Better lower response comes from a bigger horn mouth, that's why cornerloading and v-plating is so beneficial and do herds of 8 or more work the best in half space. (no walls)Rich4349 wrote:" I think part of the smoother response is due to using wider cabs (and thus bigger air chamber for the driver, just like a 'normal' sealed sub) and not only the increasing front surface of the cabs."
Does the smoothing come from the larger horn, larger driver chamber, or both? A larger horn (seems to) offer lower resistance to the air mass, so it would *seem* like a SMALLER rear chamber would be needed to tighten up cone movement and "smooth" things out. (I realize you cannot deduce audio engineering!)
17 meters ~ 57 feetHorn loudspeakers minimise the impedance mismatch between diaphragm and the air, by acting as an acoustical transformer. The horn flare provides a controlled expanding wavefront to transform relatively small diaphragm movement into a large air movement, and with careful design efficiencies of well over 100dB/W/m are easily achieved. Unfortunately, bass is again a problem, since the circumference of the mouth should be equal to the wavelength of the lowest frequency to be reproduced. At 20Hz, this means a circumference of over 17 metres, and for a square horn (less than ideal, but smaller than circular) that means 4.3 metres per side! http://sound.whsites.net/subcon.htm#s4
Your reasoning for a smaller chamber compared to a close sub seems logical to me, but I'm new to this and don't have a complete picture of all variables involved. I'm just starting to see some interaction between them.
The very high Mmd (moving mass) of the gto804 might also be a reason that a smaller chamber is not that big of a penalty or even better compared to the 3010lf and 3012lf which have a very low Mmd and to me look the happiest in wide boxes.
I'd love to see some comments on air chamber sizing and influence on output.