New Year, new system update
During holidays I updated the Trinnov Altitude 16 software and find new and very comprehensive bass management options. This made me think: do I really need a separate LFE subwoofer? It is taking too much space and unlike the Left & Right subwoofers, it is not in-wall, instead located to the left of the seating area below some shelves. Occasionally I can localise the effects coming from it.
The two in-wall subwoofers have total cone area equivalent of a 20” subwoofer. That should be plenty enough, I thought. A quick level test proved that to be the case. I played a 25Hz sinewave at a level of 110dBSPL(C) at 2m It sounded decent to my ears and as that level is 20dB higher than I will use the system I didn’t investigate distortion levels further. I decided that it is high enough for an occasional explosion to be reproduced with enough force.
The LFE sub has gone, making my partner happy as he will use the space to store more brick-a-brack.
Next job was to add more speakers. You cannot have enough speakers in a Home Theatre!
In addition to the Dolby, DTS and Auro3D templates, the Altitude16 also has a hybrid layout designed by Trinnov. This layout based on a 7.1 surround layout with additional speakers to support multiple 3D formats such as Dolby Atmos, DTS:X and Auro-3D. It uses 15 speaker plus subwoofer. I decided to modify the layout to use 16 speakers plus two subwoofers.
Dolby defines two left and right wide speakers for Atmos. They are positioned in front of the normal surround speakers. I was using JBL CBT-50-1 for the side and rear surrounds. However, I was not happy with the tonality difference to the KEF LCR speakers. I decided to switch to smaller KEF in-walls, Ci3160RL-THX, for the existing side surrounds and for the new wides as well. The front KEFs are the reference series and are pretty expensive. I opted for the standard series for the surrounds. The rear surrounds cannot physically be positioned in a wall so I left the JBL CBTs in place.
The Trinnov hybrid layout use one centre height speaker for the Centre Top front and one ceiling speaker for the Top channel (The Voice of God) for Auro-3D and DTS:X. I modified the layout to use two Front Heights instead of one, as I already had KEF Ci200RS-THX speakers directly above the L&R flush to the ceiling. I added another Ci200RS-THX to the ceiling for the Top channel directly above the main listening position. Not that I expect it to have any use of them as DTS:X seems to have all but lost the streaming market but I had a spare amplifier channel. Maybe Disney+ will finally deliver on their promise. Who knows, elephants may fly…
The above changes are in addition to the speakers on the false wall where the TV, LCR and two subwoofers are mounted in. LCR is made of three KEF Ci5160REF-THX in-wall speakers. Two are mounted to left & right of the TV in vertical and the centre one below the TV in horisontal orientation. There are two JBL Synthesis SSW-3 in-wall subwoofers. These were mounted away from the corner but now moved to the corners into the place vacated by two bass resonators, which are moved to the ceiling, next to the others. I wanted to gain as much as I can by repositioning the subwoofers to the corners. That required more bass resonators though to compensate the level increase of some room modes. Moving subwoofers to the corners has an added benefit. As they are now nearer to the side and surround speakers they can act as side subwoofers as well.
Overall the system now has 18 speakers, a 9.2.6 setup. All speakers are passive. 16 speakers other than the two subwoofers are fed by the Trinnov Amplitude-16 supplying 16x 200W. This makes the cabling very, very tidy. I still had the JBL Synthesis 2x SDA-4600 power amplifier from a previous incarnation of the system. I used it in bridge mode to supply 2x 1200W for the two subwoofers. They are fed from one of the AES3 outputs of Altitude-16 via a Topping D90SE.
There are five bass resonators hidden inside the false ceiling. These suck the five main room resonances (room modes) caused by the standing waves. Each is a tuned Helmholtz resonator made from 20cm (8”) diametre plastic water pipe. Their length set the frequency range they will operate at and the opening is adjustable for precise tuning. Once the room modes are reduced to near elimination the room frequency response became pretty flat. Only a very small amount of equalisation is required, which is done by Trinnov.
Here is the new connection diagram and the modified layout of the room. The room is roughly 10m by 10m (32’) with the listening area width reduced to 6m (20’). Ceiling height is 3m (10’). The speakers are in green and the in-ceiling bass resonators are in pink. The false ceiling is made of a combination of absorber and diffuser panels. There are shelves on the left and right of the sitting area, which act as a diffuser of sorts.
