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Looking for tips to lighten the touch

  • 1.  Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-26-2015 15:39
    Before you start pulling out the high tech stuff, this is a Knabe WGS-54 made in 2011, right at the peak of Samick's QC issues. 

    The biggest problem this piano has is that the action itself is just wrong. Everything is either sitting too low or the hammer shanks are too short, or something. None of the hammers are striking in the center but rather a bit further back on the hammer. Customer has complained from the start that the piano is not responding well and that it is touch heavy.

    Considering what it is, I have regulated it as best I can. Even going so far as to raise the blow distance a tiny bit and delay the damper timing to the point where the dampers are just barely lifting at all. While he says that it's a lot better than it was, the complaint that he is not getting the performance or dynamics he wants, and that the piano still feels heavy remain. Personally, given what the piano actually is, I think it's about as good as it's going to get.

    Player is a college kid living at home. Extremely talented player. Problem is that parental units have made it clear that replacement is not an option. At least not yet. He deserves better.

    So, today's question: What else can anyone here suggest I try to improve performance and dynamics that I may not have already thought of. 

    I just remembered I have a PitchLock Touch Rail demo in my case. I will bring that with me on next visit. Adding one of those will probably help the touch weight, but it's not going to do much for performance and dynamics. 

    -- GS

    -------------------------------------------
    Geoff Sykes, RPT
    Los Angeles CA
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  • 2.  RE: Looking for tips to lighten the touch

    Posted 01-26-2015 18:53
    The hammers are over striking and the top action needs to be elevated. The top action may need to be repositioned further back on the key frame (look at the capstan impressions in on the wip cushion). Especially if the jack is imbedding into the rep stop felt (consider key dip). If repositioning the top action badly affects the strike point, move the key frame forwards (look at the space between the key fronts and the key slip).

    The hammers will need to be tapered to reduce weight. If there are assist springs, they probably didn't place any lead in the bass keys and hoped the springs would pick up the slack.

    Moving then top action back 3 mm lowered the BW 4 g and the F 2 g on one action.

    There probably is too much down bearing and side bearing in the bass as well.

    -------------------------------------------
    Regards,

    Jon Page


  • 3.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-26-2015 23:29
    I have worked over a few of these Samick messes before. I agree with Jon's findings in general. The ones I have done needed the top action raised about 1/4". Make sure the action will clear the pinblock. I haven't yet had to change the in/out position of the action frame. The pinning usually needs redoing because of mystery sluggishness. Dampers included. Tapering hammers #1 to #88 enough to allow a slightly heavy weigh off, (65grams at #1 tapering to 50grams at #88), using a maximum of two front leads, eliminating whippen assist springs, and good solid spacing and regulation will make the thing nicely playable and better sounding. Unless the present hammers are really bright-then replacement may be the only way. Because as you reduce hammer mass the tone gets brighter. You can also swap out the brass capstans for the W,N&G aluminum ones to reduce weight by about 2 grams. Hope this helps and GOOD LUCK!

    -------------------------------------------
    Edward McMorrow
    Edmonds WA
    425-299-3431
    -------------------------------------------




  • 4.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-27-2015 11:42

    Geoff,
    Jon and Ed's recommendations are very good. I would like to add: Check the friction (down weight minus up weight divided by 2) if it is more the 20 grams you might check the balance rail pin to capstan to wippen center pin alignment. They should be in a straight line at half travel. If not, you have a serious problem to overcome.
    -------------------------------------------
    Roger Gable
    Gable Piano
    Everett WA
    425-252-5000
    -------------------------------------------




  • 5.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-27-2015 15:05
    I have not found that variations in the so-called "magic line" are responsible for problems of this nature.  Moreover, I find that some variations on this half-blow position are not uncommon and tolerated with few if any consequences.  

    Certainly if the friction is above 20 grams (even above 15) there is a problem somewhere but I would look elsewhere than the magic line. Of course, if it's grossly off then there may be a problem.  

    In general the first place to look is probably the relationship between AR and hammer weights.  Short boring will not create excess weight problems, just the opposite.  Raising the shank angle to accommodate a short bore will reduce the downweight. 

    Jon and Ed have spelled out several good approaches and Jon's suggestion to reduce the HW infers a problem with the AR relationship. Raising the stack is fine but it may also increase the balance point to top of capstan distance which will increase the AR, if I am not mistaken.   

    -------------------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    -------------------------------------------




  • 6.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-27-2015 15:07
    BTW, if the AR/HW relationship is off I would prefer to change the AR by shimming behind the balance rail.  It requires a resetting of the key height but it's cleaner and easier and without the tonal consequences of taking mass off the hammers, if that's even possible to the extent needed.  If the hammers are bored incorrectly, however, you may need to address that as well.

