Originally Posted by LTD02
hi duke... as you know, there have been some quality control problems in the past with the eng-190. do you have a source that provides consistently good quality waveguides? some folks around here would like to experiment with it, but were turned off by the bad batch or whatever the issue was.
The last batch of ENG-190s that I got directly from DDS were excellent. Beautiful cosmetically, thick but not too thick fiberglass. I still have to grind the back of the flange flat and do some touchup here and there. Occasionally there are thin spider-thread cracks in the surface gelcoat, but they're easy to hide with a correspondingly thin sharpie. One slight issue was that the custom 8-hole-flange configuration I got did not have the 8 holes perfectly equi-distanant from one another, but that was not hard to work around. Unfortunately they don't photograph very well, or I'd post a link.
Now one of the problems you guys would have is, we don't know the generation of the stock that vendors have on hand. You can ask 'em, and make sure you have return privileges, or maybe even organize a group buy.
The DDS waveguide has a larger diameter "lip" than the Geddes profile. This means the on-axis dip is shallower, but also that pattern control degrades at a bit higher frequency.
Originally Posted by ZilchLab
The Celestion Nd thread-on doesn't quite completely seat in the Pyle or Dayton clones, but does in the original JBL PT version, which does not have the metal insert. How are you resolving that in production? I have suggested that a thin resilient gasket at the transition might be an easy solution.
[Think hose washer....
I grinded down the backside of the first few Pyle horns, and then I forgot to do so on a pair and took 'em to an audio show and nobody (including me) heard anything amiss. When I got home I did a blind test and the difference was apparently inaudible. So now I don't worry about it. I end up doing some whittling on most of the horns in the throat area, as there's a little bit asymmetry in the mold. Also every now and then I get a horn with the threaded hole clearly off-center by a significant margin, and those get discarded because they'd be too hard to fix.