Double biphonical flute
Double flute with globular filters.
Roberto Velázquez Cabrera
Virtual Research Institute Tlapitzcalzin.
Firts version November 13, 2003
Some sonorous artifacts can produce sounds transformed or filtered of diverse frequencies using holes or additional chambers for that effect. Modern areas of acoustics, such as the wave's guides have explained the behavior of those filters. What is surprising is their utilization and use many centuries ago.
In this experiment a double flute with globular filters is shown which can produce sounds with two fundamentals such the biphonic singing from some zones of Asia.
Cut view of the flute and its filter.
Spectrogram in 2 D of the sound of the double flute with filters.
Spectograma in 3 D of the same sound.
In spectrograms, the peaks of the two F0 are shown clearly. The highest is the strongest. of course.
Its maximum radiated acoustic power is not high, ~ 0.004 Watts (equivalent to 85 dB a t1 m and 0 degrees, but the highest F0 can heard at quite a distance due to its pitch.