Guesstimate is about 500 lbs. I pretty much follow the Baldwin Accu-just procedure. .5 degree at tenor up to 1 degree at treble, .5 to zero at bass. Let it self load.
It was a little ordeal to use that procedure without accu- just pins but its creatively do-able. It just takes me 3 times as long to string a piano is all.
Original Message:
Sent: 12-09-2021 18:32
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
What was the load? I have been backing my loads way down as well.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-09-2021 16:11
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
As requested.
"I can appreciate the posting of experiments and explorations, it's how we improve. But the data is important. What I'd like to hear in this discussion is: this is where I began (all rib dimensions and details) and these are the changes i made (new rib dimensions etc). This resulted in a change in weight of X…
Changing the scallop simply will not result in 5lbs of reduction. Wood doesn't weigh that much. So what I want to know is where you started and where you ended up. Otherwise It's impossible to determine what actually changed and whether that change was warranted. That you liked the sound when you were done is not meaningful data.
I agree that some pianos might be overbuilt and that rib scales can often be improved. But I don't agree that most assemblies are overbuilt, certainly not with Steinways (the bulk of my experience). "
The original rib scale
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-08-2021 21:40
From: David Love
Subject: Great results not following the impedance theory.
I can appreciate the posting of experiments and explorations, it's how we improve. But the data is important. What I'd like to hear in this discussion is: this is where I began (all rib dimensions and details) and these are the changes i made (new rib dimensions etc). This resulted in a change in weight of X…
Changing the scallop simply will not result in 5lbs of reduction. Wood doesn't weigh that much. So what I want to know is where you started and where you ended up. Otherwise It's impossible to determine what actually changed and whether that change was warranted. That you liked the sound when you were done is not meaningful data.
I agree that some pianos might be overbuilt and that rib scales can often be improved. But I don't agree that most assemblies are overbuilt, certainly not with Steinways (the bulk of my experience).
i also strongly disagree that "any hammer will work". Scale tensions dictate the strength of the assembly and that often affects hammer choice. I think that is without question. The so called "impedance model" is one that is used to determine the best hammer fit for a given assembly. That is often and empirical decision, i.e., this hammer is too aggressive or this hammer is jnadequate to deliver what I need and voicing will not get me to where I want.
For pianos with similar scaling and therefore similar assemblies with respect to support, one would expect that hammer choices would be similar. Whether you go with a Renner Blue Point or Ronsen Wurzen the requirements are all within reach by normal voicing. But where the scaling and soundboard structures vary from low tension and light to high tension and heavy you would expect, and you would be right, that the hammer requirements would be somewhat different. Similarly, on older, compromised soundboards that are still functional you might expect that there might be a hammer that would be more or less suitable.
My goal with hammer selection, and this is where most of us fall and was the impetus for discussing the "impedance model" in the first place, we are not redesigning a soundboard. Instead we are developing a sense of best fit for a particular piano and that is a critical skill. That choice, IMO, is largely driven by the impedance characteristics of the existing assembly.
How light or how heavy to design a new assembly is almost a separate discussion. Many new "redesigns" I've seen are, in my opinion, too heavy, or more apt, too stiff. That creates its own set of issues that can also affect hammer choice. But impedance, which I define as the resistance to the rate of energy transfer, is an inherent characteristic of pianos and is something we deal with knowingly or not.
------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
Original Message:
Sent: 12-08-2021 09:25
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
I get that these are in-process experimental techniques...so are many of my posts, like the titanium bridge pins. I'm still not sure whether that was something I will do again. At first, after doing a whole spec piano belly with them, I thought...no. But then, after letting it sit and ignoring it for about 4 months, I went back to tune it up to sell it, and by golly that small previously horrible piano sounds damn good...I need to get some other tech ears to see what they think...but yeah...its an in process thing...proceed at your own risk.
So, in adjusting the rib, are you extending the long side scallop when you fine tune the balanced amplitude, or do you retain the long side scallop length and remove other material. The reason I ask this, is that in a previous experiment I tried, extending the long side scallop was a real bad thing to do. One needs to make sure there is sufficient connection to the rim, otherwise the near-rim conditions will board bypass the entire rib structure in the main field of the panel.
Dials set equidistant relative to what?...the clamp points?
