Ben Goff, Director at Cinema Lusso, gives EI the inside track on this technically accomplished and highly attractive cinema which recently won the Home Cinema Level 1 and Best Lighting Awards at the EMEA CEDIA ceremony.
Ben explains, “This is a high-performance dedicated home theatre, with a focus on interior design, comfort and usability. The design can be split into two distinct sections in terms of allocating of the client’s budget. During our initial client interviews, it became clear that the client placed as much, if not more value on the non-technical elements of the room, leading to more than half of the total budget being spent on interior design, seating and lighting. The basis of the technical elements with the company’s designs always begins with CEDIA Best Practice papers CEA/CEDIA CEB-22, CEB-23 and CEB-24. Additionally, standards from Dolby and published academic research papers inform the technical requirements. During a series of demonstrations, the client showed genuine interest in the audio performance, notably enjoying systems displaying outstanding dynamics and bass response.
Ben says, “Film soundtracks can have in excess of 100dB of dynamic range. Our objective is to ensure this range is faithfully reproduced, without clipping, distortion or masking. Ensuring we have dynamic headroom throughout the playback chain ensures the full range can be reproduced at ‘Cinema Reference’ levels. In order to provide a full range from the quietest passages, to the loudest peaks, our objective is to ensure a weighted background noise level at the main listening position is under 30dB SPL.”
On bass, Ben adds, “Bass Frequencies play a large role in many movie soundtracks. In order to convey realism, this content can extend to 20Hz and below, with peaks at 115dB. Our objective is to ensure that all guests enjoy a balanced bass presentation. “Subwoofers, seating and acoustic treatment are all used to reduce both seat to seat variation and inter frequency variation. Our objective is to deliver 115dB peaks to the MLP with headroom remaining in both the drivers and amplifiers. Low frequency extension should ensure a maximum of -3dB at 26Hz and -6dB at 20Hz.”
In this case the room was too small to provide true reverberation, but reflected energy can still smear detail of direct sounds. Ben says that the objective was to provide the maximise level of resolvable detail, without making the room uncomfortable to spend time in. Calculations showed that a target 0.2 second decay time would provide optimum performance.
For the video performance viewing angle is of obvious importance and client’s optimum horizontal viewing angle was determined during demonstrations as 50°. While this is slightly larger than standard, or the CEB23 recommendation, it was based on client preference.
To achieve ideal Dynamic Range in-line with the CEB23 and DCI Digital Cinema recommendation, the project objective was to achieve a minimum of 1200:1 (full on-full off) contrast ratio and 150:1 intra-frame contrast ratio. Dark materials, in a neutral pallet were used to ensure room reflections did not cause black level clipping, masking details in dark picture areas. The cinema also aimed to deliver 100% coverage of the Rec.709 colour gamut, with a maximum Delta E of 1.0 across the entire spectrum and intensity range with no visible deviation from grey through the range of the visible brightness range. The system was also designed to support 4K content throughout the entire playback chain.
The award-wining lighting design was created to make up part of the entertainment inside the room. Full colour, moving patterns are used at the beginning and end of a movie to add aesthetic impact and drama.
At interview stage the team established the room must be able to comfortably seat six adults, plus additional children using an inset floor cushion. The objective was to provide the ultimate performance in the two middle seats which are used most often whilst minimising compromises to the other four.
Technical excellence throughout
Creating the cleanest electrical feed for the room, there is a separate mains ring for the cinema, which includes power for the projector and chair motors. All devices in the rack are also protected by three Furman AC-210AE power conditioners each rated to 10amp output, over two outlets. The Furman’s Linear AC filtration ensures the AV equipment is provided with clean AC Power, reducing the effects of harmonics which may be introduced by switch mode power supplies on the same electrical phase. The main rack is on a separate ring, but shares the same phase, this includes components such as the network router and source devices, which potentially could have lower quality or electrically noisy power supplies. A fourth Furman AC210AE protects the projector in the cinema room.
The team also combined the two Anthem components on one 10amp Furman conditioner, with a combined peak draw of 5 amps.
