sclass SimpleBaseDrumFinder2 {
  double windowSize = 10.0; // seconds
  int imageHeight = 10; // must be >= segmenter.gridSize
  transient ISegmenter segmenter;
  transient new L<float[]> buf;
  transient int bufSize;
  transient BWImage lastImage;
  transient L<IntRange> ranges;
  
  L<IntRange> addFrequencyImageBrightnesses(float[] l) {
    if (segmenter == null)
      segmenter = mandatorySegmenterFromAGIBlue("Find base drum #1");
      
    buf.add(l);
    bufSize += l(last(buf));
    if (bufSize < audio_estimatedFrequencyImageWidth(windowSize)) null;
    print("Have img! " + l(buf));
    float[] data = normalizeFloatArray(concatFloatArrays(buf));
    lastImage = bwImageFromColumnFloats(imageHeight, data);
    buf.clear(); bufSize = 0;
    ranges = map rectXRange(segmenter.get(toBufferedImage(lastImage)));
    print(n2(ranges, "base drum") + ": " + ranges);
    ret ranges;
  }
}