2. Phoenix Gold, Aura to name a few. Kung masipag ka, hanap ka sa KAC ng mga 2nd hand subs

3. MDF is recommended because it is rigid and hard, which in turn produces good sound quality. Ang tendency ng plywood is mag fflex under high load. Stick to MDF, di naman malaki ang price difference, also use screws instead of nails para mas matibay ang box mo.

4. yup but its more complicated than that, pagawa mo na lang sa labas, medyo complicated ang calculations ng ported box not like sealed mabilis lang gawin. Ported box will provide you with more bass but less definition, in short malakas yung bayo pero mas bawas ang definition ng mids kasi masasapawan sa lakas ng lows. But it all depends on the port your going to use -> Slot, tube, etc.