New deep tweeters! As they like to do, the men of Blue Planet Acoustic have put us by a whole swing of subwoofers. On a proxy basis, we want to introduce you to two of them. The PR14-C and the PR10-A. Common to all new subwoofers are the passive membranes, the construction of which Tang Band has been committed to for some time. The Tang Band resonators are made of a piece of rubber and, like chassis, are simply screwed onto the case. Compared to the really cheap "Portokassen subwoofers," volume has once again been significantly reduced here, so that the construction of ultra-compact sub-satellite systems is now within reach for the self-builder. The whole thing is not extremely favorable, but the level is also much higher than for the commercially available PC speakers, for example. The PR14-C is still equipped with a conventional chassis, the W6-1139, which flank two oval passive membranes. Here you have a decent efficiency and a relatively high broadband resistance at a distance – here you have to filter accordingly via an active module. The smaller PR10-A, on the other hand, is pure subwoofer: The massive special driver, coupled with the large passive radiator, ensures a purely mechanical filter formation: Already from 70 Hertz it goes downhill with the sound pressure. But this can be passively untowed with a correspondingly large coil, so that you get a sub between 45 and 100 hertz well usable with a minimal effort. Conclusion: For applications with minimal space requirements, the ideal subwoofer.