simulations: room gain

The problem with many subs is that they are designed for a flat response in anechoic conditions. This makes them look good on paper, but when used in a room, room gain can cause boominess. For this reason, I have attempted to design for a flat response in room rather than an anechoic flat response. This is not so easy to determine however for a number of reasons:

I don't yet have the room for which I'm designing this sub, so I can't perform any measurements.

Simulating room gain would seem more difficult to get accurate results for.

The room will be 5 x 7 m with a 2.7m ceiling. (approx 15' x 21' ceiling 8').

The following chart shows room gain information from different sources:

Note that the curves shown by Adire and Collum's curve do not relate to the room in question - they are generic curves. The Adire curve is used in Adire's whitepaper publications. Collum's curve was obtained from the Vacuum State Electronics website. As these curves are generic and designed as a rule of thumb guide, I have used simulated results in preference to these. Collum's curve is conservative - at least 6 db should be added to the anechoic response to give a halfspace gain. Adire's curve seems more accurate to me.

The magenta line shows seated position. As its characteristic is similar, I see no reason to use this curve in preference to curve at 1m.

I have used the result that was simulated by LispCAD at 1m (red line). This shows a 5db gain, which is approximately a flat gain from 50 Hz and above into half space. Below about 45 Hz there is a first order (6db/octave) gain.

Note: the simulated results assume that the sub is placed in the corner.

The simulated room gain has two humps which have been excluded in my room gain chart for simplicity.

feedback, comments, suggestions?

Feedback is welcome. All this is "work in progress" and I'm constantly updating my information