The two Audio Excellence components share the next Furman conditioner. The Quatro 06 Power amp is rated by the manufacturer with a maximum draw of 10amp, however it can never be used anywhere near its maximum power. There are two limiters in place that the client cannot override, one in the Audio Excellence DSP and another in the AV processor. In total the LCR had an -8db signal level applied to each channel during setup and calibration. This reduces peak output from 600w to 175w per channel, allowing the 105dB peak SPL @ MLP, but no more and significantly reducing the power requirements. The third Furman powers the Artcoustic subwoofer amp alone, which has a manufacturer stated 5.65amp maximum load.
The actual real world power consumption of the system would have allowed the team to use to use only two Furman 10amp conditioners, however the cost to include compared to the total budget meant the benefits were well worth the inclusion.
The main AV rack for the house holds the source devices including the Kaleidescape and Apple TV used in the cinema. The Kaleidescape is fed from a UPS which protects the whole system located in this rack. In the event of a power failure, the home’s Savant control system immediately places the Kaleidescape into standby to prevent unsafe shutdown.
The lighting is on a different phase from the AV System. The down lights are wired directly to a Rako Rak8 lighting controller which has eight dimming circuits of 400W each. The Orluna down lights use a 12W watts, so a total of 72W in this room. The LED Drivers have their own electrical supply, again this in not on the same phase as the AV. There is approximately 70m of tape in the room, which can use 14.4W per meter – a total of 1000W, if all tape is at 100% for all colour channels, but there is no scene programmed to allow this. Ben says, “The four 300W power supplies would have 20% headroom at full power, but they actually have much more than this on any of the programmed scenes ensuring they are not overly stressed to manage their life expectancy.”
During the CEDIA Awards application process, entrants are always asked what changes to CEDIA standards were made during the creation of the cinema. Ben explains, “Our Subwoofer placement does not match any of the CEB22 recommended layout suggestions. This was driven by a combination of budget and need to maximise floorspace. We placed the subwoofers tight into the front corners, but we have not got rear subwoofers as per that layout. During our modelling, we established that with a single row of primary seating, the use of the front corners, without two rear subwoofers would produce a satisfactory seat to seat low frequency performance.”
Ben continues, “The room is too small to have true reverberation with simple reflections the dominant later sound. CEB22 states that the 60dB decay time should be within 0.2 – 0.5 seconds to be neither too reverberant nor artificially dead. We believe this criterion is oversimplified, ignoring a possible imbalance across the frequency range within the room. Instead of the CEB22 recommendation, we prefer to use to the formula specified by ‘Subjective assessment of audio quality – the means and methods within the EBU’ (Hoag et al. EBU Technical Review Winter 1997) which takes the room volume into account and frequency.
“This room is smaller than the recommended size for the formula to provide a result above the minimum recommended 0.2 seconds, so our target was adjusted to 0.2, with +/- 0.05 second tolerance. We took repeated decay measurements over multiple octaves to confirm our predictions from our Sabine Calculations. The room matched very closely to our predictions throughout the frequency spectrum.”
The acoustic treatment fitted into the room also contributed towards creating the desired outcome.
There was another slight variation from CEDIA recommendation in terms of viewing angle as mentioned earlier. CEDIA CEB23 sets this at 43°, however detailed client feedback and testing established that for this customer 50° was a better match as it felt more like the experience the customer had as a child when the screen felt ‘huge’.
This theory was tested by inviting the client to watch a whole movie at the company’s demonstration suite with the angle adjusted to a 50° 2.4:1 image.
Ben explains, “Budget did not allow for a bespoke screen, so we were limited to off the shelf sizes. With a 100inch wide screen selected, we had a small amount of wiggle room with the seat position to create his ideal viewing angle. The final measured position was agreed at 50.2°– 1.07x the screen width or 2.57x the screen height. This is a large screen for the room, but well within the SMPTE closest recommended 2.0x image Height or 61.8 degrees.”
The space is for exclusive use as a cinema and a very high proportion of content watched in the room is in native 2.4:1 aspect ratio.
Ben explains, “We had a limited range of projection options to achieve the 100inch wide image within the available throw range. We selected the Sim2 Domino 4 due to its compact size, allowing to be comfortably placed slightly further back in the room than many other projectors with similar throw ratios. We utilised an anamorphic lens to provide additional image width, while using all of the projector’s resolution and light output for 2.4:1 content.”
