Since so much of the science discussed in this thread is based on the work of Dr. Floyd Toole, it was requested that I post the following article Floyd wrote about how he designed his own personal system here in this thread. This way more people can read it, quote from it and comment. There is much to learn here! It's also a great opportunity to share Dr. Toole's awards and credentials, so people can see he's not just a guy with an opinion
. Here goes, along with the introduction I wrote included in italics:
So, if you are literally one of the world's foremost authorities on loudspeakers, rooms, and acoustics - and have literally written the industry accepted book on the subject -- what components and speakers do you chose for your own personal home theater and listening room? And how do you address the acoustical requirements and challenges of what is very much a "real world" (vs. custom designed) listening space?
That's the question I recently had some first hand experience getting answers to, as I had the unique honor and privilege of providing some projection system advice and guidance for Dr. Floyd Toole's recent home theater "makeover." For anyone not familiar, Dr. Toole is as close as one can get to a celebrity or legend in sound reproduction circles, and for good reason. Dr. Toole was the one to spearhead the first scientifically-controlled study of sound / acoustics at the National Research Council in Canada, starting back in the 1970s - research that continues to this day at Harman labs, which is still the largest and best-equipped acoustics R&D facility in the world. Though Dr. Toole is now partially retired, his research program continues at Harman under the guidance of Floyd's colleague and protege, Dr. Sean Olive. And the results of this research are published and peer reviewed by the entire audio industry in the true spirit of science.
It cannot be overstated how much the work of Dr. Floyd Toole has advanced the legitimate state-of-the-art in accurate sound reproduction. Dr. Toole has published numerous papers in the journals of the Audio Engineering Society and the Acoustical Society of America, as well as the aforementioned "industry textbook" on acoustics, loudspeakers and rooms. A measurement technique based on his research in the 1980s and further developed in the Harman research group is now a core component in ANSI/CTA-2034-A (2015). “Standard Method of Measurement for In-Home Loudspeakers”, Consumer Technology Association, Technology and Standards Dept., www.CTA.tech. For his scientific contributions to the audio industry he has been recognized with:
· Two Audio Engineering Society (AES) Publications awards (1988, 1990)
· The AES Silver Medal award (1996) and the Gold Medal award (2013).
· CEDIA Lifetime Achievement award (2008)
· Beryllium Driver Lifetime Achievement award from ALMA (Association of Loudspeaker Manufacturing & Acoustics International) (2011)
· Inducted into the Consumer Technology Association Hall of Fame (2015)
· The Peter Barnett Award from the Institute of Acoustics (UK) (2017)
He is a Life Fellow and Past President of the AES, a Fellow of the Acoustical Society of America and a Fellow of CEDIA (Custom Electronic Design and Installation Association).
In addition to all of that, Floyd is a man with means and impeccable taste. This is all reflected in his component selection as well as the overall aesthetic of the room (all well documented below). In creating this system, Floyd did not spare expense, nor did he waste money on "snake oil" components that often clutter up so many other supposed "state-of-the-art" or "reference" systems. As a result, the system described below can very well be described as "scientifically justified high end" -- which also sums up the approach we have when it comes to designing audio and video systems. I am proud to say that a great many of the same exact components and speakers are being utilized in our Reference Showroom (which also happily doubles as my own personal home theater ).
It is with tremendous honor I share with you the following article, courtesy of Dr. Floyd Toole himself. It was a true privilege to spend four solid days at Floyd's home, getting to know him and his lovely wife Noreen. The fact that I played even a small part in helping enhance the performance of Floyd's system makes this an even more unique and treasured memory.
Floyd, take it away!
The Toole’s Entertainment Room: 2019
By Dr. Floyd Toole
A room for lovers of good sound and loudspeakers
Those who have read my new book will have learned that much of what has motivated my research over my 50 year career has been the challenge of delivering good sound in rooms - any room. Dedicated listening spaces like recording control rooms, custom home theaters and stereo installations are able to employ acoustical treatments and methods that are not friendly to décor in typical domestic rooms. In those spaces it is routine to compromise visual aesthetics for real or imagined acoustical benefits. The decision of whether to create a dedicated custom room or to adapt an existing room is a choice driven by one’s chosen lifestyle, family needs, available space and, of course, budget.
In my case, it was lifestyle. We had no need for a dedicated “escape”room, but instead wanted a multipurpose room that was relatively normal in appearance, usable for reading, conversation, casual TV viewing, background or foreground music, and, with room darkening shades, suitable for engaging big-screen movie experiences at any time of day. Ekornes Stressless seating fits human bodies and is easily moved into arrangements suiting different needs at different times. Small movable tables replace cupholders, which are not optimum for our preferred beverage: wine. Four subwoofers in a Sound Field Managed configuration eliminate the need for massive bass traps, which is a major advantage.
The following is a panoramic photo of the room (geometric distortion included) showing seating in the conversational mode. The equipment racks are on the right, under the projector opening - in what was a fireplace space in the original house.
The room was configured in 2000, as a 7.1 system. The front wall was deliberately constructed as a low-mid frequency sound scattering surface using display niches and other depth variations (including spaces behind the fabric covered doors) to alleviate the boundary effect for that wall. Two of the subwoofers are hidden in those cavities.
This became a huge advantage when I recently decided to wall mount the inverted Revel Salon2s to reduce their visual dominance - the huge loudspeakers retreat into the background visually, but remain firmly in place acoustically. The other loudspeakers in the room are clearly visible, which would be a deal breaker in many households. In this one, I am fortunate to have a wife who has long tolerated my hobby/profession, admitting that the audible rewards are enough to offset a certain amount of visual loudspeaker clutter. This system may have exceeded even those generous limits :-)
An in-ceiling loudspeaker is used as the Voice of God. Others could have replaced some or all of the elevation speakers. But, knowing that the direct sound has a dominant effect on timbre/sound quality I decided not to compromise, and used high quality bookshelf loudspeakers in custom mounts, aiming them at the prime listening location as shown in the following floor plan.
