How do I use dedicated storage and iTunes?

Re the original question, see this procedure at the Apple support site.

That document pre-dates iTunes 11, btw, although I suspect that it remains applicable.

Regards,
-- Al

For the record, a minor correction to something that was said above. The Oyen Digital 1TB external drive does not utilize an SSD (solid state drive). It utilizes a conventional 5400 rpm mechanical laptop hard drive, in an external enclosure.

At this time, 1 TB SSD's continue to be VASTLY more expensive than the price of that Oyen unit. There are some hybrid drives, though, which contain both a small SSD and a large HDD, that are available at reasonable prices. I'm doubtful, however, that they would provide any advantage in an audio application relative to purely mechanical HDD's.

Regards,
-- Al

Adding to my previous post, some of the smaller Oyen drives utilize SSD's, but not the 1 TB drive. As indicated at OyenDigital.com, the largest SSD they offer is 480 GB. And, per their website, that lists at $410 in its cheapest version!

At Newegg.com, the least expensive raw SSD (without an enclosure) that approaches 1 TB is a 960 GB drive selling for $1,000. Some others sell for much more than that.

Regards,
-- Al