Wednesday, January 04, 2012

Surround Sound Beyond 7.1 Part 2

Back in 2007, I wrote about moving beyond 7.1 to systems with as many as 13 [11.2] channels. It has taken a few years and as of last year [2011], 11 plus c channel systems have became available in integrated AVR units. One company that has made this system possible is DENON.
The Extended System
The 11.4 [this system actually has 4 Sub-woofers] system is still based on the standard 7.1 speaker system. It uses special processing, additional channels of amplification and 4 more speakers. The additional 4 speakers are Height and Wide speakers which no only extends the width of the sound stage, but adds a sense of elevation which I'd to my surprise only added to the envelopment of the sound field.

The following is from the system owner:

"My LCRs weighing in at 100kgs each are Vaf I93. They’re a difficult speaker to drive, needing an amp which is 2 ohm stable which drastically limits the amplifier options. I’m powering them by 2 x Rotel 1090 amps which are rated at 700w into 4 ohms per channel and have 2 channels each – this leaves me with 1 channel spare and I may try biamping the centre channel at some point. The Rotel 1090 amps are 40kgs each. The LCR speakers are biwired – and yes speaker cable and interconnects make a big difference to the sound quality of these speakers.
The front wides are VAF I33 and the surrounds are VAF DC-X. These 4 speakers are powered by a Rotel 1095, 5 channel amplifier. This amp is rated at 200w per channel and also weighs in at around 40kgs. I had the spare channel powering bass shakers in the chairs but this is currently disconnected as I don’t feel it’s required with the current subwoofer setup.

The heights are VAF I91 and the rears VAF DC-X. These 4 speakers are powered by the Denon 4311 AVR. Down the track I’ll pick up another Rotel 1095 to power these speakers. I have had smaller speakers in the past for the surrounds and rears but my experience is that full size speakers for these locations make a huge difference.

The subs in the front corners are VAF MPB SW 19. They’re a powered subwoofer. The inner subs are JTR Captivators weighing in at 80kgs each. They’re a passive sub and are currently and temporarily being powered by a Behringer EP4000 amp which is giving them approx 1000w each. The JTRs are rated for a 4000w amp and I’ll be upgrading the amp shortly to get them closer to their potential. The Behringer is certainly an excellent bang for buck amp for powering passive subs.

The Denon 4311 AVR is a 11.2 receiver and we’re using both subwoofer outputs, 1 to each pair of subs. The room has been analysed with REW software and from that the front of the room has side and ceiling acoustic absorbtion panels, which has greatly increased sound clarity. The rear of the room is lined with bookcases to be useful and diffuse the sound waves off the back wall. Interestingly before the sound treatment we were getting much more sound reflection off the ceiling than the side walls. The floor is carpeted with a soft underlay and we weren’t getting any reflection off the floor that we could measure.

The REW software was further used in conjunction with 2 Minidsp’s to equalise the 2 pairs of subs. The Audyssey MultiEQ XT32 of the Denon AVR was then run after the sub pairs were equalised with the Minidsps. Result of the 4 subs running together is a very flat response down to 15Hz. Although I’ve read that different types of subs shouldn’t be used together, room measurements and listening tests show that the VAF MPB SW19s work very well together with the JTR Captivators.

I’m a huge Audyssey fan and Audyssey DSX is used for the expansion to 11 channels and a future upgrade will be to get the Audyssey Pro installer kit to take advantage of the Audyssey Pro capability of the Denon 4311.
The audio in our Home Theatre, like many people’s has been a work in progress over 12 years, starting with a 5.1 setup, then 7.1, 7.2, 9.2, 11.2, 11.4 . Speakers, amps, cables, interconnects, AVRs have all been changed many times along the way."
On the video side, the system uses a 3D capable JVC X3 and Aussiemorphic Lens MK4 along with a Radiance Mini3D. The system is 3D CIH and very impressive from the front row of seats which are about 2.5x the image height back.
The JVC Projector and MK4 Lens
The Wide Screen
I like how captured images of Scope Screens always look WIDER from an an angle. So whilst I am very impressed with the benefits of Height and Wide speakers, the question [challenge] is how do I implement such a system in my own room?



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