For live audio broadcasts and longer samples, there's a better way of delivering the sound to the browser, called streaming. Here, the audio is stored on a server that can feed the sound data as it is required in real time to connected browsers. So only as much audio as is required is sent out, rather than whole, large files.

The main advantage of this is that you (the listener) hear the start of the audio much sooner, as you don't have to wait for the whole file to finish dowloading before you can play it. It does mean, however, that the quality of playback is limited by the bandwidth available, which is not so good for dialup users.

Being designed for the web, streaming audio is usually highly compressed too, allowing reasonable quality sound over lower bandwidth links. Take a look at the RTE Radio website for examples of streamed audio - many public and commercial radio stations also now broadcast on the web in this manner.