Over the past couple of decades better laminated soundboards have been developed, and the pianos into which they've been installed are more advanced, too. The principal new type, known as a "veneer-laminated" or "surface-tension" soundboard, consists of a core of solid spruce (essentially a solid spruce soundboard) covered on both sides by a very thin veneer of spruce. This type of soundboard vibrates much more like a solid one than a plywood one, but still retains the benefit of protection against cracking and loss of crown. Pianos with these soundboards usually sound reasonably good, and occasionally very good. Although solid spruce soundboards may still have a tonal advantage, the laminated feature can be an advantage in durability, particularly in challenging climates, and may contribute to better tuning stability through the annual cycle of seasonal climate changes.
Despite the improvement, you'll generally find these new laminated soundboards only in entry-level or lower mid-range pianos. But the reason for this has less to do with their quality than with marketing: Laminated soundboards are a feature still used by manufacturers to differentiate a lower-cost instrument from a higher-cost one for marketing purposes, even when the laminated one might arguably be better. If you're shopping in the entry-level price range and a piano with a laminated soundboard meets your musical and other expectations, there's no reason not to purchase it.
The piano's cast-iron plate is the gold or bronze-colored metal framework across which the strings are strung. For well over 100 years, plates have been made using the wet-sand method of casting, which works something like this: Wooden molds are made in the image of the front and back of the plate. Each mold is pressed into a tray of moist sand, thus transferring the shape of the plate to the sand. The moisture enables the sand particles to stick together to retain the impression. The two trays of sand representing the front and back of the plate are clamped together, and molten iron of a carefully controlled chemical composition is poured into the cavity created between the two impressions. When the iron cools, the trays are unclamped and removed, revealing a cast-iron plate identical in shape and appearance to the wooden molds. Although factory engineers have largely perfected this method over the years, the plates produced in this manner are quite rough, requiring a lot of sanding and finishing work, and vary slightly in dimension from plate to plate, which is less than ideal for highly automated factories that depend on uniformity.
In the 1960s, to manufacture plates that were more uniform, and faster and less costly to make and finish, Yamaha developed the Vacuum Shield Mold Process, or V-Pro. In this method, fine dry sand is used, and a thin plastic film and vacuum pressure keep the sand in place to retain the mold shape. This process produces plates that are not only more uniform, but also show decorative detail much more clearly while requiring less finishing work.
FALL 2009 -- page 87
TABLE OF CONTENTS
Hybrid & Player Pianos
New-Piano Buyers’ Reference