Hi everybody, I am newish to home audio, but I am very good at car audio and I had the Idea of having a go at making a subwoofer box for an old car sub to use in my room for a bit of bass, can any one help me with the box design because I have tried WinISDWinSPK and have not had much luck getting a box that plays down to 20 ish. (I think the sub woofer driver is not very good low down) here are the Paramiters for the sub. Technical datasheet Impedance (Z) 4 Ohm Frequency range 35–3,000 Hz Free air resonance (fs) 35 Hz Crossover frequency (12 dB/oct.) (fmax) 2,000 Hz Peak music power 450 W Power rating 150 WRMS SPL (1 W/1 m) 93 dB Cms suspension compliance 0.45 mm/N Mms moving mass 44 g Qms mech. Q factor 3.84 Qes electrical Q factor 1.16 Qts total Q factor 0.89 VAS compl. equiv. vol. 180 l RDC DC resistance (Re) 3.7 Ohm Voice coil ind.(1kHz,Le) 0.4 mH Voice coil diameter 39 mm Voice coil former aluminium Air gap height 5 mm Force factor WxL 5.6 Tm Eff. cone area 531 cm² Magnet dioameter 125 mm Magnet weight 30 oz. Mounting cutout ø 282 mm Mounting depth 130 mm Dimensions ø 305 mm Weight 2.4 kg Am I wasting my time and materials with build a box for this sub (size of box does not matter e.g. 1-8 CF is possible by me.) I would like to have a box that plays down to abot 25 hz or lower if possable. Can anyone help me???