Hello, a friend of mine would like to install two 15-emphaser Neo SPLs in a band pass. The whole box should then be in a BMW M5. The port should play through the ski bag. My question is about how much volume we have to expect. Does someone from here have experience with the woofers and could help us to calculate a suitable housing? Music taste is actually everything. The box should be a compromise between level and draught. TSPs from the woofer: fs : 31Hz qts : 0,46 Vas : 89,5 xmax : 22,5mm I have not found any more data. But you should be able to count on that. I posted the same already in the dbdrag forum, but there came not so much resonance hope here can help us more people. For answers we would be grateful Greeting Funtiger83