Built the Krutke/Zaph L18/27TBFC

LNeilB2

Member
2001-10-23 6:41 pm
VT
http://www.zaphaudio.com/audio-speaker17.html

And damn does it sound nice. Very transparent midrange, potent bass,sweet, mellow highs.

But I have to ask - is the H1224 driver SEVERELY limited in power handling below 100hz? My pair rattles like hell at moderate volume with substantial sub-100hz signals - music, not test sweeps. I'm wondering if this batch of 1224s are defective, because the Seas H571 paper driver I've been using, with half as much xmax, has never been problematic.
 
These should be able to handle just about all the power you could dump into them. If you were over driving them, they would more likely "flutter" as they exceed Xmax, rather than rattling.

There's a possibility they could be defective. You could always pop the phase plug out and look at the alignment from the inside. A skinny screwdriver can push it out from the back.

A couple other possibilities: There's a metallic or magnetic piece of debris in the gap. I've heard of this happening before, and it's an unfortunate side effect of having an open spider. If the coil is aligned ok, you might look for some sort of debris, like a metal flake or magnet chip.

Make sure the driver, both tweeter and woofer, are well sealed. They may rattle otherwise. And finally, be sure you don't have any port tuning errors - confirm the diameter and length of the port. Not a common mistake but it does happen.

Whatever the case, your drivers should be perfect. Madisound is pretty cool about helping out people when driver problems arise, so I'd take a good look at your driver and give them a call.

John