As the title suggests, how do i built a decent sub?
I have no idea how to do it and what the components for this cost, so fire away
Funny you should say this, but I've been investigating this for some while and have started down the DIY path by investing in the power tools necessary to do the job.
This is possibly not the answer you wanted, but without the right tools, good intentions are a non starter.
I tend to buy tools on principle of "buy the best ones once and thus have bought a
Trend Plunge Router and a
Makita Circular Saw.
I work in construction and these are the 240v equivalents of the tools that several professional tradesmen recommended for the relatively light duties an amateur sub builder will demand. The Trend router in particular was a recurring recommendation. DIYers may have another idea or two, but I'll stick with the pros.
After that, if we consider that MDF is the material of choice for the box and that you will finish it (veneer, paint, whatever) however you choose, then the only important bits left are the size of box you can accommodate, the optimal driver to install in it and the amplifier to drive it.
That bit is tricky and can only be solved with intensive Googling and visits to DIYAudio and their search function. Post your requirements here (dimensions, budget, etc) and people with more experience than me may link to useful threads.
Russell