First Listen: Dolby Pro Logic IIz

Whether it's a sofa, a spouse, or a new surround-sound technology, you never really know what it's like until you bring it home and spend some time with it. That's why I was so eager to get my hands on Onkyo's TX-SR607, the first receiver to use Dolby's Pro Logic IIz technology.

PLIIz adds two additional speakers above the front left and right speakers in a surround-sound system. As I've explained in a past article, PLIIz adds a sense of height and greater envelopment to conventional 5.1-channel surround sound. It's the first of what will be at least two (and maybe three or more) competing height-channel technologies.

I got an extended demo of PLIIz a few months ago at Dolby's San Francisco headquarters. The demo blew me away-but it took place in one of Dolby's fancy listening labs, using PLIIz processing software on a computer, and a speaker system made up of professional recording monitors. So it wasn't exactly analogous to the experience a consumer might have at home.

When we received one of the first samples of the Onkyo TX-SR607, we thought it'd be nice to get right out there with a hands-on report. (A full review will appear in the print edition of Sound & Vision.) To facilitate the evaluation, Sunfire and Atlantic Technology were both kind enough to lend me additional speakers I could use for the height channels. And Home Depot was kind enough to sell me some 1x6s I could use to make some special height-channel speaker shelves. The shelves extend from directly above my front left and right speakers, all the way out almost to the corners of my listening room, giving me ample flexibility to experiment with speaker types and positioning.

I connected the TX-SR607 to several Sunfire CRM-2 main speakers and a Sunfire TS-SJ8 Super Junior subwoofer. For height-channel speakers, I switched among more CRM-2s, a pair of CRM-2BIP bipolar surround speakers, and Atlantic Technology's 1400 SR-z, which is the first speaker designed specifically for height-channel use.

I did all my comparisons in 5.1, switching the height speakers on and off to gauge their effect. It would have been nice to try a 9.1-channel system, but the TX-SR607 doesn't allow it; you can use channels 6 and 7 for the rear surrounds or the height speakers, but not both.