Talking watermelons with Michael Wagner

Michael Wagner, for those who don’t know one of the leading educators on all things spatial audio, interviewed me recently on his famous podcast.

We talked not just the watermelons, but also where the industry is, and where it goes. hope you’ll enjoy it as much as I did enjoy the conversation.

What’s been cooking?

Svarog24

Around July, the first unit of Svarog24, a 24 beamforming spherical array has been completed and despite a few minor quirks to iron out, proves to work above expectations.

Why Svarog24? We’re not building a single instrument. An entire family has been designed with parametric design approach, and it spans between a 16-channel 2.5” driver units, all the way to beefy 24-channel 6.5” Perun24. With that in mind, Svarog24 is the flagship model — not the most potent one, but the most representative one for the higher end of the range, featuring an elegant 6-6-6-6 driver layout, providing the most even distribution of speakers on the sphere, and a set of “sweet spot” 6” drivers.

Following initial tests, including several guests visiting me for sessions, we’re open to collaborations and early adopters with the first units ready to be built to order.

Testing low frequencies with Mikołaj Tchorzewski’s ambisonic/beamforming composition adapted for Svarog24.

In this place I could not forget to mention more than generous, continued support from IEM’s Franz Zotter, the ingenious mind, without whose work this project would not have been possible.

There’s more — Perun24

Staying on the higher-end of the family, the biggest member, Perun24 is currently being built. It is expected to surpass Svarog24’s potency and resolution, as it features also 24 drivers, but in a 4-8-8-4 configuration, increasing theoretical horizontal precision, and providing higher SPLs with 6.5” full-range drivers.

The Rebel — Stefan Riedel’s 393 evolved

With the upper-end of the family covered, we also tackled the lower end — more portable instruments with smaller footprint.

This development starts with “The Rebel” — an evolution of Stefan Riedel’s “393”. What’s changed?

• We retained the main idea — it is still a compact footprint Ø24cm 16-channel personal beamformer, aimed to be as affordable as it is portable.

• We redesigned the enclosure, not just in shape, but primarily with respect to manufacturing process. While original FDM PLA is great for DIY’ers, we wanted to achieve higher rigidity, sleeker production-ready look and feel and better acoustic performance. The redesign aimed at getting rid of some of quite ugly resonances I found in the original design.

• The cabling has changed — instead of 4 Speak-on connectors, we now have a single, multi-channel connector providing fully discrete wiring of all channels in a compact form factor. It’s the same connector as we use in the bigger units.

On the amplification setup, The Rebel makes use of the same approach we devised for the entire family - a custom amp rack making use of compact and affordable 8-channel amp units, just two of them instead of three.

That said, “The Rebel” is a ready for small-scale production and we are open to orders.

Supporting Independent Artists

We’re on the mission to break access barriers to spatial sound instruments and support independent artists. Besides the general affordability-focused approach, we introduced a flagship pricing policy towards independent artists.

All non-institutional personal-artist instrument purchases will be subsidized by Slovox with a 20% of the value of the instrument (as compared to institutional list price).

What’s next?

We’re open to early adopters, collaborations and putting our instruments to work. Whether you’re a sound artist interested in spatial sound, run installations or research, please reach out to us for collaborations.

There’s also a bigger project brewing — a development of wooden domes designed around the purpose of spatial sound integration. So… Stay tuned.

Patrick

Hey!

This update is technical, getting into the weeds of the progress of building a compact, spherical ambisonic arrays (or Watermelons if you will). It’s fun, but may not be a super accessible read for general audience. Enjoy!

P.

Following my previous post, a few people have reached out to me, which I really appreciate. A couple of folks also expressed in getting access to these watermelons — that’s actually quite cool! While the progress is solid, there’s still a lot to do. So here’s an update.

