Originally Posted by LTD02
this one shows roughly the gain vs. ported.
efficiency is a tradeoff. it drops in the 40hz ballpark, but increases dramatically in the upper bass as a result of loading the front of the driver. imho, this is the primary advantage of the design--it allows for using relatively low efficiency, long throw woofers, which are great for maximizing the low end bass, but then it loads them up so they have pro audio like output in the upper bass.
If you look at the efficiency curve and the FR curve, it would be a great design for car audio. As cabin gain kicks in, the deep bass drops off but still is more efficient than a ported box. Still is not as efficient as a horn but those won't fit realistically in a car for most people.
For pro sound, any efficiency gain is great to take the load off the amps with PEQ being standard. Although not as efficient as a FLH or TH, that design would allow more SPL by weight/size than ported so a win.
For PA/block party purposes, that design would be a great option. You can go low when needed but for the main output, the 40 to 100Hz band it really has the efficiency required for general music. This is what Ricci was going for so a different option when scaled to the real world.
Thanks for the info LTD, checking over the design--the four 15's I use in my garage subs won't work with the design. They will remain PPSL ported for their life. I can hit reference levels at 4 meters with "only" 400 watts of power, can't complain too much about the efficiency.
For home use, a pair of SWS15 ported to 18Hz and powered by my XTi1002 is still in the lead. Maybe my wife will want more and buy me a very good table saw and various tools to build a pair of lilwreckers. It could happen.
Now for the dual driver MAUL builds that are stuffed in SUVs to start rolling out. Nobody ever said car audio was sane, after all.... those RF subs are made for car audio.