Tuesday, December 04, 2012

Another Look AT Room Design Part 2

I thought I would take another look at room design and make it much easier this time.  Lets start with speaker placement.    

Modded ITU-R
The above layout is based on the International Telecommunications Union - Room layout.  The difference between my diagram and the original, is mine is modded to support 7.1 where the original was 5.1.  In upgrading this, I have moved the LS and RS from +/-110 degrees to +/-90 degrees [which works better with THX design] and added the pair of Back Surrounds [LBS and RBS].  I have also elevated the surrounds to 30 degrees above the LCRs [seated ear height].   

I have kept the front speakers spaced the same as the original ITU-R of 30 degrees between each and symmetrically spaced the surrounds to 60 degrees apart.  You could, [if you wanted to] move the front L and R speakers in closer so their position was +/-45 degrees.

Combining Sound With A Picture     

A few things need to change once you decide to add a picture to your audio [especially if you want the sound to actually match that picture].  The biggest thing for me is the spacing of the three front LCR speakers where I would move the L and R speaker to be just inside the lines showing 1.78:1.  This applies to both an AT screen or if the speakers were under or over the screen.  The reason is simple - studios [dubbing stages] that mix sound for film have their speakers their and if I want to hear what they heard, then I need to do what they did.  I have had my speakers in this location for over years now and would not change.  It works and provides a seamless blend of sound to picture. 

The above image is a very simplified version of my previous room design formula and is as follows - 

  1. Room length divided by 4 to find image height.  

  2. Image Height x AR to find screen width.

  3. Image height times 2 and 3.68 to find closest and farthest seating distance.  

  4. The centre point of the two extremes for seating is the distance the surrounds will be from the screen.  This then uses an arc with 60 degree separation to find the locations of the surrounds.  


Scaling It Up

This diagram is the same except I have scaled it up to 2x that of the original.  It is representative of the size I'd like to build my next room.  Projectors like the BenQ W6000 I am currently using would light this size screen without issue.  The girl in both images is the same size for a sense of scale.