Big picture:

1. IKO and IEM/Sonible work on the spherical ambisonic arrays is the Rolls-Royce class, hands down. But not everyone can afford it

2. Goal 1: come up with a practical approach to build affordable and performant SBAs (for myself, and potentially other artists), somewhere between the IKO and 393s

3. Goal 2: Push the category and research forward, both in terms of tech and artistry, with practicality and fun in mind

Progress

1. Built a 393 - not quite an achievement, but a good starter, and invaluable lessons.

2. Explored, simulated and designed possible scale-ups and other layouts (more below)

3. Thoroughly researched the market for drivers, amps, and enclosure manufacturing

4. Developed a pretty good understanding of the entire filter design thing, revived and incremented upon the IEM’s repository for simulating and filter design of SBAs.

Findings

Amps

Amps are still a challenge. I’ve scavenged nearly entire market for multi-channels, and for now I do have a compact, affordable and sufficient solution for 16-24ch, likely better than what I am aware has been used so far for SBAs on the lower-end side. But I don’t consider it a full victory - there’s a room for upgrade for me, and there’s a gap on the market for sure (which I’d love filled at some point).

Drivers

• 393s and similar scale downs use fairly small drivers, therefore it’s easy to find a full-ranger.

• The original IKO uses much larger drivers, and these are state-of-the-art, full-rangers. They are great, except for… their price.

• My main challenge was to find an alternative for large and medium size drivers. With eyes bleeding from comparing countless options, I settled for a few choices, ordered, tested, measured and even accidentally made a pair of decent HI-FI speakers along the way.

So far so good, at least this chapter closed.

Patrick on Instagram: "It’s official. We’re opening #audiophile #hifi company."

Speaker Designs and mixed order control
Building on 2019+ Zotter/Riedel work, I calculated and evaluated nearly all reasonable speaker layouts and mixed-order control schemes for configurations between 15 and 24 speakers.

I have to admit that the established approach is hard to beat - the layouts used for 393 (4th order) and IKO (4th order) hit a sweet spot in terms of combined 2D+3D spatial resolution.

Several options I explored seem to push horizontal resolution even further, which is actually promising!

Layouts like 6666 and 5775 (both 24 speakers) seem to beat IKO’s theoretical resolution, which is understandable, given 24 speakers instead of 20.

The increment over IEM’s repo scripts is extending the simulation across a range of beams and integrating results over them. This provides a less misleading picture of tested layouts, because the resolution plots can vary a lot beam-to-beam.

Control scheme
I’ve been exploring various control schemes, primarily combining IEM plugin suite and dedicated MIMO FIR filter sets. These subjects still raise many questions for further research, but it seems that reliance on ambisonics-only workflow for compositional work could be a bottle neck - my crude observations have been that the footprint of a single beam as soon as it’s encoded in ambisonics, is large. Therefore for my artistic practice I plan on using the ‘ambisonic bed’ and combine it with discrete channel control for high-precision spatial accents.

This is still pretty much an open chapter.

Enclosure manufacturing
Encouraged with the 393 ease of print, I definitely did bet on going 3D print vs plywood for the larger watermelons.

impro.dude on April 8, 2025: "Progress in progress. Two layouts: 3+9+3+1 5+7+7+5 Arranged in two wideband speaker variants. #ambisonics #spatialaudio #spatialsound #speakers #beamforming #projector".

That was a cold shower! The challenges of 3D printing enclosures grow exponentially with size and weight of the drivers, and so do costs. Anyways, It seems that I’m still on a path to 3D print those, at approx 45-52cm diameter.

Ambisonic dome anyone?
As a side effect, it seems I’ve come across a really inexpensive way build of an ambisonic array, including high-end single-cone full-range drivers, custom 3D printed enclosures, and off-the-shelf amps to drive these. Someone mentioned to me Ottosonics, and this is could be seen as taking a similar path. Silghtly pricier, but but should be easier avoiding DIY-ing the amps and with a bit higher-end drivers.

It seems now I’ll take that route for the Echotronica festival, instead of building an ambisonic system using off-the-shelf studio monitors.

