Sonorus Audio ProximitySub Controller

Listening Impressions – Session 1

It was obvious a few notes into the Stanley Clarke that bass was fast, clean and had excellent leading edge definition with no perceptible overhang. Tom Jones’ voice was quite nice, the high hat was clear and imaging was precise. The horn, drums and flute on the Charlie Byrd were also nicely handled. In each instance the drum kit was extremely realistic, tight with a significant ability to move air that I would not have expected given the rather small 10” woofer used in the Kawero.

The RAAL ribbon tweeters used in the Kaiser Kawero Classic were clearly responsible for the top end, but I questioned why the bass was as good as it was. My host then explained that a key element in the sound of the system in his room was the Sonorus Audio ProximitySub Controller, an outboard analogue control box that can be used with specific recommended subwoofers of your choice. When properly set up, the Sonorus Audio ProximitySub Controller restores what is lost in the bass between the speakers and the listening position. This was particularly evident on the Charlie Byrd recording where my host switched the ProximitySub Controller in and out of the system. With the ProximitySub Controller in the system, the drum kit was extremely realistic, tight with significant movement of air. Without the ProximitySub Controller in the system, the limitations of the 10” Kawero woofer were more evident (3 db down at 55 Hz, limited ability to move air).

The Sonorus Audio ProximitySub Controller is not intended to extend the bottom end. Instead, it compensates for air velocity lost between the speaker and the listening position. Each ProximitySub Controller requires a custom onsite installation during which Arian Jansen, the designer and his assistant determine the ideal placement of the subwoofer in the listening room and the ideal settings for the ProximitySub Controller. All of this is in the analog domain and affects only the signal going to the subwoofer. The signal going to the main speakers never goes through the ProximitySub Controller.

At this point, we interrupted the listening for lunch and a drive in my host’s Porsche 911 GT3. Lunch was at a local hole in the wall seafood restaurant and was superb. We then returned to my host’s home to finish the listening session. As I quickly learned, he had saved the best for last. The penultimate record was the ORG reissue of the Albeniz. The imaging was holographic. The tonal balance was lovely and notes were crystal clear. There was an occasional touch of leanness, coupled with an occasional tendency of particular instruments to be somewhat forward on the sound stage. Surface noise from the record (what little there was) was decoded in front of the plane of the speakers, separate from the musical event which was behind the speakers, an indication of the accuracy of the system, particularly with respect to timing and phase. The final selection was the Electric Recording Company reissue of the Beethoven Violin Concerto in D Major. Originals of this Columbia SAX are highly sought after on the collector market. While I have never heard the original, the reissue is breathtaking.  Surfaces were dead quiet, imaging was precise and three dimensional, but more importantly Kogan is a master of the violin. If the mark of a good system is that it conveys the emotional content of the original performance, then this system was truly superb.

Final Thoughts

Subsequent to the listening session, I was able to speak with Arian Jansen, the designer who was able to shed some light on what the Sonorus Audio ProximitySub Controller actually does. Arian first explained that the most difficult room anomalies to correct were those below 180 Hz: “The synergy between velocity and pressure of the sound wave is lost because of interactions between the speakers and the room.”

The ProximitySub Controller is designed to restore the natural pressure envelope caused by mostly even harmonics in real live music. The unit has three controls that are user adjustable: volume, phase, parametric shift/ equalization. When Arian installs a ProximitySub Controller in a system, before the Controller is actually hooked up, he spends a significant amount of time optimizing the location of the main speakers to achieve the best phase coherence that the speakers are capable of in the listening room and thus the best imaging precision. Then he runs a series of tests, to optimize phase and frequency by adjusting the controls on the unit. Note: a) that this is not an easy process as changing one setting may impact the other two and b) the speakers can be set up without concern about the best position in the room for bass, which will be compensated by the ProximitySub system.

When used with the Kawero speakers, the Sonorus Audio ProximitySub Controller did make a fundamental difference in the sound. The bass was clearer, cleaner with better leading edge definition. The Controller did not make the volume of the bass louder, but did seem to make the sound fuller or richer, and the bass clearer, better defined and faster. In the same manner as a result of the restored pressure envelope of the music, upper frequencies, particularly in the voice range, also seemed to benefit. Imaging also benefitted, particularly focus. There is also a significant increase in the ability to hear the acoustic space in which the recorded event occurred assuming that information is on the recording.