Building the Frame- Part 1

Hey everybody!

I'm happy to report some significant progress over the last few weeks.  Since I received my lumber order, I've been designing, re-designing and re-re-desiging the frame, but also I have finally broken out the table saw and cut out all of the pieces for the frame!

Lots of pics to follow...I'll explain what's going on as I show you what I'm working with.  :)

First, I had to construct the rails that hold up the bars and account for most of the length of the instrument (which really is close to 10 feet!).  Originally planning this one out was tricky.  Because I sincerely doubted the lumber yard's ability to keep nine-foot board lengths from bowing too badly, I decided to order pieces that would be half the length, and then piece them together to make long boards.  Unfortunately, much of the wood I received was cupped (which means it was warped along its width in a "cup" shape), and I had to be careful to select the straightest boards for this part.

Once I did, I cut four boards into eight lengths that were four inches wide, and I paired them up.

Lined up, the pieces looked like this!

After sanding them a bit (which I should have done a bit later, after connecting them...), I began work on the brackets that would fasten each set of two boards into a single rail.

 

I bought two pieces of 1/8 inch thick steel, each a 3 inch width and 3 foot length, and I cut them into quarters with a cutting wheel on a compound miter saw, so that I had eight pieces like those pictured above.  Then, I had to drill holes in these pieces where the would screw into the wooden boards I cut.

After cleaning them up and painting them black, they looked pretty good!  

I used these brackets as templates for where to cut the matching holes into the wooden rails, and then I pieced the four rails together with a bracket on each side of the joined, middle region.  In the end, I had four long, mostly straight rails that looked fantastic!

Here's a few in action, as I drew up the nodal lines on the natural, "white" bars.

As you can see, I'm putting some college texts to use...haha

Anyway, the next part was a lot of fun and really gave some tangible shape to all the designs I had been drawing up.  Next I had to select wood from the stock to use for the sides of the marimba!  Each side consisted of three sections: a three-ply top, a set of legs, and a three-ply bottom.  I had to cut out all of these pieces and fit them together like a puzzle.  I haven't glued or screwed it all together yet, but here is I what I have so far.

The top sections for each side of the marimba: two plies of ash, and one ply of cherry.  The bottom sections are the same arrangement.

All of the pieces cut out and placed in their rough location.

The middle ply layout, showing how the legs will fit together with the top and bottom sections.  I also cut out the section up top that will allow for the height change on the keyboard that lets the "white" keys sit lower than the "black" keys of the instrument.

I do want to mention that my design for the sides of the instrument saw major changes two different times.  If you compare what you see above to the the original model of the frame that my friend Nathan made based on my old drawings, you'll notice that the thicknesses of all the pieces have become much smaller, and that there are now more legs than originally planned.  Because my wood was cupped, I could not use as wide of pieces as I planned in the first place.  The new design that was implemented uses less wood, is practically free of warped material, and is still going to be just as sturdy.  

The next part was really tricky.  In order to cut slots for the rails to sit in on the sides, I had to use the rails to line up everything and place the bars on them in a way that their nodal points would be directly over the rails.  This doesn't look like it'd be that hard, but after adjusting the length of the instrument and trying to make the rails accommodate all the bars in their correct locations and STILL make it a playable arrangement, I say its a hard thing to get right!

I set up the tops of the sides that would support the keyboard, and I set the rails in their general locations.  I lined the bars up on the rails where their nodes would be over the rails, and I had to balance the rest of the set up based on that alignment.

After much trial and error, I marked the locations where the rails would sit on the top of the sides of the frame.  I already had marked where the natural bars would sit on one of the rails (the second one from the right in the picture above), and I had to make all my adjustments based on that.  Once I was satisfied, I took it all apart so the walkway would be clear for the evening.  lol

The next day, I set everything back up and checked to make sure that the marks I made were reproducible and still to my satisfaction.  I did not have to make any adjustments, but as a final test I decided to put ALL of my bars on the mock up to perform the ultimate alignment test...and also because I wanted to see all those beautiful bars set up in the way they'ed be on the finished instrument...  ;)

SUPER COOL!