    -------------------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    -------------------------------------------




  • 7.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-27-2015 19:28
    Jeff,

    Many good inputs from others to consider.

    Can we assume that suffering dynamics and performance means both tone and touch? In any case if we focus on the action we could use a few simple parameters, such as what is Downweight and Upweight on some selected notes? Is friction an issue? Are the glides properly set?

    What is the hammer bore at, say, note # C40 and A 61? It may be that the action elevation is fine but the factory bored the hammers too short, or vice versa. The standard bore equation would help.

    Measure key bed to string height, say it is 7.5" (190 mm). Next, with action on flat surface, and using a thin steel ruler, measure from the flat surface (represents keybed) to the center of the hammer flange bushing, say it is 5.625" ( 143 mm). Now subtract 143 from 190 and you have the correct theoretical hammer bore dimension of 1.85" (47 mm).

    This simple process will accomplish two things at least: 1) you will know if  the bore dimension relates at all to the action elevation (which may be wrong), and 2) if  the bore is "wrong" and you need to raise the stack now you know how much to raise it. For example, say the bore is supposed to be 47 mm per the math but you measure 43 mm on the actual hammer. Well you see that raising the stack by 4 mm will cause the hammer to center-strike and not over center. This alone will help things get better.

    Given that you are stuck with the bore as is, then you need to work backward. Subtract the bore dimension you have, again say 43 mm, from the keybed to string height, again say 190 mm, and what you have left is what should be the keybed to hammer flange center dimension of 147 mm. But if your actual measurement is only 143 mm you can see that the action stack needs to be raised. Set the action elevation (raise it) to this to get the hammer to center-strike.

    The capstan will have to be raised by the 4 mm (+ or -) to take up the slack, but the effect will be to mostly increase the dip (you will need to add punchings to the front key pin). The impact to forces and masses will be minor. Your magic line may improve or not. But the interface of jack top to knuckle should improve throughout the stroke.

    After raising the stack, adjusting the capstan, resetting the dip you need to check for strike-points and tone in the upper treble and adjust the action in or out (probably out a bit) for optimum tone.
     
    We also could use strikeweight measurements at various notes. Also, what about key leading? Is the touch inertia-heavy or downweight heavy (related but not the same thing). Ed McMorrow is right in suggesting that a heavier static DW coupled with a relatively lighter hammer and fewer leads is far less tiring to play than a lower static DW coupled to a heavier hammer and more key leads.

    This could go on and on and I know you need simple answers, but there are no simple answers. The evaluation is, however simple, and is a matter of following the steps. So feel free to contact me privately if you like (we've known each other for a long time) and we can go through a more comprehensive procedure, after which we can let the list know of what has been done.

    nick





  • 8.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-27-2015 20:07
    Great information and recommendations. Thanks. Exactly the kind of feedback I was hoping for. I revisit this piano next week and will definitely have my gram weights and ruler with me. I will report back.

    Thanks everyone.

    -- G

    -------------------------------------------
    Geoff Sykes, RPT
    Los Angeles CA
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  • 9.  RE: Looking for tips to lighten the touch

    Posted 01-28-2015 07:19
    You can set the HCH as Nick outlined, then elevate the wip rail so the WCH is 6.4 mm lower than the HCH. If there are assist springs, only have them strong enough to support the weight of the wippen, or affect the DW by about 10 grams (one lead).

    -------------------------------------------
    Regards,

    Jon Page


  • 10.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-30-2015 11:28
    I'd like to mention that this is just the sort of situation in which the Fandrich/Rhodes Weight Bench software can be VERY helpful. If, as seems likely, the initial factory setup of the action elevation relative to keys and strings was off significantly, that would not be addressed by the software, but beyond that, it would help you analyze how a change in spread, a change in capstan line, change in hammer mass, etc. would impact the touch. 

    My first step would be simply to assess friction, and the simplest way to do that is purely upweight: use weights of 10 g, 15 g, and 20 g. Place them on the key, depress key to the point of drop screw contact with pedal depressed, see which (if any) of the weights each key will lift. That will find you the worst culprits, and investigating the causes will give you a very good idea of the overall situation without the trouble of measuring DW and UW of all keys and calculating. I'll also mention the possibility of knuckle leather being loose, just something to look at. That can cause a very heavy seeming touch, without showing up "correctly" in terms of UW, DW and friction.

