This design is a Transmission line using

Woofer：Accuton (aka Thiel&Partner) C2-220/T6,
Midrange：Accuton C2-79/6,
Tweeter：Accuton C2-12/6.


Design: Transmission Line (TL) is 1.3m pipe with 5L box. A pipe end is opened front cabinet, and its area is same as driver's effective area. Polyfil was densely stuffed at the initial part of the pipe, then density of polyfil is decreasing towards pipe end. Acousta stuff is used in the 5L cabinet, right behind the driver.


Electrical network: Bass driver (Accuton C220/T6) has peak at 3kHz by about 15dB-20dB. I think that the ceramic cone driver must be optimally tuned for high-quality low frequency response. Because I believe that the metal driver is useless in high frequency, I determined about 600Hz of cutoff frequency and use a 2nd order filter. On a case-by-case basis, I may need to use a sepecial notch filter. In Mid driver, I used 2nd order filters. The cutoff frequencies are about 1000Hz and 3000Hz. In Tweeter driver, I used the 2nd order filter. The cutoff frequency is around 4000Hz. 3dB attenuation is best in this crossover design.

The loudspeaker was measured by using Cliowin, The measurement results of the loudspeaker are available here.

Patent lists of the other TL
-United States-

US02031500

US03834485

US03923123

US04128738

US04224469

US04439644

US04482026

US04837837

US04942939

US05343535

US05373564

US05815589

-Japan-

Hei06-54392

Hei10-28299

-Global-

GB2250157

-A British province in North America(Canada)-

02171118

-Deutschland-

DE4307655

You can find more information at:The Patent Office(esp@cenet)