The prime listener is close to on-axis of most loudspeakers and within the listening window (±30° hor. ±10° vert.) of all loudspeakers. The base level surround loudspeakers are Revel Gem2s for unquestioned timbre matching to the Salon2s and Voice2 L, C, R array. With flexible seating it was important that bass quality not be location dependent so Sound Field Management (SFM) was employed. Subwoofers in the rear corners of the room complete the array of four. They are all closed box 1 kW units. All loudspeakers are bass managed; high-pass filtered at 80 Hz. This was a challenge for the Salon2s, which are truly full range, requiring additional high-pass filter slope to be added in the SDP-75 processor.
The large opening to the rest of the house eliminated the first sidewall reflection on that side, so heavy velour drapes were used on the opposite wall to provide balance by absorbing much of that sound. Opaque lining provided room darkening at the same time. There is much discussion of the importance of side wall reflections in my book. They have a significant effect in stereo listening, but are unimportant in multi-channel or up-mixed stereo listening. I choose to add moderate up-mixing to most of my stereo music, finding the adjustable Auro-3D implementation in the SDP-75 to be quite pleasant. This is where timbre matching of fronts and surrounds is most critical. Movie surround effects are more tolerant.
The Toole’s entertainment room: 2019 - the “nuts and bolts”
Starting with an existing room that is used for everyday living as well as quality audio and video entertainment presents challenges. However, there are solutions. In this case there was the advantage that loudspeakers could be visible - in this household they have long ago been accepted as necessary to deliver the highly rewarding sounds. I have attempted to “soften”the technical appearance, but obviously not completely. The equipment/projector space used to be a traditional fireplace which architects persist in putting in the wrong locations for modern entertainment. I had the room rotated 180° and a new fireplace constructed.
I concluded that there was no single speaker arrangement that can perfectly satisfy all playback modes, so this is a compromise, a Trinnov suggestion. Time and experience will tell how well it all works.
The locations of the ± 60° loudspeakers required some visual compromises: a table stand on the right counter-top and an inverted, elevated location on the left to avoid head banging. The sound is fine, but I would have wished for less obtrusive visuals. These locations are perceptually advantageous and I will be experimenting with arraying the ± 60° and ± 110° speakers using various levels and delays.
From the acoustical perspective, there are abundant absorbing and scattering surfaces and objects to bring the reverberation time down to a broadband 0.4 s - a widely accepted norm for listening spaces. Much of this is not obvious — a "stealth” acoustical treatment. Large areas of heavy velour drapes and an upper rear wall that has about 5 inches of fiberglass behind acoustically transparent fabric help. Large areas of books both absorb and scatter sound. Clipped pile carpet on thick felt underlay is also effective.
Suspending the elevation speakers in earthquake territory (California) required some serious custom metalwork and sturdy attachments to the speakers. Multiple screws into the pristine piano-black finish hurt, but the existing tie-downs to speaker stands were simply not strong enough.
The powerful projector generated noise, so a hush enclosure was designed, lined with human-friendly cotton “denim” absorbing material and ventilated to the attic using a quiet Panasonic FV-40NLF1 exhaust fan. Just as I dislike putting perforated screens in front of loudspeakers, I disliked the idea of putting even coated glass in front of the superb optics of the JVC projector.
A little investigation and some lateral thinking resulted in the solution shown below - an 8-inch PVC pipe coupler, cut on one side of the central ridge fits perfectly with a bit of sanding. It allows air to flow inside the box without leaking noise. The projector is inaudible in the room.
Equipment List and Photo Gallery (text continues below pics)
Left & Right Speakers: Revel Salon2 inverted
Center Speaker: Voice2
Above powered by 3 Mark Levinson 536s
Six surrounds: Revel Gem2s
Front and rear elevation: Revel M106s
Front center elevation: Revel C205
VOG: Revel C783
Power: JBL Synthesis SDA-7200 and Lexicon LX-7 (both 200 w/ch)
Audio processor: JBL Synthesis/Trinnov SDP75-24 set up to do Sound Field Management employing four JBL Synthesis HTPS-400s
Projector: JVC DLA-RS4500 4k laser
Screen: Stewart 127-inch Firehawk (selected for its ability to reject lateral light leakage during daytime viewing)
Video switching and processing: Lumagen Radiance Pro
Apple TV 4k, DirecTV
Assorted objets d’art - apparently bronze sculptures of the female form have special acoustical scattering abiities :-)
Room: 19 x 22.5 x 8-11 ft high. Listening distance 11 ft for stereo and for ideal immersive movie viewing, 14 to 16 ft for casual listening and viewing.
The original construction in 2000 and this upgrade in 2018 were possible because of my exceptional omni-talented builder Matt Fesler who did it all: rough carpentry, drywall and finish cabinetry, floor tile, granite fireplace, metal fabrication and welding, household electrical modifications, wire pulling and hookup, hush enclosure, extractor fan, etc. I did the drawings - he made it.
Component installation and basic configuration by Toole. Video calibration by Kris Deering. Lumagen guidance from Jim Peterson. SDP75 setup and acoustical calibration by Kevin Voecks (Harman). Sound Field Management optimization by Todd Welti (Harman). System advice and guidance from John Schuermann (The Screening Room) and Steve Silberman (Roon).
Thanks to all for services rendered, equipment supplied and jobs well done! Needless to say, the images and sound are very impressive. I am more than pleased!