Need to record 30 min audio for web upload

I want to record our Pastor’s weekly message at our church for upload to our web site. I have been able to use Audacity for the recording, and it sounds great, but when I export to WAV or MP3 format, the file size is huge. Pastor’s message usually runs about 30 minutes in length. Are there any tips anyone can provide me as to what bit rate to record in or what format to export it to? I am so new to this sort of thing and probably know just enough to be dangerous. Any help would be greatly appreciated!

Thanks in advance,


It would have saved time if you had posted to the proper forum for your operating system and version of Audacity (for example, Windows 1.2.x).

WAV is lossless so will be large. If you export to MP3 it will take 1 MB per minute by default (128 kbps). You can reduce the bit rate to reduce the size but also the quality.

If you are using Audacity 1.2.x, go to the File Formats tab of Preferences and in the “MP3 Export Setup” section, reduce the bit rate by clicking on the downward-pointing arrow in the “Bit Rate” dropdown. Preferences is at the bottom of the Edit menu (or in the Audacity menu on a Mac computer).

If you are using Audacity Beta 1.3.3 or later, click File > Export, choose “MP3” in the “Save as type” dropdown, then click the “Options” button.

32 kbps MP3 for example will give you 4 minutes for 1 MB and might be acceptably good. MP3 is your best choice of the compressed formats if you want to distribute the sermon because everyone will be able to play it.


Speex would be a better format for voice only but, eventhough it’s a free codec, not all players/systems support it by default…

MP3 is more widely supported, so it’s always a safer bet. Exporting in mono will give you better results, specially at lower bitrates.

Nonetheless, if you have the time, give a try at speex.

Curiously, current Adobe Flash Player I believe supports Speex, so that’s one way of distributing it on the internet. Just to clarify, Audacity does not support it, so export it as WAV (not MP3) from Audacity and then convert it to Speex elsewhere, so that you only perform one lossy encoding.


Any plans to include speex support in audacity?

I think we are still waiting for libsndfile to implement support for it. This was supposed to be quite close five years ago.

To be accurate, .spx files can be imported into 1.3.12 on Windows by adding FFmpeg, courtesy of the included libspeex-1.dll. But FFmpeg still seems to lack Speex encoding.

Does the Mac FFmpeg installer include libspeex?


I have no idea… I’ll check that next week when I get back from camping.

In /usr/lib/local/audacity/ I find:

libavcodec.dylib (an alias)
libavformat.dylib (an alias)
libavutil.dylib (an alias)

So it looks like libspeex is not included on Mac? I’ve run the standard ffMPEG installer.

– Bill

It seems not. Libspeex is under the modified BSD licence, so is GPL-compatible.

I note also Mac does not have libfaac/libfaad which is in the Windows FFmpeg installer. While I think FFmpeg can use its own built-in AAC encoder/decoder I understood the built-in encoder was buggy and gave faulty exports (I can’t recall if this was length or volume, or both). Are AAC exports say of a 5 minute track OK on Mac?


In my opinion its always best to use the highest bit rates as long as your web host provides your enough web space. It makes no sense to use bad quality just because you wanna put something online. Thats the reason why I don’t like myspace and others to much… They don’t over enough web space to work good. AND I REALLY KNOW WHAT I’M TALKING ABOUT!°