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post #1 of 37 Old 11-10-2015, 12:19 PM - Thread Starter
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Live pro audio speaker questions

So Im not exactly sure if this is the right forum for these kinds of topics bit I figure it's worth a try because I can't seem to find any information that is suitable for what I'm trying to accomplish. And you guys seem to have a lot of knowledge on sound and speaker systems.

So recently the horns blew out on two of my passive loudspeakers that I use occasionally to add a bit more sound to my mains and I have been using them still to add a bit more low range to my setup, that's when I recently thought why don't I just upgrade the drivers and turn them into subs.

So being also a car audio enthusiast I thought why not add some beefy car subs to my application... well I came to find out that is a terrible idea due to the fact that sensitivity per watt in car subs makes those subs super inefficient and are designed to create ultra low frequencies that amplify well in enclosed car "venues" but not so well in large halls or gyms.

So now I'm kind of stuck.

I've been looking for pa woofers between the 2 or 4 ohm impedance range and it's not making the selection process very easy as I find most pa low hz woofers are around 8 ohm.

What speakers should I buy for the job?
Specs for the job
1 Ep4000 amp
2 2cu ft enclosures
12" speaker holes

Unsure what the box is tuned to but there are 2 port holes on each box that measure about 2 and a half inches across.
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post #2 of 37 Old 11-10-2015, 12:50 PM
 
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Better off asking in the diy subforum https://www.avsforum.com/forum/155-diy-speakers-subs/
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post #3 of 37 Old 11-11-2015, 08:51 AM
 
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What are you trying to do? What frequencies are you interested in? I'm guessing this is for a DJ setup.


I'd build something like this if you are trying to get lots of bass in a gym or auditorium:
http://www.data-bass.com/data?page=system&id=81
They are designed for concert level sound from 25hz-100hz @~125-128db ea. on a bridged EP4000 with room to go. Or build a pair for the living room (not kidding).
Testing:
http://www.data-bass.com/data?page=system&id=81&mset=87




These are higher sensitivity 4ohm 12's with 11mm useable excursion. They could work in that size ported box.
http://www.diysoundgroup.com/replace...ts/mag-12.html
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post #4 of 37 Old 11-11-2015, 09:09 AM - Thread Starter
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Wow you guys actually help. Instead of shooting me down like some forums.

These are the specs of my amps power20Hz-20kHz @ 0.1 THD, both channels driven
8 ohms per channel: 550W
4 ohms per channel: 950W
2 ohms per channel: 1250W
RMS @ 1% THD (sine wave), bridged mode
8 ohms: 1750W
4 ohms: 2400W
Peak Power, both channels driven
8 ohms per channel: 400W
4 ohms per channel: 750W
2 ohms per channel: 1000W
Peak Power, bridged mode
8 ohms: 2800W
4 ohms: 4000W

Can I bridge 2 speakers together by putting 2 wires in each positive and negative terminal?
Finding woofers under 8 ohms is a real pain the the butt but would be great

The boxes are both 2 cu ft (I know it's small)
The ports are 2 and a half inches across circles
I'm not looking for super low bass because it's hard to amplify that in large venue applications.
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post #5 of 37 Old 11-11-2015, 09:09 AM - Thread Starter
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And they have to be 12" speakers
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post #6 of 37 Old 11-11-2015, 09:17 AM
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This was posted above but I'll repost. Sounds perfect for this.

http://www.diysoundgroup.com/replace...ts/mag-12.html
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post #7 of 37 Old 11-11-2015, 09:29 AM
 
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Quote:
Originally Posted by Samps View Post
This was posted above but I'll repost. Sounds perfect for this.
http://www.diysoundgroup.com/replace...ts/mag-12.html
As a sub yes, but with its 800Hz high end limit it won't be useful in a full range PA speaker, which seems to be what the OP is talking about. Even if he is talking about a sub he'd have to be sure that the cabinet tuning is correct for whatever driver he intends on using.

OP, provide exact details of what you're trying to use these for.

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post #8 of 37 Old 11-11-2015, 09:39 AM
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If you're trying to get more bass in a large open area like a gym or an outdoor event, two 12's in small ported boxes is going to be like putting a bucket of water in the ocean and expecting a significant change. You'd be better off scrapping the boxes and building something that meets your needs.


