Posts tagged downbearing

Piano Bridges

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.

So you have an Upright Grand?

This is the most frequent misnomer in the piano biz.  True story.  On a daily basis people come into my shop and whisper to me “Do you know that i have an upright grand at home?”  I think they’re hoping my eyes will pop out of my head in amazement at such a rare and wonderful find – that we’ve truly discovered the queen’s jewels! Sadly… i’m a skeptic at heart…. possibly even cynical.  Y’see… the term “upright grand” was started in the 1920’s as a sales feature.  When you lifted the lid on some pianos there was this embossed slogan “Grand piano in upright form”.  This got bantered about so much so that it became a coined phrase – the “upright grand”.  And customers would then feel proud about their acquisition of a piano they thought was so much more grandiose than any other upright piano.  So what exactly were they referring to? Well… size is one thing.  Very tall old upright pianos (usually about 55 inches in height) have similar string length and soundboard area as about 5’8″ – 6’1″ grand pianos.   That said, a tall upright WILL  deliver similar depth of tone as some grand pianos, granted.  But the bigger difference that started all of this is a small little piece that was usually only found on grand pianos called an agraffe.  Agraffe is a french word that means ‘staple’.  In fact… check out the picture of my box of staples from my desk drawer.  See that? It says agrafes (missing an F for some reason…)  Agraffes on grand pianos ‘staple’ the exact position of the string to the cast iron in a piano.  It sets the left-right position spacing of the strings and also the ‘downbearing’ of the string (how much pressure the string is placing on the bridge).  Because agraffes are usually found on grands, some manufacturers who put them on upright pianos started calling their verticals upright grands.  Most don’t know of this crazy little factoid but that’s in my mind the true meaning of the term.  Ok wait… it gets better… recently someone came in and told me they had a “Concert Upright Baby Grand!”  Oh for heaven sakes… from the sublime to the ridiculous!

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