Dear all,

I have spent some time in trying to find info on how much amplifier power is needed for “sufficient head room” for each driver in an active three way setup. -Especially the mid/high and the high drivers.

I do believe that I have sufficient power for the sub’s (UREI 6290 2x600 @4ohms) and the low/mids (Crown CTS 8200, 8x200W@4ohms). But how much do I need for the “mid/high” and “high” driver.

The basics is that the need for power goes down with frequency. This of course subject to each driver, cabinets and the room it self. But assuming a perfect room and perfect drivers in their respective frequency window how would you suggest a normal power distribution would look like? What size of power amp would be needed for each driver?

Let’s assume 3-way system with a subwoofer and all drivers have the same “linear” sensitivity of 90db and all are 8ohms. Assume filter slope of say 18db and that all drivers have power capacity in their respective band.

Sub up to 80Hz
Low/Mid between 80-1.000 Hz
Mid/High 1000-10.000 Hz
High from 10.000 Hz and up

Given normal listening how much power would you use for each element? Is there any difference between music and movie’s? I understand that “the more the merrier” but that is beside the point. The relationship is the interesting point and from that it is easy to adjust for actual sensitivity for each driver.

My gut feeling is that there is really little need for power above 1kHz and that one could do with as little as maybe 30 watts. But that is just a guess on my side.

In reality it is a fully active 3-way 5.1 system with;
Two SUB1500 subwoofers in closed cabinets, driven by a UREI 6290
Each of the 5 other speakers use;
Dual 8” low/mid drivers with about 93db sensitivity in parallel operation in closed boxes, driven by a Crown CTS8200
Mid/high is 2451 driver on 2231 horn (JBL DMS-1) with 110db sensitivity, no amp yet
Tweeter is Ti025K with I guess about 92 db sensitivity, no amp yet

Thank you for input
//RoB