Hi,
At a minimum, I'd have a series capacitor to protect the tweeters against occasional power supply thumps or clicks. I lost a pair of C23's that way. The active XO was meant to be plugged in all the time and I didn't bother protecting against swings in the rail voltages. After a couple of power cuts and people ruthlessly unplugging things without switching off the amp, ferro fluid spattered on the ceramic diaphragms and they cracked.
As for zobels, I'd only bother with the midrange, and maybe the bass if the cut-off frequency is high enough and the component values are small enough. See if it makes any difference with box resonances. My theory is that because these speakers have such hard cones, there could be a legitimate control issue between the amp and the speaker box. With normal, soft-cone speakers, most of the sound that reverberates inside the box quickly escapes because the diaphragm is both mechanically and electrically ineffective at stopping it. If a wave of air pressure hits a soft cone, the voice coil is only loosely coupled and the electrical damping only makes things worse, except for low frequencies where the coil and cone actually stand a chance of moving as a coherent unit.
But with stiff metal or ceramic cones, it's a whole different story. Inside the box there will be resonant frequencies where the diaphragm becomes a node: a point of maximum pressure and minimum velocity. There will be regions with low-pressure high-velocity air, and regions with high pressure, probably corners. Naturally, there will be some 'leakage' of the box sound, and some absorption, and both of these effects will reduce ringing.
But what happens when you cancel out some of the unwanted reactance between the amp and the speaker? If the amp has ~0 ohm low output resistance, it should work even harder at zeroing out those unwanted voltages when the "outside forces" (box resonances) push against the cone. Net effect, the resonances could be quieter, but they might ring longer. So a zobel network could be a slight improvement, or it might actually make things worse. Only you can tell by the sound.
In my next system, I'm going 'oversized', so my pet hates will be less of an issue in the first place.
At a minimum, I'd have a series capacitor to protect the tweeters against occasional power supply thumps or clicks. I lost a pair of C23's that way. The active XO was meant to be plugged in all the time and I didn't bother protecting against swings in the rail voltages. After a couple of power cuts and people ruthlessly unplugging things without switching off the amp, ferro fluid spattered on the ceramic diaphragms and they cracked.
As for zobels, I'd only bother with the midrange, and maybe the bass if the cut-off frequency is high enough and the component values are small enough. See if it makes any difference with box resonances. My theory is that because these speakers have such hard cones, there could be a legitimate control issue between the amp and the speaker box. With normal, soft-cone speakers, most of the sound that reverberates inside the box quickly escapes because the diaphragm is both mechanically and electrically ineffective at stopping it. If a wave of air pressure hits a soft cone, the voice coil is only loosely coupled and the electrical damping only makes things worse, except for low frequencies where the coil and cone actually stand a chance of moving as a coherent unit.
But with stiff metal or ceramic cones, it's a whole different story. Inside the box there will be resonant frequencies where the diaphragm becomes a node: a point of maximum pressure and minimum velocity. There will be regions with low-pressure high-velocity air, and regions with high pressure, probably corners. Naturally, there will be some 'leakage' of the box sound, and some absorption, and both of these effects will reduce ringing.
But what happens when you cancel out some of the unwanted reactance between the amp and the speaker? If the amp has ~0 ohm low output resistance, it should work even harder at zeroing out those unwanted voltages when the "outside forces" (box resonances) push against the cone. Net effect, the resonances could be quieter, but they might ring longer. So a zobel network could be a slight improvement, or it might actually make things worse. Only you can tell by the sound.
In my next system, I'm going 'oversized', so my pet hates will be less of an issue in the first place.
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