And one more thing
If you’ve read until here, you’re probably quite interested. Thanks for that. I just shared a deeper writeup on the genesis of my obsession with the watermelons, and a summary of my 3D audio trip to Berlin last month.

Finally, a huge credit is due to the team over at IEM, particularly Franz Zotter, who’s been supporting me, and my silly questions thoroughly along the way. It would have been much much harder without it, if not impossible.

Please do get in touch - I love meeting ppl interested in everything 3D sound, making these tools sing, and the connections I made so far are totally awesome.

Best,
P

If you’re in Europe, Berlin is without a doubt the Paris of progressive sound scene — from electronics, through a vivid free jazz scene to sound technology. With full respect to Lutetia Parisorum.

In March I made several trips to Berlin to see people, places and listen to frontier spatial audio tech first person. It could not happen without visiting Funkhaus — the former GDR broadcasting megainvestment, which could easily belong Fritz Lang’s Metropolis, Brazil, or other dystopias, with one difference — being real.

It’s been a decade since I visited Funkhaus last time, when its revitalization started. So much, and yet, nothing changed. Same focus on sound, same magnetic people.

4D Sound - where things get real

4D Sound is the backbone of several spatial sound studios, and is one of the pinnacles of spatial audio technology. From the pioneering one, Monom in Berlin, through a few more in Europe, and a couple in North America, the technology has evolved over the last decade, but remains known to few.

What’s special about it?

Listen to a good stereo, and you’ll probably have a vague sense of space and stage. Generally it’s the musical content that touches you, rather than the physical nature of sound. Go to an IMAX or a large concert experience, and things get a tad stronger. But you’re still conditioned to believe. Paired with crowd emotions or good picture, and things start being a bit more convincing, but rarely physical. Those who seek stronger, primeval sensations, usually find joy in the gut-wrenching experiences of bass-focused events a’la Lost Lands or Bass Canyon.

But 4D Sound at Monom is different.

It’s not ignorable. And it’s not a sound pressure knock-out. It’s in the zone in between, that totally messes with your senses. You’re not listening to a sound system anymore. You’re hearing sound that’s so real, that all of a sudden your brain just stops computing. Because you can’t pair the sound with a visual cue.

Technically, Monom (and many of the 4D Sound studios) is a lattice of 48 omnidirectional speakers, distributed in a 4×4×4 spatial grid, plus 9 subwoofers in the floor. Couple it with state-of-the-art sound processing and spatialization software, and we’re miles beneath the marketing yadda yadda of latest Dolby Atmos buzzwords.

But it’s not just about the technology. William, the co-founder of Monome, treated us with a few pieces, which felt like a decent tech demo. But It’s only when he played to us a composition of his own, a soundscape inspired by extinct species, when the technology and a mature artistic vision, paired with intentional choices made a truly touching difference.

Spaes lab in Berlin

My other trip was to visit Gerriet Sharma at Spaes — the lab for spatial sound aesthetics, also in Berlin’s Funkhaus.

Gerriet’s work has been on the frontier for good two decades, including wavefield synthesis, ambisonic arrays, and spherical ambisonic beamformers, developed at IEM in Graz.

You see, there are two problems with cutting edge technology. First, it’s cutting-edge, and second — it’s a technology. So often, these two are enough to steal the spotlight, with artistic matter dragging way behind.

What intrigued and attracted me to Gerriet in the first place, was a genuine, uncompromised artist-researcher approach, and a clear artistic stance. I knew I had to meet the man, and listen to his work in person.

It happened in March, and beyond Gerriet’s generosity in sharing his experiences with spatial sound, we enjoyed a several-hours-long conversation about everything from late-stage capitalism, through education, to artistic leadership, and our role in nurturing younger generations, shaping their attentivenes and responsibility. These discussions don’t happen often and with everyone. When they do, they stick.

