StewMac tools

replacing missing xylophone tonebars with different ones

replacing missing xylophone tonebars with different ones

Postby Robert Haines » Wed Oct 01, 2014 5:45 pm

I have an old Deagan xylophone that happens to be missing the top 3 accidentals. I'd like to make it playable so I can practice with it but have had no luck finding suitable replacements for the original rosewood bars. I also have a cheapo student's tabletop xylophone (no resonators) that has padauk bars. I'm thinking of temporarily cannibalizing it for those 3 bars, even though they don't match.

Here's my quandary: the Deagan bars are suspended by a pair of holes, near the ends of the bars. The cheapo unit has a vertical hole drilled near the end of each bar, and the other end is crudely isolated with some felt on the frame. I don't want to drill into the Deagan frame, and the suspension method is clearly better, but I'm concerned that if I drill a pair of holes in each of the padauk bars, it might change their pitch.

Can anyone offer an informed opinion?

Image

Image
Robert Haines
 
Posts: 8
Joined: Thu Jan 24, 2013 4:42 pm

Re: replacing missing xylophone tonebars with different ones

Postby Mark Swanson » Wed Oct 01, 2014 7:27 pm

Make new bars. It can't be that hard, and if you do that then the other cheaper one will still be good enough for a student. I am always against ruining one instrument to fix another, and the fix wouldn't even be a very good one.
    Mark Swanson, guitarist, MIMForum Staff
User avatar
Mark Swanson
 
Posts: 1914
Joined: Thu Jan 05, 2012 11:11 am
Location: Grand Rapids, Michigan USA

Re: replacing missing xylophone tonebars with different ones

Postby Robert Haines » Wed Oct 01, 2014 9:03 pm

"It can't be that hard"? Really?

I would need a source for Brazilian rosewood -- a wood that's very difficult to find and basically illegal to buy or sell, probably have to pay more for that lumber than I paid for the xylophone, would then have to find some way to mill it to the correct thickness, figure out what the correct sizes and shapes each bar should be, cut and shape them to suit, and tune them. And even then, I'd have 3 tonebars that would still look very different from all the others, and very likely sound different as well.

Thanks for the input, but that seems to me like far from being an easier fix.
Robert Haines
 
Posts: 8
Joined: Thu Jan 24, 2013 4:42 pm

Re: replacing missing xylophone tonebars with different ones

Postby Bob Gramann » Wed Oct 01, 2014 9:27 pm

I've seen mahogany used for xylophone bars. Honduran Rosewood, padauk, and some ebonies are available at a good lumber yard. You might copy a bar you have and then figure out where to cut to tune it. After two or three experiments, you ought to have a good idea of how to make the bars you need. What you end up with might be a different size than the original, but you ought to be able to make the notes correct.
User avatar
Bob Gramann
 
Posts: 698
Joined: Fri Jan 06, 2012 11:08 am
Location: Fredericksburg, VA

Re: replacing missing xylophone tonebars with different ones

Postby Mark Swanson » Wed Oct 01, 2014 9:38 pm

Bob sees where I was going, I wouldn't make it out of Brazilian. I think you could do as good a job as the paduak ones at least, probably better and you wouldn't need to use the other bars.
    Mark Swanson, guitarist, MIMForum Staff
User avatar
Mark Swanson
 
Posts: 1914
Joined: Thu Jan 05, 2012 11:11 am
Location: Grand Rapids, Michigan USA

Re: replacing missing xylophone tonebars with different ones

Postby Robert Haines » Thu Oct 02, 2014 1:55 pm

I know that it's possible to fabricate new tonebars, and out of a variety of woods (not just the original Brazilian rosewood). If I wanted to go that direction right now, I'd be grateful for the advice that you folks could give. But as I said in the OP, I only want to make the xylophone playable as a practice instrument until I can afford to take the time and spend the money to restore the whole instrument.

