Rickety Machine

Tracks 1 to 6 on this album are binaural recordings, whereas tracks 7 to 12 are line recordings. When listening with headphones, the binaural recording creates a sound image perceived as external to the head. In contrast, the line recordings produce a sound image localized in the head internally. Please enjoy the three-dimensional sound by listening with headphones. The performance of the synthesizer system with a 24-channel speaker setup was recorded binaurally on February 25 and 26, 2025. The synthesizer system consisted mainly of a computer, universal serial bus (USB) device, line selector, buffer, filter, and mixer. The speaker units for the 24-channel speaker system were Fostex FE166NV2. The speaker arrangement consisted of eight front speakers, eight rear speakers, and eight left- and right-side speakers arranged in a rectangular form measuring 118 cm wide and 141 cm long, with all units facing inward. The front speakers were referred to as the 1st to 8th speakers from right to left, the rear speakers as the 9th to 16th speakers, the left-sided speakers as the 17th to 20th speakers, and the right-sided speakers as the 21st to 24th speakers. The front and rear speakers were placed symmetrically adjacent at the midpoint of the short of the rectangle. The 1st and 8th speakers were placed 18 cm outside the upper edge, the 2nd and 7th speakers were placed 12 cm outside the upper edge, the 3rd and 6th speakers were placed 6 cm outside the upper edge, and the 4th and 5th speakers were placed on the upper edge. The front speakers were positioned 60 cm above the floor. The rear speakers were placed using the same method as the 9th to 16th speakers. The rear speakers are 22.5 cm high from the floor. The left speakers were placed as follows: the 17th speaker was placed at the top-left corner, 12 cm beyond the left edge, at 42.5 cm from the floor. The 18th speaker was positioned 35 cm from the front, 6 cm beyond the left side, and 36 cm above the floor. The 19th speaker was placed 70 cm from the front, directly above the left side, and 29 cm from the floor. The 20th speaker was positioned 105 cm from the front, 6 cm beyond the left side, and 24.5 cm high from the floor. The 21st to 24th speakers I placed using the same method as that used for the left speakers. Compared with the conventional speaker configuration, this arrangement considers the Doppler effect caused by the movement of the sound source. The mixer facilitates sound source movement across eight speakers, and the control signal output from the USB device into the mixer modulates the sound source movement. Three mixers were used for 24-channel speakers, each managing eight speakers using a different sound source movement technique. For recording purposes, dummy head microphones were placed on a box positioned at the center of gravity of the rectangle formed by the speakers. The boxes measured 21 cm in length, 36 cm in width, and 29 cm in height. By adjusting the speaker arrangement, the balance between the left and right volumes was optimized compared with conventional binaural recording techniques.