willmerboehm wrote: Okey thanks.
Can you help me understand what happen with the RMS when speakers are wired in parallel? I have never knew what will happen, are the RMS increasing or will it stay the same as one speaker?
Two 1000Rms, 8Ohm subwoofer in parallel = 2000Rms, 4Ohm
Two 1000Rms, 8Ohm subwoofer in parallel = 1000Rms, 4Ohm
Two parallel subwoofers 1000W 8Ohm will give a load of 2000W on 4Ohm.
And putting 4 Fane's on one channel of your amplifier will add 6 dB more SPL. But the power send to one Fane will be less, i.e. 450 W instead of 750 W, which is a decrease of about 2.2 dB. Your total gain will therefore only be 3.8 dB.
Mind you, this is a theoretical value, it is probably less (< 3 dB). Thereby the sound quality will decrease because the amplifier has to take control over now 8 huge speakers instead of four. A real 'tour de force'
Buying a second amplifier will give you, with the same four speakers (two speakers put on one amplifier in bridged mode = 1800 W / speaker) a gain of 3.8 dB. Taking power-compression in account, the total gain will be < 3 dB.
But both options give you less then 3 dB gain, which is IMHO not worth the investment, but the 'second amplifier' choice would the one I would go for if necessary.
Only doubling your complete set (speakers and amplifiers) will give a noticeable 6 dB gain.