nakamichi SP-W124S box specs??
 

just picked one of these up but can't find any box specs for them any info helps but preference is to ported

I ran it through winisd and it definitely prefers a ported box, ebp 95.5 indicates this as well as the frequency response. I liked the response curve using 1.5-2.0 cubic feet tuned to around 32 hz. For a 2.0 cube box net (after speaker and port displacement) a 4" x 13.5" port will tune to 32 hz. In a 1.5 cube box a 4" x 19" port will tune to 32 hz. At full power, 350 watts, the port air velocity is under 35 m/s (this is good and should prevent most port noise...if you want to ensure no port noise (chuffing), you can use a larger diameter port or a slot port, but the length will have to be recalculated, and will be longer. Cone excursion is under 10.5 mm if you use a 25hz, 2nd order (12db/oct) subsonic (high pass or infrasonic) filter, and group delay is good. If space is an issue, a 1 cube box tuned to 34hz will work, but it will not go nearly as deep and output is much lower, but will sound good.