Building a portable 12v system |
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thattkyle
Registered User Joined: 12 July 2018 Status: Offline Points: 17 |
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Posted: 12 July 2018 at 5:21pm |
Hi all Kyle here.
I'm putting together plans to build a portable soundsystem, mainly for reggae, dub & sub variants.. also jungle and breakcore. I think i've chosen 4 MTH-30 to use as bass loaded with RCF LF12G301 - 8ohm http://www.bluearan.co.uk/index.php?id=RCFLF12G301 Ideally they'll be powered via a 12v car amplifier. Do I need 2 amplifiers for 4 bins? EDIT: I've found this online. Could I run 4 of these with this amp? https://www.caraudiocentre.co.uk/product_m-pioneer-gm-d9601_p-32194.htm in this config: I've also been thinking about building a boominator for the mid-tops but only having 2 drivers and 2 tweeters so its only firing in one direction, has anyone done this or is there something better that I can use? To power it I was going to use 1-2 12v car batteries and take them off to charge them via mains. Thanks all.
Edited by thattkyle - 12 July 2018 at 5:29pm |
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mini-mad
Old Croc Joined: 13 July 2012 Location: london Status: Offline Points: 6903 |
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The MTH30 is a 50hz horn... has a very nice upper thump to it but I'm not so sure about playing dub/jungle through it. I own 3 of these and also a THAM12 and my ears tell me the THAM12 plays lower.. doesn't kick as hard as the MTH30 either.
If you want the low notes (and battery power is really going to dictate this) then why not build a large reflex sub housing all 4 drivers? You could still run 2ohms and it will go much lower then the other two. I would at the very least build just 1x MTH30 1st to see if you like the sound and if it plays low enough for your liking as because your making it portable to make sure you don't drain the battery bank fast you would need a fairly high (sub bass wise) crossover point.
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If it sounds like a gorilla is trying to escape, turn it down.
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thattkyle
Registered User Joined: 12 July 2018 Status: Offline Points: 17 |
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Thanks for your message!
I do appreciate that I won't get real low end off small bins, i'm willing to compromise slightly for portability and the fact that it'll all easily fit in a car. As for battery power I am a little worried, not sure how I would go about running this system for hours on end. |
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864 |
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For batteries you've got two options - lithium or lead-acid. Lithium is about 4x the price per amp-hour but less than 1/4 of the weight of lead acid. So say you want about 100Ah, a lead-acid will be about £75-100 and weigh about 25kg. Lithium will be about £400 for that capacity, but weigh only 6kg. It entirely depends on your budget vs mobility requirements.
Remember the 1/8th rule of "music power" - when playing real music, your long term average continuous power is about 12.5% of whatever the instantaneous peak power is. EG if you calculate that your amp would draw 20 amps during peaks of full power into the drivers you have, then over the long term it will be drawing about 2.5 amps, and you can use that figure to estimate potential battery life. This rule is less accurate if your music includes a lot of continuous sub-bass tones, or is scored for only triangle and piccolo. edit* Put the wrong link in, here's a 10Ah pack that ought to work for £35 https://hobbyking.com/en_us/multistar-high-capacity-4s-10000mah-multi-rotor-lipo-pack.html Of course you can parallel as many of these as you like to get the capacity you want....And you should get very good life out of them, as soundsystem use isn't nearly as punishing as RC car or drone racing. One caveat that I'm not sure about is whether the voltage on these type of packs will be too high at full charge for car audio amps, which tend to specify a maximum input of ~15v, whereas these go to 16.8v when full. 100Ah leisure batteries can be found from many places eg Halfords, Towsure, Decathlon, Go Outdoors etc. Don't forget a good multi-way fuse box/distribution board. Every significant length of cable needs a fuse in it close to the source of power, even if the destination device is also fused - because in the event of damage to the insulation leading to a short circuit, both lithium and lead-acid batteries can *easily* deliver enough current to start a fire.
Edited by studio45 - 13 July 2018 at 3:01pm |
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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thattkyle
Registered User Joined: 12 July 2018 Status: Offline Points: 17 |
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Awesome, thanks for that!
I didn't know about the 1/8th rule so now running on 2-3 lesiure batteries looks like a good option. The soundsystem will be mounted on some kind of trailer / wheels anyway. Does anyone have any thoughts on mid-tops? Not too sure about a boominator anymore - I'd like tops that will fit happily on the MTH-30s that will also give the soundsystem a bit of height. |
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864 |
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2 or 3 leisure batteries plus speakers and amps! Have you really considered what it's like to push a 100kg+ trolley around?
The answer is, not much fun...it'd be a three person job. My bike trailers are ~60kg with everything on, and they are a challenge to move up any kind of hill by yourself, even with the mechanical advantage of bike gears. One battery really ought to do the job. You can always keep a spare back at camp or in the van. I used P.Audio SN6-150CX 6" coaxial drivers in my mid-tops, with a custom crossover, which took a long time to make. But if I was going to build again, I would probably go for an array of Faital 3FE full-range drivers; they would be a lot lighter, even if you used enough of them to match the output of the P.Audio driver, and need no crossover.
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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