I am so stoked to keep working on this monster of a project, and I'll be sure to keep posting as I make more progress.  I still have to assemble the sides I cut out and cut the rails to their final length.  There's still a lot to do, so PLEASE keep coming back to this blog as I continue to work.  Feel free to leave a comment or ask a question if you would like to know more about how I did something or about my future plans.  I love my readers!!  :)

Wood for the Frame

Hello all!

Looks like I have to apologize for yet another long hiatus!  Yowza...

Anyway, I'm happy to report that during the downtime, plans for the frame are close to finalized, and I have purchased most of the wood necessary to build the frame.

What is shown here is about 51 board feet of ash and a little over 9 board feet of cherry wood.  These are both beautiful species of hardwoods that will make a very fine looking marimba frame!  In the coming days, I'll be doing a lot of drawings and calculations to make sure this lumber is measured and cut correctly into the pieces I need to make the frame.

I'll do my best to keep you all updated on the progress I make in the following weeks as this project begins to come together.  My goal is to have it finished by the time I start physical therapy school in January, but at the same time I will be trying not to rush.  More posts and more pictures soon to come as I keep working!  :D

Enough Bars for Now......Let's Talk About the Frame!

Hello everyone!  I know it may seem like this project has seen a real hiatus these days due to the lack of regular updates to the blog, but never fear!  I am happy to report that in this downtime, I have actually completed the rough tuning of all 61 marimba bars!  Well...kinda.  I'll have to redo a few of the bars since they somehow didn't keep their pitch, but.........details.  ;)

The bars still have a ways to go, though.  All 61 bars still need to be fine-tuned, which is a process that I anticipate being less tedious than the rough tuning.  The difficulty in fine-tuning is obviously being patient with bringing down the pitch of the fundamental tone and the overtones, and being careful not to overshoot...going too flat is bad news, as I'd have to redo the bar completely.  I actually did this to five of the bars while rough-tuning, so I'll likely have to remake those later on, but I'll plan to save that job for later.  Since I have a full set of bars at least cut out, I can move on to another part of the project that I've really been looking forward to.

I decided that the best step to work on was the design of the marimba's frame.  To do this, I called upon the skills of my good friend Nathan Baker to render a model of the marimba frame plans I had sketched on graph paper.  Like a pro, he used a program called Sketchup to take the drawings I had done and make a 3-D model of the frame!  Here is what we came up with!

Disclaimer:
Yes, that is my face on a model up there.  That is not my real body.  :O



Anyway, a few things to note about this design as seen here.  These pictures obviously do not have the resonators added in on the marimba.  I haven't design those quite yet, but they will certainly be on the real marimba.

Also, note the long bar across the length of the frame at the bottom.  This bar is for structural support, but there will be also be an additional one going across the length in the same fashion, at the top of the frame.  This should eliminate any side to side "wobble" motion that could result from a sideways push to the frame.  Also, there will be a piece going diagonally from the base of the large end of the marimba up to the underside of the middle of the top of the frame.  This piece will bear some of the weight that the bars and resonators will put on those rails that will hold the bars.

Over all, this marimba will be just shy of nine feet long when it is constructed.  That's a big instrument! I really can't wait to see how it turns out!

That being said, progress has proved slow over the last few months, and I have school work to blame for that.  Only a few more months and I will graduate, and then I'll have plenty of time to work on this awesome instrument! (amidst working and preparing for professional school, at least...)  Hopefully I'll be able to work on this before then, but I'll be sure to post about my progress (or in case of no progress, at least my thoughts about moving forward) and keep you loyal followers updated.  :)

To those who do read these posts and continue to wish me well on this project, thank you so much!  I love you guys!!  :D

Rough Tuning and Workspace

Howdy!  Yes, another post...FINALLY!  And I have some real progress to report as well...52 bars of 61 have been successfully rough-tuned!!!

