Thanks for any explanation you can give,

Russellc

• Tweeter circuits for constant directivity horns and waveguides

• four π loudspeaker performance data

This is probably a bit off topic - I am using the 3Pi with DE250 driver and found the midrange a bit thin and the high frequency a bit too shouty. Then I push them into the corner (about 1 feet away from the back wall) and toe them in at 45 deg. The system now has a much better tonal balance (actually quite nice!!!). However, my room is only ~10feet wide and I am sitting around 8 - 9 feet from them so the speaker axis actually cross in front of me by a large amount (probably 2-3 feet??). Is it an 'acceptable' placement? Or am I trying to hide a problem in the wrong way? Thanks.

• Imaging, placement and orientation

There are a lot of things that can cause a little (or a lot) of excessive sibilance. Of course, the speaker, it's tweeter and network are the obvious ones. The DE250 is a little hotter than the PSD2002, so sometimes people forget to change tweeter resistors when upgrading, which causes a bit too much treble. Other causes are lively rooms and source material, things like that. If you've stayed with the plans, used the right components, you can rule out the loudspeakers. They're properly matched. That leaves the room, setup and source material.

In your case, I'd say you've found your answer. By having the speakers setup the way you have, you've reduced early reflections and improved imaging at the same time. This configuration works best in most cases, making the most natural sound.

BTW, what are the correct resistor values? I got the crossover and the DE250 from you together last year and wonder if the resistor is already tweaked for the DE250?

Many thanks!

For PSD2002:
R1a & R1c - 20Ω
R1b & R1d - 30Ω
R2a, R2b, R2c & R2d - 16Ω

For DE250:
R1a, R1b, R1c & R1d - 30Ω
R2a & R2c - 12Ω
R2b & R2d - 16Ω

To be very honest, in a three π speaker with a DE250, the weak link isn't the tweeter, it's the woofer. Not knocking the Delta 12LF at all, it's a nice sounding woofer, very smooth, and some people prefer it. To me, the Delta 12LF sounds very rich and warm, but it doesn't have the upper midrange smoothness of the JBL 2226. When I take speakers to shows and listen to them non-stop for a whole weekend, I find the 2226 doesn't leave me fatigued at all. When I take a speaker with the Delta 12LF or Omega 15, they sound nice but I notice I'm fatigued after about a full day or two. The combination of a properly-designed shorting ring and a well-damped cone in the JBL 22xx woofers come together to make the midrange and upper mids very smooth. I haven't found any equals yet. Hence, the upgrade path I recommended yesterday.

Do you notice the same thing with the 3-way design with the Omega? The "below ~300Hz" output is certainly there, but doesn't seem to
have any character that would get annoying after a while. I really love my 3-way setup. Not exactly a 7Pi, but close.

The problem is it's hard to resize a woofer hole and/or port and do a good job. You're limited on the tools you can use. So I understand your dilemma. Sorry, but I know of know drop-in replacement woofer you can use for an upgrade to your three π speaker. Might be worth looking at AE Speakers, to see if they have a woofer or can make one for this application. On first glance, the TD-12S specs look right.