First listening tests of Pleiades linoleum Triagular pyramid Vicky fullrange speaker

Great sound. Impressive.


It is tetrahedron (Vicky's idea) made of red linoleum.
Vicky is being making the first prototype.


It is a beautiful work of art.


Driver unit was held by hand and the pyramid held to shape by hand too folding the linoleum made net:
https://en.m.wikipedia.org/wiki/Tetrahedron



Speaker Tesla 5in (TVM ARX-130-20/4) drive unit is on front side, and the equilateral triagle cross sectional area gets smaller and smaller till everything becomes a point at the back and speaker cable gets out like a tail.


Serial number (date time code) is 19062419.


Side of each equilateral triangle is 30cm.


Diameter of speaker hole is about 11.4cm.


It was placed on top of a big table initially and directly connected to iPad mini headphones out, so listening is at low SPL.


The front sound was very nice. Approaching the 2 sides, the sound coming from them was a very nice quality deep bass with no mid frequency artifacts.


It was then placed on top of a smaller round table near the corner of the room exploring the Klipschorn effect of the walls becomes the end horn throat of the bass vibration from the 2 linoleum surfaces. Bass was even better projecting to larger distance eg 2-3 meters.


Then placed back on the big table away from corners. It was connected to a Musical Fidelity Stasis amplifier. Sound was loud clear but a bit harsh, reminding the sound of Pleiades linoleum Auratone 5C type speaker connected to Naim Nait 2 integrated amplifier. A possible reason for the transistor radio effect is the low driving impedance, see Nelson Pass higher impedance constant current drive.
http://www.firstwatt.com/pdf/art_cs_amps.pdf


The sound when connected to a class A (electrons flowing all the time) no feedback amplifier is expected to be of great class.



How would it sound to the silk smooth electron tube DL33 triode connected Pleiades DL33 amplifier or to a Pleiades BD139 one active device class A operation power amplifiers?


It is striking that by removing the drive unit and carefully placing the ear near the hole while softly playing music is in the room, the effect is like listening to a black hole. Very strange sound.


When the speaker is mounted that ugly sounding receiving point becomes the opposite, a transmitting point.


Also once the drive unit is removed it sound very bad and thin on free air.


It would be interesting to compare the sound of the tetrahedron linoleum speaker to a drive unit mounted on a linoleum large baffle.


Why linoleum anyway?
Because it absorbs reasonance without coloration. For a summary of the main points:
https://euroelectron.blogspot.com/2019/06/why-linoleum-loudspeakers.html