In Stock. 45 Day Lowest Price - 100% Satisfaction Guarantee. The BM9S subwoofer is intended to operate with the BM series monitors. It is extremely well-suited for that extra punch to the bottom in setups where space is limited. The BM9S delivers a clear, crispy and surprisingly powerful punch when you take its almost diminutive size into account. The BM9S will complement stereo and multi-channel monitoring equally well and when daisy-chaining of subwoofers is needed, it sports a low level LFE input/output. For significant control and enhancement of the general performance, the BM9S is a closed cabinet type.