http://www.audiokarma.org/forums/showthread.php?t=150939

Since pi speakers offer great interaction with 2A3 amps i am looking for a woofer concept which i can use with the econowave design.
At a first look i think of using the alpha 10 in a 3 cubicfoot enclosure...

Any suggestions?

Thanks for all responses

Frank

You'll notice the Econowave uses the same basic crossover circuit, with a bypassed tweeter attenuator providing slightly underdamped tweeter filter via the R1/R2/C1 network used in π Speakers. That makes perfect sense because it compensates for tweeter power response and matches directivity between midwoofer and tweeter. Those are the requirements for a design like this.

There are plenty of good woofers suitable for this kind of speaker. I tend to like a slightly overdamped vented alignment, which I feel gives the best overall performance in terms of size/extension/efficiency and it also works out well to conjugate room gain in typical home hifi listening rooms. It's also a great match for distributed subs, providing adequate overlap for blending and smoothing rooms modes.

My favorite woofer for this application is the JBL 2226, which is what is used in the four π loudspeaker. The JBL 2226 incorportates a shorting ring for low distortion. The cone is well-damped for smooth midrange, a requirement for the crossover frequency needed for a matched-directity two-way speaker. It provides good extension in a relatively small package, so subwoofers aren't a requirement. It also blends well with distributed subs, making it a very versatile speaker.

• four π performance data

As i understand you are not a friend of the alpha10/econowave combo.
I think the 3pi (with the delta 12lf)would be a good choice for me.

-Can i go with the puplished econowave crossover?

http://audiokarma.org/forums/attachment.php?attachmentid=90113&d=1210028233

-Can you send me the 3pi plan?

Best regards

Frank

When using the Delta 12LFA, I recommend you use the three π crossover and the physical spacing shown in the plans. The guys over on AK have made their crossover circuit use the same basic layout, so it's definitely on the right track. But I'm not sure they've tested it as thoroughly, particularly in regards to baffle placement, phase and null angles. I think the Econowave and its variants are all very much still evolving. The three π is not, it is a tested and mature design.

In fact that i have a 2a3 amp i think i will go with the 4pi- i really love the design of the speaker.

Best regards

Frank

I hope the 4pi will a better match with my 2A3 as my Altecs 605A.I can use the Altecs only with a equalizer-after 10kHz no response...and only little Bass.Years ago i build your Thermionic 3 design but is was too big...But i liked the "fat" sound.

Frank

maybe you have a suggestion for a PI aligned enclosure for the Altec 605A?

fs: 30.3 Hz
Re: 9.3 ohm
Qts: .25
Qms: 3.01
Qes: .27
Vas: 14.33 cu ft
Xmax: 0.15 inch

What crossover would you suggest?

Best regards

Frank