I have the following system:
- T.Amp E1200 amplifier (2x800W/8ohm ; 2x1200W/4ohm)
- Two passive loudspeakers, The Box PA 502 passive speakers (300W/8ohm)
- Four passive subwoofers, The Box PA 18 ECO MKII (425W/8ohm), with built-in crossover
- amplifier set to stereo mode
- amplifier left channel -> subwoofer 1 (8 ohm) -> subwoofer 2 (8 ohm) -> loudspeaker 1 (8 ohm) (via subwoofer 2 passive crossover output)
- amplifier right channel -> subwoofer 3 (8 ohm) -> subwoofer 4 (8 ohm) -> loudspeaker 2 (8 ohm) (via subwoofer 4 passive crossover output)
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Each amp channel should see approximately 4 Ohms.
The 2 subs on each channel will appear in parallel, but the internal crossover in the subs should effectively isolate the top cabinet's impedance from that of the subs, so above the crossover frequency the amp will only see the impedance of the top, modified slightly by the crossover.
So, each sub can get up to 600W and the top can get up to 800W.
However, I'd still recommend getting a line level active crossover and a second amp to run the tops.
That is because the subs claim to run up to 250Hz, which is a lot higher than most systems would ideally cross over.
Normally for a 15" PA top over 2 18" PA subs we'd be looking at a crossover of around 80Hz.
In addition, you have no way of adjusting the balance of tops:subs with the passive crossover. So for example if you want more bass the only way to get it it with EQ upstream of the amp - eg the tone controls on the desk.
The 2 subs on each channel will appear in parallel, but the internal crossover in the subs should effectively isolate the top cabinet's impedance from that of the subs, so above the crossover frequency the amp will only see the impedance of the top, modified slightly by the crossover.
So, each sub can get up to 600W and the top can get up to 800W.
However, I'd still recommend getting a line level active crossover and a second amp to run the tops.
That is because the subs claim to run up to 250Hz, which is a lot higher than most systems would ideally cross over.
Normally for a 15" PA top over 2 18" PA subs we'd be looking at a crossover of around 80Hz.
In addition, you have no way of adjusting the balance of tops:subs with the passive crossover. So for example if you want more bass the only way to get it it with EQ upstream of the amp - eg the tone controls on the desk.