:D :D :D

So now my plan in moving forward is to finish the rough tuning in the very near future, and then begin making plans for the frame!  It's really cool how this project is beginning to take shape, now...

This pic is a bit old...as I actually have all of the upper range rough-tuned, and that's not apparent in this picture.



Anyway, here are a few pictures of me getting stuff done.  :)









































This is my old workspace, and I tuned many of the bars sitting like this with a mask and safety glasses.  It was dirty work, and clean up was never really fun.  I made some awesome marimba bars, though!

Again, a huge mess.  Look at how that sawdust ripples and piles up!  It's such a pretty color, though...

Checking the fundamental (1st harmonic) of one of the bars.  As I mentioned earlier, the goal of rough-tuning is to bring this note about a half-step high of the target pitch, and once I drill the holes in them and get them acclimatized to a room temperature/room humidity environment, I can fine-tune them.  To check this pitch, hold the bar at about a quarter from the end and strike the center of the bar to produce a tone that any microphone tuner can register.

Checking the first overtone (2nd harmonic) now.  This pitch is usually need to be two octaves above the fundamental, and you can check it by holding the bar at the center (which chokes the fundamental mode and allows you to hear the overtone) and strike it off center.


Once I got tired of working in the mess outside, my dad and I managed to find a way to set up a sort of workshop in our garage.  Using our shop vac and a special dust collector apparatus that a gracious friend let me borrow (Thanks, Lee!!), I was able to work virtually dust free in the garage!

Here is my setup.  Shop vac below, drill press with drum sander on top, as well as my measuring tools, a tuner, mallets to check the pitches with, and a spreadsheet with my planned bar parameters on it.  Also a stool to sit on so I'm not doing anything like sitting on a piece of plywood on the ground... XD

Drill press, drum sander, vacuum hose ghetto-rigged to collect as much dust as possible.  What's piled there is from times I forgot to turn the vacuum on before I started sanding.  Heehee...

A regular tuner I've used for years to tune timpani with.  Standard equipment for any musician, inexpensive, and finicky enough to pick up marimba tuning pitches.

A few of the smaller bars that have been rough-tuned.  Sorry for the bad lighting...kinda hard to tell where they've been sanded, but its visible somewhat.





These were just a few snap shots of what's been accomplished so far in this project.  As I progress, I will certainly keep posting updates with pictures, insights, or maybe just silliness from me, otherwise.  Thanks for continuing to read these posts and keep up, those of you who do, and please feel free to leave me feedback on Facebook or on here if you use Google+.  Love you guys!  :D

Rough Tuning Begins

Hey guys!  Welcome to a long overdue entry about tuning the bars!  As you may know, I have now successfully cut ALL 61 BARS into their their rough, rectangular shapes!  HOORAYYYYY!!!

The keyboard arrangement, with the proper spacing between the bars (not shown here), is somewhere in the ballpark of nine feet long from side to side.  This is going to be a big instrument...  :D

Now I have come to the most difficult and daunting part of this project...the rough tuning process.  I'm not going to go into a lot of the physics behind tuning the bars, because I'd probably be sitting here typing for a few days and you guys wouldn't get to read much about how the actual progress of the build if I did, but I will discuss a few fundamentals that I have had to understand about crafting the bars into the proper shape to produce proper tones.

Each bar, when struck, produces not just one tone, but several at once.  While one note is most apparent (called the fundamental, or the first harmonic), there are many overtones that are produced as well, and they all contribute to the overall sound and quality of sound of each bar.  When tuning the bars, it is important to know not only what to tune the fundamental to, but some of the overtones as well.  (some overtones are nearly imperceivable and not necessary to tune).  While some very high end, commercial marimbas out there tune several modes of vibration on each bar, controlling many different overtones, I plan to only tune the fundamental, the first overtone, and the second overtone of each bar.

