Mbira Tuning Kit
A mbira tuning kit is something every serious mbira player should have. While a seasoned mbira that is well cared for does not often need tuning, occasions do arise when it is necessary to tune your mbira. It would be traumatic to have a loose key on your mbira half an hour before a performance and not know how to tune it!
The Tuning Procedure
There are many books that discuss the mbira tuning process. This section will describe a quick, common sense survival technique for getting your mbira back in tune as quickly as possible. I use the notes from the beginner song, Karigamombe as the guide to relative pitches of the first four notes on the top-left register of the mbira dzavadzimu. Having tuned those keys to the karigamombe sound, you can tune their octaves on the bottom register. Using karigamombe, or any other song you can keep extending the range of notes noting until the entire instrument has been properly tuned.
The Physics of Mbira Tuning
Mbira keys are held or bound onto a wooden soundboard. The top ends of the keys rest directly on the top end of the soundboard. The lower portion of the upper section of the keys rest on a metal bridge that is mounted in the recessed portion of the mbira soundboard. An additional metal bar is placed over the top end of the soundboard over the keys, thus binding the keys at the soundboard and metal bridge contact points. The mechanism for binding the keys is either strands of wire traversing thru the soundboard and binding between 4 and 5 keys together. The portion of the key the sit directly under the top metal bar is the tuning point. This is a common point for all keys and their length is measured from this point toward the lower portion of the soundboard. The curvature of the key directly under this bar provides flexibility in defining each note.
Tuning a mbira notes means slightly varying a key's contact point with the top metal bar. When a key is loose or out of tune, often "push" the key upward by placing a hard piece of wood at the end of the key to be tuned and tapping it with a tack hammer until it 'pops' out at the top of the instrument. Noting the keys contact point with the bridge, very slightly bend the key at that contact point downward (narrowing the the angle). When you attempt to slide the key back down by tapping its top end, you will notice resistance while the key is relatively short and the pitch much higher than that of the target pitch. Continue to tap the key and noting the pitch. When the pitch is exactly what you want, then it is tuned. This is a very tricky process. If you make the curvature of the key too narrow, when you try to refit the key back under the bridge, the resistance may enough to "lift" the bridge and possibly loosen surrounding keys. Thus, you may end up with more than one key to tune. Tuning a mbira is and incremental process and requires great care and patience. Best of luck in this process!
The Tuning Kit
Finally, the tuning kit! I use a tuning kit that consists of a tack hammer with one half of its handle sawed off. This sawed off piece makes a great wooden piece for loosening (popping) out keys without damaging the bottom ends of the keys. Often this sawed off piece can be too 'fat' for some mbira - so you might want to get a rectangular hardwood piece about 1/4"x1/4"x1-14". A third tool that I use is a very short (1/2") flat screw driver. This is ideal for sliding keys along the bridge. Often, a key will have a rattling noise when you play it not because it is out of tune, but because it is 'touching' an adjacent key. You can 'wedge' the flat screw driver against the target key and tap the top of the screw driver until the key has moved enough to not be touching another key. A fourth tool you can add to your tool kit is a rivet (or a "nail set") ordinarily used to receding nails into wood when say one build a wooden deck or veranda. This rivet would be used to individually isolate a key being tuned from the to end of the keys. Thus the rivet would 'select' the key and the hammer taps on the rivet. Finally an invaluable tool that you can add to your toolkit and just regular sandpaper. For new mbiras, depending on who made then and how careful the seller was to ensure the instrument is playable as delivers, some key might have wrought metal etchings at the end making it scratchy for the thumbs or finger to play. This is where the sand paper comes in. I always encourage new mbira owners to take the time to sandpaper the underside of keys played by the index finger regardless.