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The La Favre 5-octave marimba

You may contact me at jlafavre@jcu.edu regarding these web pages.

Log of Progress.

Marimba keys (blanks) cut, not tuned yet, 10/30/03. Keyboard will be about 8 feet long. 5 octaves (C2 - C7), 61 keys

Update 12/14/03, all five octaves rough tuned (C2 to C7).

Update 12/24/03, holes drilled in all bars to accept cord. (CLICK HERE for photos - page 1 of building marimba) To optimize the positioning of holes, the nodes for the fundamental of each bar were located by an empirical method (sprinkle with salt and strike bar lightly several times - salt accumulates at the nodes). Due to the non-uniform character of wood, some nodes vary from the ideal position. In order to develop a straight line path for the cord, a linear regression analysis was applied to the node position data, thereby allowing positioning of the holes as close to the true node positions as possible while still maintaining a straight-line path for the cord. The natural notes were divided into three groups for linear regression because the bars are not graduated evenly, but increase more in length in the bass region. The sharp notes were divided into 5 groups for linear regression (one group for each octave).

Update 12/27/03, maple purchased from saw mill for frame. (CLICK HERE for photos - page 1 of building marimba) Most of the milling of the rough lumber completed. Construction of frame underway.

Update 1/3/2004, construction of frame complete. (CLICK HERE for photos - page 1a of building marimba)

Update 1/11/2004, resonators for B3 - C7 and C#4 - A#6 assembled into ranks (CLICK HERE for photos -page 2 of building marimba).

Update 1/19/2004, top four octaves of resonators fitted to frame (CLICK HERE for photos -page 2 of building marimba).

Update 1/28/2004, resonator suspension system completed (CLICK HERE for photos -page 2 of building marimba).

Update 2/1/2004, started fabrication of bar posts and mounting of bars on instrument (CLICK HERE for photos -page 3 of building marimba). Holding off on fabrication of bass resonators for now because I want to research a design change in the shape of these tubes.

Update 2/8/04, finished installation of natural bars on instrument (CLICK HERE for photo -page 3 of building marimba).

Update 2/15/04, finished installation of all bars on instrument (CLICK HERE for photo -page 3 of building marimba). Currently working on bass resonator tubes, testing configuration with tubes made of poster board (photos will follow soon).

Update 2/21/04, finished model of bass resonators (CLICK HERE for photo -page 4 of building marimba). Currently working on a bass resonator (E3), will braze the tube sections together today (2/23/04).

Update 3/1/04, finished brazing two bass resonators (CLICK HERE for photo -page 4 of building marimba).

Update 3/9/04, finished brazing four bass resonators, 7 remaining. (CLICK HERE for photo -page 4 of building marimba).

Update 3/15/04, finished brazing all bass resonators! (CLICK HERE for photo -page 5 of building marimba). Currently fitting bass resonators to instrument.

Update 3/21/04, finished mounting all bass resonators. (CLICK HERE for photo -page 6 of building marimba). The instrument now looks much like a finished product, although there is plenty of work remaining. Work remaining on the bars is: 1) finish sanding, 2) apply oil-based polyurethane, 3) final tuning, 4) apply polyurethane to arch (final tuning requires careful sanding of arch, thus finish can't be applied there until tuning is complete). Frame needs to be finish sanded and then coated with a water based polyurethane. The stoppers for the resonators will be of the adjustable type. At this point most of the parts for the stoppers have been fabricated. The plywood discs will be coated with a chrome paint, the remaining parts needed will be fabricated, then stoppers will be assembled and mounted to bottoms of resonator tubes. Then the stoppers will be adjusted for proper resonance. Each bar will be evaluated for tone quality and any found lacking will be replaced with new bars (an evaluation at this point in the project indicates that at least one bar is not acceptable - the variable physical properties of a natural material like wood can be expected to yield some bars that don't sing properly).

Update 4/12/04, finished fabricating all adjustable stoppers for resonators (CLICK HERE for photo -page 6 of building marimba). Installation of stoppers into resonators is complete for bottom octave. All miters for bass resonators have been finished (epoxy applied, painted with chrome paint).

Update 4/18/04, finished installing all adjustable stoppers in resonators. (CLICK HERE for photo -page 6 of building marimba).

Update 4/29/04, one coat of polyurethane applied to all bars. (CLICK HERE for photo -page 7 of building marimba).

Update 5/11/04, three coats of polyurethane applied to all bars. Frame rail on audience side inlaid with the name La Favre in African Padouk. Frame finish sanded and two coats of semi-gloss polyacrylic (water based) applied. One coat remaining for the frame. Then final tuning of bars will commence. Hope to have instrument finished sometime in June.

Update 5/17/04, finish application to frame complete. Top three octaves of instrument final tuned. One bar needs to be fabricated again due to a tuning error. The end is in sight!

Update 5/24/04, all bars final-tuned and finish applied to arch (i.e. they are done!). The F4 bar was found to have its fourth harmonic in error (about 80 cents too low and not salvageable). A replacement bar was fabricated and rough tuned and should be finished in a few days. There remains some minor miscellaneous work to complete the instrument. This includes fabricating the end posts for the bar cord system and assembly of the cord tensioning system (turnbuckle and spring). A few bar posts need slight repositioning because there is not enough clearance for the bar width. All bar posts need to be aligned again since they were removed to accommodate finishing of the frame. Some extra felt needs to be applied to some bar posts to assist in centering the bars over the resonators. I am still mulling over some additions to the resonator stoppers, including the incorporation of a small handle to the bolt to facilitate the movement of the stopper. I also found that I apparently made an error in the length of the A#3 resonator (it is too short). I may need to make another one. Hope I don't find any other surprises. If not, the instrument should be ready within the week.

Update 6/7/04, marimba is now complete (CLICK HERE for some additional photos -page 7 of building marimba). The instrument was evaluated by Chester Englander, Katy's percussion teacher. I followed his advice in lowering the accidental rank (sharps) and moving them closer to the natural rank. We think the instrument has a good sound.

 

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