If you own Altiverb 5 HTDM you can upgrade to 7 XL and experience the new features of Altiverb 7 XL.
Altiverb 7 is the industry standard convolution reverb plug-in for Mac OS X and Windows. It uses top quality samples of real spaces to create reverb, ranging from Sydney Opera House to the cockpit of a Jumbo Jet. Altiverb 7 is efficient on the cpu, offers many parameters to tweak reverb, is total recall automatable, and has 64 bit support. Every month Altiverb 7 users receive new impulse responses for free.