Re Craig and Richards experiment:
the anti node is the point of maximum amplitude and excursion. I think you may be mis-understanding what they are proposing. In all their re-crown projects, the bridge is off what would be considered the crest of the crown(crest is not necessarily or usually centered).The crest of the crown is controlled by the rim being beveled or flat, or a combination of the two. Reason being that the crest of the crown, in accordance with their tests, is the location that is less compliant and most resistant to load. Bridges are set slightly off to the side of the crest. Their view is that the loudest area of the piano soundboard is not at the crest, but slightly off to the side.
I think this challenges the mental concept that many of us may have, that the board is a simple diaphragm, pulsing in simple opposition to simple transverse string movement. And I think any of the scientific demonstration of SB nodes has shown this...it is not a simple up and down thing at the bridge.
This, by the way, agrees to some degree, with my own diagnostic explorations. In experimenting with mass loads, in existing or old boards, the location right smack under the bridge is not usually the ideal location for the mass. Slightly off to one side by just a couple of inches, and wolf tones open up in the treble. Its really quite amazing. As well, in trying to address unwanted resonances, which a wolf tone is, the way to defeat a resonance is to impose an asymmetrical force to the system. So, the intellectual bias, that middle of the system is best, which we probably all assume, at least at first, is something that has to be tested and challenged, and experimented with.
I know you and probably all techs are of the belief that mass loads are the work of the devil....but sorry...biases and beliefs die hard. One needs to see what benefits a laser guided, asymmetrical, rib applied mass load, has to offer our imperfect constructions. Especially what it has to offer in the existing imperfect boards we face every single day, day in and day out, on the job, and in the concert hall.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-07-2021 23:45
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Jim,
Please remember that this is still experimental and i am exploring and trying different methods.
On the scalloping I'll remove any material on the long side to match the deflection on the short side from the bridge location. The short side, i always make the scalloping the same length and match the long sides deflection to it. If a piano has 4" scalloping i'll keep it, or if it has 6" scalloping i'll keep it. Its the long side i manipulate. Dial location is set equidistant. Good question on the jig setup, which shows you have tried this before. I was having that problem with clamps, but the square hole/wedge setup works fine.
I found that there is an interesting natural layout of the rib structure, kind of a natural twist involved that is somewhat synchronized with the curve of the bridge. Up in the treble the long side is on the curve side. Then there always a symmetrical rib ( I call the pivot rib) then the long side switches to the spine side for the rest. Don't know if it means anything though. Just an observation.
What Craig was doing was not exactly the same. In my view, the bridge location is a driving point, which has a different function than nodes and anti nodes. I want the driving point to be where the board has maximum movement for energy distribution. An anti node is more of a little boost for the radiated energy. So i don't think Craigs experiment is valid.
So far, on panel thicknessing i have been using pairs of dial indicators on each rib location, and placing weight on the bridge to check deflections. Then plane and sand to get the long side to move like the short side. So for this method, the corner area that others remove with cut off bars have been a valuable area for equalizing and centering the bridge. I'll probably post a video in the future on the panel thicknessing when i'm satisfied i have a procedure i'll stick with.
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-07-2021 22:32
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
OK....now we're getting somewhere. A couple of questions:
On the scalloping, are you reducing the thickness of the thinned portion of the rib to center the amplitude? Are the indicators located at the point where the scallop becomes full dimension height?
How are you determining where to thin the panel to match the rib scalloping?
Clamping the test rib effects the deflection of the rib big time. How are you clamping the rib so that you are not influencing artificially the clamp stress, in a way it will not be influenced when glued in to the rim?
Are you aware of the interesting work Craig Hair and Richard Blais are doing in their re-crown conservation work? They feel there is decent evidence to suggest vintage board makers were in fact tuning their ribs, but tuning them so that the bridge is located on an anti-node, which generally is not centered on the span. Beveling of the rim or only beveling certain parts of the rim, also effect the center of amplitude and other nodal behavior of the rib.
Craig Hair Richard Blais Wave motion of a piano rib 3 videos
Note that in your centering the amplitude, mass loads are used as a diagnostic. There are other ways to use mass loads as a laser like diagnostic. Many boards exist that don't need to be torn out, especially given the scarcity of fine old growth spruce. Using diagnostic tools, without bias as to what constitutes a true blue piano board , can return those boards and their excellent aged wood to excellent musical service.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-07-2021 21:56
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Jim,
I agree with most of what you said,but, i did explain what i do empirically in the first opening post.
I removed 5 lbs of weight off of the Baldwin SD6 soundboard. Here is some other changes, although you have heard them from me before. I redesigned the rib scale for evenness, scalloped them differently, so they place the bridge in the center of amplitude, and tapered the panel so that its synchronized with the scalloping.
