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trolly soundsystem - mini line array - WITH PHOTOS

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Category: General
Forum Name: 12v Powered Systems
Forum Description: From Mini-rigs to ICE, all your low voltage audio needs here...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=27593
Printed Date: 27 March 2026 at 8:25am
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Topic: trolly soundsystem - mini line array - WITH PHOTOS
Posted By: davey t
Subject: trolly soundsystem - mini line array - WITH PHOTOS
Date Posted: 08 June 2009 at 10:56pm
Just thought i'd share this with you...

So i've been commissioned to re-build a 12v soundsystem mounted on a trolly for an act which tours various festivals in the uk. I'm using a lot of the design from my 12v mobile disco system i did last year but with some differences. 

They play a lot of rock and talk a lot over the system so the mids have to be really clear. Also people gather round in a semi-circle so it has to be very wide dispersion. Also shouldn't block the view of them.

Last time I used PA horns from skytronic but i'm worried about the dispersion and clarity. So this time i'm going to build a mini line array covering 250hz to 2khz. I'm going to use ten 4" drivers per side then a compression driver on wide horn for the treble. Using lots of smaller drivers also means you can put more amplifier power in from a 12v rail without needing to boost the voltage. 

4" drivers will give a seperation of 10cm which should be ok up to around 2kHz right? 

This is the double 15" kappalite 3015 loaded bass. Worked a charm last time. This time i've made it a manifold to try and protect the drivers a bit more and strengthen the box etc. 

Here's some eye candy for now. I'l keep you updated. 






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Minirig portable soundsystem movement



Replies:
Posted By: studio45
Date Posted: 08 June 2009 at 11:27pm
oo and indeed er. looking forward to seeing that :)

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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA


Posted By: rich_gale
Date Posted: 08 June 2009 at 11:47pm
awsome.  cant wait to see the line array mid high section.

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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: _djk_
Date Posted: 10 June 2009 at 10:57am
http://www.lowes.com/lowes/lkn?action=productDetail&productId=87378-000073428-68001&lpage=none - http://www.lowes.com/lowes/lkn?action=productDetail&productId=87378-000073428-68001&lpage=none


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djk


Posted By: davey t
Date Posted: 22 June 2009 at 10:48pm
I'l let the photos speak for themselves





They sound amazing. Really efficienct and clear and LOUD. Very hifi.

If you're at Glastonbury this week make sure you make your way over to Avalon between 3 and 6 to check them out!




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Minirig portable soundsystem movement


Posted By: rich_gale
Date Posted: 22 June 2009 at 11:17pm
very very awsome indeed!  whats your external power source?  and i like the mini hf horns - are they custom? loving the colour scheme.


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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: jethrocker
Date Posted: 23 June 2009 at 4:53am
Very striking, looks wicked :) Liking the (active?) crossover panels.


Posted By: toiminto
Date Posted: 23 June 2009 at 7:43am
that system looks sweet indeed! What's the height of the arrays? Can't really tell from the pic.

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http://soundcloud.com/toiminto


Posted By: davey t
Date Posted: 23 June 2009 at 8:44am
Originally posted by rich_gale rich_gale wrote:

very very awsome indeed!  whats your external power source?  and i like the mini hf horns - are they custom? loving the colour scheme.

The line array speakers run off 12-24V dc with an active crossover seperating the mids and HF. There's also a switch which youy can turn the low cut for the mids on or off. Very useful if you want to run them full range or with a bass bin


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Minirig portable soundsystem movement


Posted By: darkmatter
Date Posted: 23 June 2009 at 2:38pm
very very very nice.

I'm going to paint my speakers orange tooSmile

I wish I had your knowledge of building active crossovers.


Posted By: Meat
Date Posted: 23 June 2009 at 3:19pm
Looks sweet Dave. Loving the colour.

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Don't test the champignon sound


Posted By: biotec
Date Posted: 23 June 2009 at 3:25pm
I have been using high power DC connectors made by a company called anderson.
 
They are generally used for charging vehicles such as forklifts and jump starting race cars. The military use something similar so that the DC electrics in comms vehicles can be powered by an external power source when the engine isn't running.
 
