That's six months now I use two boxes of this type.
These two boxes are driven by an amplifier QSC PLX Series.

The bass is warm, deep and round. it does not bleed, it does not blow, in short, is very accurate.
The bandwidth is 40 Hz to 300 Hz with a cutoff frequency of 100 Hz recommended (That's how I have filtered with the processor CT1 brand).
RMS power is 400 Watts.
Sensitivity: 97 dB / 1W/1m
Maximum sound pressure: 129 dB
Impedance: 8 Ohms
The HP is 15 inches.
Remember, however, that this box does not have a crossover and it is the blow intended for use in bi-amplification with an active filtering.
For the filtered version liabilities, it will take SUB15F.

Small (53 X 47 X 46 cm) and lightweight, this little box is a marvel.
The price is 560 Euros per piece costs Sennheiser or 669.76 Euros.
Finally, if it again, I will take it without any problem and without any hesitation.
But I would still curious to try the SUB18R which is his big brother. If it's in the same spirit, it must be something!