SHI and SSR explained

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Sonorus Holographic Imaging (SHI) is a new recording technology that when played back on a conventional stereo sound system allows the listener to be enveloped in a three dimensional sound field. 

Sonorus Stereo Revelation (SSR) is an application of SHI that reveals the three dimensional sound field captured inside in an existing conventional stereo recording at its full potential.

To get a better understanding of how SHI and SSR differ from conventional stereo it is important to first go over the basics of conventional stereo recordings and identify what the limitations are.

In its simplest form a stereo recording is made with two microphones, one for the left channel and one for the right channel. In most cases these are directional microphones placed closely together in front of the music ensemble. Instruments left from the center will appear louder in the left channel and instruments right from the center will appear louder in the right channel. Instruments in the center will appear equally loud in both channels. 

The typical stereo system has the speakers positioned in front of the listener approximately 20 degrees to the left and right of the center line. When the conventional stereo recording is played on the typical stereo system it will give an impression of a left to right separation of instruments and also the ambience of the music hall that was picked up by the microphones will be audible. Even though there is resemblance to the original sound heard in the music hall it does not sound at all like the sound heard in the music hall, especially for someone who is not trained to listen to stereo systems. It may work a lot better for experienced listeners who spend a lot of time listening to stereo systems and are used to listen through the shortcomings of conventional stereo recordings. Most audiophiles have experienced those moments when they show off their systems to 'untrained listeners' that those listeners can appreciate the beautiful sound of the system, but cannot hear the soundstage. The untrained listeners only hear sound coming from two speakers, beautiful as it may be.

The reason for this phenomenon is actually quite obvious. The two speakers are real life sound sources that the human hearing can easily identify and locate. The recording that is playing on the speakers on the other hand may contain all the necessary information but it is not recognized as a real source because none of the details add up in the right way for our hearing to identify it as a real sound source. After listening to it many times and with the knowledge what an ensemble in a music hall looks/sounds like, most people will start recognizing the phantom imaging of the instruments.

The question is why the information that was captured on the stereo recording cannot immediately be recognized by our ears and brain as a realistic display? 

The answer lies in the simple fact that we play the recording back in a way that has absolutely nothing to do with the way we recorded it. We are listening to two speakers in front of us that are spaced somewhere between 8 to 15 feet apart. Nowhere in the original music performance or recording session is there anything that resembles the speaker setup or hints to that way of playback. So it is no wonder that our ears and brain have a hard time recognizing that rendition of the recorded information as being something that resembles the sound we heard during the original performance.

(Listening through headphones is obviously distinctly different, but not any better if it comes to sound staging and ambience. Addressing the problems associated with conventional stereo on headphones requires a totally different approach and is not compatible with SHI.)

Addressing the problems of conventional stereo starts by accepting reality. Reality is that the typical stereo system has two speakers in front of the listener that are spaced 8 to 15 feet apart. Reality is also that there are not really any other speaker set up options that are better. So the first step in the development of SHI was to recognize the typical speaker set up as an integral part of the recording/playback chain. The good news is that everybody listens pretty much to the same general set up so that the impact thereof can be characterized quite accurately. 

SHI was designed to place any virtual sound source most anywhere in the horizontal plane around the listener (and to a limited extent in the vertical plane) utilizing a typical stereo speaker set up. It achieves that goal by mimicking the sound on your ears from a phantom sound source to be substantially the same as it would arrive to your ears from a real sound source, so that your brain interprets the phantom sound source to be really there in the three dimensional space.

By using several microphones that capture the sound of a performance in different places in a music hall, SHI is able to realistically recreate the three dimensional soundstage and ambience of the original performance. And unlike a conventional stereo recording, this three dimensional soundstage and ambience is immediately audible for 'untrained listeners' as well, because the odd characteristics of playing music back over two speakers has been dealt with in the SHI process.

SHI lends itself very well for new recordings but it can also be used as a post production tool utilizing the information available on existing multichannel recordings.

Development of the SHI process has been done completely in the real-time analog domain because there are no unnatural shortcuts possible in that case. In an earlier stage of the development that included some digital filter parts the credibility of the 3D sound field was compromised. The human brain doesn't need much comprise to poke through the illusion, so the absence of unnatural shortcuts in the real-time analog domain has proven to be paramount in creating a comfortable and lasting 3D experience. The fully analog nature of SHI makes it very suitable for analog recording and vinyl records, but the very low noise floor and distortion levels of the process makes it also suitable for direct conversion into hires PCM or DSD files.

SHI addresses the problems with conventional stereo but requires information from at least four microphones/channels to recreate the three dimensional space.

SSR is an application or continuation of SHI that starts by accepting yet another reality. That reality is the fact that almost all existing recordings are made with conventional stereo recording techniques. No chance to stick a few extra microphones in the recording space after the fact. 

Even though the conventional stereo microphones cannot pick up sound in other places in the venue they still register most of the soundstage information and a substantial amount of ambient information, albeit in a way that is not immediately recognizable by the human ear. 

By using a remarkable feature of the SHI process it is possible to reproduce both the soundstage information and the available ambient information in a three dimensional way similar to true SHI recordings. The SHI process cannot project exactly the same sound source in more than one location in space. Kind of a natural feature since the same sound source cannot exist in two different places in real life either. This feature makes it possible to pre-condition the same stereo information in a few different ways and use it in multiple places in the SHI process to recreate the original soundstage and a substantial part of the original ambience of conventional stereo recordings. SSR can recreate a sound field of almost 180 degrees around the listener from a conventional stereo recording, where a multichannel SHI recording can reach to as far as 270 degrees around the listener. 

The SSR process has proven to be successful in retrieving 3D information from the majority of existing recordings, especially those from the analog era where phase and time information are fully predictable. For recordings made in the digital age, some of which are using digital stereo enhancement techniques, it happens a bit more often that they don't work well with SSR.

To download some samples of  recordings  using SHI and SSR please visit: https://yarlungrecords.com/sonorus/