Harman Kardon 2" speaker enclosure transmission line design

This design is specifically made for 2" drivers made by Harman Kardon, they are widely available on the usual sites, and tend to be cheap. using 2 of them in parallel gives a 2 Ohm load, that is driven by a class-D amplifier (ideally something with the TI TPA3128 chipset) PCB design for an amp + USB soundcard are available as well.

Assembly is simple, loosely fill enclosure with wool for speakers, and use wooden dowels to attach both sides together. add hole for a cable and then either use good quality double sided tape or silicone glue to air-tighten the enclosure. the wooden dowels are actually sticks from large size cotton buds, cut sideways to make them sharp, and i use a steel dowel tool to slightly widen the holes to get a good tight fit. some force is required to force the two sides together, but once sealed, its stable and durable.

Sound Quality: You will be surprised how good these sound, the sound is crisp and tight, bass is very good for the speaker size and its very nice to listen to, i use these as computer speakers, and they regularly surprise me with how deep they can go, for the money its an excellent deal!