Dr. K’s MTM – Tower Version

Dr. K’s MTM – Tower Version


Designer:
henhez

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
This is a version of Dr. K’s MTM, in a ported 41″ floorstanding enclosure

Design Goals:
I wanted to build a furniture quality speaker that would rank highly on the WAF. I also wanted to use paper-backed real wood veneer for the first time.

Driver Selection:
Drivers are identical to Dr. K’s MTM.

Enclosure Design:
Enclosure is made of 3/4″ MDF with three window pane braces and roughly 1/2″ roundovers on the baffle and rear.

Enclosure Assembly:
I wanted to build the entire cabinet without using screws, nails, biscuits or any other fastener except wood glue. I cut a rabbet on all four sides of the baffle and rear panel so they would slot right in.

Crossover Design:
The crossover is identical to Dr. K’s MTM.

Tips & Tricks:
You can use regular Titebond to apply the veneer. I rolled a thin layer on the cabinet and on the veneer then let it dry for roughly 30 minutes. Then I used a dry iron to melt the glue and apply the veneer, see pictures.

Conclusion:
I am very pleased with the way these speakers look and sound. It took me nearly 6 months to finish them but, it was worth every minute!

About the Designer:
I’ve built half a dozen projects from Parts Express but I’ve never made anything that looks and sounds as good as these!

Project Parts List:

Dayton-Audio RS180S-8 7″ Reference Shielded Woofer 8 Ohm
Dayton Audio RST28A-4 1-1/8″ Reference Series Aluminum Dome Tweeter 4 Ohm
Dayton Audio DNR-7.0 7 Ohm 10W Precision Audio Grade Resistor
Mills 2 Ohm 12W Non-Inductive Resistor
Dayton Audio DMPC-2.2 2.2uF 250V Polypropylene Capacitor
Dayton Audio DMPC-12 12uF 250V Polypropylene Capacitor
Dayton Audio DMPC-15 15uF 250V Polypropylene Capacitor
Dayton Audio DMPC-20 20uF 250V Polypropylene Capacitor
Dayton Audio BPA-38NI HD Binding Post Pair Nickel
#255-198 Jantzen 0.025mH 18 AWG Air Core Inductor
Jantzen 0.33mH 18 AWG Air Core Inductor
Jantzen 0.70mH 18 AWG Air Core Inductor
 #255-404 Jantzen 0.33mH 15 AWG Air Core Inductor
Jantzen 1.2mH 16 AWG Copper Foil Inductor
Paper-backed Sapele veneer

9 Comments

Add yours
  1. 1
    Robert

    Very nice work. I know what you mean about the sound of the MTM configuration./ In the nineties, I built such a system using Focal drivers. The MTM consists of two Focal 5K013L and the Focal TC90 tweeter. This section is high pass filtered at 125hz, the lower section is a pair of 15 inch floor firing woofers loaded in a pair of 7 cu.ft. ported enclosures.

    Again, very nice work. Congratulations.
    Robert

    • 5
      henhez

      Sorry for the delay! I don’t get notifications. The boxes are 41″H x 9″W x 12″D. However, the Baffles are 41″ tall and the rear panels are only 39.5″ to achieve a roughly 11 degree tilt. I think it adds a nice aesthetic (and perhaps sonic) benefit. I have drawings of the box construction. If you give me your contact info I’d be happy to provide them.
      Here is the info I used to choose the port (from the original Dr. K’s post) I did the 4″ option, I believe they were 5″ deep:
      “A larger “extended bass” version of the tower would be approximately 1.7 cu. ft., tuned to 35 Hz via a 3″ x 6-1/2″ port. Again using 3/4″ MDF, this cabinet would measure roughly 9″ wide, 40″ tall, and 12″ deep. Note for these larger cabinets, a 3″ diameter port is preferred, and a 4″ port is an option if you are going to be running the speakers at high power.”

    • 7
      henhez

      I wish I could but I honestly haven’t heard enough speakers to make a comparison. They sound good but you can tell they are lacking in the lower registers. Maybe I should have gone with the 3″ port instead of the 4″.

  2. 8
    Kelly Graves

    Beautiful!! I built a pair of Wayne J”s Eros in mid 90″S. They used a pair of Vifa premium 7″ woofers and a
    Scan speak D2905-9500 in each tower with series crossover, and were like Dirk Diggler. They could play soft or loud and just rocked out and made me smile. I miss the 90″s, my old speakers and my redhead :-). But I wouldn’t trade Class d and Spotify Streaming for any old technology, period. Enjoy….

  3. 9
    K.G.

    Beautiful!! I built a pair of Wayne J”s Eros in mid 90″S. They used a pair of Vifa premium 7″ woofers and a
    Scan speak D2905-9500 in each tower with series crossover, and were like Dirk Diggler. They could play soft or loud and just rocked out and made me smile. I miss the 90″s, my old speakers and my redhead :-). But I wouldn’t trade Class d and Spotify Streaming for any old technology, period. Enjoy….

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