12" drivers for live pa |
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Unknown Enemy
Registered User Joined: 03 October 2007 Location: Kent Status: Offline Points: 266 |
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Posted: 12 July 2009 at 9:49pm |
Just having a think about this really as I'm thinking of getting in to small live pa work.
Went to a local festival today. Just local bands and all that but as you do, you have a look at what pa is being used. Looked home brew. Looked like 1x double 18 or 15 per side with a horn loaded top. Speakers were massive and tbh, the bass did sound a little one note. Bit boomy but anyway. After having a play with some sims and after reading threads on here, I was looking at 3x double 12" cabs per side for the bass (not sure about sub) 6 double cabs give around 140db at 54hz but go down to 34hz (133db) before hitting the xmax. The downside is that it requires 7500 watts to get there. Does that sound ok or is that quite a lot? The idea around this was the small compact size of the cabs. Total size for all 6 cabs is under 500 litres. Soooo.......good idea or think again? |
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Tony Wilkes
Old Croc Joined: 02 August 2004 Location: West Midlands Status: Offline Points: 4840 |
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That's exactly what my 12" subs are for except just used a a pair a side. You can run 2 pairs a side (4 drivers) from one of Andy's 5000,s and expect about 131db 137db peak.
You should not need much in the way of LF EQ so that saves loads of power. If you send me your proper email address I will send you a PDF of the double cab. Tony |
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Unknown Enemy
Registered User Joined: 03 October 2007 Location: Kent Status: Offline Points: 266 |
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Hello Tony,
Thanks for the PDF. Looks like a nice and simple build. Do have one question. How come the drivers are in a separate box but joined together if you get me? Is this because if one driver fails, it wont kill the working driver??? |
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Tony Wilkes
Old Croc Joined: 02 August 2004 Location: West Midlands Status: Offline Points: 4840 |
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You can either run it that way or I always put a hole say 150" diameter in the brace towards the back of the cab. when you realise exactly how hot the drivers get it makes sense to me to stop heat rising from the lower driver motor directly on to the upper driver. One of the reasons I do the ports the way I do is to have a chimney like affect with cold air at the bottom and hot air escaping at the top. I know pepes will take the piss but it really does work. Tony |
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Unknown Enemy
Registered User Joined: 03 October 2007 Location: Kent Status: Offline Points: 266 |
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Interesting.
Is having the port on the rear going to be a problem? I understand why you have placed the port on the rear of the cab but from most if not all pa speaker cabs, the port is on the front. Would it work if the port was on the front but was made of flexible tube so it can be directed at the rear of the driver to help aid cooling? |
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Tony Wilkes
Old Croc Joined: 02 August 2004 Location: West Midlands Status: Offline Points: 4840 |
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Probably just easier to make a shelf port and not be paranoid about temp. like me, or put 2 off 100mm ports at the bottom of the box. Make the box higher to accommodate the ports and just reduce front to back size to compensate. Keep the box at 80L gross volume.
The only time rear ports would cause a problem would be if you needed to have the box really close to a wall of if you had a big enough stack of them so they started to become directional. The box is so small I reckon there is always going to be room for a bit of a rear gap. Tony |
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Unknown Enemy
Registered User Joined: 03 October 2007 Location: Kent Status: Offline Points: 266 |
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lol.
Thinking about it, the better you can keep the driver cooler, the longer it will last and possibly more power you can chuck in to them before the limits of the driver is reached??? |
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kevin tyler
Old Croc Joined: 15 April 2007 Location: Spain Status: Offline Points: 3402 |
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hello tony
how much does the driver cost in your 12" sub.
it looks very smart and portable too.
cheers
kev
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Joe Grime
Young Croc Joined: 28 February 2004 Location: E London Status: Offline Points: 850 |
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Hi,
Here are a couple of pic's of our Sub12's
link to plans
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Tony Wilkes
Old Croc Joined: 02 August 2004 Location: West Midlands Status: Offline Points: 4840 |
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Joe,
Nice looking build there mate. The thing with the BMS driver is that it is a genuine sub driver and it forgoes a few db of efficiency to achieve that. Having said that because it then requires very little EQ to sound good it can save loads of amp power that way. I bet your boxes are very good around the kick region? Which driver did you use? Nice to see someone else that's happy when its small (tale of my life). Tony Edited by Tony Wilkes - 21 August 2009 at 12:50pm |
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Joe Grime
Young Croc Joined: 28 February 2004 Location: E London Status: Offline Points: 850 |
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Tony,
We used b&c 12ps100 drivers, wanted some weight rather than use neo's to stablise poles the for void mycro8 tops. Running them 1 per channel off a void kryo 7. We get a very clean musical bassline from these (bit of eq at 66hz). Sometimes put an X1 under these when heavy sub is required.
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