    -------------------------------------------
    Fred Sturm
    University of New Mexico
    http://fredsturm.net
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
    -------------------------------------------




  • 11.  RE: Looking for tips to lighten the touch

    Posted 01-30-2015 16:47
    You can have high friction with a 30 g upweight. You need to survey DW as well. The balance rail hole could be too tall and too tight, tight bushings too.

    -------------------------------------------
    Regards,

    Jon Page


  • 12.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-31-2015 13:48
    True, it is theoretically possible to have high UW (30 g is way high) and still have high friction. But have you ever run across a piano where that was the case? I merely suggest that as a practical matter, measuring only UW (i.e., checking each key with a weight and noting the ones that can't lift 15 g) will get you much faster info than going through the whole analysis. It will show you the tight key bushings, the notes with tight centers, the rubbing parts, etc., in the vast majority of cases. I'm after maximum efficiency in use of my time. 

    OTOH, if more of an in depth analysis is needed, at least a spot check of DW vs. UW is a must: but friction must have been dealt with in order for that information to have value, as high friction will mask and distort information based only on mass. 

    -------------------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
    -------------------------------------------




  • 13.  RE: Looking for tips to lighten the touch

    Posted 01-31-2015 16:43
    I have found high UW with high friction many times. I have also found low UW with acceptable F.

    -------------------------------------------
    Regards,

    Jon Page


  • 14.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 01-31-2015 16:53
    Measure twice cut once.  To measure the DW along with the UW doesn't take that much longer and gives you a lot more information which you will ultimately need anyway.  Even if it took you 15 seconds to measure the DW that's only 20 more minutes.  What one does see is a low UW with a low BW and not necessarily excess friction. With the BW you can determine the SWR (though I prefer the geometric method for this), you can know the exact amount of friction and make sure you aren't shooting in the dark.  You will want the DW along with the UW at some point so you may as well have it from the start.  

    That being said I would start by addressing all the friction points before taking UW and DW measurements.  Make sure the keys are eased and not binding on the balance rail pin, flip the stack and see what kind of swings you are getting on the hammer flanges, check the wippen centers at the same time, powdered teflon on the knuckles, lube the key pins and capstans.  

    Short cuts usually make for long delays.

    -------------------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    -------------------------------------------




  • 15.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-01-2015 18:06
    Obviously my mention of a "shortcut" of just doing UW as a first step leads to all sorts of push back as to why that is the wrong approach. I certainly don't advise it as the one isolated thing to do. However, I do find it to be a very useful way to find out a lot of things quickly. As I pointed out, it will find those rubbing parts, the tight key bushings, the close to frozen hammer flanges very efficiently (i.e., it will find the notes where those items occur - you still have to hunt for the why). 

    We tend to focus more on DW. UW will tell us more faster (in a practical sense, things to be corrected so that you can now see what you have). And it will identify where the major friction problems lie in a majority of cases. I will repeat, in slightly more detail, what I said initially: I am not writing things down. I am simply going through with 10g, 15g, and 20g weights, seeing if each key will lift at least 10g. This is one minute of work. Flag those keys that won't lift 10g. See if you can figure out why they won't lift 10g, and correct it quickly. Now go through with 15g. The 20g is mostly for a a possible case where there is very little friction and there may well be a mass problem (usually too heavy hammers). If all or most of the keys will lift 20g easily, that is pretty indicative. In five minutes I have made a good bit of progress toward an assessment. I know far better what I am facing, and I might know some of the things I should be addressing first.

    As I wrote before, my personal recommendation for in depth analysis is to use Weight Bench software, which will include geometry and UW/DW/BW, and provides accurate means for predicting the results of changes you may make. 

    -------------------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
    -------------------------------------------




  • 16.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-01-2015 19:56
    Am I correct that all these measurements are taken with the damper pedal depressed?

    -------------------------------------------
    Geoff Sykes, RPT
    Los Angeles CA
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  • 17.  RE: Looking for tips to lighten the touch

    Posted 02-02-2015 06:40
    Think positively, the pedal is not depressed, the dampers are raised up.

    Another way to look for sluggish keys is to raise the dampers :-), press down a group of keys with your hand and observe any slow returns at both the key fronts and hammers.

    -------------------------------------------
    Regards,

    Jon Page


  • 18.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-06-2015 00:39
    I serviced this piano today and here is what I found.

    String height note 40 = 203mm : flange center = 148mm :: difference = 55mm :: bore = 48mm :: difference = 7mm
    String height note 60 = 201mm : flange center = 148mm :: difference = 53mm :: bore = 48mm :: difference = 5mm

    The grooves in the hammer are most definitely showing on the back side of the hammer. They pretty much stop at the center point. This demonstrates to me that the hammers are overstriking and the stack needs to be raised. 

