Bridges are beautiful aren’t they? And true to form, they serve the purpose of connecting – of filling the gap.  Many know what a bridge is on a guitar or violin but many do not know of piano bridges.  What is the purpose of the bridge anyway? Well simply put, the bridge transfers the vibration of the string to the soundboard where the tone is amplified.  So the EFFICIENCY of transfer is critical to retain the sound produced at the string.  Effectiveness comes from 5 elements and they are:

Position – if the bridge is positioned on the soundboard incorrectly, the tone will be compromised

Material – many are made from maple or mahogany

Downbearing – how much pressure is being placed on the bridge by the strings

Notching – cutaways leading up to the flat surface on top

Laminations – most bridges today have at least a “cap” which is a cross laminated piece to reinforce the bridge for structural integrity.

When bridges go terribly wrong… most people when purchasing a used piano don’t look for cracks in the bridge.  They ALWAYS look at the soundboard but quite often don’t consider the bridges.  If the bridge is cracked, the tone “bleeds” from one string to the next and will not have any substantial sound or sustain.  The other thing which i will point out is that inexpensive pianos have a gazillion laminations (it looks like plywood).  I swear there’s more glue on some of the cheap pianos than there is wood.  I’ve NEVER heard a GREAT piano with more than a few laminations.  If you see one with 10 ply or more… take note to the sound.  Chances are, the tone is also very comprimised. 

On a completely different note, at a recent trade show (NAMM 2011) Petrof introduced a redesign of their spectacular grands and interestingly the bridge at the very high notes on the piano is BLACK! That’s because it’s made out of ebony – which they claim makes excellent transference of high note tone. I have to confess… it was a favorite piano to play when i was there. Beautiful.