If I were ranking Ronsen hammers in terms of firmness I would rate them in this order from softer to harder:
- Bacon
- Weickert
- Wurzen
- VFG
How the hammers present in terms of tonal spectrum will depend on other factors, for example, hammer profile (how thick is the felt), crown shape, amount of filing, etc.. Profile is probably the most important factor (along with mass). A relatively soft Bacon felt hammer can produce a nice spectrum of high partials if the hammer is quite trim and a VFG hammer can produce a somewhat dull spectrum if the hammer is quite bulky. Treble sections are quite sensitive to excessive mass and/or excessive thickness of felt as the partials that we don't want damped already have a period quite close in length to the string contact time. Excessive mass, strike point width or felt compression during impact will damp those partials and the tone will be left wanting. Finding a good starting point is important so that the least amount of manipulation is necessary. One thing you can do is swap hammers from higher sections to see if a less bulky hammer doesn't achieve what you want before you add lacquer. If it does then consider a healthy filing first.
Varying approaches to what to do with the shoulders on these types of hammers I find curious given the contrary approaches. Some techs advocate a very strong solution in the lower shoulder, others prefer a needling of the lower shoulder. Since I believe the goals are often similar it makes me wonder whether the approaches are driven by and personal bias and verified more be a placebo effect than anything else.
The function of the low shoulder is to support the compression of the top of the hammer on impact. As the top of the hammer compresses the low shoulder offers both some countering which aids in the hammer restoring itself to its precompression shape. If the shoulder is too firm and has no give then the compression of the upper part of the hammer is restricted, i.e, the hammer spring is effectively too stiff, too much energy is delivered to the soundboard via the string and we get something too percussive or harsh (short version). If the shoulder is too soft…well, can it be too soft? It's a good question. I'm not convinced that the hammer shoulder can be too soft unless the overall hammer is too soft. If it is the hammer absorbs too much energy, increases it's contact time with the string and the tone is lacking power and partial development.
Since hammers come out of the box fairly consistent in terms of stiffness, it is unlikely that the shoulder will be extremely soft while the area around the crown will be too hard unless it's made that way in the pressing using heat. More likely if the hammer is too soft then the entire hammer is too soft and needs to be hardened, or stiffened. That being said, the crown of the hammer will always be stiffer than the shoulders because of the pressing process which wraps the felt around the molding giving the most stretching and compression to the crown and the least to the shoulder. That is as it should be.
If the entire hammer is too soft, the best approach, then, is to simply saturate the hammer with the required solution to stiffen the entire hammer. It's unlikely that you will stiffen the shoulder too much. For that purpose I've written about the solutions and types of lacquer that I prefer, one which remains flexible. Pianotech sells that type of lacquer and there's some discussion that the lacquer that Steinway uses for dipping is also this type of "soft setting" lacquer that remains somewhat rubbery after it cures.
Applications should simply be over the top of the hammer or in from the shoulder as you prefer but a uniform amount which saturates the entire hammer to the core. I have done the apply lacquer from the side method and did advocate it at one time but in the end trying to control the wicking effect I think is a waste of effort and a strain on the back to tilt that action onto it's side.
Solution strengths, ideally, might vary in different sections with the weaker solutions being applied in the bass and the stronger ones in the high treble.
Once the lacquer has cured and you find some unevenness the focus of voicing should be on the upper part of the hammers. See illustrations below.
Phase 1 marks the area of needling when the low shoulder is too firm. This doesn't really apply to Ronsen hammers as the low shoulder simply isn't too firm. As I mentioned, the fact that some techs choose to actually beef this area up with strong solutions of lacquer and some techs offer that this area needs to be opened up on these hammers suggests at best some disagreement, at worst some confusion. I think best to just leave it alone. Renner and other hammers are another story and will need this area addressed to offer more give for the upper part of the hammer and a release of tension over the crown to open up the spring (see above illustration) (Note: I prefer this inverted triangle as the "avoid" place, though there are times when needling in this area can't be avoided. That shouldn't be the case with Ronsen hammers unless they are over lacquered).
Phase 2 is where it is likely that Chris should start to address the aggressive VFG hammers. Play and test at all levels and work toward the crown. I often turn the three-needle voicing tool so that the needles run parallel to the string line when working near the crown.
Phase 3 works nearer the crown with the needles pointed slightly away from the strike point. Again, here I work with the voicing tool turned so that the needles are in line with the string line. This is for delicate refinement
A comment on so called "Angel Shot" voicing. My own personal opinion is that this is effective but should be limited in use. The original procedure was a "through the string" procedure with a single needle so in the picture below the keyboard is to the right. It works because it softens the area very near, or on, the crown, widens the strike point as the needle will expand the felt near the strike point putting softer felt that is just off the actual strike point in contact with the string and damping some upper partials. It also allows the felt over the crown to release some. The problem with this method, if used in it's original concept, is that it always needles just one side of the hammer. If you do this repeatedly it will swell the distal side of the hammer and create a hammer which is somewhat lopsided in shape. One time to make a quick change fine, but I would argue against repeated use or this or as a method for addressing the entire set. Some balance between front and back of the hammer should be the routine.
Final refinements are done with direct crown voicing, una corda, etc.
To wrap up, the situation with VFG is that even though the hammers have been lacquered I would address the issues with Phase 2, 3 and final phase. I would ignore any shoulder needling (though if it makes you feel better the placebo effect is real). I would make sure in lacquering that a uniform application that penetrates fully has been applied with slightly stronger solutions toward the treble. Second and third applications, except in the very top notes, are rarely advisable but if you've applied the initial application poorly or too weak a solution you often don't have much choice. Lacquer changes the response characteristics of the felt especially on the backside of the hysteresis loop so if some hammers have more or less lacquer than others they will have a different timbre and no amount of needling will resolve that completely.
Good luck
(Sorry, no time to proof for typos)
Note: illustrations are taken from a book I'm in process of writing so are subject to copyright.
David Love
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David Love RPT
www.davidlovepianos.comdavidlovepianos@comcast.net415 407 8320
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Original Message:
Sent: 07-16-2018 00:27
From: Chris Chernobieff
Subject: Reducing Power in a Ronsen Hammer question
So i'm trying the Ronsens VFG felt hammers. This set was very soft.
Some basic steps I took:
Tuned
Hammers mated to strings etc etc.
Juiced around staples first (5:1)
Listened.
Applied juice to sides above mouldings Bass 15:1. tenor 10:1, treble 5:1 then over top.
Lower treble section still somewhat soft, applied a second application.
Now power has been developed. Piano sounding crude but i'm in the ballpark.
I have not juiced the shoulders at all.
Now i'm working on smoothness, finding notes i like and altering the neighbors i don't to match.
Question:
Some notes are too powerful. Curious what go to technique others have in this situation. Is the needling technique (in the picture) used by anyone?
It uses a single needle aiming for the middle of the "triangle" zone from the horizontal. Since the lacquer stiffened that area, wouldn't it make sense that a needle can reduce that.
Thanks in advance
-chris
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