Home Theater Design School
Excellent training and documentation about putting together a private screening room is available for free, online. We are eager to see the knowledge and insights and experience of decades of industry research and best practices make their way into the broader community of enthusiasts. Using these techniques, no matter what one’s budget, one can get the most enjoyment out of one’s system.
If you don’t have time or interest for the “whole enchilada” right now, the first section, called “THE BASICS,” will cover the major topics in four short articles.
If you want to go a little deeper into key specific topics, these posts can help:
Choosing Speakers. There is actually science and engineering standards that make this much more reliable than buying at random.
Setting up subwoofers. No more one note thump, but a full rich accurate experience of the lower octaves.
Acoustic treatment. Or, making your room sound good, which is about 50% of the audio experience — and yet it can be the cheapest audio upgrade you have ever done. (Don’t just always kill side wall reflections and yet kill some issues with funny names like SBIR.)
Acoustic Isolation. Or, what is sometimes called “Soundproofing,” which seems to keep sounds from escaping the theater and bothering other people, and, to keep sounds from outside the theater getting into it, and distracting you from the movie.
Setting up your room for good audio.
Setting up your room for good video.
THE BASICS
Nyal Mellor, from Acoustic Frontiers, has put together excellent, brief overviews. One could almost define the shell and layout of a theater from this handful of summaries. Using only these materials will still put your room's performance ahead of 80% of the rooms people create.
Home theater seating layout: 5 key design and placement tips
The first task that should be done in any home theater design is choosing the number and type of seats. That’s probably surprising to most enthusiasts as they think that equipment is the first thing that should be selected! In fact seating choices end up dictating a lot of other things including...
www.acousticfrontiers.com
Home theater viewing angles, distances and sightlines
Horizontal Viewing Angles The horizontal viewing angle is the angle subtended by a straight line from each side of the screen to the seating position. The main two standards in the commercial world are the SMPTE and THX specifications as summarized in the diagram below: 36 degrees from the last...
www.acousticfrontiers.com
Amplifier power / SPL calculator for home theater THX reference level
A question that frequently comes up when designing a home theater is 'how powerful an amplifier do I need?'. The answer to the question depends on a few things, in particular how sensitive your speakers are and how far you sit away from them. When we design a home theater we want it to meet...
www.acousticfrontiers.com
Room Acoustic Design Insights: Five Steps to Amazing Bass
Here at Acoustic Frontiers we use these five acoustic design techniques to create amazing bass. Bass that is tight, articulate, defined, impactful and even. Most people have not heard just how good bass can be when the room is taken out of the equation. Optimize the room dimensions For new build...
www.acousticfrontiers.com
VIDEO TRAINING (deep dives)
There are an endless number of videos about home theaters, gear, and related topics, on YouTube. Many are, at best, thinly veiled sponsored content, lifestyle shows, or similarly non useful ways to spend one's time when trying to learn about private cinema design -- even if they are entertaining and inspiring.
But some of them are really good. The following seem to have withstood the test of time and the BS detector.
Anthony Grimani has been teaching theater design at CEDIA for years, and has stayed on the leading edge of the topic. He worked at Dolby and at THX before striking out on his own. He is a CEDIA Fellow, and makes his living designing theaters and theater technology.
A while back he shared his training courses online, for free, via a couple of YouTube channels. So instead of paying thousands of dollars to go to CEDIA and take these classes in person, you can learn a lot by watching and digesting these videos.
AV PRO EDGE (the best collection of Grimani presentations; this isn't all of them, but this seems like the best ones)
AUDIOHOLICS (great that they let Grimani go into such detail, but these tend to be less thorough than the AV PRO EDGE seminars)
Get the Best Bass for Your Home Theater P3: Wrapping it Up
THE INDUSTRY STANDARDS
Grimani and other leading designers have gotten together under the banner of CEDIA, the CTA, and international standards bodies to document performance and engineering goals for private screening rooms. These are very useful once you have a grasp of the concepts as a quick reference guide to the goals to strive for when creating a room.
