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It is currently 23 Jan 2021, 10:24

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PostPosted: 06 Mar 2013, 23:29 

Joined: 14 Aug 2012, 23:44
Posts: 102
Location: Australia
@Turk 182

I didn't get a chance to try the alternative wiring. I was too intent on getting the things wired up and operational, as it'd been a long time since I ordered the panels.
Looking at the speaker from the front, with driver #1 at top and #4 at bottom, they are wired up - red terminal to positive of #1, negative of #1 to positive of #2 and negative of #2 to black terminal. Drivers #3 and #4 are wired similarly. In other words Drivers #1 and #2 in series with each other, drivers #3 and #4 in series with each other and then both series pairs parallelled.

There is significant research into the speaker boxes and the volume of the box is deteremined by the drivers that you are using. The dimensions are based on a golden ratio which is 1.6 : 1.0 : 0.6. and the more drivers you put into the box, the internal volume of the box increases accordingly. For instance if one driver was resonant at a particular frequency in a 10 litre box, then if you put four drivers in, the volume should be 40 litres.

The mini-line array (MLA) is slightly different in the fact that the volume is calculated based on a single driver and then more drivers are placed in that same volume. Also for a proper line array, like you see at a concert, they are supposed to be curved so that the sound from the drivers at the end of the array reaches you at the same time that the sound from the centre of the area.

The internal dimensions of my boxes were 262 x 262 x 1250 mm which is 85.8 litres but there is bracing inside, which reduces the volume slightly. This of course doesn't correspond with the golden ration because 1) when I used this for a volume of 85 litres, the 'golden' dimensions were too large for the space that I had to put them in and 2) I needed a longer front face to ensure that all the drivers were nicely spaced and 3) originally I was going to use eight drivers (but that was overkill)

The port is calculated at 50mm diameter and 55mm long. This is not very long, due to the fact that the cabinets are built out of 25mm MDF. It sits direct centre on the back of the box and the centre of the port, from memory, is 100mm from bottom edge of back panel.

Cheers Nodz

PostPosted: 07 Mar 2013, 06:19 

Joined: 26 Oct 2012, 21:00
Posts: 203
Location: ontario canada
if you get a chance try wiring your #2 and #3 as the start point i.e. 2 to 1 series and 3 to 4 then parallel the two legs making the center pair the start point of both your series legs.
rewire only one so you can listen to both for comparison.
in my experience with large multiple driver arrays in pro pa setups this scheme can have significant impact on the overall sound. i'm also finding this to be true is my tinkerings at home.

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