8bit conversion

Does anyone know how to convert an Audacity file down to 8 bit? - not WAV or MP3 - but ‘native’ Audacity format. The manual says 16bit is default (i.e. lowest) - I am stumped

What are you actually trying to do? No applications other than Audacity can play Audacity project files.

Do you want to export an 8-bit Sun/NeXT 8-bit PCM file with AU header and extension? If so, click “Other uncompressed files” when you export, click the “Options…” button, then choose the AU header under “Header” and signed 8-bit PCM under “Encoding”.


I am doing a project for RMIT IT course - new to all this stuff - the Audacity manual says 16 bit is the default, and files can’t be saved in ‘native Audacity format’ in 8 bit. My tutor has set a question, which says it can. The object of the exercise is to compare file size from default rate to 8 bit. Thankyou for the answer - I will blunder through - do you mind if I get back with problems, as I say, I am a novice in this area. Thanks Q

There is no such description of what you have in single quotes in our Audacity Manual http://manual.audacityteam.org/o .

I suggest you make sure you have the latest Audacity 2.0.3 from here http://audacityteam.org/download/windows and then use our Manual as above (trash whatever alternative manual you are reading as it is incorrect for Audacity 2.0.3).

Then I suggest you ask your tutor to view this topic and explain more clearly what he is asking you to do.

Bit depth (16-bit, 8-bit…) is not a “rate” in itself, although for uncompressed formats it is one factor
that determines the bit rate.

For uncompressed formats (like WAV), bit rate = (bit depth) x (sampling rate) x (number of channels).

So, for a recording with a 44100 Hz sample rate, 2 channels (stereo) and 16-bit depth:

44100 x 2 x 16 = 1411200 bits per second, or 1411.2 kbps

If you want to most easily compare 16-bit and 8-bit file size, first choose the “WAV (Microsoft) signed 16 bit PCM” choice when you export.

Then export again (don’t change the project rate) but this time choose “Other uncompressed files”, then click “Options…” then choose “WAV (Microsoft)” header and “Unsigned 8 bit PCM” (there is no “signed” PCM version with WAV headers). This will be half the size of 16-bit.

Then choose an ADPCM type from the same “Options…” button. ADPCM is 4-bit, so it will be half the size of 8-bit.


Thank you for your post.

I think the problem is one of definition.

I appreciate Audacity is a platform for generating audio files, but ‘aup output’ if I can call it that, is not playable outside of the Audacity software. Why would it be, that’s not its purpose.

I also understand you can generate an Audacity file, then export it picking the options you indicated - that I understand. That is what the tutor was saying, as it turns out. (I didn’t read it that way).

The issue I would still like to clarify is this. If I import, say, an .aiff file, and save it as an .aup file - I can’t do that in 8 bit - “that” means saving it as an .aup file, in the Audacity environment. If I want 8-bit from the Audacity environment, have to export it in a ‘non-.aup’ format. Yes, Audacity is facilitating that, but its not in .aup format, but say .wav.

I hope this clarifies my question.

Audacity is a multi-track audio editor. It gets used in many different ways according to the needs of the user, but primarily its design goals are to provide an open source solution to high quality audio recording, editing and production and to be as easy as possible to use for all. The broad scope of these design goals have brought to Audacity millions of users around the world, using Audacity for all sorts of diverse projects. The “native format” for Audacity is the “Audacity project”, which you can think of as a “production environment”. Audacity projects encompass much more capability than can be accommodated in any standard audio format (multiple tracks, labels, envelopes, and so on).

For an overview of the relationship between Audacity Projects and audio files, see here in the manual: http://manual.audacityteam.org/o/man/audacity_projects.html

If you read our documentation, there is no suggestion that you can save an 8-bit AUP. You can choose 16-bit, 24-bit or 32-bit resolution at “Default Sample Format” in the Quality Preferences, so those are the native bit depths for AUP.