The Dampp-chaser Humidity Control System

We recommend to all our customers the installation of a Dampp-Chaser in their piano.

A principle benefit is to stabilize the piano's soundboard and with that, the tuning that sensitively rides on top of it by way of the bridges. If the soundboard swells with an increase in humidity, the pitch of the instrument is incrementally raised. But not evenly: the soundboard is like a diaphram, and the bridges over which the strings pass start near the rim at one end, go out across the middle, and then down to the other end.

Plus the bass strings have their own bridge. And the wound wire of the bass is more flexible than the plain wire of the tenor and treble. Basically, the less change in the moisture content of the soundboard, the more consistant and musical a tuning will remain during the year.

Another major benefit is that the soundboard will live a longer, healthier life. The less it swells and contracts, the less likely it will be to crack over time.

Because an upright piano is enclosed by its case, the Dampp-chaser will help to keep the action screws tight. They become loose largely by the wooden parts swelling against their screws and compressing themselves in the damp season and then retaining enough compression each dry season to eventually cause noise, changes in spacing (with parts potentially hanging up on each other), uneven wear, and the possibility of stripped screws.

For a grand, the Dampp-chaser Company offers the Undercover, made of acoustic speaker cloth, which is upholstered to the under side of the rim, covering the system and buffering between the Dampp-chaser's operative area and the ambient atmosphere. This about doubles the efficiency of the system and makes for a tidy, inconspicuous presentation.