Linkwitz Riley Filter Implementation

[Roysyboy]

Having just built an active subwoofer for my hi-fi system, I am now embarking on building fourth-order Linkwitz-Riley filters in order to "roll-off" my main hi-fi speakers so as to get the subwoofer to take-over some of the bass range of my main speakers in order to avoid the noticeable bass-resonance in my main speakers (that I have been listening to for the last 25 years) around about 68Hz.

The Linkwitz-Riley filters use operational amplifiers in unity-gain configuration. I chose OPA2134 op. amps. but, my question is: could I use, instaed, simple discrete (two transistor?) unity-gain buffers instead of op. amps.?

From memory, (I am a retired electronics engineer) the NPN-PNP unity gain buffer configuration has a voltage-gain closer to 1 than the Darlington Pair. Is this a desirable requisite for implementing the Linkwitz-Riley filter?

(Apologies for the techno-speak here, I am really aiming this new thread at at-least-budding analogue design engineers)

[simon5]

Hi, a technical question like this would have more answers in the Loudspeakers and/or Solid State forum instead of the Subwoofer forum. It's also related with loudspeakers/solid state because you use it to rolloff your mains so...

There's alot more traffic there, you could ask a moderator to move the thread or repost a new one there.

You'll find an answer there, I'm sure about that.