Home Theater Audio: Immersive Audio Design Recommended Practices (CTA/CEDIA RP22) revised for 2023
“This recommended practice provides guidance for the design and specification of audio reproduction within private entertainment spaces. Industry professionals follow these practices to deliver the optimal performance for the equipment and the space. “.
Free download: RP22 Recommended Practice for audio design
(formerly: (CTA/CEDIA-CEB22 R-2018): Home Theater Recommended Practice: Audio Design (CTA/CEDIA-CEB22 R-2018) )
Home Theater Video Design (CTA/CEDIA-CEB23-B)
"CTA/CEDIA-CEB23-B describes how to determine a recommended screen size based on the primary seating position. It also discusses how to mask portions of the screen when the shape of the video image doesn’t perfectly match the shape of the screen. It covers recommended room lighting, and coloring for walls, ceilings and carpets, as well as a number of other factors that should be considered when setting up a home theater."
It is available for free: Home Theater Video Design (CTA/CEDIA-CEB23-B)
While these documents are excellent at explaining the performance GOALS of a home theater, they aren't written to explain the METHODS for achieve those performance goals. So, there are two posts here that try to explicate them a bit. (This is an ongoing project.)
Setting up your room for good audio.
Setting up your room for good video.
MISC TOPICS
Screens
Make sure your screen can be lit up properly.
Nits / footlamberts (ftl) are what one uses to determine how bright a particular size and gain of screen will be.
Use the calculator at projectorcentral.com and remember they are quoting max power, max noise level numbers, with no age on the laser or bulb.
Standard target for SDR content is 15ftl, and HDR ideally needs 30ftl but some people use dynamic tone mapping with 25ftl and don’t mind the results.
And screen type will really matter. For example: There aren’t any neutral gain woven screens, so your calculator should reflect the true .6 to .8 gain of a woven screen. https://pixelht.com/25-acoustically-transparent-screen-materials-reviewed-and-measured/
With most popular projectors in the $2k to $25k range these days, a max of a 160” diag 16x9 screen is probably the very largest reasonable size, unless the screen is woven, and then that’s a little too large for reference level video.
But that’s not enough immersion, you say? You can get any level of immersion with that size or even a 140” screen just by moving your seats closer. That will also make it easier to achieve reference audio levels since the speakers and amp have to work less hard to reach reference level at a shorter distance.
Subwoofers
Todd Welti literally wrote the book on subwoofers and was interviewed by AVRANT.
AV Rant #737: Interview with Todd Welti on Subwoofers - AV Rant
We are proud to present our interview with Todd Welti, Distinguished Engineer at Harman International Inc. Enjoy!
www.avrant.com
is a link to their summary of the interview but also has links to all the technical details including the key harman docs here as well as good info from other innovative people in the field like Geddes, the multi-sub-optimizer, etc.
The AVRANT guys try to simplify the science a bit and will often settle for Good Enough. That's fine. They are assuming their primary audience isn't going to measure with REW and do time alignment and EQ with a miniDSP. And I think there is a strong case to be made that most people, even those interested in a good home theater experience, aren't going to take it to that next level of measuring and aligning.
But some of us don't stop at 80% good enough, and want to get to 90% or more, if the cost is minimal and it just takes some time and brain cells. So it is GREAT that they let Welti and his research speak in more detail and precision than they would usually discuss. He even schools them at one point on their standard recommendation of lateral corner placement of two subs and points out there are a few much more reliable ways to position two subs.
More at: Subwoofer setup: location, time alignment, distance...
Center Channels
Some people watch this video and think: Well I sit on axis so the off axis response of the horizontal center speaker only impacts other people in the room.
Alas, much of the sound we hear is reflected sound not direct sound, whether it be from diffusion elements, or other reflective elements in the room.
Even a room with acoustic treatment consists of 70% or more reflective surfaces, even if it is designed according to CEDIA and CTA guidelines (RT60 or RDT of around .3 seconds.)
If that reflected sound doesn't have the same frequency response shape (often called "even" or "consistent" dispersion) then we are hearing a lot of poor response that doesn't match the direct sound, which muddies the sound and exacerbates issues like "dialog intelligibility."