onkyo tx-sr607

Recently, Steve Guttenberg, our resident audio guru, took a listen to the first AV receiver to offer Dolby Pro Logic IIz. And he wasn't impressed.

Pro Logic IIz is the latest surround format from Dolby Labs. This one utilizes "height speakers" placed above the left and right front-channel speakers. The configuration Guttenberg tested utilized a 7.1 configuration (a standard 5.1 setup, plus 2 height speakers), but Pro Logic IIz is designed to support 9.1 as well (7.1 plus 2). That will presumably be supported in future

According to Dolby's Web site, the advantages of Pro Logic IIz are as follows:

With Dolby Pro Logic IIz, rain in a movie now seems to be actually falling on the listener's roof, concert videos bring a more intense sense of being at the performance, and orchestral works deliver more palpable depth, power, and connection.

In games, the added dimension increases the realism and immerses players more deeply than ever in the action.

Because it processes only nondirectional sounds for the height channels, Dolby Pro Logic IIz maintains the integrity of the source mix and the effects are always appropriate to the material. The added dimension complements the sound from the rear-surround speakers, adding spaciousness while honoring the original intent of the content creator.

Alas, Guttenberg could barely hear a difference when Dolby Pro Logic IIz was engaged: "The height speakers didn't make a discernible difference. I couldn't hear them at all, so I increased the height speaker volume by 3 decibels. Still no difference."

Needless to say, Dolby and Onkyo (the maker of the TX-SR607, which is the first IIz-compatible hardware) weren't too happy with that evaluation. So, we told them we'd give it a second chance, with more ears in the room.

For Round Two, Steve Guttenberg (again), Executive Editor David Carnoy, Senior Associate Editor Matthew Moskovciak, and I crowded into the CNET audio room.… Read more

The Dolby Web site is bubbling with excitement about its new processing trick, "With Dolby Pro Logic IIz, rain in a movie now seems to be actually falling on the listener's roof, concert videos bring a more intense sense of being at the performance, and orchestral works deliver more palpable depth, power, and connection." The "z" in Pro Logic IIz signifies the Z axis, otherwise known as height.

Sounds interesting, but when I setup and listened to the first receiver (an Onkyo TX-SR607) with Pro Logic IIz, the height speakers didn't lift my spirits.

Pro Logic IIz can, depending on the receiver's capabilities, either augment a 5.1 or 7.1 channel speaker system with two height channels. In other words, in a 5.1 channel system with Pro Logic IIz you'll have five speakers in the front of the room--left, center, right, left height, and right height--plus a surround speaker to both sides of the main listening position.

The 7.1 system with Pro Logic IIz uses the same speaker array--plus two rear surround speakers.

Once you have a receiver equipped with Pro Logic IIz, and wall mount the height speakers three feet or higher over the main left/right speakers, you're all set. You won't have to buy specially encoded movies or music.

According to Dolby, "Pro Logic IIz identifies and decodes spatial cues that occur naturally in all content--stereo and 5.1 broadcast, music CDs, DVDs, 5.1 and 7.1 Blu-ray discs, and video games. Dolby Pro Logic IIz processes low-level, uncorrelated information--such as ambience and some amorphous effects like rain or wind--and directs it to the front height speakers."

Nice idea, did it actually work? … Read more