SRS Labs via offers SRS Labs iWOW Premium for iTunes for Windows or Mac, model no. iWPCM-35, for $14.99. With free shipping, that’s the lowest total price we could find by $37. (It’s also $9 under the best price we could find for a downloadable version.) This iTunes plug-in purports to provide surround sound, 3D audio, and more using standard headphones, desktop, or notebook speakers.