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Having fun building small desktop 2.1 systems!

I think Tom Z. posted something very similar on PETT about having fun building smaller desktop systems...

Recently I've built a couple small desktop 2.1 systems. One system for our home computer and one for my at work station. Right now we are listening to our home system which uses a single ND91 driver per side in 1 liter sealed boxes with some stuffing. I measured them in place and came up with a passive RL contour network. For an amp I bought a Fosi Audio ZK-TB21 amp module. I installed this amp module in a $1 cigar box with a reclaimed 20 Vdc/3.8 Amp laptop brick SMSP. For the subwoofer I built a 4.2 Liter ported box tuned to 50 Hz and installed a ND105-4 woofer. Holy Moly! This little system is rocking out our entire family room, living room, and kitchen with some great sounding Christmas Jazz music! Great fun! Merry Christmas everyone!



  • Stupid high fun factor!

    Don, Donno, or "Hey you" all work for me, But never "Mr Johnson"
  • Is it too late to ask Santa for some pics?

  • You're only lacking a 500uF cap per side short of being my PC project. (ND90-8/ND91-8/Aura NS3-193-8A)

    Still, yes- these itty bitty things can be quite fun!

  • I mostly have the parts to build a couple 2.1 systems. A pair of Tang Band 6.5" subs, one Dayton 2.1 amp and one Chinese 2.1 amp (like the PE/Lepai but about $20 cheaper). Just need to decide on the "2" part. Honestly, I might just shop around and see what 3-4" commercial speakers I can find and modify.

    I have a signature.
  • @Wolf said:
    You're only lacking a 500uF cap per side short of being my PC project. (ND90-8/ND91-8/Aura NS3-193-8A)

    Still, yes- these itty bitty things can be quite fun!

    I tried the 90 and the 91. The 91 sounds and measured much cleaner. I also modelled with and without a 500 uF cap and since this 2.1 amp has a HP at 150 Hz it didn't really do anything, so I left it out.

  • @kenrhodes said:
    Is it too late to ask Santa for some pics?

    Yeah, too late for Santa.... but I'll hook you up:

    These 2.1 monitors are ~1 Liter sealed boxes that are completely full of fiberfill, not tightly packed. The baffles are solid red oak and the 1/2" birch ply cabinets are veneered with cheap, Menards, cherry that was left over from my in-laws sound bar project (2 years ago?).

    These little drivers are the ND91-8 that I bought from Dan P. with a simple 2 part contour filter that tames the midrange response quite nicely.

    Here is the complete system. I still need to roll some black Duratex on the small subwoofer box. It doesn't need to look pretty as it will either hide behind my computer monitors or on the floor under my work station.

    I could have easily fit this 2.1 amp board and the laptop brick power supply in a much smaller cigar box, but: I really loved the look of this particular box, it's nice to have extra room inside to keep noisy things away from each other, and I have plenty of space at my work station for it.

  • I built this small subwoofer with left over 1/2" particle board. It uses a single ND105-4 woofer I had sitting on the shelf from about 12 years ago. Externally the enclosure is 6" wide, 14" tall, and 6.5" deep. The port is 40 mm diameter and 10 inches long, and is down firing. The internal walls right behind the driver are lined with a little bit of open cell foam. Using my measured T/S parameters the predicted F3 is right at 42 Hz.

  • edited December 2021

    You should veneer the sub with cigar paper then lacquer the crap outta it.
    Nice work dude🤘

  • edited December 2021

    I built something similar for my wife last year using the Peerless TC9 and ND105-4. Your sub is a little more stylish than mine, with those nice arches. Mine is just a tall black box under her desk. I was also surprised and how good and loud a little system like that can sound. Probably the same basic amp board in the one I bought on Amazon.

  • Very cool Craig , so your post had me out looking for a another 2.1 amp . Found one similar to yours but looks like yours is missing the provisions for BT on the board ? My shitty eye sight could be off. The one I got today has an antennae that mounts somewhere on the board , I need to look at closer when I have time. P.S. have a " 24V 6amp" PS coming , not sure if thats going to be an overkill or not?

  • The one I got does have BT onboard, but I haven't tried it.

    I first powered this board up from a large linear 24Vdc, 5 Amp power supply (harvested from a control panel scrap out) to test it out and have a listen. No noticable sound difference between that and the laptop brick I tore apart and installed here. I also had a listen with a Dell laptop brick that is 19.3 V, 3.36 A. They all sound the same through these little speakers. The speakers reach their limit and sound bad before the amp or PS fall apart.

  • Sick!

    Similar I'm loving the 2.1 amp at PE and a ps95/830946 setup. I've built two or three and they definitely surprise people.

    Love small surprising setups

  • I made one with a couple dsa90's and a dcs165 for the sub. Powered it with the DTA2.1 amp - sounds
    pretty good!

  • Zebrawood = You win!

  • Agreed. That veneer looks great!

  • Nice work Craig these little systems are pretty gratifying to build! Bkuetooth is really convenient to have as well.

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