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Inconsistent Bar Resonance

harrysundown 2 February 2025

Finally doing some maintenance on my Jenco 3-octave vibraphone, for which I received some helpful advice here in the past.  What I've done so far:

- Replaced both cords, all the post insulators and the dampening felt with brand new ones from Century Mallet

- Leveled a few posts that were sticking up too high (long story) 

- Dampened any buzzing metal on the frame 

Overall it is sounding wonderful in comparison to where it started, but two issues remain and I'm not sure what can be done about them if anything:

1) Some bars are just less resonant than others.  That is, when you strike them you hear more of the thud of the mallet and less of the vibrating bar.   I took this video to capture what I am hearing (https://vimeo.com/1052752404/9e6e94fad6?share=copy).  As is hopefully audible, descending from the middle A#, it sounds good, then the A sounds pretty good, but you start to hear more thud at G# and much more at F#.  Eventually it starts to sound better down at E.  This is the case with or without the resonators in place. 

2) The low A# exhibits a metallic rattle sometimes when hit.  I initially thought it could be hitting bare metal of the post but it actually just seems to be it rattling against the cord.  Video here: https://vimeo.com/1052755308/65be885115?share=copy .  The cord tension is at what I believe is standard -- I tied the knots in the spring-hook connectors such that I had to pull pretty hard to connect them together.  The rattle still occurs if I tighten it more.  Again this is brand new para cord from Century Mallet.  

Also, can anyone explain the tradeoffs of para cord vs "soft" cord?  I bought some soft cord from Century as well.  Might it impact #2?

Thanks for reading!

 

Comments

Randy_Sutin Tue, 02/04/2025 - 14:18

Sounds like either the bar is cracked or the posts are impinging on its ability to ring. You’ve already eliminated the resonators and all the bars use the same cord…

So, I would check to ensure that you don’t have bent posts. That can be fixed. If the bars are cracked, it’s likely not worthwhile to spend money to have new bars made because a new bar would likely also sound very different from the existing ones; maybe even better, but it wouldn’t blend in.

harrysundown Wed, 02/05/2025 - 23:31

Thanks Randy for the suggestions. I have two different problems but I assume based on your response that it is in regard to #1 (less resonant bars). I am inexperienced, but it strikes me as unlikely that it would be cracked bars because I see no cracks and there are 6 bars exhibiting the same behavior so they'd need to all be cracked for that to be the explanation. Posts that are "impinging on its ability to ring" was my first instinct, but I've had such trouble adjusting the posts in any way that meaningfully mitigates the issue that I had gotten curious whether it might be something else. But I am betting you are right and I am just not making the right adjustments.

I have gone through and carefully made sure each post is vertical and as parallel with the bar direction as possible (when looking top down). Some posts were such that the cord would be un-level so I did my best to tweak the heights (by prying a few up here and there). Still the bars seem to often settle to one side after a few strikes such that they are up against the rubber of the post on one or both ends of the key.

I feel like I must be missing something.

wyndorps Fri, 02/07/2025 - 05:11

I have several bars here with a crack. However, to the naked eye, this can hardly be distinguished from normal signs of use and small scratches. But in fact, these bars are sonically dead.
If someone plays with heavy mallets and a lot of dynamic impulse, as is the case with the bars I received, I can imagine that several bars have cracks.

harrysundown Sat, 02/08/2025 - 19:30

How would one determine if a bar is cracked? I have examined them all up close with a flash light and I really don't see anything. There are surface scratches, but they sure do look to be just that.

IndianaGlen Sat, 02/08/2025 - 21:01

I’m sure someone has more experience than I have with cracked bars; however, I’ve run into a two cracked bars and both were dead-ish but they were more noticeably flat by almost a semitone. It may have been a coincidence, just sayin’.

I’ve heard of people using two strands of loosely twisted Venetian blind cord (like 3 wraps per inch). I’ve never done this myself.

IG

Vince H Wed, 03/05/2025 - 11:46

Using loosely twisted strands of narrow gauge Venetian blind cord is a good way to stop the "string buzz" that comes with paracord and other slick cords people try to use on vibe bars. Another option is to get some cotton blind cord and sand it to roughen up the surface; however, cotton quickly wears out if you are gigging a lot and removing the bars often, so I prefer the Venetian blind twist as an approach.
HOWEVER--I have not had the Venetian blind twisted cord approach resolve the inconsistency of sustain from one bar to the next that sometimes occurs. You could continue to fuss with the tension on the cord. This is a real problem with almost every vibe I've played on. John Mark Piper sells some special cord and also uses a different method of creating tension on the strings. Check out his web page for more info on that. You could purchase from him or keep exploring for other solutions.

I would suggest continuing to explore the post insulators and experimenting with that as it is the most likely culprit.

This may be a problem you must simply live with as it might have to do with the initial manufacturing, tuning, or even the bar geometry selected by Jenco.

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