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Tjatse TM & Voxel - 2.1 home theatre system

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  • Tjatse TM & Voxel - 2.1 home theatre system

    Project Level: Intermediate

    Project Time: 10–20 hours

    Project Cost: $250

    Click image for larger version  Name:	tjatse_voxel.jpg Views:	2 Size:	51.7 KB ID:	1417677

    After I got a hold of a Lepai LP210PA plate amplifier I wanted to make a small 2.1 system. I have always liked the look of asymmetrical baffles, so the design of the Tjatse is based around that idea. I used the Dayton DSA115-8 for the woofer and the Peerless DX20BF00-04 for the tweeter.

    A little information regarding the name of the speaker:
    Tjatse is a jötun in Norse mythology. He is the father of Skade whom is unhappily married to Njord.
    These speakers are paired to a front firing sub-woofer based on Paul Carmondy’s Voxel design.

    The cabinets are constructed from 12 mm (0.5 in) Baltic birch plywood. All joints are rabbeted except for the front baffle. The baffle for the monitors measure 14,5 x 22 cm. The volume of the enclosure is 3,2 liters. The baffle for the monitor and the sub-woofer have a 5 mm round-over on the sides. The cabinets are lined with acoustic felt and stuffed with polyester.

    I decided to paint the front baffle black on both the monitors and the sub-woofer. The rest of the cabinet was given several coats of beeswax and then polished.

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    The crossover gave me a bit of a headache to design. I wanted to use a third-order electrical filter for the tweeter and a second-order electrical filter for the woofer. However, I never managed to match the phases with this topology. So in the end the I ended up using a second-order filter on both the tweeter and the woofer. I would have liked a steeper slope on the tweeter. I placed 0.22 uF cap parallel to the coil on the low-pass filter to control the cone breakup of the woofer (a trick from the Overnight Sensations).

    Click image for larger versionName:	frequency_response.pngViews:	1Size:	44.4 KBID:	1417676

    The monitors are ± 3 dB and measure almost flat except for a small peak around 9 000 Hz. I have not added any BCS to the circuit since the speakers are design to be placed close to a wall. The frequency response is near-field and baffle corrected below 400 Hz in the graph. The monitors are connected to the Lepai plate amp which has a 100 Hz built-in high-pass filter. The sub-woofer is has its low-pass crossover set to 120 Hz. This setting would of course be adjusted to suit the room in an actual setup.

    This was a a fun project to build. Any comments or questions are welcomed. If anyone would like to build these, I can post the CAD drawings with measurements for the baffle.
    Last edited by solbero; 07-25-2019, 05:49 AM.

  • #2
    Nice job, nice writeup. I finished my S2000 TMs and MTMs Baltic Birch cabs just like yours. Attractive and simple to execute.


    • #3
      Originally posted by djg View Post
      Nice job, nice writeup. I finished my S2000 TMs and MTMs Baltic Birch cabs just like yours. Attractive and simple to execute.
      The S2000 is a great little speaker. I built a pair of them for a family member, and I was really impressed with the sound they put out of such a small enclosure. I also agree with you on the finishing. If the plywood is of a good quality it can be finished really nicely. I have never tried veneering any of my speakers since veneer is prohibitively expensive where I live.


      • #4
        Here are the CAD drawings if anyone would like to build these speakers. Built in 12 mm birch plywood. All measurements are in millimeters.