From the photos that I posted, it's pretty clear that the Deagan is not a very valuable instrument, and it's in rough condition. If I was interested in getting into a full restoration project, there are a number of things that would need to be done -- not least of which would be having the 3 missing bars fabricated by the experts at Century Mallet as well as having them refinish and tune all of the bars. I would need to strip and repaint the frame and obtain or fabricate the missing resonator tubes. But that's not what I asked about.

The "donor" xylophone is a no-name instrument that was made maybe 10-20 years ago, probably in the Far East. It will never have much value (far less even than the Deagan) nor will it ever be more than just a musical toy. But more to the point: if drilling the two suspension holes in the padauk bars would not change their pitch then -- other than cosmetically -- they would not be ruined and could, once I am able to restore the Deagan, have their bars returned to make them a complete set once again. If I didn't want to keep that set, I could pass it on to someone who wanted it.

That leaves me with the original question: would drilling the holes be likely to change the padauk bars' pitch?
Robert Haines
 
Posts: 8
Joined: Thu Jan 24, 2013 4:42 pm

Re: replacing missing xylophone tonebars with different ones

Postby Bob Gramann » Thu Oct 02, 2014 5:55 pm

I don't know. But, you could make a bar out of anything and run the experiment. I would expect that the hangers for the bars are at the nodes of vibration. The nodes may not line up between the two instruments. I would then expect that hanging a bar from the wrong point wouldn't necessarily change the pitch but would cause it to damp more quickly. Drilling a new hole somewhere other than the node would change the vibrating mass. I don't know how much you would have to change the mass to make the change in pitch noticeable. Good luck.
User avatar
Bob Gramann
 
Posts: 698
Joined: Fri Jan 06, 2012 11:08 am
Location: Fredericksburg, VA

Re: replacing missing xylophone tonebars with different ones

Postby Nate Scott » Fri Oct 03, 2014 2:54 pm

I used to make marimbas for zimbabwean-style marimba ensembles - I've made about 50 instruments of various sizes, mostly using paduak and mahogany for the keys.

Bob is correct. The suspension points should be located at the primary nodes - theoretically about 22% toward the center from either end of the bar. I say theoretically because wood is not homogeneous, and as you tune a wooden bar by removing mass near the center, the primary nodes actually migrate outward slightly. Experimentally, the node is where you can touch the bar with no dampening.

If you drill a hole to suspend the bar, you are removing a bit of mass from the bar overall, but as long as the hole is on the nodal point, it won't affect pitch or dampening, Small deviations from the nodes (< 0.10") will have small effects. Any pitch changes caused by drilling the will affect the overtones more strongly that the fundamental, and they can be corrected with careful tuning (removal of small amounts of wood in specific places on the underside, easily done on the round part of a belt sander).

I would make new bars and duplicate the suspension method used on the instrument already, else your keys new may not blend in sonically. Same with wood selection. Cocobolo or might be a good substitute for BR, especially at the upper register of the xylophone where the overtones are higher and less noticeable.
Nate Scott
 
Posts: 72
Joined: Sat Jan 07, 2012 5:25 pm
Location: Portland, OR

Re: replacing missing xylophone tonebars with different ones

Postby Beate Ritzert » Sun Oct 05, 2014 10:23 am

But isn't a realy well matching wood unimportant to make it just playable? I would tend to experiment with some rests i have around, maybe (swamp) ash, maybe even alder, maybe oak, maybe walnut, maybe apple, peach or something the like. I would further regard this as an experiment to learn which woods are more suitable and which less. And i am aware that many woods from the dalbergia family are especially suitable ... but we need alternatives to all woods mentioned so far because it is (IMHO, of course) just a matter of time until they will run into massive protection.

If, e.g., apple turned out to be usable that might be optically really interesting in the context of a full restauration...
User avatar
Beate Ritzert
 
Posts: 413
Joined: Thu Aug 02, 2012 8:20 am
Location: Germany

Re: replacing missing xylophone tonebars with different ones

Postby Nate Scott » Mon Oct 06, 2014 5:28 pm

I agree that using something other than rosewood would a worthy approach in terms of exploration or to make just playable. It depends on Robert's goals for the project. There are undoubtedly lots of great sounds to be discovered in lesser used species.

