Passive components in a bi-amp config

[THUMP LUMP]

Obviously, passive crossovers are not needed with an electronic crossover. But, I'm thinking that passive components may still be needed. It would seem that impedance circuits are not needed but, frequency attenuation circuits could be. Am I thinking in the right direction here? Are there more passive circuits that could be used if needed?

[Jay_WJ]

See this example:

http://www.diyaudio.com/forums/showt...49#post1716549

Passive components were used to put baffle step compensation and meet the desired acoustic target rolloff.

[Drew Eckhardt]

Originally posted by THUMP LUMP
Obviously, passive crossovers are not needed with an electronic crossover. But, I'm thinking that passive components may still be needed. It would seem that impedance circuits are not needed but, frequency attenuation circuits could be. Am I thinking in the right direction here? Are there more passive circuits that could be used if needed?

There's no reason to use passive speaker level components on the speaker side of an active cross-over. They can be done on the active side with no interaction with unit-to-unit or output level dependant impedance variations for a lower parts cost.

Baffle step can be done on the amplifier side by boosting low frequency output, instead of padding down sensitivity at high frequencies.

If you're not building the amplifiers (where an extra power op-amp is $6 sharing the same heat sink, power supply, and enclosure) it may be reasonable to use a passive cross-over between tweeter and mid-range.

[Iain McNeill]

one of the benefits of bi/tri-amping is that you have a single amplifier driving a single speaker. The amplifier has good control of the speaker because all the reactive (delay causing/energy storing) components have been eliminated (except the voicecoil & moving mass of course) Adding BSC, notches and impedance correction components defeats the object. If you're going to the bother of designing active filters, go all the way and craft the exact responses you need for each driver.

The only exception I can think of is if you're using tube amps with relatively high output impedance in which case, some impedance compensation between amp & speaker could iron out wrinkles in the amp response which you'd like to assume is flat, DC to light

[THUMP LUMP]

Well, I'm not designing my own active filters or building my own amps. I'm just thinking, for example, The crossover point that works between the woofer and tweeter is 2500hz and I find, after doing some near field frequency response measurements, that there is a nasty hump at 7000hz on the tweet. I was just thinking that a filter there would be the easiest way to go.