INTRODUCTION

Profile.

 

I am a mid-70's born machine automation & industrial engineering engineer from Tampere, Finland. I started my hi-fi hobby in the early 90s. I got acquainted with the manufacture of the speaker when my first speakers were Hifi 6/2 models. Tuomela's “Build Hi-Fi Speakers” (-92) had to be read from cover to cover several times. Then my working life took me to the late ’90s and I was mainly on industrial machine / factory installation projects around the world 160-279 days a year. Projects typically lasted from 5 days to 3 months. As a rule, I did automation / process commissioning. The work was so intense that hobbies were limited, including hifi. Then -06 , I became a father and settled down to work in various product support positions at home. Then from 2007 onwards I was a product manager, which included e.g. leading product development projects. Until 2017, I made a trip of 50 - 100 days / year in the world. The international field is more familiar than the domestic one. As a mechanical engineer, I have a strong understanding of materials engineering and also an understanding of electricity due to machine automation studies and work experience. It is now a 100% own company from the summer of  2018. The design of the speaker seemed natural on this basis, as the hifi hobby has always been close to my heart.

I use partners in the design and engineering of structures. In fact, I have developed methods and an electro-acoustic design. Production design and material technology have been taken into account in the design. The products can be made by hand in small batches and also on an automated line if required. So it wasn’t meant to carve a speaker out of a single tree. Continuous quality development and monitoring are part of the figures. The speakers are 100% Finnish handcrafted.

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Technology & Objective.

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The design of the speaker concept began with a hobby project in 2013, when the intention was to make a speaker with a sound image centered behind the speaker. First, the idea was to make several small dynamic full range elements into Quad-63-style sectors and delay circuits so that the sound would have originated from the point source just behind the speaker.

There would probably be a way to not have to use overly exotic structures and electronics. The design of the ribbon element began in late 2017. The goal was still the same and a couple of other variables were added to the soup.

I remember that sometime in the late 90s in Tampere, someone was selling legendary Dutch Audiostatic electrostatic speakers. The best “3d” sound is probably what I’ve ever heard, but the optimal listening area was enough for just one person. It was as if I had beaten my headphones on my head as I sat in the stereo sweet spot. The directivity was thus quite high for one accustomed to ordinary box speakers. Clearly, the speaker was not designed for listening to background music, for example.

Another electrostatic speaker manufacturer with a curved stator. The overall horizontal orientation of the top feels narrow (30 °) even though the curved shape expands the listening area. These generally have omnidirectional basses, usually in a closed or bass reflex housing. The power response drops significantly, being darker. Impedance can drop, even below 1Ω at higher frequencies. So not the easiest load for amplifiers.

Then there are these large-sized magnetostatic + ribbon combinations in which elements of different sound ranges are placed side by side side by side. The sounds of the different sound areas leave laterally at different times and also travel a different distance to the listening position, causing the phases to begin to cancel each other out with too large an angle difference. Only a small limited listening area is ok. By lowering the crossover frequencies, the problem is reduced. Second, the dynamics of the basses are limited because the motion deviation of the planar membrane element is small. A large surface area is required to obtain adequate bass reproduction. However, these speakers typically have low sensitivity and low impedance. In some models, the impedance can go below 1Ω in the top octave. So requires a very efficient amplifier to work.

The intention was therefore to design a loudspeaker whose sound propagates mainly as a dipole in a cylindrical manner by increasing the vertical directivity. Sitting in a stereo triangle would be a deep three-dimensional sound. Going outside the stereo triangle, the sound would hardly darken. The listening area would not be limited to one point in terms of frequency balance and could also be listened to as background music away from the stereo triangle. The elements should be on the same vertical line. The speaker should also be smaller than disc-shaped dipole speakers, but bass reproduction would still be sufficient. Also, the room would not need to be attenuated more than a normal living room, as long as only certain distances to the interfaces are realized. The speaker should also have an easy load on the amplifier (8Ω) and a sensitivity about  90dB / 2.83Vac.

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Best regards,

Mr. Antti Sipola

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HIFI2022 -hifishow is the biggest hifi event in Finland - Organized since 1978.
This year showtime is 10-11. of September.
Show is located on congress premises of Helsinki Messukeskus (fair center) and congress hotel Holiday Inn Expo. Welcome to see us! K212. HIFI2022 hifimessut - Hifimessut