I'm building a site for a client who is selling mp3 and midi files, and I'd like to allow their customers to "audition" the clip before buying. I want them to listen to a 30 second sample - so I want to preselect part of the file that they can listen to on the product page. Any tips for how to achieve this? I realize I can do it the hard way by building and uploading separate mp3 files that are just the 30 second bits, but it would be nice to just do it on squarespace.