Adrift in a Sea of Bells


My cohort Eleanor Mills introduced me to The Soundgarden at Central Park Elementary School several years ago. Eleanor goes there on a regular basis to “wake up the bells.” She has developed an intimate relationship with these bells, their interesting harmonics and how they all speak to and blend with each other. I have been privileged to play along with her on several occasions. Here is a short sample of Eleanor waking up the bells at a recent play date:

The Soundgarden was designed and constructed by Andrew Preiss in honor of Greg Taylor, a local musician and teacher at Central Park School who died in 2007.  It is made of steel cylinder tanks (often referred to as bottles) cut to varying lengths to produce a variety of tones low to high. There are 8 large tanks and 12 tank tops positioned along M shaped bar (see photo). As you can hear from the clip, these rough cut steel tubular “bells” send out a sweet and sour soup of tones. Eleanor has discovered a variety of techniques in her playing that pull a rich and interesting sonic landscape from them.

These days our group prefers to pop up and perform soundscapes in interesting spaces with little notice. So the Soundgarden is a perfect spot for us (once I discovered there was electricity available. As an electronic musician, electricity is a necessity🔌). In order to produce a soundscape that would compliment the bells, I wanted to analyze their harmonic character. So I took my tuner down to the Soundgarden and hit each bell and held up the tuner. Well, the diverse harmonics that spring forth from the bells were just too much for the tuner – it was all over the place and seemed inaccurate to my ear. For example, the two tanks on the right in the photo above are clearly a minor third apart to the ear. Yet the tuner registered A# to F, which would be a fifth. This was a puzzlement.

I found a more accurate method of analysis by recording each bell individually and studying them on a spectrum analyzer. This approach was revealing and somewhat tedious. However, the rewards made it well worth the time spent scrutinizing the spectrum analyzer to pinpoint precise frequencies as they arose and decayed in the bell tone. I was able to track overtones up into the 5th and 6th octaves above the fundamental tone of each bell.  Most of the overtones are enharmonic overtones (meaning the frequencies are not in a whole number integer relationship to the fundamental frequency of the bell), so they tend to be slightly more dissonant than consonant.

One interesting discovery was the presence of undertones in the bells. The two middle bells hanging on each side of the structure had tones that popped out underneath the perceived fundamental tone. The mystery of the heard minor third opposed to the measured perfect fifth was solved by this discovery. The fundamental tones of the two bells as seen on the spectrum analyzer and perceived by my ear are A# and C# – voila! the minor third. The bell that sounds a C# had an undertone of F, thus the tuner picked up the undertone. Interestingly, the center two bells on each side all had undertones and the tuner picked up on these undertones as confirmed by the spectrum analyzer.

So I had fun putting all the frequencies on charts to compare and contrast them. It was interesting to note how true (or not true) the bell overtones were to charted pitches. For example, a concert A is 440 hz but the bell tone frequencies that fell in the 400 block of A were closer to 432 hz (something to chew on for all the 432 hz tuning conspiracy theorists.) I charted all the over (and under) tones to see which tones were the most prominent. The most frequently appearing tone was a B, which is the tone of the natural world and deep space. The next most frequent were A,D,F and G. The least frequent tone was G#, but that one popped up alot in the tank tops.

In the final analysis, I used a pentatonic scale of BADFG for the soundscape called “Adrift in a Sea of Bells”- and it is a work in progress. Tonight we will play to a prerecorded track of the piece, but you will get a taste of it. My computer decided it was tired and started dropping audio as I was playing the soundcapes at our runthrough last Sunday. So we will not play “The Sound of Sirens” tonight because I really need to trigger and sculpt that piece with Ableton. We will perform that next time we play.

I believe the weather will turn in our favor, so please join us tonight at 7 pm for a Post-Moog sound offering. We will be at 724 Foster Street at the Sound Sculpture in front of the Central Park Elementary School. Bring your own chair and join us for an hour or so. Look forward to seeing you there!

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