Originally Posted by ---k---
I'm a little suprised by the FR graph you posted. It appears to be a very natural sealed sub response, without any LT/EQ used to boost the low end. I thought you were using the onboard DSP to extend the low end. I remember when I saw the demo with your early design in St. Charles, I was really impressed with the low end, and it sounds like your beta testers are equally impressed.
So, what am I missing? Does Kevin and Warren have that much room gain? Or am I misreading your FR graph?
I also remember you mentioning that you wanted to have a couple differnt programs in your DSP, one for a big room (with less room gain?) and one for a smaller rooms. Does this work out for you?
BTW, I do think that this is a real killer sub for those looking to spend over $1500. Congrats.
The part you might be overlooking is the relation of the size of the enclosure and the frequency response you see. I don't know of any pair of 15" woofers that will fit in this size enclosure and give you this sort of response without electronic correction of some form. There are also some less obvious advantages to the chosen design so far as efficiency and real playback levels in typical use. That said, the response is still fits a 6dB window (+/-3dB) down to 19-20Hz out to about 200Hz. The scale shown isn't that large, so remember that the graph is only showing 5dB/division, and the left hand side is 8Hz.
If you look back I have always stated that a ground plane measurement will show nominal extension into the 18-20Hz range. The interesting part is when you place it in most rooms used for home theater, especially dedicated spaces. WarrenBuffet, this thread's original poster, has a room that was a little more of a surprise than expected, as the response in his room that opens on the left to much more space still showed in-room response that was flat to the 10-12Hz range appart from a modal peak in the 30-40Hz range. I'll see if I can post graphs from his room. I was out of town this weekend with another install, and the response in this room after killing a 40Hz modal peak was +/-3dB from 10Hz to 100Hz. I think I might have shaped the response closer to +/-3.5 dB over that range by the time I was finished. The addition of that extension has been quite noticable and significant in my experience thus far.
So yes, many rooms do have that much room gain, as I have been documenting for quite a while now, going back to when I started taming bDeaps for use in home theaters. The SubMersive is designed to take advantage of any available gain, and has been doing exactly that in installations thus far. Every room has its quirks, and there are cases where some locations have shown holes at some frequencies down low, but the gain is always there in some useful form. For those with huge, vaulted rooms that are open to the rest of a huge house, the BMF design will probably suit the need better, although multiples of the smaller SubMersive, while costing more, will still offer advantages in large spaces if you have EQ available and measns of measurement.