Pouaka tanguru - Bass bar

Te pouaka tanguru - making bass bars

A bass bar is essentially a one-note marimba, a single bar suspended above a large box with the chamber tuned to match the pitch of the bar and therefore amplify its resonance. I couldn't find any information on how to make one of these at first, so I had a go at replicating the C bass bar my friend Priya let me borrow from her school. Priya is a fabulous Orff teacher who got me into this approach in the first place, and has been a great support and collaborator in my teaching journey.

I made the box using plywood to match the size of the original (made from MDF), tilting the bottom toward a small gap for rainwater to escape, then tried to tune the chamber. It was hard for my electronic tuner to pick up the note it made when struck, but I eventually set the aperture adjuster to what seemed like the right note. The next step was to make a bar.

With bass instruments like these it's good to adjust the harmonic overtones as well as the base notes when you tune the bars, as these are the other main sounds you can hear. In the picture above you can see where I've tuned the base note by scalloping in the centre of the bar, and tuned the first and second harmonic by cutting notches at the appropriate distances along the bar. You can also see where I mucked up and dropped too low, and had to raise the bar's pitch by removing wood at the ends! This doesn't happen often thankfully, but drilling with an auger means the effects can't be seen once the bar is in place.

The finished bass bar. I originally mounted this on rubber pads with a nail through the middle to hold it (see top photo) in the usual style, but vibration noises made me seek another way, and I eventually replicated a hanging method I saw on maker Chris Banta's website, which fixed the problem.

Unfortunately the I-pad I've been using to record footage can't pick up the deep resonance of this instrument, but I might add a video later if I take my own recording setup to work one day. Our akonga enjoy playing it during lessons, and I'm planning to make a G and A to add to this C bar.