Sound waves traveling through the bar, produced by the energy transferred into the wood from the strike of a mallet, travel in several different directions across the bar, and they all contribute to one, rounded out vibration pattern that produced sound.  While some of the minor ones travel in transverse, horizontal or even diagonal patterns through the bar, the modes of vibration I will be concerned about are the first, second and third transverse modes, which produce, respectively, the fundamental, first and second overtones.  Below is a diagram of each wave's pattern as it travels through the bar:

My doodling may look a bit SKETCHY. (get it???!!!)  These drawings represent bars viewed from the side and the wave patterns that travel through them.

The first wave is the first transverse mode, and it produces the fundamental, which is the most prominent tone that can be heard from the bar.

The second wave is the second transverse mode, and it produces the first overtone, which usually is tuned to be two octaves above the fundamental, so it matches its pitch.

The third wave is the third transverse mode, and it produces the second overtone, which is really only perceivable in the mid to low range of the instrument.  It will be tuned to a different note from the other two, usually an octave plus a major third interval above the first harmonic.

Given those pitch differences, an example of a properly tuned middle C bar (called C4) will have a fundamental of C4, a first overtone of C6, and a second overtone of E7.

A marimba bar, when properly tuned, has an arch shape cut into the bottom.  This shape allows for the bar to vibrate more freely in the middle, and produce clearer, longer sustained tones.  Here is a diagram of a tuned bar:

(just ignore the letters for a second...I kinda borrowed this image.)

Cutting this arch shape is difficult, and at first I had a lot of trouble figuring out which tool was the best for the job.  One does not want to simply cut AN arch for the sake of the shapeliness, but the arch has a purpose: removal of wood from the bottom of the bar to form the arch LOWERS the pitch of the bar.  A flat, rectangular plank of wood with no cut produces a tone that is fairly high, so cutting this arch is how we tune the bars!  If one wants to lower the fundamental, you must remove wood from the very center (about where that letter B is).  To lower the first overtone, one must remove wood from just beside that center (between A and B).  To lower the second overtone, one must remove wood from even further away (about where the A is and a little further out).  Why does this work in this way?

If you look at the wave diagrams above, observe where each peak and trough of the respective wave patterns are.  For example, since the fundamental vibrates the most at the very center of the bar, removing wood from the center of the plank would most alter the fundamental.  The first overtone peaks just outside the center, and the second overtone peaks at the center and approximately at the quarters of the length of the bar.  Seeing the pattern?  To tune each of these three modes of vibration we must strategically shave off wood in locations where each respective wave would peak!

Soooo...this task was a bit daunting.  If I were to lower the pitch too far by cutting too deep of an arch, its is very difficult to bring back up, and attempting to raise it again would require some unsightly alterations to the edges of the bar, so I don't want to go too low!

Ultimately, The tools I decided to use were a router and a drum sander.  The router, especially for the bigger bars, is handy for removing a lot of the wood from the middle of a bar that I know for certain would not be necessary.  So the router really is a time saver.  The drum sander, which is really a drill press with a drum sanding attachment on it, is what I'll use to whittle away at the bar to form that pretty arch shape and tune the note properly.

Disclaimer: the diagrams are not really drawn to scale...I just doodled again.  :)  I plan to put up photographs of this process in the future.

The very first bar I tuned was A2.  This is a fairly large bar, and it is on the lower register of the instrument.  The rough plank was about 13/16ths of an inch thick.  I used the router to trim out about 1/4 of an inch thickness out of the middle of the bar:

Then I took an initial reading of what notes each of the three modes of vibration were registering.  I don't remember exactly what each pitch was, but I remember they were all way too high, which was to be expected.  It was time for the drum sander to do its work in lowering those pitches!

I used the drum sander to first form the curve of the arch on either end of the bar.  This allowed me to progress with the tuning with at least the proper, arcing shape in place.

At first I sanded mostly in the middle of the bar to lower the fundamental, which was SUPER high compared to where I needed it to be (I think it was at an F4...?)  I basically wanted to make the intervals between the modes correct as early as possible, so I could sand more evenly as I progressed.

