hz DSP Group TrueSpeech9kbs65.9k8ktruespeech.wav
8000Hz Mp3 8k8kbs60k8kmp38.wav
8,000Hz Lernout & Hauspie CELP4.8kbs35k8kcelp.wav

The above are wave files - even if they have the mp3 codec they will have the ".wav" or ".dct" extension. For a broader overview of other file formats, please see the Sound File Formats page.

Recommended Codec
NCH Software currently recommends GSM6.10 8000Hz for voice recording.
Problem Formats
The ACM codec shipped with Windows 2000/XP called "Microsoft G.723.1" has a bug which means it cannot be used for encoding / recording. Please do not attempt to use this format.
Discussion Forum
If you have any questions in ACM codecs or are generally interested please see the Sound Formats Discussion Forum.
Software that Support ACM
A number of the NCH Software professional audio software applications include the Audio Compression Manager: