Dolby Pro Logic IIz Header

Dolby® Pro Logic® IIz adds front height channels to surround sound, creating a 7.1 or 9.1 playback system for home music, movies, and video games. Dolby Pro Logic IIz brings enhanced spatial effects, added depth, and an overall airiness to the listening experience.

Introduces a new dimension in surround sound listening

Includes the proven quality of Dolby Pro Logic IIx, with an added dimension of height

Enables increased flexibility for expanding a 5.1 playback system to a 7.1, or a 7.1 system to a 9.1

Provides a significant competitive differentiator for audio/video receivers (AVRs) as well as home entertainment and gaming products

Offers an encoding aspect for a near-discrete listening experience

By adding front height channels, Dolby Pro Logic IIz creates a 7.1 or 9.1 playback system that enhances the spaciousness of music, movies, and video games, bringing a new dimension to surround sound listening.

An additional pair of speakers located above the front left and right speakers enables Dolby Pro Logic IIz to introduce a vertical component to the horizontal soundfield of a conventional 5.1 or 7.1 surround sound system.

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

As is the case in existing Pro Logic IIx technology, the height extensions don’t require new kinds of program content to drive the height channel outputs. Instead, the extensions are designed to effectively add depth and dimension to existing program material.

Dolby Pro Logic IIz also incorporates an encoding aspect that enables content providers and game developers to maximize the added dimension by creating entertainment with height elements of near-discrete quality.

With Dolby Pro Logic IIz, rain in a movie sounds like it’s 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. That’s a home theater experience your customers won’t soon forget.

Why Dolby

While 7.1-channel surround sound has taken the home theater experience to new levels, room layouts and space limitations won’t allow every setup to accommodate the back speakers of a 7.1 Back system.

Dolby Pro Logic IIz solves these problems by adding front height channels through a pair of speakers mounted above the left and right front speakers in a home theater surround sound system.

Extensive listening research established that adding a height dimension to a home theater with a 7.1 system brings a greater sense of realism than the addition of surround speakers in the horizontal plane. People are also far more sensitive to directional cues from sounds that occur in front rather than behind. Front speaker placement is the ideal next dimension in home theater surround sound.

These added channels also provide the flexibility for designing a surround sound system with up to 9.1 channels. With 9.1-channel AVRs there are even more options, including state-of-the-art 9.1 playback with surround and back speakers, and two front height speakers.

Because Dolby Pro Logic IIz is based on proven Dolby Pro Logic IIx technology, it’s just as easy to implement in AVRs, with height channels offered as another option on the speaker setup menu.

Improves the spatial presentation of current 7.1 surround sound setups

Provides the installation flexibility for setups where rear surround sound speakers aren’t practical, while delivering a dramatic alternative listening perspective

Ensures realistic and enveloping sound from music or movie sources

Works with original stereo or multichannel sources

Requires no special encoding or separate mixing by the content producer

Makes speaker positioning and wiring simple

Popular Science Best of What's New 2009

In 2009, Dolby Pro Logic IIz was recognized by Popular Science magazine as one of the top 100 innovations of the year, winning the coveted Best of What's New award in the Home Entertainment category. Each year, the editors of Popular Science review thousands of products in search of the top 100 tech innovations of the year—breakthrough products and technologies that represent a significant leap in their categories. Read more about the Best of What's New award.

Dolby® Pro Logic® IIz incorporates all of the features and capabilities of Dolby Pro Logic IIx. The following information summarizes existing Dolby Pro Logic IIx implementations and what’s added for Dolby Pro Logic IIz.

Ability to generate up to 7.1 channels from stereo and 5.1 sources 

Supported decoding: 

Pro Logic mode  

Virtual Compatible mode  

Music mode  

Movie mode  

Matrix mode  

Dolby Digital EX mode  


Supported upmixed output configurations based on stereo sources: 

2 to 3 [L, R to L, C, and R] 

2 to 4 [L, R to L, R, Ls, and Rs] 

2 to 5.1 [L, R to L, C, R, Ls, and Rs] 

2 to 6.1 [L, R to L, C, R, Ls, Rs, and Cs] 

2 to 7.1 [L, R to L, C, R, Ls, Rs, Lrs, and Rrs] 


Supported upmixed output configurations based on 5.1 sources with independent Ls and Rs channels: 

5.1 to 6.1 [Ls, Rs to Ls, Rs, and Cs] 

5.1 to 7.1 [Ls, Rs to Ls, Rs, Lrs, and Rrs] 


The features listed above allow Dolby Pro Logic IIx to provide a true surround sound experience from a variety of sources. However, all the outputs derived by existing Dolby Pro Logic IIx decoders are located in a horizontal plane. The Dolby Pro Logic IIz extensions to Dolby Pro Logic IIx allow it to derive height channel outputs that significantly enhance the spatial experience.

In addition to the features already described, the height extensions offer the following new features and configurations:

Ability to generate audio of up to 9.1 channels that include height channel outputs from stereo, 5.1, and 7.1 Back sources. 

Supported upmixed output configurations based on stereo sources: 

2 to 7.1 Height [L, R to L, C, R, Ls, Rs, Lvh, and Rvh] 

2 to 9.1 [L, R to L, C, R, Ls, Rs, Lrs, Rrs, Lvh, and Rvh] 


Supported upmixed output configurations based on 5.1 sources with independent Ls and Rs channels: 

5.1 to 7.1 Height [Ls, Rs to Ls, Rs, Lvh, and Rvh] 

5.1 to 9.1 [Ls, Rs to Ls, Rs, Lrs, Rrs, Lvh, and Rvh] 


Note: For 5.1-channel sources, Dolby Pro Logic IIz height extensions operate only on the Ls and Rs channels; L, C, R, and LFE channels are bypassed.

Because new formats (such as Blu-ray Disc™) allow content to contain up to 7.1 discrete channels from Dolby Digital Plus and Dolby TrueHD audio programs, the height extensions support 7.1 Back sources and offer the following upmixed output configurations:

7.1 Back to 7.1 Height [Ls, Rs, Lrs, and Rrs to Ls, Rs, Lvh, and Rvh] 

7.1 Back to 9.1 [Ls, Rs to Ls, Rs, Lrs, Rrs, Lvh, and Rvh]

Note: For 7.1-channel sources, Dolby Pro Logic IIz height extensions may operate only on the Ls, Rs, Lrs, and Rrs channels; L, C, R, and LFE are bypassed.

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