Active vs Passive trade offs?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi guys

I looking at making/buying a PA system. Where I live there are plenty of bush doofs (pirate raves). It will mostly be used for a live DJ set up. Im thinking a line array with several large subs. For about 100 people, all outside.

Im just wanting some advice/design for something that would fit my needs. Anything considered as nothing has been made or bought yet.

Thanks
 
Administrator
Joined 2004
Paid Member
I love active because it's faster and easy to set up and strike. But I have a number of friends in the pro sound world who hate active. :) With active you won't need any amp racks and heavy speaker cable, but you do have to run both power and XLR to each speaker stack.
 
Passive is safer in the rain. You have a chance of getting the amps into some sort of rain-resistant location. The speakers have to go where they cover the audience properly. Maybe out in the rain. Downside- expensive 2 mm or 2.5 or even 2.8
mm speaker cables that might be stolen.
I use 2.5 mm (10 ga) even in my living room. 55 amp rated, better damping factor, and seems to limit high freq IM distortion versus 16 ga. zip cord on the same speakers.
 
Last edited:
I own a bit of both. Passive is easier outdoors as the electronics can be sheltered from the weather and dirt, passive speakers with weather resistant drivers can take direct rain without any ill effects.
There doesn't have to be a performance difference between an active or passive system but you will pay handsomely for active boxes that outperform a DIY effort with the best available drivers. You don't need a line array for 100ppl a standard 4 box system will suffice and be easier to transport and power.
 
Happy to discuss it here if you like, or you can PM me here or send me an email through my website.

So far, I have the following:
Mains: 2x Faital Pro 10FH520, 1x 18Sound ND1460 on an RCF HF94 horn
Subs: either Faital Pro 15HP1060 or Beyma 15P1200Nd. Pretty much a ported box, tuned to 40Hz. The different drivers are within 1dB of each other, so they get used interchangeably.

Amps are Powersoft at the moment - only recently upgraded.

It's a usefully modular system that gets pretty loud and sounds decent. The mains can keep up with 8x subs just fine for bigger events. For smaller stuff, I just take fewer subs and give the mains an easier time.

I'm working on a smaller set of mains with 1x Faital Pro 10HX230 per cabinet, although the passive crossover is proving to be some work.

Let me know if you've got any questions.

Chris
 
Thanks Chris

I will check out some suppliers for those drivers. Im keen to just go with something proven and reliable.

I see you are running 3 diff amps, one for each section. Do they get feed from a rack crossover? That sub amp looks big. Can that run 4 or are you just going for lots of headroom?

If i go with the same drivers could you send cabinet plans? I really dont have time or experince designing or simulating. But can cut wood no worries!

Cheers
 
The pics you're looking at are out of date - I'm running Powersoft now, although I'm not allowed to upload photos/info on the new amps just yet.

The Crown MA12000i was used to run all eight subs (2ohm/ch). I normally recommend against running 2ohm loads on amplifiers, since there aren't many amps that deal with it well. Since it's a top-end touring amp, it does the job just fine.
If anything, the MA12k was under-powered for all eight subs. It's happier at 4ohm/ch (4500w/ch), which would be about right - ideally I'd give each sub around 2KW.


I don't think I ever drew up plans for the main speakers, but they're nothing difficult in terms of design - just a ported box big enough to fit the drivers in, with 4x 3" ports on the back. The reason for that is that I can block off some of the ports and vary the tuning frequency.
For instance, 4x open gives a tuning around 80Hz IIRC (ie, lots of midbass power handling, but no low bass), 2x open gives a 60Hz tuning (fine for rock bands in smaller venues without subs), 1x open gives a 44Hz tuning (any situation where you want bass extension, and are willing to trade it for output).

FWIW, I don't think the HF driver is hugely critical - any decent 1.4" exit 3" diaphragm unit would get the job done. The midrange drivers are something special, though - there aren't many 10"s out there that will take 1KW and still sound good.

The sub plans and discussion are on this forum somewhere.

It's worth noting that the subs were designed to be small and go flat to 40Hz. You'd get more output per driver from bigger boxes, if budget is a concern.

Chris
 
The 12FH520 should be good. You could probably use just one of those per side. Wouldn't quite be as loud as 2x10", but a 2x12" cab is getting rather big.
Haven't used the 12FH520 myself, but I've used a few of their drivers and would trust their top-end 12" midbass to do the job well.

Chris
 
I build a set of trapazoid 12+1 cabs a few years back with the Eminence Deltalite 2512 and Selenium D210ti. If I did it again I would make the boxes a bit more functional with a monitor angle and use a different horn and driver... probably a larger CD with 1.4" exit, but even as they stand they get plenty loud and sound quite good when high passed over subs. These Neo drivers sound very tight and controlled compared to the ceramic Delta12 that I have used in other boxes.


6790885803_f85cd0fc6e.jpg
6804925129_b9681f7627.jpg
 
If you are doing bush parties with power from a generator I'd strongly suggest you pick speaker designs that are as efficient as possible.. especially the subs, then get whatever drivers are required. There was another member here a couple years back that was trying to do something similar and he built two 15" or 18" tapped horns and a pair of synergy horns for mains IIRC. A system like this with only 1kw/ch would produce the same SPL as a reflex based system with 4kw/ch. Having done some generator events myself I can tell you a 4-5kw gas generator is starting to get pretty big and heavy, I wouldn't want to move a 10kw generator through the bush by hand.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.