Originally Posted by BUSHIE
Why do you and most of the guys put the putty with duct tape around the horn.
Wayne has stated that he doesn't think that the horn needs any treatment. When I built my 4Pi's I would snap my finger on the raw horn (plastic) and detect a slight ringing, I wrapped mine in putty and no more ringing. Does it make a difference in final result? I think you would need some really good test gear and do an A/B test to find out.
Just a heads up for new Pi builders, Wayne has written about the fact that the horn that he used is going out of production. He has found anouther source and will be selling a drop in replacement for the Eminance horn. From what he says about the horn it may be worthing of an upgrade.
from his site:
"There is no suitable alternative to the H290, now designated H290C. The horn/waveguide properties are very specific, and it cannot be substituted without a complete redesign/test cycle. The biggest issue is the position of the acoustic center, which is affected both by the acoustic load and the depth of the device. The size and shape of the H290C are precisely set to provide the right beamwidth, loading and acoustic center.
The problem many people are facing is that Eminence discontinued the H290 horn. They were getting them from an overseas supplier that has stopped making them. We are now making the H290C horn/waveguide - and in fact, have updated the profile to be a pure catenary flare. It is essentially a plastic version of the wood horn we've been making for years, so we could leverage the design work we've already done.
So my suggestion is to purchase the horns from us. There are other suppliers that still have the H290 in stock, but it is rapidly dwindling. Besides, our new H290C is an improved device, one that can be considered an upgrade. It uses the same baffle cutout and mounting holes, so it's an easy bolt-on replacement. "