How can I use iWeb to create website that contains a lot of downloadable audio files?

The important thing is not to put the audio files directly into iWeb: if you do that then every time iWeb decides it needs to upload the entire site you will find yourself uploading all 15GB of audio files, which won't make you happy. Start by uploading the files to the server - in folders as suits you - and then link to them in iWeb.

If you want them to download rather than play, you may be able to set up an .'htaccess' file in the folder which will force a download - it depends on whether your hosting service will allow this. The method is described here:

http://www.wilmut.webspace.virginmedia.com/notes/missing/download.html

Here is an example of a simple link which produces a download (without the process described the audio file would play in the browser in a blank page):

http://rfwilmut.net/stars/dawson2.mp3

Then all you need to do is to provide a link, designed however suits you, in your iWeb page. If your server won't allow the .htaccess file then you will have to ask visitors to control-click (Mac) or right-click (Windows) on the link and choose 'Download linked file' or equivalent - not so convenient; or otherwise zip the files first, which won't much reduce their size but will force a download (and of course the recipients will have to unzip them).

If you want the files to play in a player in the page, you can use an html snippet to provide a player as described in this page (you will also need to upload a script to the webspace - this is provided in the page):

http://www.wilmut.webspace.virginmedia.com/notes/qtembed.html

As an additional point: if you are using embedded players in a page, and you have a number of items there, the disadvantage is that they will all load every time you load the page. I prefer to use pop-up players - you can see the effect by clicking the 'play' buttons on this page:

http://www.rfwilmut.clara.net/stars/fields.html

The pop-up players are simple web pages you would create outside iWeb using TextEdit, and you would again use an html snippet for the javascript which opens the new page. The method, including the necessary coding, is described here:

http://www.wilmut.webspace.virginmedia.com/notes/qtplayer.html

Create a zip of each audio file. To find out how to create PC compatible zips, see the bottom of this page...

http://www.iwebformusicians.com/iWeb/PDFs.html

Upload these in a folder to the root folder on your server using an FTP application...

http://www.iwebformusicians.com/Search-Engine-Optimization/Upload.html

Create a text or image link to each file...

http://www.domain-name.com/folder-name/file-name.zip

If the link is clicked the file downloads.

If you want to have a whole album to download, put the audio files in a folder and zip the folder rather than the files inside.

You can place any amount of audio players on a page using the HTML5 audio tag. Just set preload="none" in the code shown on this page....

http://www.iwebformusicians.com/Website-Music-Players/HTML5-Audio.html

If you have more than two or three it makes more sense to use a playlist....

http://www.iwebformusicians.com/Website-Music-Players/music-box.html

http://www.iwebformusicians.com/Website-Music-Players/XML-Playlist.html

or this if you want reponsive...

http://mobile.ezmacwebdesign.com/audio-player/audio.html

Please note my Notes pages are now at http://rfwilmut.net/notes