S19 4-Way Dipole Radiator

S19 dipole-radiating speakers

The quality of dipole loudspeaker accuracy is improved by using a small 5" midrange driver from 400hz to 2khz. The tradeoffs are higher complexity and more difficult design process to take account of polar response changes.

Push-pull dipole subwoofer section

The dipole subwoofers are w-frame to benefit from vibration cancellation. They are long-throw Dayton RSS256HF-8. The woofers are Seas Excel W22EX001 and W15CH001, and the Tweeters are Seas DXT.

The w-frame sub's cancellation topology really works. It's quite mesmerising to see the drivers pumping air furiously yet there is no cabinet vibrations. Seen below is how clean they are crossed at 120hz. The subs are -3db at 20hz.

Please follow the build progress at HTGuide Forum.

Topology: Active 4-way
Radiation pattern: Dipole
Directivity: Dipole from 20hz - 2khz then forward-directional
Frequency response: 20hz - 20khz.
Sensititivity: ~88dB
Dimension (H, W, D): 117 x 31 x 31 (cm)
Amplifiers: 8-Channels required (4x stereo amps)
Crossover: Two 2x4 MiniDSP

Update 12/3/12
Outdoor measurements of early prototype to investigate the frequency response of small midrange.

Update 25/3/12 - Seas Excel W15CH001 received and tested
Update 2/4/12 - First prototype of S19M (magnesium)
Update 20/4/12 - S19/MT - Titanium dome Tweeters (Vifa DQ25) used for improved resolution.
Update 31/8/12 - Started the final design of the cabinet and wood choices
Update 2/9/12 - Cabinets completed
Update 23/1/13 -  I have been living for quite a while with these speakers. I havent' had any desires to build something new !
Update 28/6/13 - Frequency response in the critical 1khz-20khz region showing ±1db (XT25)

Update 13/9/13 - The 4x Dayton Reference subs requires large power to drive them to xmax.

Update 21/7/15 - Amateur video of S19