S17 - Constant Directivity Dipoles

While the S16 provides smooth directivity, they are lacking rear radiation. In this iteration I want real dipole radiation front and back, and uniform to very high frequencies. This can only be done with extemely short front-to-back distance.


The "tweeters" used areTandBand 3" full-range. They allow three things to happen:

- Dipole peak to occur very high in the frequency range, allowing constant directivity
- Very open rear chamber for good rear frequency response
- Low crossover frequency.


The directivity plot was measured indoor so there is room for improvement when I take it for outside measurement later.

Follow the discussion at DIYAudio.

These are respectable uniform dipolar radiation, impossible to achieve with traditional methods like back to back dome tweeters.

The tradeoff is high frequency resolution of the 3" fullrange drivers.

Visits and GTGs

Social events are part of a hi-fi hobby and as an amateur enthusiast I had been very lucky to enjoy the company of friendly visitors and as a guest to others.

GTGs (Get-Together) and Events

PSE-144 GTG - 27/9/2015
After hearing unity variants before (original unities, Yorkville) it's great to hear these PSE-144 from Red Spade Audio at Joz' house. I think they are the 'Ferraris of loudspeakers'.

Redefy TWO GTG - 2/9/2015
Spectacular speakers built by Henry at Martin's place. They follow the Econowave philosophy using FaitalPro drivers and waveguides.

Same64 (Marian) DIY speakers - 1/9/2015
Listened to great passive build by Marian. 12" subwoofers, 5" TangBand metal fullrange and small Dayton AMT

2013 Melbourne Audio Show - 18/10/13

Great event, and even better than the last 2 year. Beautiful venue.
I was most impressed with the build of Kyron Kronos. Although acoustically it's not the latest generations of dipoles (like lx521, Nao Note) there was definitely nothing wrong with the sonics of these loudspeakers.

Red Spade S3 GTG- 20/1/13
Measured S3 Unity Horn prototype. Excellent directivity to ~250hz !  I can't live with the size, unfortunately.

Matt's Hoyt-Bedrford - 22/7/2012
Had a great evening at Matt's listening to Hoyt-Bedford fullrange driven by valve amp and Kuzma + SOTA turntable.

Musikelectronic Geithain 901K (Pure Music Group) - 24/6/2012
Attended GTG at Pure Music Group Mornington.

These are exceptional speakers. They actually managed to build Cardioid radiating speakers from 30 to 250hz. This is not an easy task. 

LINN high-end system (Warren's) - 3/6/2012
At Patterson Lakes, which is very close from my place.

-->Synergy Horns GTG - 5/11/2011
Measurements and listening to various implementation of Unity Horns. We had Yorkville Unity by Tom Danley and Paul's DIY versions. They sounded great.

Report at StereoNet Australia.

The Australian Audio and AV Show

October 21st 2011

Roger's Unity Horns - 21/5/2011
My second visit listening to his Unity Horn system. These are extreme-SPL setup, the horns themselves are 100+db utilising compression drivers and 8 Misco midranges.

2x Unity Horns. Real ones from Tom Danley and only two in Australia (!)
2x 18" AE woofers, ported
2x 12" woofers in bandpass configuration
1x 18" Maelstrom, sealed

The system would easily power a hall and I don't have to mention the ease of which they play loud passages.

Linkwitz Orion - 25/2/2011
A very rare chance in Australia, this is my dream loudspeakers and are the reference for Dipole speaker design. Created by Sigfried Linkwitz himself their resolution and projection is very hard to match. The reason I don't have them is the lack of $14000 (or $4000 DIY) to own one.

Ching Chung's system (Switzerland) - 22/9/2010
Ching Chung is a collector of "ultra-fi". These are esoteric and very expensive equipments. Among his collections are Halcro amplifiers ($120,000+ !), Cary amps/pre, and various loudspeakers from Martin Logans to Cain-Cain fulrange horns which he likes most.

Waveguide GTG II at Paul Spencer's - 5/3/2011
This was the second get together between waveguide enthusiasts. This time we had more waveguides, compression drivers and even a plasma tweeter!

Read the results here on Paul's blog.

