Shown left are the Twins in a vertical array. This is a monopole arrangement which provides broad horizontal dispersion and narrower vertical dispersion.

This may be a good choice in reverberant spaces where it is beneficial to reduce reflections off ceilings and floors.

Connecting the four as a group in series/parallel maintains an 8 ohm load but increases continuous power handling to 400 watts. This configuration is capable of 120dB/watt/metre whilst maintaining linear coil travel.

Mutual driver loading should drop the f3 to around 35Hz and its highest frequency in this configuration with all four receiving the same input signal should be no greater than 160Hz.

To avoid response anomalies caused by lobing due to the distance between the drivers, a staggered crossover configuration may be implemented to extend the frequency response of these stacks (See Dipolar Array Section!).

With secure rigging the array can be flown enabling angled cabinets for a curved array and “gain shading” may be applied where different levels may be set to individual cabinets, usually more to the top one or pair to account for near and far audience distances. Separate power amps required and measured set up essential.

The flown array may apply to the cardioid stacks as well shown on the following pages.

A variation to modify dispersion is shown right.

This arrangement of front facing but horizontally staggered drivers will have reduced horizontal dispersion when compared to the in line vertical array version.

Configuring as a Dipolar Array

The vertical stack can be configured to achieve of dipolar array. These include tight vertical dispersion and dipolar response pattern whist minimising lobing.

Just stacking drivers causes response anomalies due to their physical spacing as frequencies rise but when configured correctly will provide superb vertical dispersion control. To avoid lobing and response anomalies the upper and lower cabinet need to be crossed over no higher than 160Hz and the middle two cabinets may extend to around 450Hz.

This will provide an optimum smooth and controlled narrow vertical response the purpose of which is to reduce many of the problems associated with floor and ceiling reflections. The preferred crossover types with their zero degree polar tilt at crossover are the Linkwitz Riley filters. Active crossovers and EQ (either DSP or analogue) offer all the usual benefits over passive methods and at these low frequencies are mandatory!

Delays between Wide Boy subs, Twins stacks and DML panels to “re-align” their acoustic centres will be required if the different loudspeaker sections are displaced from each other which is likely to be the case in most venues.

DSP will definitely be required!!

It may be noted that a system of Wide Boys, 4 x Twins and stacked DML panels are sensitivity matched at around 95dB/watt/metre each.