They are a very safe way of connecting a DC power supply to a consumer and I think they would work very well for 12v sound systems where the batteries are in a sepaarte unit to the amps. I am not aware of a flange/bulkhead mount connector though.
 
They make them in a variety of amp capacities.
 
I get mine from http://www.torberry.co.uk - http://www.torberry.co.uk
 
You need a crimper to connect the cables to them but if you don't want to buy one you could get an autoelectrician to crimp them for you. I have a big hydraulic crimper if you ever need to do very thick cables. I recently did some 95sqmm battery cable for my truck!


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me so horny, me love you long throw.


Posted By: studio45
Date Posted: 23 June 2009 at 3:37pm
looks amazing davey, you have (only just) made me want to come to glasto :)

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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA


Posted By: greeef
Date Posted: 25 June 2009 at 5:03pm
are you using the wharfedale 3038lb?

I'm working on a very similar array at the moment, but with a ribbon tweeter line alongside it. I noticed a very distinct "bloom" with my prototype - the loudest point is most certainly in the middle of the array, and it is very noticeable when moving your head up and down a couple yards from the speaker.

I think that curvature for this design is really important - i am working on a baffle assembly design that will allow me to curve the baffle for each show.

http://www.alfordmedia.com/linearray/index.html

the pdf link on this page is where i am gleaning this from. Put simply, placing the speakers higher, and with a J curvature, will result in a much more even response throughout your audience area and less spillage beyond it.


Posted By: carrot
Date Posted: 09 July 2009 at 9:02pm
which 4" cones did you use?

cheers.


Posted By: davey t
Date Posted: 09 July 2009 at 10:05pm
yea, the wharfedale ones.. great for the money. I use them for lots of projects... they have a nice low Vas which suits small boxes and a pleasant sound. I've found that they work best in sealed boxes. 

The array sounded great... I think the rig needs some tuning still though, its all been very rushed and we've never had chance to play around with it. 


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Minirig portable soundsystem movement


Posted By: rich_gale
Date Posted: 09 July 2009 at 11:13pm
yo davey.  does your vibe class d bass amp get warm or hot at all?  i been playing with my class d monoblock and even at idle its getting pretty damn hot...  this is running from a lithium pack that is measuring 16.6volts (4 cells fully charged to 4.15v per cell).  i was always of the belief that car amps had an operating range between 9v-18vdc..  recon the 16.6v is doing damage?

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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: davey t
Date Posted: 10 July 2009 at 9:16am
Yes, they're only really designed to run off an alternator - hence 14.4v maximum. You should be running it from 3 cells really. Mine never got warm. Have you measured your idle current draw? Should be about 1 amp. 

I always charge my lipo cells to 4.2V

sounds interesting though - post us some pics!


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Minirig portable soundsystem movement


Posted By: rich_gale
Date Posted: 10 July 2009 at 10:05pm
yo davey.
 
yes, i stupidly calculated the cell count using the 3.7v standard voltage.  not the fully charged voltage.  i thought id be getting 14.8volt but infact have over 16.5volt.  i decided to keep to 4.15volt per cell to limit the stress i put on the cells.
 
 
photo doesnt really show whats going on, but i got 14 parallel groups of 4 cells wired in series.  multimeter shows 16.58v.  looks like i might have to give up on the idea of using an automotive amp for bass, and just use another sure 2x100w class d tripath. 
 
when running the car amp from a 12v source i see a 1025mA idle draw.  from the 16.6volt battery i am seeing 1250mA.  for some reason i thought the amp would draw less idle current when at a higher voltage input..  ????


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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: SamV
Date Posted: 10 July 2009 at 11:06pm
Maybe the higher voltage means it's got fans etc going to keep cool? 16.5v is deffo pushing the amp. I think it's only the bigger SPL amps that can take upto 18vdc.


