Double languid pipe report


Have spent the day to gather more data from my double languid experiment. The object was my big experimental wooden pipe 55*55*878 mm that has an adjustable upper lip and flue. The flue was in all cases kept at the same 1.15 mm.

One series had the pipe far end stopped, pitch about 95 Hz, filename starts with '38' signifying cut up in mm. A second series '23' is with the same pipe open with about 180 Hz.

Each series has three cases in the following order:
bar: the bare pipe without any special gadgets, pressure 1 kPa (4"WC)
rol: with a 22 mm dia roll outside the mouth, pressure 2.5 kPa (10"WC)
dub: with a second languid inside the mouth, pressure 2.5 kPa (10"WC).

Pressure and cut up were set for an Ising intonation number ( about 2 for the bare pipe, and about 3 for the 'rol' and 'dub' cases. Without such braking devices the pipe overblows with this higher Ising number.

My chaotic lab set up on the floor is seen on the photo. Audio was picked up only 0.3 m (1 ft) away to get rid of some room acoustics, and with a mattress piled up behind. The second languid was made from .7 mm iron sheet, slightly curved, with sides folded down. The distance between languids was set at about 6 mm at the mouth. Extends inward about 75% of the pipe depth. A narrow handle extends to the back pipe wall where it is held by a screw. Detail  photo attached.

This section view shows the approximate placement of the intonation roll and the second languid, respectively.

Spectra for pipe closed, bare, with roll, and with second languid
Spectra for pipe open, bare, with roll, and with second languid

Audio file 38brd.mp3

Audio file 23brd.mp3

Audio level settings constant. The only changes made except screwing and clamping the various devices was to adjust blowing pressure, which will raise power. Attached two sets of mp3 audio files plus spectrum and waveform images.

Significant influences on waveform and spectrum. As known before, a roll is no good with the closed pipe. The dual languid is good with both the open and the closed pipe.

Johan Liljencrants

06-10-24, rev 08-01-08