Project Time: 1-8 hours
Project Complexity: Hobbyist
Project Cost: $100-$500
Dayton Audio ND91-4 3-1/2″ Aluminum Cone Full-Range http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-224 Beston RT001A Ribbon Tweeter http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1060 Peerless 830878 3-1/2″ Passive Radiator http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1060
The enclosure is the Knock-Down MDF 0.04 ft³ Micro Bookshelf Speaker Cabinet Pair. http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-7060 Instead of porting I opted for the Peerless 3.5″ passive radiator with fs of 29hz, with the active drivers fs being 65hz this gives a well needed subtle bump in the lower end of the spectrum.
The crossover is a 5khz high pass in series with a 2 OHM 20watt Resistor on the tweeter crossing it at around 5Khz and giving it around 8ohm impedance. this is in parallel with the 3″ full range that has a .25mH coil knocking the top end off at around 5Khz with a soft 6db roll off.
IT couldn’t be simpler, You cut the right sizes holes in it then glue and screw, videos are available for the knock down kits on youtube. The tweeter doesn’t need a large hole just 2 wire holes as it is surface mount. Do not screw this tweeter down too hard ad the back is slightly raised and you will deform the ribbon if you do(learnt this the hard way trying to get it flush)
This was very successful if not for the most important reason, it was allowed to come into the lounge room 🙂 Apart from that, the Frequency response is there, its small, and the clarity of this thing is unbelievable, i was dubious about a $30 Ribbon but it easily competes with those 4 times the price. And when all the reviews about the daytona 3″ full range say its surprising how much bass this little fella puts out, they’re not wrong. I’m thinking about building more for the hole surrond set up they are that good and leaving the OBs on there own stereo amp for music.
About The Designer
Rob is a long time audio and electronics professional in the TV and radio Broadcast industries, in engineering,audio mixing and communications.