depends on efficiency difference between drivers and baffle step correction as the main ones. Insertion loss in the pass band isn't too bad.
If you have 3dB baffle step then that's 3dB you are throwing away through most of the band before you start!
But it then gets complicated by the fact that 2 40W active amplifiers will go louder on normal music than a single 80W even with lossless crossovers. Rod Elliot claims an extra 2x in effective power, although that is more a wet finger number.
If you have 3dB baffle step then that's 3dB you are throwing away through most of the band before you start!
But it then gets complicated by the fact that 2 40W active amplifiers will go louder on normal music than a single 80W even with lossless crossovers. Rod Elliot claims an extra 2x in effective power, although that is more a wet finger number.
You can use XSim to explore this question. It let's you look at power, voltage and current on each device.
You can also use the 2-way, 2nd order LM-1 schematics if you would like:
A Speaker Maker's Journey: LM-1 Bookshelf Crossover
Pretty run-of-the-mill design. However, this design has less BSC since it was designed for bookshelf/desktop use. Otherwise as Bill points out, there would be more loss in the woofer section, and more padding on the tweeter to match.
Best,
Erik
You can also use the 2-way, 2nd order LM-1 schematics if you would like:
A Speaker Maker's Journey: LM-1 Bookshelf Crossover
Pretty run-of-the-mill design. However, this design has less BSC since it was designed for bookshelf/desktop use. Otherwise as Bill points out, there would be more loss in the woofer section, and more padding on the tweeter to match.
Best,
Erik
BTW, so the power loss in a BSC depends on how you do it. I tend to prefer to incorporate this into my low pass filter, as opposed to using a dedicated circuit. On another speaker which uses an 18W/4531, the power across the inductor is about 15% of the amp output.
I set the amp to 10 W and look at the wattage on L1. That's actually higher than I expected!
Best,
E
I set the amp to 10 W and look at the wattage on L1. That's actually higher than I expected!
Best,
E
Usually not more than one third, say, playing pink noise, at least 2/3 go into voice coils, and at most 1/3 into resistors. Unless the cross-over has no resistors, then the loss into resistive parts of inductors and capacitors is rather at most 1/10.
You know, the big argument for active is the increased dynamic range, not the reduction of power loss.
A 25 W amp and 125W amp driving a 2 way have much greater theoretical dynamic range than a single 150W amp and that excludes power loss in the crossover.
Has to do with how voltage and power are related. Power is related to the square of the voltage. So the total Vpk-pk available from a 25W + 125W combination exceeds the 150W single amp.
Best,
E
A 25 W amp and 125W amp driving a 2 way have much greater theoretical dynamic range than a single 150W amp and that excludes power loss in the crossover.
Has to do with how voltage and power are related. Power is related to the square of the voltage. So the total Vpk-pk available from a 25W + 125W combination exceeds the 150W single amp.
Best,
E
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