Does your piano have a buzz in it? Here are some tips on how to find what is causing the buzz.
The worst offenders are the ones least likely to occur but I list them first.
1. Soundboard – Inspect the soundboard for cracks. A soundboard is made from side-glued planks of wood. Sometimes a crack will form as two planks become separated. At certain frequencies, the adjoining wood can create a buzz. To test, press your finger on the crack with moderate force, play the note that is causing the buzz. If you can’t reach the crack, remember that you can have someone crawl under the grand piano and access the crack from that side too. In an upright, you access the soundboard from the back of the piano. (Use a helper.)
2. Ribs – The crown of the soundboard is reinforced by the use of ribs, glued perpendicular to the grain of the soundboard wood. A rib can become separated from the soundboard. This is not uncommon for pianos that have been in a dry climate for a long time. If you can slide a business card between the rib and the soundboard, then you need to get that repaired even if it is not the cause of the buzz. Press your finger against the rib as explained in item #1. If the buzz goes away, or even if it only diminishes, you have located the source. Your technician will drill a hole through the rib, glue the rib again, and install a bolt to secure the rib.
The remainder of the items below occur more often and are easier to repair.
3. You need to listen intently to locate the source of a buzz. This is a real challenge, and all technicians love to discover the source of a buzz. Your ears aren’t trained like a technicians (actually, it is the brain that is trained), so let me help you here. The source sound will be masked by secondary sounds. Let me explain. When a a buzz is generated, that sound is amplified by the soundboard. It is also redirected across the entire surface of the soundboard. Because of this, it will be hard to detect where the sound is coming from. Now listen more intently. There is a very slight difference in the quality of the sound. The secondary sound is actually a reverbation. It has an ever-so-slightly chorused (out of phase) quality to it. As you listen, work in sections. Isolate larger areas first, then hone in on specific areas. Proceed to step 4.
4. Anything that is fastened to a piano can become unfastened, unglued, loose, out of alignment. The things that are moved most often are the ones that come loose first. Makes sense? Sure. So let’s check the things that move most often. Remove the front top panel of the upright piano, or music desk of the grand. Press on the parts of the case, the music desk, close the top (or open it). The pedals in an upright use rods. Find them on each side of the action. (One or two may be on the back side of the action.) Press your finger against the top of the rod and play the key. On grands, get on your back and check the pedal assemblies. Check the screws that you see. Case screws are a likely suspect. The lid support screws are often the cause.
5. It can be frustrating. Relax. Use your ears. Frustration detracts from concentration. Remember, you are the thinking being. The piano is the inanimate object. Don’t let it out-smart you. :)
6. If you have a grand piano, do not attempt to remove the action unless you like to hear the sound of hammers snapping off their shanks. It is hard to damage an upright action (unless you try to remove it.) On grands, remove the fallboard. Life CAREFULLY so you do not gouge the wood on the arms of the case. You will be tempted to lean it against a wall. Don’t do that. They fall. Lay ti on the ground away from pedestrian traffic and away from the piano. Do not remove the action, just look into the area where the action is and pull out pieces of paper, pencils and Lord knows what else is in there! Don’t worry about the dust. Dust does not buzz.
7. In an upright, remove the front board. Look inside the case and you will find two or more screws, easily accessible, securing the front panel with the music rack on it. Remove it and lay it on the floor. Check for paper and pencils and other debris.
As you do all of this, keep striking the note periodically to check to see if the buzz changes or disappears.
As you can see, there are a lot of steps involved. That is why you need to rely on your listening skills first. The object of this exercise is to find the buzz on the first try, without removing any case parts. Keep striking the note and listening until you are certain you know what is causing the buzz. When you certain, check that item. Proceed to the next guess if needed. Work on one area, one suspect at a time. If you are just banging away on the key, touching everything in sight, you are going to get frustrated. Listen. Stay focused. Make good guesses.
After you find it, you are permitted to reprimand the offending part. Save your worst words for when you put the case back together – you will need them. :)