Alright, so here'* the deal. I want to build a nice sound system in a very small package. Not looking to spend a fortune. I want to build a set of very compact bookshelf speakers with a great frequency response. This will be a gift for my father in law who'* birthday is coming up in a month, who also just finished a difficult and stressful treatment for lung cancer. He'* on his way to recovering now.

For those who don't know, the basement bedroom (which is easily over 500 sq ft) used to be his office, but with the lung cancer, he moved his office to his bedroom. He gave my wife and I the basement bedroom to renovate and live in as they asked us to stay with them for a while to help him with anything he might need since he'* an IT consultant and I'm an IT engineer. Down here he used to have a badass sound system using my two Polk RM40T'* (google them) and a 12" sub. He used to blast it all the time and play his classic rock for the whole house to hear. Well, he can't do that anymore, and I feel bad since warmer weather is coming and we'll probably be here a while longer.

So, given he doesn't have much space up in his bedroom office, I wanted to make him a set of speakers that will blow him away but be small enough to fit on his desk.

Here'* the plan.

Midbass Drivers
The heart of this system, two 4" midbass drivers that would be better classified as full range. Capable of reproducing 60hz-10k hz.

http://www.parts-express.com/pe/psho...number=290-212


This is a larger version of the Aura NS3 3" driver that packs an insane punch for a 3" speaker. People have built boxes and tuned them down to 40hz successfully. Very large excursion for a 4" driver, and good power handling. Best of all, cheap. I will be using 2 of these per cabinet.

Fast forward to 1:42 to see what these can do: http://www.youtube.com/watch?v=LUNsxdyPnyM


Tweeters
Since the midbass drivers aren't exactly full range all the way to 20khz, I opted for a "helper" tweeter to complement them.

http://www.parts-express.com/pe/psho...number=275-030

Don't let the price fool you, these sound quite amazing.



Binding Posts
'nuff said
http://www.parts-express.com/pe/psho...umber=091-1250



Capacitors
2x
http://www.parts-express.com/pe/psho...number=027-408

10x
http://www.parts-express.com/pe/psho...number=027-400


For making my own high pass crossovers for the tweeters. I will add the larger one first, then test while adding one of the smaller ones one at a time in parallel until the tweeter sounds too hot, then back off one. Simple.


Acoustic Foam
http://www.parts-express.com/pe/psho...number=260-516

Hope the thickness won't matter. I was supposed to get 1/2" but accidentally got 1-1/2".


Port will be built using 1" ID PCV at 113mm length.


Boxes will be 6 liters of volume each, which comes out to .21 cubic feet. I'm going to try for thinner, taller cabinets. Undecided on what material to build these out of. I still have a lot of 3/4" MDF remaining from a previous project, but that'* likely going to be too thick.

http://www.taydaelectronics.com/

andrei, you MAY want to check out tayda for a wider array of caps, and likely at a lower price, even though from the looks of it, they're only drops in the bucket already.

Yeah, the cost was pretty low, and I figured I'd order them from the same place as everything else to cut down on shipping cost.

i'll admit, i didn't check the prices of the woofer or the binding posts, but yeah, this looks to be a pretty low buck setup already.

i know i'll be watching for results...

I'm playing with WinISD right now and I was previously recommended a 6 liter enclosure with a 1" port at 113mm length, but the frequency response isn't as great in the lower end as I would have hoped with those figures, so I might go up to 8 liters. I love this software.

Looks like youve been shopping at PartsExpress, looks like a sweet build, Dayton makes quality stuff

Bit of a change of plans. After modeling these drivers in WinISD a bit more, I've discovered their potential. I've also been on diyforum and the partsexpress forum reading about these drivers and people are getting insanely good sound out of them. They're tuning their ports to 38hz. Apparently these have a 10mm peak Xmax and at 32hz they only it 8mm. Absolutely incredible amount of bass from 4" midbass drivers. A couple of guys on the forums had to check and double check their subs when testing these out to make sure they were off because of the amount of low end bass they produce.

In any case, the new plan is for slim floorstanding towers. Luckily for me, someone has already done it and I'm basically going to replicate this. I punched in the volume and port tuning numbers into WinISD and they will be nothing short of spectacular.



Furthermore, I'll be building some proper crossovers for these. Crossed at 3.3khz, these are said to have excellent staging and a very flat response.



Images compliments of partsexpress.com forums.

wow very interesting! I wish i could hear them in person!

Updates? Also, where can others learn to do such cool things?

Keep the awesomeness coming! Also, make sure that the speakers don't get so huge that they'll no longer fit into the bedroom.

Just got the 2.5" drivers and the Lepai amp in. Apparently there were a lot of quality control issues with the previous versions of this amp, mostly due to an incorrect power adapter. I plugged this amp into one of my Polk Audio Montor 40'* (dual 5.25" drivers) and turned it up. Absolutely amazed at how much power, bass, and clarity comes out of one of these.

I then hooked up these drivers in free air. From a start, I'm they like to over-extend their excursion and start distorting, but part of that is the break in period. These will *require* sealed enclosures. I tested them quickly by placing them on the mouth of a similarly sized cup and pressing them down. Amazing bass response. These will make very nice cubes.

The rest of the crossover parts came in, but I'm still waiting on the new drivers themselves. Also got the 2" ID double flared ports for the floorstanding drivers. Very sexy. Pictures to come.