For instance, take a look at what @squiers007 has done in his gym. The four huge boxes behind the deadlift platform are horn subs designed by Bill (above). They have a lot of space to fill, but they're designed to do just that. https://www.avsforum.com/forum/155-di...0-s-t39-s.html
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post #9 of 37 Old 11-11-2015, 11:24 AM
 
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Quote:
Originally Posted by Dubrance View Post
Wow you guys actually help. Instead of shooting me down like some forums.

These are the specs of my amps power20Hz-20kHz @ 0.1 THD, both channels driven
8 ohms per channel: 550W
4 ohms per channel: 950W
2 ohms per channel: 1250W
RMS @ 1% THD (sine wave), bridged mode
8 ohms: 1750W
4 ohms: 2400W
Peak Power, both channels driven
8 ohms per channel: 400W
4 ohms per channel: 750W
2 ohms per channel: 1000W
Peak Power, bridged mode
8 ohms: 2800W
4 ohms: 4000W

Can I bridge 2 speakers together by putting 2 wires in each positive and negative terminal?
Finding woofers under 8 ohms is a real pain the the butt but would be great

The boxes are both 2 cu ft (I know it's small)
The ports are 2 and a half inches across circles
I'm not looking for super low bass because it's hard to amplify that in large venue applications.



If you are asking whether you can run 2 amp channels to both drivers in parallel (1st amp channel to both speakers, and the 2nd amp channel to both speakers too). NO, you can't run 2 amp channels to 2 speakers like that. You can run 1 pair of wires from each channel to each sub. Or wire the subs in series and run 1 bridged amp to them.


LOL, I know the amp specs. I have 3 of them in my living room. They are tapping the clip lights right now playing some Megadeath countdown. BTW those #'s are too high.


Here is a better set of #'s
https://www.avsforum.com/forum/155-di...l#post10689199
It's an EP2500 with a ep4000 nameplate on it. If you open it up the transformers are still labeled ep2500.


Don't get me wrong, I think it is almost universally a bad idea to use a pair of 12's for subwoofers for pro audio in big spaces. I'd start with a pair of Othorns and then build 2 more. But I'm glad to help or point you in the right direction if you answer my questions:


What are you trying to do?
What frequencies are you wanting this to play? 30hz+, 300hz+, 3000hz+?
How loud do you need them to be?
Do you have outboard dsp for these amp channels?


Break out the tape measure and be EXACT. ...to the 16th

How big exactly are the interior measurements of the box? Exterior dimensions with the wall thickness would work too. Is the interior port diameter measurement 2.5" diameter, or is it 2.375"? How long is the port?
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post #10 of 37 Old 11-11-2015, 12:53 PM - Thread Starter
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I'm looking for something around the 40hz+ range the boxes are exactly 2.467 cu ft with .5 in walls. The port holes are exactly 2.5 in
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post #11 of 37 Old 11-11-2015, 12:55 PM - Thread Starter
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Across but are cirlcles. Not sure the diameter
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post #12 of 37 Old 11-11-2015, 12:56 PM - Thread Starter
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Oh and it's for dj use
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post #13 of 37 Old 11-11-2015, 01:06 PM - Thread Starter
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I dont have onboard dsp. And as loud as possible. I'm using them to complement my alto pa speakers to add a little more low end because the bass to high ratio leans more to the highs with my altos.
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post #14 of 37 Old 11-11-2015, 02:48 PM
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You need to buy 8 of these, in two big 30hz ported boxes.
http://www.parts-express.com/dayton-...oofer--295-036
Wired for dual 2-ohms.

you will need 1 of these for XO's and EQ:
https://www.minidsp.com/products/min...p-balanced-2x4
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post #15 of 37 Old 11-11-2015, 03:28 PM - Thread Starter
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post #16 of 37 Old 11-11-2015, 03:53 PM
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What does your system consist of? no crossover or processor like a dbx driverack pa for speaker management? might help if everyone knew what you have and want to add too. just sayin
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post #17 of 37 Old 11-11-2015, 06:18 PM
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Quote:
Originally Posted by Dubrance View Post
Powered with 12 of these bridged:
http://www.powersoft-audio.com/en/do...datasheet/file

and 1 of these:
http://www.turbinemarine.com/generators.html

That should fry the dress off the bridesmaid.

