Originally Posted by penngray
I wonder if its more of a size issue. Its hard to sell large horn designs, the logistics behind shipping, installing them too would be a nightmare in the pro audio world. Ported enclosures are easy to build and sell.
It could be, but I don't think size is much of an issue for the cinema line. Look at the huge four driver midhorns. They also don't care about weight. I'm sure JBL could do a few things to squeeze a tiny amount of performance out of their setups but it obviously doesn't make sense to them. The cinema line is pretty much 100% performance oriented. Klipsch does still use horns for bass and obviously Danley does too. Outside of that, most of the commercial Cinema guys use direct radiators for their bass (JBL, QSC, EAW, etc).
The main advantage I see for a bass horn is the acoustic low pass filter inherent in the design. IMO, this is the biggest advantage to front baffle mounted bass speakers, at least in a one-off home setting.
Originally Posted by 04FLHRCI
If you want an ultimate performer, I'd go with 4 of any of those drivers in 2 PPSL boxes. Build them with a slot port that you can plug and convert to sealed if you feel like trying them in sealed with eq. Any of these subs will perform well down low sealed with EQ. The 21SW152 will do the best because it will have far more displacement than the other two. It is likely marginally weaker in the SQ department but I would take that tradeoff for the flexibility.
If you give me some general footprint dimensions I can make a quick sketchup model to see if a PPSL will work.
I don't think you can underestimate the advantage of the acoustic low pass filtering effect. Without the acoustic low pass, when a 80hz tone is played, upper harmonics are also present, unfiltered. It doesn't matter if the electronic crossover is set to 120hz, you will produce harmonic distortion well above that. IMO, that is why people say they can localize bass up to 120hz. They are really localizing the harmonics. This is why Geddes uses bandpass designs in his multisub subs. They are placed around the room playing up to 120hz and you can't localize them because the harmonic distortions are filtered. The PPSL would work similarly but with greater extension.
I'd guess you don't see them often commercially because it is just cheaper and easier to use one better driver. It is much easier to mass produce a box without a manifold. For a DIYer it isn't a big deal and you are already using top of the line drivers.