thanks, scp53

I know the 1Pi (Alpha 8) is great. I helped a friend build some 1Pi kits and he uses them for main, center and rear with a retail sub, very nice indeed. I was very impressed and will recommend to anyone looking at this size and power class of speaker. It is interresting that he did not have issue with the magnet under his TV, but I can not say if yours will be the same. All considered, My first thought the other day was 1Pi and That is still what I think. Wayne has everything you need, and probably has a good idea how to pad down the apt 50 to work in a 1Pi, since I know you want a horn on top.
Thomas

scp53

scp53

I've used a handful of successful arrangements for speakers like these. The eight π loudspeaker uses an Alpha 10 on a midhorn and reflex-tuned rear chamber for the bass. I use a PSD2002 with 1.6kHz crossover. The one π, two π and two π tower speakers use a smaller tweeter crossed over higher. For many years, I used the KSN1038 piezo tweeter and I could count on very good performance from that part. But it looks like I'll be switching to the Vifa DX25 soon because the KSN1038 has been discontinued.

The KSN1038 is a compression horn driven by a small cone diaphragm. Performance is good particularly for the money. But supplies are nearly exhausted, and I'm not sure if and when CTS will find a buyer for the tooling. So I've redesigned to use a Vifa DX25 dome tweeter, which is silky and smooth. They're more expnsive, but they do sound nice.

I considered using the APT tweeters when making the change, but I decided on the Vifa DX25 instead. I used a first-order filter on the Vifa, and I suppose that might work on the APT too. But unless a person is very careful with input power, I'm not a fan of first-order crossovers on compression drivers. It's too easy to over-drive them and send the diaphragm into the phase plug.

thanks, scp53