Whatever wood you choose, some characteristics to consider in a marimba key stock are grain orientation [/////], hidden grain defects, and the surface hardness of the material. Some playing techniques can be particularly brutal on the keys; it's not unheard of for keys to split in use.
Nate Scott
 
Posts: 72
Joined: Sat Jan 07, 2012 5:25 pm
Location: Portland, OR

Re: replacing missing xylophone tonebars with different ones

Postby Clay Schaeffer » Fri Oct 24, 2014 7:32 am

Small pieces of Honduran and other rosewoods can be found on ebay for reasonable prices. Being a "makers" forum it is natural for us to suggest making new parts rather than cannibalizing a perfectly playable (albeit low quality) instrument.
Clay Schaeffer
 
Posts: 1047
Joined: Fri Jan 06, 2012 12:04 pm

Re: replacing missing xylophone tonebars with different ones

Postby Rich Wickstrom » Sun May 01, 2016 11:09 am

For what it's worth, my son and I spent the last year building a concert grade xylophone from scratch (see photo). The bars are made from Honduras Rosewood. I am almost done documenting the project, including the bar construction and tuning, on my website at http://supermediocre.org/index.php/rich ... e-project/. Perhaps this info will help you.
Attachments
IMG_1615.JPG
Our finished instrument
Rich Wickstrom
 
Posts: 7
Joined: Sun May 01, 2016 10:59 am
Location: Albuquerque, NM

Re: replacing missing xylophone tonebars with different ones

Postby John Mueller » Mon May 02, 2016 5:50 pm

Traditionally Marimbas and Xylophones were made from Honduras Rosewood not Brazilian. in your tuning removing small amounts of wood from the underside of the middle of the bar LOWERS the pitch removing wood from the underside of the ends RAISES the pitch.
John Mueller
 
Posts: 71
Joined: Sat Jan 07, 2012 12:29 am

Re: replacing missing xylophone tonebars with different ones

Postby Robert Haines » Tue Nov 08, 2016 5:12 am

Thank you, Nate! I appreciate the experienced advice.

Nate Scott wrote:I used to make marimbas for zimbabwean-style marimba ensembles - I've made about 50 instruments of various sizes, mostly using paduak and mahogany for the keys.

Bob is correct. The suspension points should be located at the primary nodes - theoretically about 22% toward the center from either end of the bar. I say theoretically because wood is not homogeneous, and as you tune a wooden bar by removing mass near the center, the primary nodes actually migrate outward slightly. Experimentally, the node is where you can touch the bar with no dampening.

If you drill a hole to suspend the bar, you are removing a bit of mass from the bar overall, but as long as the hole is on the nodal point, it won't affect pitch or dampening, Small deviations from the nodes (< 0.10") will have small effects. Any pitch changes caused by drilling the will affect the overtones more strongly that the fundamental, and they can be corrected with careful tuning (removal of small amounts of wood in specific places on the underside, easily done on the round part of a belt sander).

I would make new bars and duplicate the suspension method used on the instrument already, else your keys new may not blend in sonically. Same with wood selection. Cocobolo or might be a good substitute for BR, especially at the upper register of the xylophone where the overtones are higher and less noticeable.
Robert Haines
 
Posts: 8
Joined: Thu Jan 24, 2013 4:42 pm


Return to Wind, Percussion, and Miscellaneous and Experimental Instruments

Who is online

Users browsing this forum: No registered users and 1 guest

Your purchase from these sites helps support the MIMForum, but only if you start at the links below!!!
Amazon music     Amazon books     Amazon tools     Rockler tools     Office Depot    

The MIMF is a member-supported forum, please consider supporting us with a donation, thanks!
 • Book store • Tool store • Links •