Re: Pianoteq 5 impressions
Strings can also get some rusty, ans some piano technicians use solvents to remove the rusty, making the string revestments (spiral) thinner too.
Interestinmg to think if the agging parameter of pianoteq also simulates the thinning of strings.
Also, there might be the age of the strings. As most 'real' pianos will in general not have brand-new strings most of the time, it would be interesting to know the influence of aging strings. The strings suffer from inelastic deformation (the same happens with guitar or violin strings), meaning they loose their tension. This is the main reason any instrument using strings has to be regularly re-tuned, AFAIK. But the inelastic deformation also more or less causes the strings to become slightly thinner and (as far as I know) slightly 'softer'. Less rigidity should mean softer partials and increased harmonicity, which could in my opinion be one reason (apart from its hammers' felts) an older piano might sound a bit 'thinner' and also less bright and harsh than a brand-new one; I guess Philippe will know more about whether this is a real effect.