Pi Speakers, Go Big

[Bill Epstein]

After I built Paramours way back in 2001 I went looking for high efficiency and found Pi Speakers. The 'Mours and Theatre 4 pIs were a big hit at the first mid-West Show in Lima, Ohio back then, filling the auditorium there. Since then I've built 2 Pis, 2 Pi Towers and my current 4 Pis with B&C DE-250s, latest H290C horns and JBL 2226s.

I'm surprised there's so much attention paid to single driver speakers in these parts and so little to high efficiency bass reflex/horn designs.

I've built a few Fostex designs over the years and heard lots of BLHs, Voigts and other single driver horn designs. There's a lot to like about crossover-less designs in terms of imaging but every one I've heard sounds like an AM radio with the characteristic upper mid-range peak. BSC fixes and other attenuations result in polite, colorless sound. Just my opinion, of course, everyone hears a little differently, otherwise there wouldn't be hundreds of entries in lists of speakers.

Even with a true catenary Constant Directivity horn, a 2 way bass reflex/horn will never win any imaging prizes but for tone and timbre in a high efficiency design, there's nothing close.The best speakers I've ever heard, and the best sound of show at the 2005 CES were the XLH 1812, a $50,000, 1500 LB., four-way design with the enormous JBL 2370 horns. My 4 Pis go as low, are more efficient and have nearly the same truth of tone and timbre. 1.8 single-ended, directly heated, direct coupled parafed watts plays to over 100dB in my 12x15 room.

 Something to add to these discussions for certain.

[xcortes]

I have five pi pro four speakers in my home theater powered by five Paramours. My version uses all JBL drivers which was the non plus ultra version when built ( about eight years ago). I recently moved a pair to the main system to test them. In my case there's no contest, they lacl the finesse of either my 755As or of my big horns (with RCA 1443 drivers). The midrange is harsh in comparison. But then again, the midrange of 99.99% of the speakers is harsh in comparison to the 755As or the 1443/1428s. But that's just me that I'm a midrange tone/smoothness fanatic.

[Grainger49]

I have been holding off a day to see if I could come up with better wording of the later part of this post.  Nope, it comes out like below.

When I first got into Bottlehead kits about 13 years ago a local Bottlehead, Matts, invited me to bring my speakers over and see if his Paramours would drive them. They didn't.

So we settled in to listen to his Pi speakers.  Amazing dynamics and volume from tiny boxes.  I was impressed.  He also introduced me to Eva Cassidy.  I have bought all of her CDs now and a few thick LPs.

But Bill's Pi speakers have an addition on top.  I have seen this before at Phil Sieg's house.  He had that tweeter.  Sadly, it looks like butt cheeks to me, I'd prefer it to look like cleavage, but it just doesn't jell in my mind.  They have very good dispersion and look quite unique!

[Bill Epstein]

Actually, the fat ladies butt cheeks are JBL 2366s atop the XLH 1812 speakers from the 2005 CES. They were a one-off proof of concept by a Beijing designer, Hou JianZhong, who runs the largest Pro A/V outfit in China. You want flying arrays for an 100,000 seat venue, he's your man.

The horn drivers are 2"-2446, the pair of 6"s were locally sourced, the slot tweeters are JBL 2405 and the 18" woofer, 2441. I corresponded with Jian and he wrote that they were voiced with 'male speaking voice for naturalness'. That obviously worked.

The much smaller 4 Pis have the latest H290C Constant Directivity horns of Parham's own manufacture and his latest crossover, which make a substantial improvement in natural timbre. The horn drivers are B&C DE-250s. The new horn requires a 15Ohm resistor in parallel with the B&Cs and I found that the Duelund C.A.S.T. unit was audibly worth  (assuming your an Audio Filbert!)  the ridiculous price .

Xavier, I'm intrigued by your comparison of your 4 Pi Pros with, I'm assuming 2426 drivers and 2370 horns "sounding shrill" vs. the Altec 755s which I've never heard. The JBL 4430 Monitor with the 2370/2426 pairing was "dark-sounding" in my opinion and led to a lot of mastering with treble over-emphasis in the rock n' roll albums of the 70s. The 755s must be really mellow. The Altec 288 1.4" compression driver with 2" throat segmented horns is quite mellow, especially compared to the 1" format Altec 802/806/902 and comparable to the B&C DE-250/H290C. You might want to look into making the change.

[Grainger49]

Bill,

Thanks for the explanation.  Was there really a kitten at CES?  I'm happy mine have grown large enough that they can't get into the Dungeness subs' ports.

I am always somewhat deflated when I find that an expensive part is worth the price.  Your Duelund C.A.S.T. resistors and my V-Cap Teflon caps (Eros output cap) are just two examples.  I'm betting the BH DAC will be another.  It is due on Friday.

Great speakers, the Pi!