    Clearance from top of flange screw to bottom of stretcher is about 11mm.

    Based on what I believe I've learned from this discussion, current plan is to raise the action stack by about 6mm and re-regulate. 

    Question: Can I use something as simple as washers on the screws to shim this up, or do I actually need to make a shim that will run full length between the front and the back screws of the action brackets? Is wood OK or should this be metal?


    Touch weight:
    Full regulation about a year ago. All friction points have been checked, lubed, teflon lubed, eased, etc. Knuckles and jacks are aligned correctly. This is current touch weight on two notes, with dampers lifted. (Sadly, I did have to "depress" the sustain pedal to accomplish lifting the dampers.)

    A3 : DW = 40g :: UW = 12g :: difference = 28g
    A4 : DW = 39g :: UW = 19g :: difference = 20g

    Not to forget that this is a three year old entry level Knabe, by Samick. The plan is to re-evaluate touch weight again after the above action work is completed. If there is no significant improvement then I am thinking of keeping it simple and going with a TouchRail system. According to Scott Jones, this should allow me to reduce the DW by up to about 10g with no problems.


    Looking for further comments on this project.

    Thanks everyone.



    -------------------------------------------
    Geoff Sykes, RPT
    Los Angeles CA
    -------------------------------------------




  • 19.  RE: Looking for tips to lighten the touch

    Posted 02-06-2015 07:19
    You can place spacers under the bracket feet. For that thickness, fashion wooden shims. I have also built up with thick card front rail punchings and installed a pan head screw for support on lesser rises.

    The touch weight is too light. The BW is 26 and 29, I would shoot for a BW of 38 grams which means removing 12 to 9 grams, respectively, of FW. Are there assist springs? If so, relead the keys for a BW of 48 grams and tension the springs to target 38 g (just supporting the wippen). With a 38 BW on those two notes: 52/24, 48/28. With F being 14 & 10. A sample from the bass would have been nice.

    Elevating the top action may alter the Strike Point and it may have to be repositioned. Also, the capstans may need to be replaced with longer ones if  backing them out that much causes them to be loose-fitting. When raising the top action, make certain the WCH is 6.4 cm lower than the HCH.

    Another aspect to watch for is the excursion of the jack. At rest, the knuckle core should align with the jack center (Action Spread usually is 113.5 mm). With the key fully depressed, the jack should be just in front of the knuckle and not jammed into the stop felt at the end of the rep lever.

    -------------------------------------------
    Regards,

    Jon Page


  • 20.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-06-2015 10:09
    Jeff,

    Now that we know some facts, raising the action is the way to go. The original bore of 48 mm appears to be more or less standard, thus "correct" as processed at the factory. So one wonders what happened when it came time to set the action stack height; or is the pinblock and entire string plane set too high.

    No matter. given your data, it may be that you need not turn the capstans up terribly far after you reset the stack. Think of it this way. I assume that you set a blow to 44 - 46 mm in your recent regulations.

    (If not, then I cannot imagine what else you might have done, in which case ignore most of what follows).

    In order to set a workable blow relative to (what we now know to be) a too-low sitting stack and / or a too-high string plane (unlikely I guess), you must have already turned the capstans up beyond some normal range. Now as a thought experiment imagine things as they are and with the blow set to 45 mm; now imagine that the stack screws magically unscrew and remove themselves after which the action stack floats upward off the frame and off the capstans by 6 mm, but the rotational components stay locked, i.e. the whippen and hammer shank do not drop. You can visualize that your blow distance is now too short by 6 mm requiring you to "lower the capstans" so as to regain your 45 mm blow distance. So the jury is out as to how much capstan movement or extension will be necessary.

    RE your touchweight. Friction does not seem to be an issue, but as Jon has pointed out the DW is too low.

    But you cannot trust these measurements at this time and you will need to take new DW UW tests after the blow is reset. You did not report on any visual per the action component configurations after you regulated the action. Specifically, in order to set the blow to 45 mm in the current setup, the whippen beam would have had to rotate beyond level (many whip beams at rest sit 1 degree or so below level). But more importantly the hammer shank and knuckle would have rotated by something like 2.5 degrees, and this is at rest. The jack at the knuckle, at rest, will not be interfacing at 90 degrees but at greater than 90 degrees, and it is in this little pocket of first rotations (first 2 mm of key dip) where inertia and friction are the highest.

