91色情片

The treble of pianos is often weak. Now the British piano makers, John
Broadwood of London, have found a way to strengthen the treble (GB 2 329 276).
According to Broadwood, piano strings tend to pull away from the frame when they
vibrate, reducing the energy passed to the soundboard. The new piano has a bar
which extends across the strings of the top twenty treble notes. As the strings
vibrate they press up against the bar, which transfers the vibrations to the
sound board. Broadwood says this improves the treble tone quality.