for the 205Ti driver. The fr chart shows them starting to drop off in level below 1.2 or 1.5kHz., down at least 4dB by 1000Hz, probably horn flare dependent to some degree, the ferro fluid should help when operating closer to Fs(did not notice the spec) by damping the resonance some. The 4 Pi Pro's run the 2226H's out to 1.6kHz. without problems, why not just cross at 1.2kHz/12dB/octave like selenium says? Sam