Soliloquy-TA (Tang Band W5-1685 with HiVi RT1C-A)

tang band W5-1685 HIVI RT1C

the TA Series

AmpsLab is proud to announce our first Time-Aligned speakers, the Soliloquy-TA. It doesn’t use electronic delays. It is fully passive. Time alignment is by horizontal displacement of drivers.

Soliloquy-TA vs Soliloquy

The Soliloquy-TA is a compact 2-way bookshelf version of the Soliloquy. This bass reflex has an internal volume of 13 liters whereas the Soliloquy is a slim tower of 25 liters. The second major change is the HiVi RT1C planar tweeter replacing the Seas 27TBFC. Thirdly, the tweeter now reverts back to on top of the W5-1685. In the Soliloquy, the tweeter sits below the mid-woofer. Due to these changes, the Soliloquy-TA tonal character is vastly different from that of the tower version.

Tang Band W5-1685 RAW Frequency Response

W5-1685 RAW FREQUENCY RESPONSEFig 1 – W5-1685 RAW Response. Mic at 1 meter, tweeter axis, 1/12th octave smoothing

The Black plot in Fig 1 is the RAW response of the W5-1685 in a 13 liters box with a baffle width of 8.5″. Due to room limitations, measurements below 400Hz are Nearfield.

The extension of the response is admirable. Furthermore, it doesn’t exhibit the severe cone breakup that some mid-woofers do. With a response like this, the W5-1685 will have no problems crossing over to the RT1C at 4kHz.

Crossing to HiVi RT1C-A Planar tweeter

Fig 2 – Tang Band W5-1685 Low Pass and HiVi RT1C-A High Pass Response

The plots in Fig 2 show the acoustic slopes of the W5-1685 and the RT1C. The two drivers are crossing at 4kHz, which is a good sign. The RT1C crossover cannot be below 4kHz. If so, distortion will occur.

Soliloquy-TA Frequency Response

SOLILOQUY-TA Frequency ResponseFig 3 – Summed Response of Tang Band W5-1685 and HiVi RT1C-A

The summed response of the W5-1685 with the RT1C tweeter is in Fig 3. No smoothing from 500Hz onwards. In this plot, the two drivers are actually time-aligned.

Time-Aligned Reversed Null Response

Fig 4 – RT1C wired in Reversed Phase

The proof of time-alignment lies in the response when the RT1C is wired in Reversed Phase. In the Violet plot in Fig 4, the tip of the null is -40dB below the fundamental. This indicates that the W5-1685 and the RT1C are time-aligned. The response looks exactly the same when I time-aligned the RS180s with Dayton H812 horn lens previously.

the Sound of Soliloquy-TA

I mentioned at the start of this article that the Soliloquy-TA is tonally different to the Soliloquy. Due to the smaller volume, the Soliloquy-TA is not bass shy in Full Space. Though the bass is louder, it is not boomy nor does it bleed into the mid-range. It has great dynamics and definition.

As for the mid-range and treble, I can find no issues. Voices are not shouty or too forward in the soundstage. The treble is excellent. The RT1C planar has a finesse that dome tweeters just don’t have.

Crossover Values & Box Dimensions

If you like to build this project, kindly send me a mail for a free copy of the crossover and box dimensions.