With the last few boards, i began to notice that when the excess weight was removed, the well known impedance problems were going away. No vice grips on bridge pins or brass weights needed to fix annoying loud notes. No riblets needed either. I wasn't concerned at all about hammer weight (not enough or too much from an energy input point of view) as i have been using the same hammers on the last 10 pianos, regardless of size of piano. Before i started being concerned about the weight of the board, the final outcome was unpredictable, with riblets often being needed to blend the notes.
2 videos aligning the Center of Amplitude
https://www.youtube.com/watch?v=b7PUihwYMOY
https://www.youtube.com/watch?v=54MUvzuiquU
Performance on the Baldwin when delivered
https://www.youtube.com/watch?v=Mmnd5fpC3Hw
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-07-2021 20:31
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
Chris <The title of the thread was chosen to emphasize the value of empirical methods.
Well... it didn't work. Your title and presentation achieved the opposite of your supposed intent.
This thread supposedly isn't about impedance, but that's all we are discussing. We could have discussed various empirical methods that you are discovering for yourself, but we are not. Instead, fueled by the title and your presentation, we are not discussing impedance, which, of course, we are discussing , even though this tread is not about it. We are not discussing impedance, by discussing impedance. The whole thing is rather absurd.
How about just telling us what you did empirically?
There is no conflict between understanding a complex system theoretically, and understanding a complex system in a hands on, holistic, concrete , empirical way. Some brains can utilize theoretical and abstract concepts, and some brains get tripped up in the abstract. There is no conflict between these two approaches. They are in fact complementary. Each approach can inform the other.
To some brains , like mine, theoretical concepts and terminology are an impediment to understanding the complexity of the structure as a whole. This is not because there is no theory that explains it, but because my brain cannot process the sheer complexity in an abstract way. Instead I, and it looks like you, understand the complex system, in a more holistic, hands-on, real-time, visual, empirical way. I actually get slowed down and confused by the theoretical, but I can understand it, if I can touch or see it.
That does not mean theoretical abstraction is incorrect. It means some brains can work better from the abstract to the concrete, and other brains can work better from the concrete to the abstract. Both can master the system in their own way.
You are having trouble seeing that your way of thinking is not the only way it is possible for a human brain to grasp the system we are working on. Or said another way...there is no "one true way", Grasshopper, they are all complimentary.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-07-2021 14:56
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
David,
A misrepresentation again.
First, i only have to prove my results to my clients, not you.
Second, i have presented oodles of data, here and elsewhere. I have published many rib scales, and discussed how i arrived at them and what i was after. I have also made hundreds of videos of many of my procedures. Further supported with the observable conclusions of comparing weights of before and after soundboards on a digital scale. Also on several videos.
So its not that i have refused to post facts, its that all along the way you have dismissed those facts.
Steinways, are light boards, but they are laid out incorrectly in my opinion. They weaken too much where it needs to be the strongest. I can usually remove a 1/2 to 1 pound off, and rearrange the parts slightly to work better and be more durable.
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-07-2021 13:32
From: David Love
Subject: Great results not following the impedance theory.
I do have degree in psychology actually. Focus on cognitive psychology and the psychology of perception (that's why I have to make my living as a piano tech). But it does have interesting applications in our trade. However, I did stop short of my doctorate so calling me Dr. would be inappropriate.
Impedance is a fact that is indisputable in soundboard performance. Whether or not we use impedance formulas is beside the point. We respond to impedance characteristics of the board in several different ways from assessing a design and comparing percussive power to sustain or voicing or changing hammers. In soundboard design I don't use impedance formulas. There are other formulas, for example load bearing, that allow us to quantify changes in a way that directly affects impedance. The assessment we make especially along the power/sustain continuum is an evaluation of impedance in which both mass and stiffness play a role though stiffness is probably more the issue there. Mass loading, btw, something you mentioned, is often to compensate for something that is too stiff in order to slow the board down. Mass is not a substitute for stiffness. Riblets are designed to add stiffness with minimal mass. Most boards that get compromised do so because they lose stiffness and thereby the impedance is lowered and they become more percussive with shorter sustain. It is natural then to assume, or at least question, whether removing 5lbs of material might compromise the board's stiffness.