Posted By: rich_gale
Date Posted: 10 July 2009 at 11:50pm
i been thinking, if the current draw has only gone up by 250mA when using the amp at 16.6v i was gonna make a small case with a 120mm fan(80mA) to keep it cool.  the memphis car audio website says all their class d amps have a regulated supply meaning the amps cant get damaged by higher voltages, but the heat coming off the thing worried me a bit. i wonder if a fan is worth the extra 80mA current draw if it means the amp will be ok running off the 16.5v...?  I was gonna be making a little box to house all the amps and crossovers in anyway so fans wont be much of a hassle to include if it means the amp will be kept cool running at the higher voltage.     

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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: davey t
Date Posted: 13 July 2009 at 4:16pm
Yea you've got over 20w over quiescent power draw there heatin up your amp buddy. It should be rated to dissipate almost 100w though whithout getting hot. 

Careful with them flying leads off your lipo batteries - you don't wanna go shorting them! unless you're trying to light a bbq... get yourself some high ampage RC t-connectors

What charger are you using?


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Minirig portable soundsystem movement


Posted By: davey t
Date Posted: 13 July 2009 at 4:23pm
Just to briefly explain, class-d amps and smps dissipate power through the switching on and off of the mosfets - this is due to the intrinsic capacitance in the silicon. When they switch, you are filling up the capacitance with charge and then dissipating it, hundreds of thousands of times a second. The higher the voltage - the more energy being stored in the capacitance and hence the higher the switching losses which is why you see that 250mA difference

but you're right, it will pull less amps at a higher voltage when its actually driving the speakers hard - its the low volume consumption thats higher where the switching losses dominate. 

Look up "choosing the right mosfet for class-d amplifiers" by IR for more info


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Minirig portable soundsystem movement


Posted By: rich_gale
Date Posted: 13 July 2009 at 4:35pm

yo dave.

 
cheers for the insight.  id imagine what im feeling is more than 20w of heat build up(its on the border between warm and very warm).  but i doubt its as much as 100w, so its worrying that its getting so hot.  weired.  in your opinion would you think that if i can keep the amp cool with a fan, will the amp still be likely to be killed by the higher voltage?  max voltage is 16.8v at full charge.
 
charger is this:- http://www.rccarsandtrucks.co.uk/1643_1_2083532.html - http://www.rccarsandtrucks.co.uk/1643_1_2083532.html
 
the carpet colour doesn help, but if you look closely i have a tamiya RC battery plug on the end of the pack. 


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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: davey t
Date Posted: 13 July 2009 at 5:37pm
Ah, of course.. would be silly not to have a connector :)

Yea those chargers will work nicely but don't balance the cells.. you can get away with not balancing them if you're not doing many charge cycles and only charging to 4.15V though I guess. check the voltage across each cell every few charges to check they're all within 50mv of eachother

Lipos rule though don't they - and they're so cheap now thanks to the RC market


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Minirig portable soundsystem movement


Posted By: rich_gale
Date Posted: 13 July 2009 at 6:02pm

im amazed by the power to weight ratio with this thing.  the cells are old, but so far with testing i think i have about 18ah(from 16.8v - 11.2v).  and the weight is around half of a yuasa sla battery of the same capacity.  incredible.  if i purchase a balancer to go between the charger and the pack, will i need to run wires from each cell?  or does the balancer just connect using the two wires i already have? 



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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)


Posted By: davey t
Date Posted: 13 July 2009 at 10:51pm
No, you need a connection to every battery cell 

When you buy the packs they come with the high current t-connectors and low current 4/5/6 way connectors for balanced charging. 

look it up. you should know about this stuff before using lipos. 


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Minirig portable soundsystem movement


Posted By: Grinner
Date Posted: 17 August 2009 at 1:27am
i am like this project very much
an would like to know how you wired the drivers in  the  tops up . an what ohms the amps see
i have built the booty bass bin an will be testing it this week.
them 4" drivers are very cheap to experiment with. an worth the bulk buy on ebay.



Posted By: SatriaSoundPro
Date Posted: 27 September 2013 at 4:40pm
please the plan b30 tw audio........regards



Posted By: bitSmasher
Date Posted: 27 September 2013 at 10:38pm
Thread resurrection... Pics don't work, but is this the orange system in the banner image on Doppler's Facebook page?



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