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Hi Michael.
The best spot to hold the bar to hear a particular vibrational mode is the mode's nodal position and the best spot to hit it is the mode's antinode. For the 2nd overtone - figure out where the string holes will go for the fundamental nodes. Now split the span between the two string holes into thirds. You want to hold the bar on one of these spots - about a third of the gap between the string holes. You cab hit the bar either right in the middle, or pretty much right next to your fingers - either side. You may find that the fundamental tends to also activate a little. If this confuses the sound for you, then try holding the bar a little more firmly - experiment with holding the bar either with a finger either side of the edge, or either side of the face - either side of the face tends to stop the fundamental a little more. Also the fundamental will tend to activate more if you hit the middle of the bar as that is where its antinode is also. The least fundamental or 1st overtone will be sounded if you activate the second overtone by striking between your fingers and the string hole - even right on the string hole sometimes.

Also.... The harder and smaller the mallet head you use, the greater the componant of upper overtones to the overall sound. For this reason, when I want to hear the fundamental, I use a bigger softer mallet, and when I want to hear the higher overtones more, I tend to use a smaller harder mallet.

Hope this helps
Jim McCarthy

#75

Instrument BARS & tuning / Re: My stroboscobic experience

Last post by Jim McCarthy - January 03, 2009, 09:28:14 PM

I know what you mean about the frustration and using one of the older stroboscopes - you Do need to use your ears and possible some reference tones in the earlier stages of tuning. On the plus side though, having one of those tuners puts you way ahead of the game in other ways. When it comes to accuracy and especially when it comes to tuning the higher pitch notes and harmonics where there is just not enough sustain for a digital tuner to recognize the pitch. This is especially true for idiophones - In fact the mechanical strobe tuners are really the very best tool for the job. With experience the ears tell you what you need to quickly enough for the rough tuning. Without the experience and practise though - I can see how you would prefer the digital version.

For those interested - peterson tuners have recently released version 2 of their software stoboscopic tuner - the premium version has a feature especially designed for short sounds with contact sound components. Costs about 100 bucks for the premium version I think. If anyone has any experience with it, it would be nice to hear about it!

Jim McCarthy

#76

Instrument BARS & tuning / Second overtone help

Last post by MStaples - January 03, 2009, 01:41:10 PM

Where is the optimum place to hold the bar and where is the optimum place to whack the bar when trying to produce the second overtone? I believe I can see the different posibilities (from the node / anti-node diagrams in the P3 marimba e-book) that emphasize the second overtone and attenuate the others. I've tried all combinations without success. Trouble is, I'm also dealing with a strobe tuner that forces me to search for the note being produced by twiddling dials. That's a lot for a newbie, so if someone could suggest the optimum holding and sounding combination, I'd feel better that that variable was out of the mix and might find the second overtone needle in my stroboscopic haystack.

Thanks!

MS

#77

Instrument BARS & tuning / My stroboscopic experience

Last post by MStaples - January 03, 2009, 01:23:08 PM

Tuning my first marimba bars and using a (vintage) Peterson 420 strobe tuner on them, was very frustrating at first. Then I learned how to properly read the tuner. The 420 is not an autosense strobe tuner, it doesn't just display the note it hears. You first dial up the note that you expect that your instrument will create, then you play the note to test it.

So, for instance: to test a bar for being 4C, you would set the tuner dial to "C", whack the bar and look at the display. The tuner is able to measure in a range covering eight octaves: 1C - 8C. The tuner display uses 8 octave rows to indicate the perceived octave, but they are marked 0-7.

So, if your bar successfully produces a 4C, the indicating pattern will not appear in the "4" range on the display, but in the "3" range.

Sigh.

If this helps anyone using a 420 or the like to tune their bars, I'll be glad of it.

MS

#78

Instrument BARS & tuning / Re: First overtone help

Last post by Jim McCarthy - January 01, 2009, 07:04:27 PM

Hi Michael
I'm afraid it's not good news from me!
I certainly don't know of any way to raise the pitch of one mode without raising them all – I'm 99% sure there isn't one. CERTAINLY there is no way at all, to raise the pitch of any mode at all, in a SIGNIFICANT way without actually making the bar shorter, which would destroy your nodal positions etc. Once you lower past a semitone or even ½ a semitone it CAN be a matter of throw it out and start again.

As you are pretty close to your target pitch, it might be worth having a go though, although that's a pretty big difference with the fundamental. You are correct saying that the overtones are similar to the fundamental with the "go too far" problem - but you might be able to manage it. It might not work too, but you have nothing to lose - at any rate the experiment will really teach you a lot about what works with your timber etc.

You would have to start by raising the whole bar to the point where the overtone is at least a little bit above the target. Then remove timber from the bar arch RIGHT IN THE VERY CENTER. The closer to the exact middle you can get the more it will effect the fundamental without changing the 1st overtone. I think you will find the overtone is still lowered too much anyway, but it's worth a shot.

The real trick is to work as hard as possible in the very early stages of shaping the bar, to get the 2 octave relationship of the overtone correct. This usually means starting your sanding more in the middle. Once you get the relationship correct - hopefully BEFORE the final target is achieved!.... then you sand a bit and test... sand a bit and test - etc working all the time to lower the tones together whilst keeping the relationship correct. The tricky thing is that you can easily lower the 1st overtone more than the fundamental by sanding closer to the nodes away from the bar middle - BUT - the reverse is not so much true. Or at least the isolated effect is not so great. Sanding right in the middle does tend to lower BOTH tones. You can get the fundamental moving a BIT more than the overtone, but it's more difficult than the other way around.

Hope this helps you out Michael.
Jim

#79

General Discussion / Re: Homemade mallets

Last post by Jim McCarthy - January 01, 2009, 06:41:57 PM

Well anything is possible Ray - I mean everyone is a little different, but it probably is more to do with lack of experience a you say - that's not a criticism of course btw. In fact I can very much see how the thicker shafts would seem easier in some circumstances. The real problem comes when adjusting the gap between mallet heads quickly - especially the smaller gaps.
Jim

#80

Instrument BARS & tuning / First overtone help

Last post by MStaples - January 01, 2009, 05:01:15 PM

I have a marimba bar I'm making that hopes to be a 3G# bar someday. Unfortunately, partially through the sanding process I find that the bar reads flat 3A# (which I think is fine for this point in the process) for the fundamental and flat 5F# for the first overtone (not so good I think). I assume that sanding the first overtone below its target note is not a different problem than sanding the fundamental too low and only a very small amount can be done to raise its pitch (by carving an end corner of the bar). Is there another solution?

Thanks!

Michael S

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