I questioned what you expressed originally as a standard procedure of removing 5 lbs of material from the board as potentially problematic. On Steinway pianos which, I rarely find overbuilt, removing nearly a third of the weight would be worrisome. I've asked you several times to give me the details for example changes in panel thinning or changes in ribs dimensions to account for those changes, exactly where you removed materiel from and the before and after dimensions so that I can make some quantitative assessment of what it is that you're doing. So far you've not responded with any real data so as far as I'm concerned you're just blowing smoke.
I have no doubt that some assemblies are overbuilt but until I see the data I have no way to assess what you're doing. I don't need your baseless snark or self congratulations, just the facts sir, just the facts.
------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
Original Message:
Sent: 12-07-2021 11:36
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Dr.'s David and Jim,
I'm just asking a piano related question. Not to question your Psychology degrees, but your evaluations are quite far off.
My question is "How is an Impedance formula used in Piano Technology?"
I don't remove weight for its own sake off my boards, as David has falsely implied. I have removed 5lbs through engineering refinements that were made possible because existing designs are basically overbuilt. In all the other branches of acoustic musical instrument making, that's pretty much what everyone else is doing too.
Its bad design that can add excess weight and create tonal irregularities. I've addressed those issues by applying what I've learned from the previous boards, and not making the same errors on the next board.
How does the impedance formula solve those problems? Like I have already stated, an electrician has a meter and can measure it immediately and make a determination as to transistor and wire choices. There's no such tool for hammer/ string/soundboard mating.
The title of the thread was chosen to emphasis the value of empirical methods.
Thanks,
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-06-2021 23:00
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
Well let's be clear, Chris is, in fact, is the only one who really knows how old the world is...every one else is either a scoffer or a pretender.
I envy that level of certainty about everything.
Interesting thing is, that he doesn't realize, that if you want someone to consider your point of view, hitting folks in the head, doesn't tend to convince folks of anything. Well...it does convince them of one thing...that would be to avoid conversing with you. If you want someone to listen to what you may have to say, and consider your thoughts, it works way better, if it is stated with some modicum of positivity and camaraderie...some shared experience.
The negativity that accompanies all his declarations of truth, is simply not an effective way to get his point across.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-06-2021 21:39
From: David Love
Subject: Great results not following the impedance theory.
This is like having a geology discussion with someone who thinks the earth is only 6000 years old.
------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
Original Message:
Sent: 12-05-2021 17:34
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Well Jim,
The definition is on the internet.
Webster: Impedance- the ratio of the pressure to the volume displacement at a given surface in a sound-transmitting medium. There are quire a few videos of electricians measuring it on electrical circuits with meters.
My post, was a claim, because no one has fully explained how you use the impedance theory in practice making soundboards or matching hammers to them.
Other techs have said i'll have impedance problems when reducing soundboard weight without offering proof as to why they say that.
So i have asked " how do you measure the impedance of a soundboard? And the Hammer? And use that info to predict an impedance issue?
So instead of espousing a theory, to force a curious person down a theory hole. How about a real conversation about techniques that are actually used in practice to fix or prevent soundboard/hammer matching issues.
There was discussions in the past about mass loading, then there is also riblets. But these are "after the fact" fixes.( I've left out the music wire choices because riblets, mass weights on bridges, and vice grips on bridge pins indicate a soundboard problem). I think, the problem is the design, and that a good working soundboard will accept ANY hammer. My claim is that a soundboard made correctly via "light in weight" and an "even rib scale" will address the tonal focal problems. That is what my last soundboard and hammer choice showed.
I used Renner Blue points on an Baldwin SD6 with a light weight board, and the same hammer on both a Baldwin R and M&H A, with lightweight boards. All were beautifully balanced across the scale. None have riblets, mass loading, and with original scales used.
I was told the removal of 5lbs of weight would cause impedance problems. It didn't and hasn't.
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-04-2021 14:53
From: Jim Ialeggio
Subject: Great results not following the impedance theory.
Chris,
Intentional or not, throwing out a term, any term, without clearly defining that term, sporting a negative connotation, is a "dog whistle". Dog whistles elicit emotional responses but communicate nothing...by design. Dog whistles are only useful for someone wanting to create division, and seek advantage. They do not communicate actionable information.
Since I am fairly certain you did not intend this post to be a dog whistle, it behooves you to define, what it is, you are not following. We need a clear definition from you, as to what exactly the "impedance model" is, in your mind. Since the term and context is yours, you need to describe what is is you are not following. I have no idea what you are referring to precisely.
