Today I came across two different pianos that each had a buzz in one of the bass strings. Although, this is isn’t 100% necessarily the cause for a bass string buzz, these strings both put off a particular sound that is often described as a “sizzle”. To the trained ear, this sound is unmistakable. Can you detect it in the videos below?
This sizzle is caused by the copper winding around the steel core of the string coming loose from the core. There isn’t much that can be done to remedy this aside from string replacement, but there are a couple of tricks which sometimes work, but more often don’t.
The first “trick” is to simply squeeze the ends of the windings with pliers to crimp the copper back to the core.
The second thing that can be done is to loosen the bass string, remove it from the hitch pin, then twist it in the direction of the winding one full turn, put the string back onto the hitch pin, and pull it back up to pitch. This same method is also sometimes used to bring dull, dead-sounding bass strings back to life. Sometimes it works, usually it doesn’t.
I have found that once this happens to one or two strings, it’s a problem that will eventually happen to neighboring strings. Generally, my customers decide to just live with the buzz, which is often very quiet, until the point at which enough of the strings are problematic to justify replacing the entire set of copper wound bass strings.
I mentioned in the first sentence that this isn’t necessarily the cause of the buzz. Another fairly common source of a bass string buzz is that it is vibrating against a damper wire. This is possible to happen on some vertical pianos, but is almost exclusively a grand piano problem. The solution is to the bend the damper wire to resolve the problem. The buzz-against-a-damper-wire sound is much more of a traditional buzzing/vibration sound and not so much a faint sizzle. The following close-up shows how little tolerance there is for the damper wire’s placement adjacent to a bass string.
Now, if you hear this distinct sound, you can impress your piano technician by asking if a winding is coming loose!