Need help w/ eird Olympus file format[SOLVED]

I have a venerable Olympus VN-960PC that I just love, and it still works well. My ONLY issue with the thing is that I cannot find a Voice File Editor to use with it! Many times, there are long silences in my recordings that I would like to edit out. I have been able to OPEN the files quite easily using some voice-file editors (e.g. Nero); but cutting out the silence in a recording which is (say) half-silence, results in a file size that is TWICE as large (or larger) than the original! (I am aware that Olympus employs an ADPCM/four bits “compression” thing, which is totally non-standard.)

I just downloaded the newest Audacity (including plug-ins), and I have “messed around” with exporting a copy as a 16-bit WAV file. However, even without any editing, Audacity exports the file to something that is FIVE TIMES the size of the original!

I just wondered if anyone had tackled this particular type of Olympus file before, and had any suggestions as to how to work with it.
(1) I did not try “importing” the file into Audacity; I just did “File|Open.” Would I gain anything by importing it?

(2) Is there a plug-in/converter that I need to download and use? (links and instructions are appreciated…)

(3) WAV is a very easy and comfortable standard for me to work with; however, if I HAD to convert the file to something like MPG (within Audacity), that wouldn’t be a TERRIBLE outcome.

(4) I know, I know: “Spend $30 and go buy yourself an MPG-based recorder!!” But I hate to throw out gear that still works; and besides, I’d still like to edit some of those old files.

Thanks for your expertise,

So unless you resave the WAV in the same bit-depth-reduced format that Olympus uses, you will increase the file size.

If you want to export to 4-bit ADPCM WAV, choose “Other uncompressed files” when you export, click “Options…”, choose “WAV (Microsoft)” header then choose an ADPCM encoding. See here .

If there is existing audio in the project window, Import will import into the same window as that existing audio.

If there is existing audio in the project window, Open will import into a new project window.

If you want to export as MP3 instead of ADPCM WAV, please add the LAME MP3 encoding library to your computer. See .


Hi Gale,

Thank you for a complete, concise and annotated response! I don’t know how I would have figured out this routine by myself.

One question: you said:
“If you want to export to 4-bit ADPCM WAV, choose “Other uncompressed files” when you export…”

Am I correct in assuming that even though the Export category is called “Other uncompressed files”, exporting to the 4-bit ADPCM WAV format (as you describe) will result in “compression” similar to that claimed by Olympus? (from their website: “Adaptive Differential Pulse Code Modulation (ADPCM) compresses files by saving them as WAVE files with a bit depth of four bits rather than the 16 bits typical of other audio formats.”)


ADPCM is not “compressed” in the same sense as, for example, MP3 compression, but it is still “compressed” in the sense that it produces a much smaller file size than a normal PCM WAV file.

Perfect! Thanks, Steve. I will give it a try and see what happens.