So I sanded away in the middle and the just barely to the left and the right of the middle to lower the fundamental and the first overtone.  The second overtone needed only a little bit of lowering, so I didn't take much out of the ends near the arcing part.

Notice how thin the middle is!  Marimba bars are very thin in the middle, so they vibrate strongly, yet are still surprisingly sturdy.  The middle and around the middle was mostly flat for such a low register bar, and the arc was still very prominent.

When it was finally completed, I had a nice arch cut in the bar, and all of the intervals between the notes were just right!  One thing to note, though:  this process is merely ROUGH tuning.  When I say I finished ROUGH tuning this bar, I actually tuned the bar about a semitone above what the final pitch it will be.  The reason for this is that before I'm done with these bars, I'll need to drill holes in them in order to run the cord that suspends them on the frame.  Removing more wood in this way will lower the pitch further!  Not by much, but still an amount that makes me want to tune the note sharp.  At the end of the rough tuning of my A2 bar, the fundamental was A#2, the first overtone was A#4, and the second overtone was D6.  After drilling the holes and fine tuning this bar, the modes will be at A2, A4, and C#5, respectively.

Here it be:

So far, I have managed to complete the rough tuning of 12 of the 61 bars!  They all look and sound amazing....

One of the bars is missing for this photo, but nonetheless...12 are done!!!

Future updates are likely to be slow in coming, as I am now back in school and am very busy during the week.  On weekends, I will continue working on this amazing project, and I will most certainly keep posting my thoughts and methodologies as I go along.  I hope you'll continue to read along!  :D

Cutting Out the Bars

Howdy!  This past weekend, my dad and I made HUGE steps toward this project looking more like a marimba-- We cut out most of the bars!  Out of the 61 total bars that will eventually make up the full, five-octive keyboard, 44 have been cut to the proper dimensions, leaving only 17 to go!

Cutting out the bars was a multiple-step process.  Each bar needed to be cut to a different length and width, with dimensions so precise we had very little room for error (some of the widths required us to cut measurements as precise as 32nd's of an inch).  To begin cutting a bar, the first step was to use a compound miter saw in order to chop the raw lumber into a more manageable length, which would be close to the length of the bar we planned to make.  Then, we had to rip (cut with the direction of the wood grain) this board to be the precise width of the bar we were making. This was done with a table saw, which allowed us to cut a very straight line over nearly two feet (the first bar was over twenty-one inches long!).  Once this width was cut so that we had two, perfectly straight edges length the length of this bar, we went back to the compound miter saw and chopped the bar to be the appropriate length, making sure to also have two smooth edges along the widths.  One we had done this, the bar was then the proper size!

Does this mean that the bar is in tune and ready to put on the instrument?  I wish it were that easy.... Later on, I will describe how tuning the bars works, as a raw-cut bar produces a pitch that is much too high in its untuned state.  That is for another post, however.  :)

Dad and I managed to cut out the largest 44 bars on the instrument with only minimal scrap wood left over.  So far, this project has turned out to be very cost effective!  We may be able to finish the smaller, 17 bars that are left without having to order more lumber which I really hope turns out to be the case.

Here be a few pictures!

Making sure we know how to use the table saw.  XD

Justin, my silly older brother, likes playing with Photo Booth on his iPad.

"I sure can measure a straight line, guys!!"  lol

Here is the C2 bar, which is the lowest pitched bar we're making, compared to the keys on my xylophone:

That thing is HUUUUUUGEEEE!!!!!

And finally, here are all of the bars that we cut this past weekend.  This much work in two days...AWESOME.

Next time I update, I'll hopefully have all of the bars cut out and ready for tuning.  Tuning each individual bar will definitely be the most difficult task in this entire endeavor, but I'm up for the challenge.  Those of you who have been reading these posts, thank you all so much for your support and encouragement!  I hope you guys will continue to follow along with me as I press on towards my goal of creating this beautiful instrument!  :D   :D