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

Lumber For the Bars

Hey guys!  Yesterday morning, some of the lumber that will be used to make the bars arrived!  64 pounds of glorious ex-tree material in a beautiful cardboard and plastic wrap arrangement!

Okay, maybe I'm a little enthusiastic about the packaging...it wasn't incredible or anything.  But what was inside the packaging certainly was!!

This particular type of wood is called African padauk.  Generally when you look at most higher end commercial marimbas, you'll often see bars that are made out of either Honduras rosewood or this stuff.  Personally, I chose to go with the padauk because of its amazing orange-y reddish color and the fact that it costs only about a third of what the rosewood does.  Before I purchased any sizable amount of lumber, I bought a small, craft-size sample of the padauk, and I made a few practice bars with it in order to make sure I enjoyed the sound.  While the practice sample was not the same dimensions as what I will be using for the actual bars, I still loved the tone I got out of it, which was rich and had a lot of sustain.

I ended up purchasing 19 board feet: Six 7" by 60" boards and one 8" by 30".  This will be enough lumber hopefully to construct a little more that half of the bars on the instrument.  It will be interesting to see how this works out, as the instrument I am building, which will be a five-octive, C2 to C7 range, will use a lot more lumber on the bass end than on the higher end.  While one board can only fit the first six bass bars on it, a board with the same dimensions would be able to make up several of the smaller, higher bars.  I'll ultimately have to order a few more boards, but not until these are all spent.

19 board feet of the padauk cost about $300, and I'm estimating that I'll need to purchase about an extra $150 in the near future to complete the keyboard.  I won't know for sure how much more I need to order until I've exhausted my current supply.  While this is a lot of money, I know that I'm saving a ton by not buying a commercial instrument and making my own in the first place.  Besides, I know that this whole project is an investment that will provide me with many wonderful, musical experiences for the rest of my life!  Oh the joys of playing music!

Here are pictures of the wood grain as best as I could get them.  Overall, this wood definitely has a lot of character, and it sounds amazing in bar form.  I'll be working on marking the boards for the cutting to begin before long; I'll be sure to post again once I've cut some of the bars so I can show you guys!  :D

Prologue

Soooo...I'm *blogging*!!!  Never thought I'd be on one of these...or even type that first sentence.  First time for everything, I suppose!

Anyway, I'm here on Blogger in order to journal the progress I make in the next several weeks (or possibly months) on a special project that I have begun working on this summer.  I knew this project would be very special to me, and I decided that while I don't normally do the blog/journaling thing, I would definitely want to return to the thoughts I have here at the beginning processes of this project, as well as to the many entries I will post here.  I'm no expert in this medium, but I do hope all who read this will be entertained and perhaps even learn something as we go along.

Those of you who know me likely know I am a musician.  If you were to ask me what I play, I would tell you that I am primarily a drum set player, but that I also play guitar at my own leisure.  As a percussionist back in high school, I actually had to learn how to play several instruments, including rudimentary-style concert snare drum, marching percussion instruments, assorted auxiliary percussion instruments, timpani, and something that many percussionists cringed at (at least at my high school), mallet instruments.  Mallet instruments are arranged as all keyboard instruments are (piano, organ, etc), but are played with yarn, rubber, metal or plastic mallets in order to produce a tone from a bar of wood, fiberglass, metal or possibly some synthetic material.  The most common instruments in this category are the bells, the xylophone, the vibraphone, and my personal favorite, the marimba.

When I was younger and played only bells, I didn't enjoy mallet percussion very much.  But when I got into high school and was able to play on the vibraphone and the marimba, I found a lot more enjoyment in making music with them.  The marimba had a deep, earthy tone that  I fell in love with pretty quickly. Here was an instrument that produced amazing bass tones at the low end, and clear (but not unbearably piercing) high tones on the upper end.

I don't know exactly what it was that attracted me to the marimba so much, as most students just saw it as the big ol' wooden thing at the back of the room that was really hard to haul around in the band trailers and that no body really knew how to play that well.  All I knew was that I really loved the way it sounded when I finally learned how to play a piece on it.

After high school, I basically lost my regular access to a marimba, as I didn't play with Wingate University's ensembles on a regular basis and I didn't own one of my own.  Somehow I got into my head that if I loved the instrument so much, I would find one that I could regularly practice on and become a solid marimba player with.  I began searching online for marimbas to purchase, but I knew that I wanted a full-sized instrument that would look and sound beautiful.  Turns out that my expectations were a bit high...any five-octive marimba that isn't abused is easily eight thousand dollars, which I simply didn't have.

Then, the best idea EVER hit me.  Marimbas are just well-crafted bars of hardwood, with resonators and a stand that won't fall over.  What if....Yessssssssss.....What if.....

....I were.....

...to build my own?

BOOOOOOOOMMM!!!!  YES!  I would BUILD my own marimba!

....How exactly do I do that?

Well, it's true that marimbas are actually pretty simple in design, but making one sound good is tricky business.  The bars must be perfectly shaped in order to be tuned to an exact pitch, and one small mistake could be expensive to correct.

Nonetheless, this is the big project that I have been reserving this blog for.  To build my own instrument for practice and for performance would be an incredibly rewarding challenge.  I would be able to take back up a passion that I, at one point, thought would just simply have to be lain to rest.  I will be using this blog to post notes of my progress, pictures of each step, as well as my own thoughts and things I've learned about the technical side of instrument making.  I sincerely hope that all who read and follow this blog will enjoy what pops up here, and please...if you want to comment or link this page somewhere... DO SO!!  I'd love to hear what you guys think!

So far, I have not begun to build anything yet.  I placed an order for the lumber I will use to make many of the bars, and that big load of beautiful padauk should arrive tomorrow in a big UPS truck!  I'm incredibly excited to begin working on this project, and I look forward to seeing what it has in store for me!  :D