Lowering custom sound quality?

I'm currently in the early stages of a project that will eventually require custom sounds. However, the sounds that I intend on using are much higher quality than the original Doom sounds. What would be the best way of lowering their quality just enough that they would not sound out of place with the stock sounds? I'm not very familiar with Audacity and audio editing in general.

.wav ?

In Audacity there should be something called "Project Rate" in the lower left corner of the window, you can use that to lower the quality to 11025hz.

Lay your hands on a copy of the Windows XP Sound Recorder (there's a links around here somewhere) and use that instead, it has more features than its successors.

• Load your sound sample and select "Properties" from the File menu
• Leave format conversion at "All Formats" and click on Convert Now...
• Under Name, select "Radio Quality" or "Telephone Quality" (most Doom sounds are Telephone Quality), leave the format at "PCM" and click OK
• The Properties window should have updated size and format details, click OK
• Test the changes and Save As... (give the sample a new name) if satisfied. Otherwise, select "Revert" from the File menu and try again