Dual 15 PA Speakers

Pwnage1337

Member
2016-04-02 9:16 pm
I recently picked up some Peavey PV215 PA speakers, and love them. I have 2 more channels on my Behringer amp that i'd like to use (garage party)

Wondering if anybody has built their own dual 15" PA speakers?

Been eyeing up Daytons PA-380, appears to have great reviews. Is this a suitable speaker for a dual 15 PA speaker build?

Does anybody manufacture empty PA cabinets that you can put your own drivers in and save some $$ while still using quality components?


If someone could point me to a place that possibly has plans/designs that'd be great. I've seen freespeakerplans but have a hard time decoding whatever language they use.


Thanks!


Jeremy
 

conanski

Member
2013-03-31 3:53 am
Dual 15 PA cabs are not common to find in kit form.. can't say I have ever seen one actually. This design draws lots of criticism for good reason, it can produce the equivalent output of a pair of single 15 cabs and having the drivers stacked in a column is better in terms of polar response than having two cabs side by side pointed in the same direction, but the most common and least expensive versions like those PV215s have a couple glaring shortcomings that are responsible for their bad rap. Those flaws are all centered around the small 1" exit compression driver, it can't operate low enough to cross over to the 15's at a frequency that is below their beaming threshold of around 800-1khz, so the crossover is usually up around 2khz and then the boxes have a narrowed response between 1-2khz, and the cone breakup that most cheap 15's produce plus the comb filtering resulting from operating 2 large drivers like this at these frequencies produces poor SQ right in the middle of the vocal range.

There are a couple things that can be done to counteract some of this, one thing is to employ a quasi 3-way crossover so only the upper 15 actually goes all the way up to meet the CD, the lower one is low passed at 300-500hz. This does sacrifice some output and it does not eliminate the notch in the dispersion from 1-2khz but it addresses the comb filtering problem.
The other solution is to use a larger 2" exit CD. Those can be crossed as low as 500-800hz thus eliminating the comb filtering and beaming issues at higher frequencies, and these large CDs generally produce much cleaner output in the vocal range. The only downside is they often cost at least 3 times as much as a 1" CD.. expect to pay $300+ for one and of course they require larger more expensive horn flares and they are larger and heavier and therefore typically require support inside the cab.

I found a set of empty 215 cabs last year and loaded them up with 15's an 2" exit CDs I had on hand, and I have to say they are some of the best sounding boxes I have ever owned. But that is after I spent a full day measuring them with a test system and developing some custom DSP processing for them. I also own a wide selection of powered and passive 12+1 and 15+1 PA speakers and none of them produces as much clean output at these 215s. But there is still a downside, my boxes weigh in at about 150lbs and are close to 4ft high yet they produce little low bass, that requires even bigger boxes or some very specialized 15" drivers. And even if you do use drivers that produce good bass in reasonable sized cabs, you really want your speakers elevated so you're not just firing into peoples bodies, but when you do that you lose boundary loading and away goes your low bass response again, so in many cases you still need dedicated subs. This is what I was planning to do all along with my 215s so I selected drivers for maximum broadband output and completely ignored response below 80hz, it might sound silly but these are part of my high output system and they will always be stacked on top of subs, and I have lots of smaller more portable speakers to use when I don't need the output capacity of the 215s.
 

conanski

Member
2013-03-31 3:53 am
You want cabs that have a reasonable sized horn to start with.. the PVs are pretty good in this regard actually, you need room to fit the larger horn that is required to load a CD to a lower frequency. And then you could load any 15 you want, the cutout needed is close to the same for all of them although cast frame drivers are a little larger than stamped frame drivers, but it's nothing that can't be dealt with.
 

Cuppa Joe

Disabled Account
2010-07-18 6:24 pm
Seattle/Tacoma
Right, 2x15"+1" boxes are nothing but compromise & unnecessary weight, better to use single (or smaller) mid drivers & add subs. Many go with the 2x15" arrangement thinking they've avoided the necessity for subwoofers, only to find later that true subs are needed anyway & now they have to lift those over-sized top boxes onto their subs.

As for pre-made empty enclosures, check out Case Outlet / GPA on eBay.