Lagrima Drum
Lagrima (Spanish for "teardrop") is a multi-toned drum inspired by the sounds of Uruguayan Candombe. The idea is to mix the multiple tones of two drums into one.
Cut a Piece of Wood
Take a piece of wood (sized based off of how big or thick you would like the drum) and cut it into a teardrop shape. That shape will allow for different sound pitches.
Cut Out an Outside Piece
Cut an outside piece (slightly larger than the original teardrop piece) that will fit on the outside of the drum body. This piece will serve to hold the head in place later on.
Cut Out a Drum Head
Chose a drumhead (preferably skin or synthetic one ply) and cut out the head to fit the size of your drum. Keep in mind that you will need extra room to the side of the drum in order to fold it over and tack it down.
Heat Drumhead
Place the already cut head on the body of the drum. Slowly (to not burn or later rip the head) apply heat to the head. Consistent, slow, heat with a heat gun is the safest and most productive method to safely stretch the head.
Bend and Reshape Head
After applying sufficient heat to the head, carefully push head through the cutout piece. This will serve to hold the shape in place. This may take multiple tries but try to keep from moving the head so it may cool into the right shape.
Tack the Drumhead Into Place
Using tacks and a hammer, secure the head onto the drum. Nails could work but tacks just help secure the tension. Be careful to keep tension throughout the head while hammering.