Going the extra mile for the customer, despite knowing that the client has only watched one movie since installation which was not in the 2.4:1 aspect ratio, the team created a special button which locks any content filmed in IMAX into 2.4:1. This is called the ‘Batman Button’ as that single movie was The Dark Knight. Options to accommodate both formats were considered but were beyond budget and the customer was happy with the result.
Another key requirement in entering the CEDIA Awards is to show how the company has accommodated additional customer requirements or overcome and technical challenges.
Ben reveals, “The client wanted to place his personal stamp on the room in a clear but subtle way. We decided to incorporate his family coat of arms into the upholstery of the bespoke sofa. The artwork provided was too complex to be embroidered. Our graphic designer simplified the design, replacing the family motto with the client’s name, at his request, before being approved by the client’s father, both at design stage and a production sample.”
It was also decided that all the triangle lighting panels needed to be removable for servicing and maintenance reasons. Each triangle is attached on a button fix system, allowing it to be easily removed. In the event of a triangle being damaged, it can be removed, re-upholstered and returned without taking the room out of use, or a large section of the wall out for service.
Speaker placement is of course highly important in any high-performance home cinema. The first choice in this regard was to ensure the correct orientation of the room design to deliver the seating and audio performance required placing the full width window at the back of the room.
Getting into the meat of the design, Ben explains, “We wanted to balance the three core elements of the audio reproduction within the available budget. With budget split between dynamic range, timbral accuracy and spatial resolution. In demos and consultation with the client we agreed that ‘quality was better than quantity’ so an extended channel count was never considered. The 5.1.2 speaker layout skewed the overall performance towards increased dynamic range and timbral accuracy in-line with client preference. We used higher quality speakers and amplifiers than would have been possible if the budget was split further.”
Ben continues, “We knew early in the design that the speakers would need to be mounted fairly close to the back of the acoustically transparent screen. Research published by both Newell and Brawn has highlighted the detrimental effect of positioning speakers too close. Our in-house testing found that in this proximity, a soft dome tweeter with a smaller initial radiation area led to both greater insertion loss and comb filtering from the screen interaction than a horn loaded compression tweeter, which can create a larger surface area of screen interaction reducing the screen impedance.
“We performed our own electrical testing using a range of content and established that during bass heavy passages, the total electrical signal output to the LFE channel is often as much as 4dB higher when LCR content is routed to the LFE via traditional bass management. Knowing that subwoofer selection would be a challenge, we decided that full range LCR speakers were required to reduce the demands placed on the subs.”
Ben continues, “With these two requirements, we searched for a full range horn loaded speaker, capable of 105dB peaks flat to 40Hz in a 100mm deep or less enclosure. We were unable to find a suitable speaker within budget, so a two-part system was selected with separate bass extension modules to extend the LCR range, with no redirection needed to the LFE channel.
“To ensure maximum dialogue intelligibility, we wanted significant headroom between the maximum displacement limited SPL and the calibrated maximum output. In our baffle wall configuration, the Audio Excellence Vertex 2 is comfortably capable of reaching 105dB at our seating distance with plenty of headroom. With the large reserve of available power from the amplifier, the LCR speakers avoid clipping and cone distortion at reference level playback.”
The team says that Audio Excellence were especially well suited to the close positioning to the screen because they feature pre-installed foam on the front baffle reducing high frequency standing waves between the screen reflection and the speaker baffle, in turn reducing high frequency comb filtering. A pair of bass extension subwoofers were placed behind the screen to provide the required full range performance. Using a dedicated DSP processor as a digital crossover, this pair of subwoofers receive the level matched sum of all content below 100Hz from the LCR channels.
Ben adds, “We selected a 100Hz crossover from the LCR to bass extension subwoofers, reducing the required cone displacement compared to 80Hz, in turn reducing cone distortion at post calibration max SPL. The mounting position between the LCR speakers ensures they are acoustically tied to the LCR and any content which should be localisable, will retain its position in the mix due to identical vertical plane and all five front speakers positioned horizontally within one wavelegth at 100HZ (343cm).
