Our showroom - speaker placement
When we say better…
We wanted to build the highest performance cinema demonstration priced below £100k in the UK, and the best home cinema demo facility full stop in the South West of the UK.
We're pretty sure we did it.
We worked really hard to design a cinema system with better performance than others at a similar price. First, we worked on the speaker placement, to give a better result for more of the audience.
Front Speakers - Left, Centre, Right (LCR)
A common design method is to work out the speaker locations from a point between two rows of seats.
Common, but wrong.
The first problem is that although there is a best sounding location where everything is just right (also known as the Reference Seating Position) no one actually sits there.
Instead, we choose a row to optimise for performance, and then check the other. It's usually the front row, unless the client strongly prefer the back row for their own use.
All seats should be inside the relevant industry guidance from Dolby, ITU, THX, and CEDIA - if at all possible.
Typical, but flawed:
Back row outside guideline 22.5-30º
Better:
Both rows within Dolby guidelines;
front row meets ITU guide of 30º
The second problem with the more common approach, is that if you start from the middle, one row almost always ends up outside spec. Typically, the back row has front speakers too narrow - so it compares badly to the studio where they mixed the soundtrack, and doesn’t match what the director signed off on.
In our room, we went for 30º wide at the front row, which puts the back row into spec too.
30º is the angle the ITU suggest for Left and Right speakers - and all good studios are designed within ITU guidelines.
Our placement gives a better result for both rows.
What is the ITU?
Everyone has heard of Dolby® - Dolby Surround, Atmos, and so on, because they have consumer-facing products.
The ITU (International Telecommunication Union)
By contrast, the ITU (International Telecommunication Union) set the standards in film and TV production. All serious studios and dubbing stages are built according to ITU guidelines.
Dolby's consumer surround placement guidelines were themselves based upon ITU standards, but diluted to 22.5º - 30º, to suit the requirements of a standard living room. The studio guidelines - for Dolby Atmos production - also suggest 30º.
As well as the ITU, there is research going back 50+ years, which all suggests that 30º is the ideal angle for front Left and Right speakers, when used with sound for picture.
Further reading from the ITU (PDF copy of ITU-R BS.2159-6 - quite technical)
Dolby, Dolby Surround and Dolby Atmos are registered trademarks of Dolby Laboratories
Surround speakers
Not in front, and not on the wrong side
Lots of systems put the surround speakers (SL, SR) in front of some listeners. You also see the Surround Back Right (SBR) or Left (SBL) on the wrong side of some seats.
This is just plain wrong - the sounds are coming from the wrong places! That's the exact opposite of preserving artistic intent faithfully.
With more care, you can arrange things so that everyone hears sound coming from the right places, which is better.
Typical, but flawed:
Surround Left / Right
Back row far outside Dolby spec,
sound comes from in front of those listeners
Surround Back
Both rows outside Dolby spec!
Sounds on the wrong side.
Back row far too close to speakers
Better:
Surround Left/Right
Both rows within Dolby spec;
Sound is either level or behind
Surround Back
Both rows within Dolby spec;
Sounds are all on the right side.
Listeners kept away from speakers.
Front wide
We chose front wides because otherwise there’s a large gap between the Front and Surround speakers, which causes a hole in the illusion when a sound event moves around the side walls. Filling the gap gives a smoother transition when sound events move, making the illusion more believable and increasing your feeling of immersion.
You’re more surrounded, so you’re more convinced, and that's better.
Front wides give a smoother transition
as objects move around the room
In all, the placement we've used is much less common than is typical at the price point - and we’re certain it’s better, since all listeners get a demonstrably better result.
