Obviously, we use the same SB Acoustics Aluminum drivers that Buchardt, Revel and others are using, since they are extremely low distortion designs (by former Scan-Speak masterminds). I even think it’s the best driver in its class, except the new Purify drivers (which were not available then). We decided against a ventilated cabinet, because in a small 2-way design it’s very difficult to get a clean midband even with passive radiators. Also designing a noiseless and resonance-free port is not that easy. So, went with a closed cabinet and to meet our SPL goals we had to put in three (!) SB drivers and a lot of amping power. That was a quite expansive decision but gave us the best results. The two drivers in the back are used to create a cardioid radiation pattern which extends the constant directivity to apx. 250 Hz. Below that frequency all three woofers do play bass in parallel (in phase). Since we have full three channels per speaker, we can apply different radiation patters (right now there is no-cardioid, supercardioid/135° and hypercardioid/180°).

Roland