“The left and right speakers are at 24° angle from the main seating position. This is at the narrower end of the Dolby recommendation. This position was selected for multiple reasons, including a desire to place them behind the AT screen, rather than outside, tying the audio to onscreen effects. The left and right speakers are mounted square to the screen, rather than angled towards the main listening position. “We would have liked to experiment with a toe-in up to and including crossing in front of the main seating position, but the room size limitations prevented this due to the additional depth required reducing the width of the walkway. The wide dispersion and off axis performance provided by the horn waveguides on the Vertex 2 mitigates the negative effects of this square mounting.”
The lack of rear wall, combined with the proximity to the seating, drove the decision to select five bed channels rather than seven, because any surround rear speakers would have been heavily compromised. The team also decided to use two height speakers instead of four due to the single row of seating, limited room depth and limited budget. Ben says, “Though four overhead speakers would have added another dimension to the spatial resolution, it was not possible to place them within guideline angles. Using two speakers, positioned at the correct angles, allowed us to use the same model of speaker as the surrounds and maximise amplifier quality over quantity within the budget.”
The surround speakers are positioned with tweeters just above non-reclined seated head height and 100°on the horizontal axis. This position provides an uninterrupted path from each surround to each listener, whether reclined or not. While 100° is marginally outside the Dolby 5.1.2 recommended placement of 110-120°, this position was chosen to avoid placing the speaker deeper into the room corner where it would have created unwelcome colouration. For the subwoofers, extensive testing and the room’s size and shape concluded that the only viable option was to place two units tight into the room corners. This provided an acceptably smooth frequency response to the single row of seating, whilst giving the most boundary gain to aid in room low frequency extension. To ensure the room is always comfortable, the team worked with the client’s existing HVAC contractor on the selection and placement of a fan coil unit inside the bulkhead which houses the projector.
An impressive achievement here from Cinema Lusso, made even more impressive as the room and budget presented genuine challenges for the team, which were overcome with aplomb to produce an award-winning result.
Essential Kit List
Artcoustic: 2 x Spitfire control 1 sub
Audio Excellence: Control 48 DSP
Audio Excellence: Quatro 6 4 Channel power amplifier
Audio Excellence: 2 x Raijuu 1 In Wall High Performance Sub-Woofer
Audio Excellence: 4 x Vertex 1 Audiophile In Wall Surround Speaker
Audio Excellence: 3 x Vertex 2 Audiophile In Wall Speaker – Ultra low profile
Blustream: 4 x Precision 18gpbs HDMI 2m UHD HDMI Cable,
2 x Precision 18gpbs HDMI 5m cable
Cinema Build System: Ultimate Track 10 Lengths of 18mm fabric track for creating acoustically transparent walls
Furman: 4 x AC210 Power Conditioner Compact 10amp power conditioner
GIK Acoustics: 6 x Alpha 4A Broadband Absorption Panel with Scatter Plate
GIK Acoustics: 6 x Monster Bass Trap Bass Absorption Panel with Range Limiter technology and Scatter Plate
GIK Acoustics: 4 xT70 Bass Trap Tuned Membrane Bass Absorption panel – 70Hz frequency tuning
GIK Acoustics: 8 x Verifusor 17Root QRD Diffusor
Ineva Seating: Bespoke Seating based on McFarland design
Kaleidescape: STRATO 4K Ultra HD Movie Player – 6 TB
Middle Atlantic: BL1 1 space (1 3/4 in.) flanged aluminium blank panel, black brushed finish
Middle Atlantic: LBP-6A L shaped lacing bar with 6 in. offset, 10 PC
Middle Atlantic: RSH4A5XX 5 space black brushed custom rack-shelf
ProtoPixel: 2 x 8 Channel Controller LED Controller
ProtoPixel: Node Pixel LED Scene playback device
ProtoPixel: 70 x WS2813 RGBW LED Tape LED Pixel tape, with redundant data channel
Screen Excellence: SCE Discovery 100 2.40:1 Enlightor Neo AT Screen
Sim2: Anamorphic Lens 2.40:1 Wide aspect Anamorpic Lens
Sim2: Domino 4 UHD Ultra High-Definition Cinema Projector
Somfy: Motorised Curtain Track