If you’ve ever seen a car commercial, you may have heard a phrase that says something like “To hold your precious cargo.” Generally this type of phrase is used to signify that a car has a high safety rating and is ideal for families. To better illustrate the idea, the term “precious cargo” is accompanied by imagery of sleeping children in the backseat. This is a way for automobile manufacturers to express that their vehicles are top quality and made from durable materials that will hold up under the stress of daily use. In this way, an automobile is not much different from the case of a grand piano. Like a car, the case holds a great deal of sensitive and precious cargo and, like a car, the case must be able to withstand years of regular use.
If you’ve ever shopped around for a grand piano, you may have heard a sales person talk a lot about the inner and outer rim – and you may not have understood exactly what this meant. Essentially, a grand piano is built in layers.
First is the case, which is basically a shell. The case is what people see from the outside – the flawless, shining finish that gleams under stage lights, much like the outer metal shell of a vehicle. Inside this shell, however, is another layer that is often referred to as the inner rim. This is the piece of wood that the sounding board and plate are attached to with a special glue. Generally people do not see the inner rim unless the lid is lifted and they look down inside and, even then, the inner rim is covered with the sounding board and the frame.
Most of the time the inner and outer rims are made of durable woods such as laminated beech, maple or spruce. In some of the best quality grand pianos, the inner and outer rims are created out of one piece. The reason for this is to provide not only additional support for the piece inside, but also to ensure top quality 
sound. In other pianos, the inner rim is built first and the outer rim is built around it. However, regardless of the method of building the rims, the overall quality of the piano depends largely on the manufacturer and their attention to detail.
When you compare grand pianos for purchase, be sure to ask about the materials from which the inner and outer rims are fashioned. Although lower quality woods may bring down the price, they will also reduce the quality of the sound and the durability of the instrument.
Another thing to keep in mind about the inner and outer rims of a grand piano is that these are the pieces that hold the sounding board into place. Generally, the sounding board is referred to as the piano’s voice because this is where the vibrations of the strings are amplified into audible sound. In other words, if the inner and outer rims are the vehicle, then the sounding board and strings within are the precious cargo.
Have you ever seen the inner workings of a grand piano? What did you notice about the quality of the parts?