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DIY Home Theatre Project, 2003

This is the Home Theatre I build in 2003. The project took me a good 200 hours of work excluding all the time spent beforehand doing all the planning. Below you will find a description of what I did. If you have any questions or comments, you are welcome to contact me on my commercial photography page.

Ray tracer
The first and second pictures were generated using the Povray ray tracer. I created them before starting construction because I wanted to get some idea of what the room was going to look like, especially with black walls! But this was not the only colour scheme I tried. Many others were thrown out based on what they looked like in the ray traced pictures. It took a lot of time learning to use the ray tracer but it is something I will certainly use again to visualize crazy decorating ideas.

The room was designed to have a relatively flat frequency response with no curtains and carpets that will absorb the high frequencies more than the low frequencies. Instead, the reverberation time was brought down to a theoretical 0.5 seconds by adding 6.7m2 of wide band absorption. This was achieved by building sound absorbers - four 1.2x1.4m boxes containing 200mm thick low density fiberglass. Two of the four absorbers were placed at the back of the room and the other two on the sides. (The one absorber is visible in the last photo on the left side of the room.) This placement has the added benefit of absorbing early reflections creating a theoretical initial time gap of about 15ms. The sound absorbers were made from 16mm MDF board and spray painted using Plascon Velvaglo E30-7. They were filled with two layers of 100mm thick Owens Corning Aerolite 10kg/m3 fiberglass and covered with speaker cloth. A reverberation time test is shown below:

The platform was made from 16mm chipboard. To be on the safe side I used two layers of that on all the horizontal surfaces. I also filled the cavities with fiberglass to avoid it sounding hollow when you walk on it. I found that there are only two ways to avoid squeaking: You have to make sure that there is a gap between sections or that the sections are very well tied together. To get rid of a squeak I had to disassemble part of the platform because the large horizontal section was touching the back wall, but was not tied to it. By leaving a small 5mm gap the problem was solved.

I experimented with three different types of black paint: low gloss, matt and ultra-matt. In the end I liked the ultra-matt Plascon Cashmere E30-7 most. It took four coats of paint to get a good solid black finish. If you are thinking of painting a room black, make sure that this is the last thing you do. After painting the room black, it will be too dark to do any other work in. (Don't ask how I know.)

The floor is Poliface Home M611 - Cherry. I tested laminated floors made by four different manufacturers by dropping a sharp object onto the samples. There were no noticeable difference between them - all very easy to get damaged. Initially I was disappointed with the Poliface product. The colour was not consistent and there were many defects - mostly small chips around the edges of the boards. With a lot of juggling I managed to complete the floor without using defective boards. And luckily for me the colour inconsistency is only visible under high colour temperature lighting, like sunlight and flashlight. Under low colour temperature tungsten lighting the problems disappear and it looks really good.

Recommended reading
The Master Handbook of Acoustics - F. Alton Everest
Sound Studio Construction on a Budget - F. Alton Everest

Copyright 2001-2010 by Barnett Erasmus.
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