Meeting Report: April 2022 – Involve Audio Demonstration

With COVID restrictions significantly eased, the Committee has made the decision to trial some in-person events as well as to maintain some online events for the 2022 meeting calendar.

On Monday April 11th a small cohort gathered in person for the first time in over two years for a Section Meeting. We visited the Involve Audio facility at Mentone, where Charlie Van Dongen demonstrated his designs for the complete surround sound chain with improved soundstage imaging – decoding, amplifier, loudspeaker processing, as well as electrostatic loudspeakers.

The feast provided - pizza and sandwiches
Charlie’s hospitality was most appreciated – photo Rod Staples

On arrival, we were greeted by a veritable feast of pizza and sandwiches along with soft drinks to start the evening.
We thank Charlie and his accounts person John Di Paolo for their generosity.

Charlie making his introductory remarks
Charlie welcomes us to his facility –
photo Rod Staples

Charlie started out by introducing his colleagues David Alexandrou – head of electronics, Ron Berger -electronics and software development, and Wayne Cary – mechanical and process audio consultant, who would assist him with the demonstrations.

In his introduction, he briefly covered their sister company Zenaji which he explained has developed a high-capacity rechargeable Lithium battery technology which offers a much higher number of recharge cycles than the existing technologies, indicating that the product is assembled on this same site.

Moving on to audio, he then described their Sound Master product, a 2-channel to surround decoder, and the Y4 System – a complete Surround system comprising a 10 Channel amplifier driving 4 dual electrostatic speakers and dual woofers. Then Charlie previewed their new products to be released soon – the Amp Master, a compact six channel Class D amplifier for imminent release followed a few months later by a companion preamplifier fitted with MM and MC phono inputs as well as a built-in vinyl de-click and de-pop feature.

He briefly spoke on their supply difficulties across a range of materials like cases, wood, and semiconductor chips. He described how this was affecting their ability to deliver product, and in some cases forcing redesign to use more available parts.

Following this introduction, we were broken up into two groups with a small group to go into Dave’s office for a session with the Sound Master decoder and the larger group going into the main demonstration room for a more wide-ranging demonstration session.

For us in the larger group, Charlie first demonstrated an effect present in traditional “box” speaker cabinets where imaging and focus can be significantly affected by changing the driver configuration from normal to either coaxial or dipole.
He used a pair of speaker boxes configured to be able to operate in any of these three modes.

Charlie and Wayne are setting up to demonstrate the effect of different speaker modes
Charlie sets the scene for the speaker configuration
demo – Wayne stands by to sync the switching

As he switched modes, the effect was clearly audible to the “golden ears” amongst us – a test facilitated by the well-synchronized mode-switching of Charlie and Wayne. Charlie suggested that the biggest improvement was with the dipole configuration, but that the concentric also improves the focus.
A truly fascinating demonstration.

Charlie stands with some Y4 hardware
Charlie describes the hardware – photo Rod Staples

He then moved on to their hardware designs, describing the evolution of their surround decoder and the psychoacoustic effects involved to achieve a quite believable surround effect from stereo sources. He showed examples of design prototypes from the first generation to the current DSP iteration of the decoder, and the various current and future companion amplifier products.

Charlie moved on to describe, then demonstrate their Y4 system.
This is a system of eight electrostatic speakers (configured as four pairs front&rear/left&right) plus two woofers. They are driven by a ten-channel amplifier with integrated stereo->surround decoder and their patented “sweet-spot” technology.
He explained that each speaker in a pair is driven by a slightly differently-timed signal to minimize the usual sweet-spot limitations.
Regarding woofer positioning, Charlie also suggested that, despite the “common knowledge” that “bass is non-directional, so woofer positioning is not critical” he believes that the human brain does perceive directionality in bass signals but compensates for it to make it non-obvious. However, he suggested that this (neural load) causes brain fatigue, and listening will be more enjoyable if the woofer(s) are placed front-centre, and not asymmetrically offset.

A listening session followed where we all could experience the quality of the system, and the absence of any narrowly defined sweet-spot. There was a clearly defined and consistent surround effect wherever the listener was positioned.

Dave Al;exandro is describing his space and its equipment
Dave expounds on the Surround Master and its effect

In smaller groups we then moved to Dave’s space where he explained the Sound Master decoder and demonstrated it on the new 6 channel amplifier system, 4 x bookshelf electrostatics, and a woofer. Dave then discussed their experiences of the surround effect that can be achieved on the Stereo Master with standard stereo recordings, commenting that quite significant surround effects can be recovered from many stereo recordings. This was suggested to be a product of the microphone techniques used in the original recordings. He played some examples of stereo tracks being decoded into surround and described some projects their technology had been used on.

We thank Charlie, Wayne, Ron, and Dave for their hospitality and for the most interesting demonstration sessions.

For those interested in Charlie’s ideas, inventions, and products his February 2021 Zoom presentation to our Section may be of interest. The Meeting report, with video and slide deck is at:

Other Links:

Surround Master –

Y4 system –