The Voice Sub is a horn system designed by Bernd Timmermanns with a P.Audio WN-10 R as driver.

It's a front loaded bass horn. The woofer is placed invisibly within the horn, in a sealed cabinet. Inside the subwoofer, in front of the sealed cabinet a pressure chamber is situated ending in a horn.

The design is relatively simple since only a few angled boards need to be cut.

The speaker may be driven by a subwoofer amplifier or any other type of amplifier; the frequencies below 35 Hz, however, should be cut off to ensure that the woofer doesn't struggle too much.

Suitable and affordable is e.g. the Reckhorn A-402, available on the Internet at www.reckhorn.com.

An excerpt from the Hobby HiFi review

"As a practical implementation we combined the bass horn first with The Voice 3 from Hobby HiFi 3/2008 and then with The Voice Kompakt from issue 3/2009. Especially the larger “3” shows such an acoustic stability that the usage as full range is no problem at all. Even though it would have been possible to increase the dynamics by employing the high pass from the satellite filter of the A-402, we liked the non-filtered “The Voice 3” in conjunction with the sub, cut-off at 75 Hz (cut-off control on the A-402 to the left), just a little more. The phase control needs some experimenting, though. A recommendation is not possible since the positioning of the speakers plays a major role. Satellites and subwoofer merged into an integral whole, while the bass performed brilliantly. "The Cost of Freedom" by Marla Gien puzzled with the well known ferocious bass, which was remarkably clear on top of the richness. And the introductory bass beats of the “Hotel California“ live version (The Eagles: “Hell Freezes Over“) displayed a sublime vehemence – first class. Listening to the "The Voice Kompakt", the high pass filter of the A-402 was set to the one o'clock position representing a cut-off frequency of 115 Hertz.

We had sealed the bass reflex port with damping material. The cut-off frequency control was set to the 11 o'clock position. Again we had to experiment with the phase control until it was spot-on. In General, this trio was, despite the considerably smaller satellites, a match for the first combination. Once more, Marla Glen puzzled with a fat but clear bass, and again the Eagles made the listeners wince at the introductory bass beats. Only at hefty levels the larger “The Voice 3“ showed her superiority."
 

Our kit consists of

Kit without cabinet, price per speaker - not available