WIth a clear definition from you, maybe we can arrive at a shared definition. Then, there will be room for communication and for folks to consider thinking differently, about how they approach this whole topic.
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-03-2021 20:26
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Keith,
Thank You for some of the inside stories.
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-03-2021 11:01
From: Keith Roberts
Subject: Great results not following the impedance theory.
Chris,, yeah Dale had me build his soundboard press, it was about the first thing I did in his shop. He had a dished caul that used go-bars. A hydraulic one on a base the firedept could use to break in doors. The pressure tubes that were mounted on 2 x 10s were too short to span the dished caul. I cut the caul down, shortened the all thread rod to fit and plumbed individual valves so you could set up and pressure each rib separately. Then I built a heavy simple base for it. I think he had pressing a board down to an hour.
I got to listen to a few boards. Getting a board to boom took a week or two of curing. He had one Steinway B in the final room and it had an ethereal sound that made my eyes water. Literally. My bench was in that room and people would stop and play a few notes,,,,, it was like they were stunned. One person said it made his mouth water.
Dale commented on the old boards he took apart and how on the bass end, the short sort of corner board was a wide grained cruddy piece of wood. I believe you can actually separate the sound board from the rim along that board and free up the sound. About the last time I saw a board,, he had put a cruddy piece of wood there.
It's all good in practice but it will never work in theory.
------------------------------
Keith Roberts
owner
Hathaway Pines CA
209-770-4312
Original Message:
Sent: 12-02-2021 14:16
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
Ian,
Why thank you for the unexpected compliment. These were Renner Blue Points and i voiced them this way. Bass section I applied B-72 (1 pass for bichords, 2 passes unichords about a 1-16 mixture), top 6 notes also received B-72. The rest i applied All fabric softener (2 passes with a mist sprayer) to the shoulders which opens up the sustain. (I covered the tips with 1/4" masking tape). All of these procdures are not Renner approved. But the velvety sound is a plus. I then finished of with 150 to V-shape (Darrel Fandrich called it Viper voicing) then 600 to smooth and 1500 to slighty brighten any softies that appeared.
Keith,
Funny you mentioned Erwin. He's really intrigued with my concept of making boards lighter also. He just texted me the other day, and said he had removed 2 lbs off of a Steinway O. I can't wait to hear any feedback from him.
David,
That's my point, most are overbuilt. Especially so with off brands. For the most part Steinways are the lightest because of the diaphragmatic, but it could be done better.
I did a 20 video series of the Baldwin rebuild. Go to playlist and look for Baldwin Restoration on my channel. One video, i have the old board and the new board side by side. 5 lbs hardly make a visible notice. It's subtle.
-chris
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
Original Message:
Sent: 12-02-2021 13:49
From: David Love
Subject: Great results not following the impedance theory.
Without knowing the before and after dimensions (panel thickness and rib dimensions: length, width and depth and include crown and downbearing settings) it's hard to make any comment. How do we know the assembly wasn't overbuilt to start?
------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
Original Message:
Sent: 12-01-2021 21:42
From: Chris Chernobieff
Subject: Great results not following the impedance theory.
I post this NOT to be snarky or as a calling out of others, but to further the conversation for positive advancement. I was concerned about some of the past postings regarding impedance mismatching. Since my theories are somewhat opposite in nature, as mine is empirically based rather than theoretical based. My theory was to make a soundboard as light in weight as is structurally possible, and to apply a light downbearing load so that less energy is wasted getting the mass to move. Essentially energy efficiency.
Attached is a link to a video i just posted on my youtube channel of a pianist coming to my shop and playing on a Baldwin SD6 i just rebuilt. The soundboard is 5lbs lighter than the original was. The hammers i used are Renner Blue Points. So if there was going to be an impedance concern, this was it.
There was no soundboard impedance issues perceived whatsoever by me or the pianist. No barking, loud, or obnoxious wolf tones. No under power or over power. By going "light in weight" only resulted in a fully responsive, singing, and full dynamic range piano.
So what better test than asking a competent pianist to put the piano through the lightest and heaviest pieces in the repertoire?
And getting real time feedback? Besides its always interesting and educational the dialog that can happen between Pianist and Technician
Anyways, I hope you'all enjoy the video.
-chris
https://www.youtube.com/watch?v=QFC7pOCDWho
------------------------------
Chernobieff Piano Restorations
"Where Tone is Key"
chernobieffpiano.com
grandpianoman@protonmail.com
Lenoir City, TN
865-986-7720
------------------------------