Looks like some stains on the bass strings where the hammers have been striking- wonder if someone used something at some time on those hammers that caused that?... Dampers do look well settled and getting older (we would probably replace such).
But really, it is hard to determine technical problems with dampers from pictures- for instance a picture cannot tell me if the felt is definitely hard (a zinging or buzz when the damper returned on vibrating string would), or where in the travel of hammer they are lifting- are they all clearing the strings, or are some touching the vibrating string. And for instance, If a damper begins to lift too early in the hammer's travel- you normally can expect a note not
to dampen properly (bleeding, or prolonged sustaining would occur).
- I did not hear any significant "bleeding" on the sample notes that you played staccato.
- I do hear that the tuning is out- but, still, I think it's pretty good for doing it yourself (the unisons do have some noticeable beats to them). I agree with Beemer - the audio is a bit piercing at times.
As far as agreeing whether the action "would improve noteworthy" with replacement of hammer flanges- this too is difficult to judge from here, as I do not know what your action feels like right now...It could very well be that the flange center pins are are fine, and that the spring and cord are your only issues there...What I would suggest is that you put out a little bit of money (minor amount really), to have a local technician come out to look it over-- for an estimate for work that would need to be done to it to get it into the playing condition that you would like.
This shouldn't cost more than 100 Euros (at most), and it would give you very specific areas listed on paper that you could then know needed addressing.
My guess is that if this piano has broken flange cords, that there are many other issues that are requiring immediate attention as well... It probably has not been regulated in a very long time- meaning it would be hard to say in that situation what is causing any unwanted sustain in notes (until they are in proper regulation that is).
As for the hammers- they do definitely sound bright (but 70's Yamahas are bright)...There are many options to this-
- Usually, we need to get the regulation done first- since this affects the tone, volume, and sustain of the strike... Hammer travel distance and let-off are big factors for volume and tone. As is timing of damper lift in that travel- if a damper here or there is not lifting off the string entirely, it will create a dull/dead sounding note (one that has little or no sustain), or a zing. And again, if dampers lift too early- they "bleed" (continue sustain beyond play of note).
There are many options for softening hammers-- everything from needling (voicing), to that of using water/alcohol mix, or fabric softener even (which I don't particularly like)... Good discussions have taken place already on softening hammers (below is an example of one- do a search) ---http://forum.pianoworld.com/ubbthreads.php/topics/2077111/Hammer%20softening%20solution.html
But, really- at least a decent regulation of the action should be accomplished in order to get everything working in its proper order.
Get a book out of your library, or buy one --- many good technical books for the average Joe/Jill to follow...
Arthur A. Reblitz, "Pianos, Tuning, Servicing, Rebuilding"
Mario Igrec, "Pianos Inside Out"
These are two good books (the Igrec book "Pianos Inside Out" is the more detailed and cost $$) that can help guide you through the problems you wish to cure here.
But, in closing--- at least have a local tech get you the info of problems on paper. That can save a lot of time and heart ache
Hope this helped.