Speaker Related Projects

   3-Way High Efficiency Speaker
(Lavoce, Dynaudio, Foster 3-way. October-2023)

   LCR MTM 3-Channel Speaker
(Three MTM Speakers in One. July-2023)

   Mini7bt - A Minimus 7 Portable Bluetooth Speaker
(Minimus 7 and Dayton Audio. Spring-2022)

   2-Way Ribbon Tweeter Speakers
(Vifa and Pioneer. May-2020)

   Transmission Line Speakers
(Aborted attempt at a TL. September-2012)

   Acoustic Research AR-4x Rehab
(Rehab of a garage sale find. January-2016)

   Infinity RS-4000 Rehab
(Rehab of a garage sale find. June-2015)

(A tall, thin, upwards firing omnidirectional speaker. May-2010)

(A powered subwoofer using a 12" driver and 15" passive radiator. Jan-2010)

(A computer speaker; redux. December-2005)

(A computer speaker in a light canister. Jan-2005)

(10" vented subwoofer in a cardboard tube, powered by a Parapix amp. May-1999)

   MTM Center Channel Speaker
(A Madisound design. Nov-1997)

   2-way Surround Speakers
(5" woofer and 1" tweeter. July 1997)

   3-piece mini system
(6" DVC bass module mated to 4" car speaker. June 1997)

   3-way Vented Floorstanding Speaker
(vented 10" woofer, 5" mid and 1" tweeter in a 4 ft tower. Summer 1995)

   NHT1259 Subwoofer
(A 12" woofer in a sealed architectural pedestal. Winter 1994-95)

   Inexpensive Speaker Stands
(Particle board, sand and spray paint. Fall 1994)

   2-way satellite
(6.5" woofer and 1" tweeter. Summer/Fall 1994)

Audio Electronics Related Projects

  900 MHz Audio Receiver
(Better use for bad headphones. Jan-2008)

  Buster - A Simple Guitar Amp
(Perfect for the beginner. Jan-2010)

  A PC-based Audio Console
(Use a PC to play tunes. Jan-2010)

  LM-12 Amp
(Bridged LM-12 opamps. Aug-2003)

(A CD player and FM tuner from spare computer parts. Oct-2002)

   Quad 2000 4-Channel Amp
(Premade modules by Marantz. May-1998)

   Zen Amp and Bride of Zen Preamp
(by Nelson Pass. Apr-1997)


  Using Wood in Speakers FAQ
(Work in progress)

   MDF FAQ for speaker builders

   Woodworking Tools for the DYIer
(HomeTheaterHiFi.com Oct-1998)

  Some Thoughts on Cabinet Finished for DIY Speakers

   Large Grills Made Easy

   Some Parts Suppliers

Other Useful Stuff

   DIY Audio Related URLs

  Veneering Primer
(by Keith Lahteine)

   How to get a Black Piano Finish
(by DYI Loudspeaker List members)

   Sonotube FAQ
(by Gordon McGill)

   Excerpts from the Bass List
(Oldies but Goodies)

DIY Loudspeaker List

  DIY Loudspeaker List Archives

3-way Vented Floorstanding Speaker - Crossover

The crossover was designed by Madisound for a $35 USD fee. They use LEAP and measured driver data to predict frequency, impedance and phase response. A schematic for the crossover is also provided. In my particular case, the AC-10 woofer could not be measured by Madisound since this is not their stocked item. Instead, the published T-S parameters were used.

I mounted all crossover parts onto a piece of 9x12 inch peg board. Inductors were carefully placed to avoid mutual inductance. Components were purchased from Madisound and consists of air and iron core inductors of varying gauges (Madisound), polypropylene (Solen), mylar and electrolytic capacitors, sand cast and non-inductive (Lynk) resistors. Inexpensive parts are used only in non-critical areas and could be replaced with premium parts at additional expense and board space. Refer to the schematic for circuit details. All parts are tied to the board with plastic ties when possible. Caulking is used on all parts for adhesion.

The tweeter circuit consists of a 3 ohm non-inductive 10 watt Lynk resistor in series with a 8 mfd Solen polypropylene capacitor. Parallel to the tweeter is a 23 ohm 15 watt 5% power resistor and a 0.15 mH small gauge air core inductor. For the midrange, the 70 mfd capacitor is really a 60 mfd and a 10 mfd Solen polypropylene cap in parallel. Both the 1.3 mH and the 6 mH are medium gauge inductor; the former is air core while the latter is iron core. The 4 ohm resistor is two 8 ohm Lynk non-inductive resistors in parallel for more power handling. The 6.8 mfd cap is mylar. The woofer has a series 6 mH heavy gauge air core inductor. The 12 mH inductor is iron core. The 800 mfd capacitor is a 200 mfd and 600 mfd non-polarized electrolytic in parallel. Another 200 mfd NP parallels the woofer. Lastly, the 8.3 ohm resistor is three 25 ohm 25 watt 5% power resistors in parallel. The remaining parts are not critical and consist of a 0.35 mH small gauge air core inductor, a 30 mfd NP capacitor and a 7 ohm 15 watt 5% power resistor.

The midrange was tested in both normal and reverse polarity. Under reverse polarity, a 10 dB dip appeared at the woofer/midrange crossover region. Thus all three drivers are wired in normal polarity.


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