Kobak, the OQS Array — a hunt for the authentic, live, immersive audio recordings
Audiophiles are eager to see and hear recordings in which “3D space” is part of the music and sound waves being reproduced, and they can immerse themselves in it at home.
Sadly, in most cases of commercial (popular?) music, it is only a digital gimmick. The engineers create it in the post-production phase, using all sorts of digital reverberation plugins and devices for the instruments and voices. It is “fake” space, not real.
The modern way of making recordings builds on post-production much more than authentic live recordings, quite a bit like how cinema production uses green box (chroma keying) or LED wall technologies for VFX and color correction in the finishing production phase.
Post-production became more important than a really honest live music recording. The famous albums from the late fifties and early sixties were made with very few microphones, three or four tracks of tape recordings, and practically without any serious post-production. The production was almost completed live, with minimal post-event enhancement. We think it is one of the most important reasons why those sixty-year-old recordings are so authentic, real, entertaining, and enjoyable.
So, when we started My Reel Club® recordings, we wanted to go back to this way of recording: minimal mics, minimal tracks, and minimal or no post-production at all.
I have known István Kishonti, the sound engineer, for ages, and I knew he was experimenting with 4 discreet channels, ambient or “holographic” recordings where there are no reverberations in the post, just the pure ambience of the recording space.
I invited Istvan to make high-res digital, tape, in stereo and high-res digital 4-channel recordings for us at the Hifi Show in Budapest. We were in the largest 176 sqm ballroom, which had plenty of space for the audience and musicians.
So, in October 2023, we made live recordings at the XXII Hifi Show in Budapest. Six mini-concerts were recorded in stereo (on tape and in DSD256) and in 4-channel “quadraphonic” digital format, as pure and raw as the technology allowed. We think the result is really immersive.
A unique microphone technology, developed by Istvan made it possible.
During the early ’80s, Jürg Jecklin published an engineering report in the Journal of the Audio Engineering Society. The article described a technique to use omnidirectional small diaphragm microphones in a true stereo microphone array for two-channel recordings. The setup made it possible to utilize the benefits of omni microphones, bringing directionality to the array by a disk between the two microphones. The Jecklin disk was born, later renamed as OSS (Optimum Stereo Signal) setup
The OSS array proved its excellence. Since it became popular, some modifications emerged. The shape remained the same, but even Mr. Jecklin modified his original concept of enlarging disk diameter and microphone distance.
Istvan Kishonti, a Hungarian sound engineer and scientist, developed a new array while gaining experience using two OSS arrays separated by a third large disc for quadraphonic recording in the early 2000s. After some further thinking, the idea of the new unified array emerged.
It is called “the Kobak” (nickname of “head” in Hungarian) or OQS (Optimal Quadraphonic Signal). Kobak can be considered as four perpendicular jecklinlike plates melting into each other, dividing a sphere into four segments, each containing a flush-mounted microphone. The result is surprising. Using stereo, there is a good separation between the front and rear half-space, giving a chance to optimize the balance of direct to reverberant sound despite the true omnidirectionality of the whole array. The stereo signal is perfect for both headphone and loudspeaker reproduction.
What about four-channel reproduction? Why four instead of surround (5.1)?
Simply speaking, 5.1 (or more and Atmos) is good for film and effects, but terrible for capturing the surrounding ambient sound.
First, the five channels are not equal in 5.1. There is a misunderstanding even in quadraphonic reproduction, considering directionality. As there is no main direction for us in the real sound space, since we can turn around any time to observe sound sources in interest, the reproduced sound space should cope with it in theory. While in the real sound field, humans can localize sound from any direction with a certain precision without turning towards the source. This is not true in the reproduced four-channel sound field generated by four equal-quality channels. In the quadraphonic field, there are four equal directions that can always be perceived only with two speakers in front of the listener.
It is of utmost importance to understand our inability to analyze virtual sound sources in the leftmost or rightmost directions while facing these two front speakers. To perceive what is happening to the left or right, the listener should turn there to listen to two speakers with two ears again. This is the limitation of quadraphonic reproduction, and the importance of the virtual sources always showing via two speakers in all four directions gives the necessity to consider all directions equally.
In arrays with more than four channels, primarily for film and video, there is at least one dedicated channel for dialogue located obviously on a screen, designating the main direction.
The other serious problem with these arrays is that virtual sound sources can be reproduced perfectly only with two speakers or via headphones.
Every additional speaker further degrades the pinpoint precision in localization. So, only the two or four-channel techniques can provide speaker pairs for good virtual reproduction.
Thus, the 4.0 to 5.1 or higher surround arrays are different in setup, usage concept, and reproduction. Kobak (or OQS) is designed to capture a real, immersive 360-degree sound space. Like its predecessor, the Jecklin disk (OSS), it proved its excellence over the last twenty years.
Istvan Kishonti of eurOpus Audio Ltd designed the device, which has been used for hundreds of recordings since 2002.
You can download stereo 44,k/16 bit, and DSD256 samples of our “Kobak” recordings:
Copyright by Koscso Media Engineering Kft/eurOpus Audio.
All rights reserved.