    Well, anyway, given all these mind games you still may find the DW UW BW FW friction thing not right so hold off on that TouchRail, especially given that this device's primary function is to lower DW on a heavy system and cannot be used to raise DW (as far as I know). Measure touchweight again later and report. If later reports continue to show a too-light DW the "correct method" is to remove portions of the key leads (hope to see you at WestPac where I am giving a class on an accurate way to do this that eliminates guesswork and messed up keysticks).

    Since you should have the action at your shop for adjusting the stack height and roughing in a regulation at the bench, that would be the time to address resetting the leads. But if whippen assist springs exist, adjusting these might be a partial if  not complete fix.

    Jon also mentioned the HCH dimension as it relates to the WCH dimension of 64 mm; this is an interesting dimension that doesn't normally surface in these discussions. The 64 mm (63.5 mm actually) dimension is the vertical distance down from the hammer center (HC) to the Whippen Center (WC) and exists in the stack irrespective of the the keybed or string plane. This dimension is difficult to measure as it is one of the rectangular components of the spread, and thus the spread dimension is the practical one. There are only two ways or a combination of the two to change the spread. One is to adjust the whippen rail in or out, or to adjust it up or down or some combo.

    So, if you make sure that the capstan centers on the the whippen cushion (more or less a tad) then your horizontal component is basically in place (something like 94 mm but also difficult to measure) and this is a starting point. Now given a 63.5 mm vertical drop and 94 mm run the diagonal action spread works out as the hypotenuse to 113.5 mm. The spread is relatively easy to measure so go from there and take heed of Jon's remarks as to jack top excursion. If the spread is not 113 or so then a whippen rail adjustment may be called for. Again, report back later.

    nick


    -------------------------------------------
    Nick Gravagne, RPT
    Mechanical Engineering
    Nick Gravagne Products
    Strawberry, AZ 85544
    gravagnegang@att.net
    928-476-4143

    -------------------------------------------




  • 21.  RE: Looking for tips to lighten the touch

    Posted 02-06-2015 20:32
    I have a Machinist's Gage which I picked up at a used tool store. it's great for measuring HCH and WCH. It also acts as a string height for trials or for setting the TautLine Regulation Guide string height.

    Another nifty tool I picked up at the used tool store was an Eyeletter. I was used to stamp eyelets in shoes or some other products be it comes in real handy for swaging key leads.

    -------------------------------------------
    Regards,

    Jon Page


  • 22.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-23-2015 13:10
    Any alternatives to Jane Jones for tech support at Samick? I contacted her two weeks ago about this problem to see if they might have a solution and and have yet to hear back. She doesn't respond to emails and almost never answers her phone or return calls.  

    -------------------------------------------
    Geoff Sykes, RPT
    Los Angeles CA
    -------------------------------------------




  • 23.  RE: Looking for tips to lighten the touch

    Posted 02-23-2015 15:09
    It's a weight and geometry issue. If you don't know how to grapple with those issues, pass the job to someone who does.

    -------------------------------------------
    Regards,

    Jon Page


  • 24.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-23-2015 20:07
    Jon, that was really unnecessary. I understand what the issue is, and thanks to you and others, have a pretty good grasp on how to approach it. The repair really is within my skill level or I would have handed it off to someone else long before bringing it up here.

    With my understanding of rumored factory problems that may have been occurring around the time this piano was made I was hoping Samick might have a more direct fix. Like perhaps providing action brackets of the correct height as a warranty fix. Yes, all the regulation and other followup work would still need to be done but at least I would have the correct part in place rather than trying to force a fix on an incorrect part. Dealing with Samick is hard enough. Snarky comments like yours really add nothing to the conversation.

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    Geoff Sykes, RPT
    Los Angeles CA
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  • 25.  RE: Looking for tips to lighten the touch

    Posted 02-23-2015 22:24
    It's been so long since the beginning of this thread that I though you still didn't know what to do. Waiting for help from any manufacturer is only delaying the inevitable, they'll just tell you that it's supposed to be that way. Lighten the hammers, correct the geometry and key leading. Simple as that. Just do it.
    -------------------------------------------
    Regards,

    Jon Page


  • 26.  RE: Looking for tips to lighten the touch

    Registered Piano Technician
    Posted 02-23-2015 22:29
    Making sure you get paid to do the work properly might be the most difficult part of the work.

    -------------------------------------------
    Edward McMorrow
    Edmonds WA
    425-299-3431
    -------------------------------------------




  • 27.  RE: Looking for tips to lighten the touch

    Posted 02-24-2015 17:40
    Ed McMorrow: "Making sure you get paid to do the work properly might be the most difficult part of the work."

    I couldn't agree more, Ed.

    Keith McGavern, RPT
    Shawnee, Oklahoma, USA
    -------------------------------------------