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Due to the massive semester shifts caused by Covid 19, I can no longer realize the planned industrial development project with my (mechanical engineer) students this semester. Therefore, I have to prepare an own development project.


I would like to have the students develop a classification unit for vibraphone and marimba mallets.


When looking for new mallets, I noticed that there are on the one hand quite undifferentiated names for mallet qualities (hard, medium hard, medium soft, soft) and on the other hand even mallets of the same manufacturer and type can vary quite significantly in different batches.


I now wanted to give the students the task of developing a classification unit for mallets with the following features
• 3 or 4 100% reproducible strokes of different hardness (from soft to strong)
• It should be struck on 3 vibraphone bars (F3, A4 and F6) and possibly 3 marimba bars (which would make sense?). The bars always remain the same and are part of the classification unit.
• The resulting sound (attack) is to be recorded using a microphone and the frequency spectrum is to be determined using FFT.
• The rebound behavior of the mallet should be recorded.
• The evaluation should, in a presentation that is also to be developed, enable clear statements about the sound of the mallets that are comparable across different types.


What do you think about the idea?
Are there any further suggestions?


IndianaGlen Thu, 03/19/2020 - 15:02

There are way more knowledgeable people on here about mallets than I and my knowledge my FFT understanding is limited too; however, this is really interesting and I had a few thoughts that may or may not apply, but here goes :) My guess is you've probably considered many or all of my thoughts below, but I figure it doesn't hurt to speak up.

1)I'm not the only one who has noticed that mallets can get harder over time. John Mark Piper did a post where he softened up older mallets with a hammer and a wooden stool.
2)Mallet shape also changes the sound. Tony's older mallets had a mushroom head, his newer ones do not, it may be worth pinging him why he changed.
3)I've noticed more on extended octave vibes that the lower notes speak a lot differently (i.e. create some really strong overtones that overwhelm the fundamental) with different mallets.
4)Have you thought about using Hidden Markov models to see if you can recognize mallets?
5)I think the holy grail is to find a mallet that sounds warm on the low end but doesn't feel/sound soft at the high end of the vibe.
6)The bars are sonically much different if the damper is either up or down.
7) Do marimba players use different mallets playing on the low end, vs, the high end?
8) Shafts made of different materials should be considered.
10) Dang, I wish I was back in College :)

wyndorps Fri, 03/20/2020 - 13:18

The only thing I found about mallet specification is here at malletech.

To 1:
Sometimes mallets collect dust when playing. With humidity and pressure (when playing) this becomes a good sticky mass and compresses the mallet.
I have successfully washed a mallet set in warm water. But this is probably not possible with every mallet.

To 2:
Mushroom head mallets have two different hardnesses depending on how you hit the bar (see Malltech Link).

To 3:
The larger the mass of the bar, the more mallet mass you probably need to excite it in the fundamental.

To 4:
Not really. But it may be an interesting approach.

To 5:
Yes, exactly, although I would currently focus on "finding", not "manufacturing".

To 6, 8:
That is why I want to use real bars from both vibraphone and marimba and record and evaluate the different hit levels using microphone recordings.

To 7:
I think so.

To 8:
You are welcome!
I don't know exactly whether my students will be so happy with it too!