The Pine Box (desktop speaker)
My first speakers were built by finding wood at the hardware store that I had only to cut to length (and somehow cut a hole of roughly the right size). On my desk I am using a pair of speakers (with updated drivers) that I built like that some time ago.
I wanted to investigate a way to upgrade these speakers. I'm calling it the "Pine Box" for now anyway because it's possible to build it with 12x140 DAR pine from Bunnings etc.
It's been awhile and looking around, some new drivers from Tang Band looked... really interesting. For a desktop speaker, small is good, high output isn't relevant. Here's a couple of concept designs, first, tall and thin:
And here wide and short:
I think I like the short one better... what about you?
PS. I know a 3.5" subwoofer sounds ridiculous, but these new drivers seem to have actually managed to meet the promise of a "micro subwoofer." As long as low sensitivity and output is OK. Which I think it is for a desktop. Graphs later.
Comments
Here's the modeled response of the subwoofer, purple is sealed, red is ported, green is with passive radiators. The response of the ported enclosure is phenomenal but the ports are too long to fit in the box (or too small to not chuff). The PR version has an f3 of 42 Hz which is still pretty good.
This be the sub:
http://www.tb-speaker.com/detail/1230_04/w3-2088s0f.htm
http://www.parts-express.com/tang-band-w3-2088s0f-35-rbm-micro-subwoofer-4-ohm--264-951
OK so I think I'm going to try one of these for the fullrange driver:
http://www.madisoundspeakerstore.com/approx-2-fullrange/vifa-ne65w-2-fullrange-driver-4-ohm/
Need to find a tube of about 60mm ID for the "enclosure."
Hah hah - http://www.officeworks.com.au/shop/officeworks/pack-post-send-mailing-tube-60-x-420mm-comts420
Guess I'm running out of excuses not to order the parts from PE....
If minimizing diffraction ripple is a goal, the baffle for the top driver needs to be a lot bigger than I expected. Something like this:
In red below, the predicted response due to the baffle. It occurred to me that the top driver could also be run "open baffle" and the green curve shows the baffle response in that case.
Tall & thin takes up less desktop area and is easier to make. As is a one piece baffle with smooth lines...
I think ye be right begorrah
Still waiting for PE to get those little passive radiators in...
http://www.parts-express.com/peerless-830878-3-1-2-passive-radiator--264-1060