Hi is there anyone here can help with box design?
I'm looking to make a 4th order box 110cm wide x 148cm long, question is how high, what size chambers and port size to tune it to 33Hz?
I will be using 25mm ply and 2x 15" L7's if that helps
I think you should try diyaudio.com (subwoofer or caraudio forum) for full help. They're probably gonna ask for the Thiel Small parameters, so be prepared. Coincidentally, with a 4th order BP, the low end is tuned by a closed chamber (without ports), the ports tune the upper part of the spectrum (around 80 - 100 Hz) and a port surface area that's 1/4 of the drivers combined Sd is a good starting point.