More information about pianos

What is the difference between an Overdamper and an underdamper?

At a glance…

If you lift the top flat panel of the piano to view inside of it, you will be able to determine what type or style of action is in the piano: whether the piano has an underdamper action or an overdamper action (there are variants of over and under damper mechanisms to be discussed at as time allows).

The photographs show how the action will appear, looking into the piano from above, how it looks in situ in the piano and from behind the action to demonstrate the situation of the dampers above the hammerheads.

Overdamper

If the hammers are not clearly visible and are obstructed by a wooden board, or occasionally by metal rails, it is an Overdamper.

Underdamper

If the hammers are clearly visible it’s an Underdamper.

While an Overdamper piano can be well usable, they have shortcomings:

– They simply do not damp anywhere as well as an Underdamper – you will clearly notice a resonance after letting the keys up.

– They tend to have a noticeably different key touch compared to an Underdamper which is often heavier and more mechanical in feel.

– The general mechanism is more laborious and slower in response and in coming back to “rest “.

– An Overdamper is more difficult to work on and while any field technician/tuner ought to be versed in the service and tuning procedure of such, it appears many are not, and we increasingly hear of tuners saying that Overdamper pianos cannot be tuned or that they personally are unable to assist with service.

This should not be the case and in fact there are a few particularly good Overdamper mechanisms out there, some being difficult to distinguish in use from an Underdamper piano, but even so will be regarded as a lesser instrument compared to another with an Underdamper action.

The adjustments required for good regulation, hammer alignment and the like are simply more difficult and laborious to achieve for the technician and so very few Overdampers are properly serviced when tuned.

The awkwardness of tuning them also often means that they are not finely tuned as human nature is generally a little lazy and so a tuner is more reluctant to go back to strings already passed in initial tuning to tidy-up notes which are perhaps passable but not in fine-tune.

The result of this over time can unfortunately mean a piano which is not in its best state and customers are generally told not to expect more from their Overdamper than the mediocre – even if in truth it could be improved.

• Overdampers are considered obsolete and as such carry very little, often no value in monetary terms. This means that should you choose to invest in one and consider repair and service, the money invested will not be recoverable in resale.
  The value of the same brand of piano can be on opposite ends of the value scale depending on which mechanism it contains.

While the value of a piano is often in its use and the enjoyment gained from this, it just doesn’t make sense to purchase an Overdamper when you could get an Underdamper with a better outlook for the future.
If a child begins their career on an Overdamper, an upgrade will be required in time as they progress, because an Overdamper will not produce the technical ability required for serious practice.

This does not mean you should write-off your treasured Overdamper piano as we look for different values in what it is we require from a piano.
If you are happy with the performance of your Overdamper piano there is no reason not to keep it provided the condition allows for pleasant use and reliability.
We see many Overdampers much loved by the family who owns them. Pianos often having great sentimental value which outweigh the purely practical considerations.
Many pianists are not proficient enough to be bothered by the differences between the actions.

More about the Overdamper action…

Given the era of the Overdamper, many are aesthetically the most beautiful and of the most antique styles of pianos and may be bought for that reason.  Many collectable pianos of developmental interest are Overdampers.

The era of Overdamper actions seems to have been over in general by around 1910 but some makers did continue using the system even beyond that date.

In this light, some factories never produced an Overdamper.

Thus, age is also not indicative of which system is present.

More considerations about Underdamper and Overdamper Action pianos…

An Underdamper is infinitely more desirable as a playing instrument. Very few, if any, technicians and tuners would advise you to purchase an Overdamper.

We have bought Overdamper pianos in trade but usually because of aesthetics. As mentioned, many of the most spectacular casing styles contain this action.

Nobody nowadays will recommend an overdamper piano for purchase, but… one can be swayed by the fact that the some of the overdampers left on the market are masterpieces with intricate details that establish themselves as feature furniture items.

Given that overdampers were no longer being built by around 1910, many have exquisite casings and timbers, desirable to someone who loves antiques.

Some overdamper pianos are actually really good, notably some of the Blüthner, Görs and Kallmann and Ibach versions in our experience. We have had about five in our stock over the last fifteen years because these pianos were really special and maintained their tuning.

Many pianos built between say 1880 and 1910, roughly, can have either style of action, so age alone is not indicative.

It must be noted that whether the piano you are looking to purchase is an Overdamper or Underdamper cannot be the only criteria as many Underdamper actions are not viable for other reasons, but in plain terms it probably indicates immediately whether a purchase ought to be pursued further or not.

Many factories of piano builders indeed made both versions of piano consecutively or changed their actions over time, so the piano brand does not show which action is contained in the instrument in question.

Can an Overdamper be converted to an Underdamper?

Yes, but the massive amount of labour and parts required would make it non-viable.