Peerless XT25SC40-04 tweeter in SEOS waveguide, distortion and compression measurements

Hi All! I'm working on a home theater project and am trying to reality check myself as to whether this performance stacks up, and if I ought to stand by this tweeter combination or move on to something else.

My goal is to be able to exceed 105db at one meter, allowing me to approach reference levels at about three meters. I have attached a small Peerless XT25SC40-04 ring tweeter to a DIYSG SEOS-8 waveguide, and have mated it to a Peerless HDS-830869 woofer with an active crossover for testing. The crossover on the woofer is a 4th order lowpass at 1400hz, and the tweeter has a 1st order highpass to shape the response and a 4th order highpass at 1200hz.

speaker front.jpg


Overall, I think I'm getting somewhere but need better cabinet design to reduce some diffraction issues. I'm not a great woodworker and that does not come easily to me, so I'm second guessing a lot at this stage. The Peerless woofer is no longer available, so I'm looking for other options. The other options tend to cost more, so I set out this morning to answer... can this combo hang?

Here's a graph with 1 meter gated measurements stepped in 3db increments.

tweeter compression.jpg



Here they are again with 3db offsets to lay them all on top of each other. I can't figure out how to set one as reference and the others as deviations from that- I've seen some people do it, can anybody point me in the right direction to do that too?

tweeter compresion overlay.jpg


It seems like it comes up just short of 105db before compression is significant. Perhaps that's OK.

Now here's distortion at about 86db:

tweeter distortion 86db.jpg


Mostly 2nd order, and over 40db down. Looks alright!

Now at about 95db:
tweeter distoriton 95db.jpg


3rd order is starting to come up, but is that level low enough? I see reviews of commercial speakers (not even very expensive) that can do better.

Finally, here's how hard I pushed it. About 107db:
tweeter distortion 107db.jpg

Second order is pretty high, and higher order products are starting to show up, though still at fairly low level.

So, is there a better way to go? Any feedback is welcome, thanks for your time.
 
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