DSP GTG part II at Roger's - 5/12/2010
This time I constructed an instant-switching box. We could instantly switch between any two DSP units (both 4 channel inputs and outputs). This method is much more revealing and immediate than ABX blind test.

The reference speakers were Roger's very high resolution Unity Horns. Again, I felt I could not detect differences between DSP units although some prefers miniDSP.

DSP GTG part I at Keith's - 31/10/2010
We were very lucky in Melbourne to have a population of the following DSP crossovers to test:
- Behringer DCX2496 (Paul Spencer)
- Behringer DCX2496, modified (Cybermurphy's)
- Behringer CX2310 (Keith's)
- DEQX HDP-3 (Keith's)
- MiniDSP (Gainphile's)

The loudspeakers used were Acapella Violons powered by Cary monoblocks and SGR amplifiers. Some thought that MiniDSP is the best sounding, but I could not hear any difference between any of the units (with the exception of DEQX which did not operate properly).

Craig's Jazzman
Craig lives only 5 minutes from me, and offered free leftover stuffing from his Jazzman project. I had a listen to them. These are very intricately built speakers.

Very beautiful, very smooth sound and deep bass. We had great listen of Dire Straits and Muddy Waters LP.

Acapella Violon GTG at Keith's -
I enjoyed Keith's drop-dead gorgeous setup. A pair of Acapella Violon running actively with 4 (!) Cary monoblocs.

The dynamics and presentation was simply stunning! This was the first time for me to hear horns too.

Legend Tikandi & DEQX GTG

Tiono's System (Singapore) - 20/10/2010
He is my university colleague and avvid collector of vinyl. His system consists of Sonus Faber monitors, Adcom GFA amps, and REL subs. He particularly pay attention to intricate electonic details (as electrical engineers do!)

He has since replaced the loudspeakers with Magnepan planars.

Adam Tensor GTG at Michael's - 22/8/2009
A very enjoyable afternoon listening to a pair of Adam Tensor Delta. They had sand-filled enclosure. "The Prof" is also coffee connosieur and cycling fanatic. Showed us great pics of "Tour de France".

DEQX and Legend Tikandi - 20/6/2009
I travelled to Mark's beautiful house in Emerald to listen to a pair of Legend Tikandi. These Australian loudspeakers are using the venerable Seas Excel and Visaton Ceramic-coated aluminium tweeters. They are actively driven with DEQX DSP units.


Weekday GTG - 7/12/2012
Marian wanted to hear the ultra compact S20z so I arranged a mini-GTG. Warren and David came along and Mike dropped his NaoNote for me to have for a week ! We listened to S19, Pluto clone, Warren's Linn Bookshelves, and S20z.

Waveguide GTG IV - 18/12/2011
Roger and Paul visited to measure various Celestion drivers. The driver is an excellent match to Pyle Econowave waveguide. Results of measurements at DIYAudio

Melbourne audio round-trip GTG - 27/11/2011
Paul, Warren, Matt, and Mike visited as part of a round-trip GTG. We later then went to Craig's place to hear the Jazzman and then to Trevor's to hear the Zingali horns. Report here.

Olivier & Inken from 2pi-online.de - 29/3/2011
Dropped by from Germany on their Aussie holiday to listen to S16, S15, and Pluto.

Olivier posted his impressions of my speakers on his site. His observation and preference is very much similar to mine.

Waveguide shootout I - 16/1/2011
A group of waveguide type speakers enthusiasts got together in Bonbeach for the 1st round of shootout. We had various compression drivers and horns of various shapes and sizes from D220Ti, DE250, BMS, Econowave Pyle, Oblate-spheroid, etc.

Paul Spencer had written about this event in his blog, he clearly explain how to read sonogram plots, etc.

Dipole - Omni Show & Tell - 27/6/2009
Paul Spencer and I arranged GTG in Melbourne to present dipole and omni speakers. I had my s8 and analogue-driver Pluto clone, and Paul presented his Vifa based dipoles (with Rythmic subs).

At the end of the day the visitors were most impressed with Pluto clone!

Paul's visit

Selwyn's visit

JPHoward visit