Types of Upright Piano

Overstrung vs. Straightstrung

This refers mainly to upright pianos, as there are relatively few grands without overstrung frames.

In a straight-strung frame, all the strings are strung parallel, and are vertically (or obliquely) positioned, whereas in the overstrung frame the bass strings are strung over the middle section in an "X" style.

In an overstrung frame, the diagonal lengths of most of the strings provide a richer sound than its straight-strung counterpart.

Straight-strung Frame

Overstrung Frame

Underdampers vs. Overdampers

All piano actions are fitted with a damping system, otherwise each note struck would continue to sound until those strings stop vibrating. But the two types of damping systems are fundamentally different.

The Overdamper system is generally found in older pianos, and is not so effective in cutting off the sound, as the dampers are positioned above the hammers, and make contact nearer the top of the strings, reducing their effectiveness.

The Underdamper system is more efficient as the dampers are positioned below the hammers, and operate via damper-springs. This system is found in the better quality traditional uprights, and in all modern ones.

Underdamper Action

Overdamper Action

Sizes

Height

The smallest of upright pianos are no more than around 32in (81cm) tall; examples of this might include the Eavestaff `Minipiano' and many U.S. built `spinet' upright pianos of various makes. The largest can reach a height of over 60in (152cm). A good example of this is the Bechstein Model 6, which has strings as long as in a medium Grand. Richness of tone quality improves as the soundboard gets bigger, and the strings correspondingly longer.

A modern Bentley 'compact 85' upright in a teak case

The interior view of a 1930s Challen 'miniature' upright

A large c.1915 Neufeld upright in an ebonised case

The interior view of a 1908 Bechstein model 7 upright

Width

This does not vary much as the number of notes (85 or 88) remains constant. The exceptions to this are 6-octave (and even smaller "yacht" pianos), all of which are usually smaller in length, and in height.

Overall Conclusion

The most favourable combination would be the better tone with the most efficient dampers (i.e. Overstrung with an Underdamper action). However, this is not to say that some straight-strung uprights were not high quality pianos, though the best ones were produced by the better-known manufacturers, and these in turn were built with underdamper actions. Either way, "big" is "beautiful" tone-wise, whereas the smallest pianos are often unrewarding to play, owing to their short strings and poor dynamic range.