You did say LOUD right?
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post #18 of 37 Old 11-11-2015, 06:41 PM
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Sounds about like the Iron Maiden concert i went to a couple years ago had...I was in the 3rd row with 12 subs 5 ft away from me,,,,Loudest show I have ever heard...and ive been to alot of concerts over 30 yrs. My ears hurt the next day.
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post #19 of 37 Old 11-11-2015, 07:45 PM - Thread Starter
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So I currently have 4 alto 15 active pa speakers each 800w, 2 active alto 12 speakers each 800w, one passive peavey 15 with 2 horns, 1 xm6-300 300w mixer, 1 ha-120w mixer that comes with 2 60w 12 with horns (horns blew out, that's why I'm trying to upgrade the woofers) and a numark mixdeck quad for its cdj functionality. I'm just trying to add a tiny bit more bass. I've used them before and they definitely add more bass in their current state but they sound cheap. And I have a ep4000 that I want to make use of.
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post #20 of 37 Old 11-11-2015, 07:50 PM
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How about BFM horns? Inexpensive and a lot of feedback from people in the industry. You might even be able to reduce your total equipment list and amps by using more efficient designs.
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post #21 of 37 Old 11-11-2015, 07:52 PM - Thread Starter
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Like what if I got this?http://www.fullcompass.com/prod/0755...FQqFfgodn28MsQ

The box recommendation is under 1 cu ft, so wouldn't having 2 cu ft amplify more of the low end hz?
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post #22 of 37 Old 11-11-2015, 08:02 PM
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Sounds like you need subs...get a crossover and a couple 18's problem solved
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post #23 of 37 Old 11-11-2015, 08:04 PM - Thread Starter
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Why would I need a crossover? Wouldn't a lpf for the subs work just fine?
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post #24 of 37 Old 11-11-2015, 08:05 PM - Thread Starter
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I guess for me it's a shame that I really want to put those speakers to use.
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post #25 of 37 Old 11-11-2015, 08:14 PM
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Quality over quantity. What size crowds are you doing and how big are the venues.
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post #26 of 37 Old 11-11-2015, 08:17 PM
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Quote:
Originally Posted by Dubrance View Post
Why would I need a crossover? Wouldn't a lpf for the subs work just fine?

Thats what a crossover does pa management. Go research dbx driverack pa2 and behringer dcx2496 and you will see what im talking about. you can find driverack pa+ on craigslist alot.

Last edited by doc5150; 11-11-2015 at 08:23 PM.
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post #27 of 37 Old 11-11-2015, 11:38 PM - Thread Starter
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Well I've played for 20 people but I've also played for 500 people. It just depends on what my clients want
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post #28 of 37 Old 11-12-2015, 01:13 AM
 
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Are you 17 and have been doing this for 6 months, by chance?


If you want loud for cheap from 40hz-300hz:
Follow the suggestion that Bass that Hurts gave you for the 8x PA460-8 18's for <$750


Put 4 of each in 2 boxes.


Build the boxes 42"x42"x24" and add 6x 6" pvc ports that are 14" long each to each box. That tunes it to 35hz. Wire all 4 subs in parallel for a 2 ohm load and put that on one channel of the EP4000. 900W per cabinet.


Add a BW4 high pass filter in DSP at 27hz to control excursion.


That gives you this response and output for both boxes @ 1m: -3db down at 40hz -10db down at 30hz.





Or just build 1.
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post #29 of 37 Old 11-12-2015, 05:25 AM
 
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Quote:
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Why would I need a crossover? Wouldn't a lpf for the subs work just fine?
Half the reason for using subs is that it takes the low frequency load off the mains, but only if you have a crossover.
Quote:
So I currently have 4 alto 15 active pa speakers each 800w...I'm just trying to add a tiny bit more bass
Reality check: speaker size and power requirements increase exponentially as frequency goes down. The notion that you will add more bass to four fifteen inch loaded mains using two twelve inch loaded subs is as technically sound as the idea of increasing the speed of a cigarette boat by adding a sail.
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post #30 of 37 Old 11-12-2015, 05:26 AM
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That is a huge enclosure...noway any mobile dj or band can haul that around. wont even fit thru doors.....just find some used 18 in jbl pa subs on craigslist or new...like the prx or srx lightweight models and your set. He is using this for a mobile application, not home theater I have been setting up PA for a band over 10 yrs and its a pain...especially hauling the stuff in and out of places.
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