The classics - ambisonic arrays

Ambisonic dome arrays are the ‘classic’ of the surround sound. Usually they consist of a range of 16-32 speakers arranged in rings or a dome. Paired with a deliberately crafted sound design or compositions, they can deliver an intriguing and engaging experience.

This sort of a technical approach is what I envisioned for Echotronica festival, as one of the main layers for turning the temple into a musical instrument, especially that the architecture itself is dome-shaped and literally begs for it.

Back to Spaes - although the sound system was not surprising in any single way for me, Gerriet’s compositions made it sing.

A thing about Sharma’s work is that his language is clear, minimalist and abstract. It makes perfect sense, because if your focus is on spatial dimension of sound, anything that resembles the music we all know, draws us away from the focus on space. It’s the curse of temporal linearity, and cliches etched so deep in our perception, we don’t even realize they exist.

Get a sense of Sharma’s language by listening to his compositions like Firniss or Longspaces.

But it’s not the ambisonic dome that was the highlight.

Spherical Beamforming Arrays

While envisioning the core ideas of Echotronica festival, my main focus was on the intersection of sound with space and architecture — the very same subjects I explored years ago in Rebirth film.

With that in mind, a core question arised:

How do you make architecture actively involved in shaping the sound, rather than being a mere canvas?

Most of the sound systems focus on chasing some sort of perfection and fidelity, treating architecture as an enemy. In the ideal world, the architecture should not even exist.

I question this narrative.

For me, how the sound interacts with space, and how we perceive space through sound is perhaps the most intriguing aspect of sonic experience.

This is where spherical beamforming arrays become interesting. How does it work?

The idea behind ambisonic domes is that you listen to the sound coming from outside of the dome inwards, and as long as you sit in a hotspot, this should (and sometimes does) feel like a 3D sound field. You kinda know it from the IMAX. Frankly — this works only as long as as you are willing to accept the convention, and in my experience, feels a lot like listening to a lot of speakers, not a sound field.

Spherical Beamforming Arrays (SBA’s) turn this idea inside out. The instrument is put in the center of the space, and projects precisely focused sound beams outwards. The beams bounce off the architecture (or the reflective screens), and when they reach you, your brain reconstructs the space.

In some way, you listen to space, through sound.

Listening to the IKO and Sharma’s compositions exactly confirmed what I imagined about this instrument. Similarly to 4D Sound at Monome, it was damn convincing. I listened to sound and space. Not speakers.

I got hooked. Then I got obsessed.

Decades of research and the IKO

SBAs story starts in the Ircam’s 1980’s research driven by the desire to reproduce the nature of real instruments. But the early cubic 6-speaker design never delivered. The project got buried for years.

In 2014 it was picked by the team of Franz Zotter of IEM in Graz, and from there a decade of innovation sprung. As a result of the OSIL project, the current model of IKO was devised - a 20-speaker icosahedron, capable of 3rd order ambisonic projection. Here’s a good article going into the who what and when of the OSIL project.

There exist probably about a dozen of IKOs in the wild, primarily in the research centers, and just a couple in the hands of artists, including the one Sharma works with. The original IKO is a marvel, but requires a truly deep pocket or institutional funding.

What if you badly want one?

Plans and ambitions - building a Poor Man’s IKO

I spent the last couple of months learning everything I could about SBAs, and came up with a small library to organize my learnings. Dozens of papers later, I’m slowly building understanding of these… and building my own.

Based on IEM’s Franz Zotter and Riedel’s later research it’s possible to build a much smaller and more affordable version - called 3-9-3, for speakers layout. Several other downscales have been made recently, including 1-7-0 and 1-7-1.

As a warmup exercise, I’ve just wrapped a 393 build myself.

But that’s just a warmup. Last month kept me busy imagining the path forward — building something new, based on the new research on the post-IKO mixed-order beamformers, like the 3-9-3, but comparable in size and power to the IKO. Or even larger.

And that’s the reason this post waited over a month.

The progress? Coming in the next one.

How’s your coffee?