The round porthole has been Marantz’s brand signature for seven decades. For the Model 10 flagship amplifier, Sound United briefed us to turn that porthole into a high-resolution, audio-reactive display — without losing a gram of its analog soul.
Marantz amplifiers have carried the round porthole since 1953 — it is one of the few visual signatures that hi-fi collectors recognise across generations. The business tension was simple: the porthole was analog, the competitive landscape (NAD, Naim, Cambridge Audio) had moved to higher-resolution branded GUIs, and Marantz needed a next-generation flagship that spoke to a buyer who grew up on retina displays but still wants the amp to feel like a serious instrument.
Sound United’s ID-UX group needed a prototype that would prove the display could carry Marantz’s brand language in a modern, GPU-driven medium — and then a path to put that prototype on the shelf as the Model 10’s actual front panel.
We organised the work in four phases spanning ten months: Analyse → Conceptualise → Visualise → Prototype → Integrate. The Analyse phase mapped competitor display approaches and audited what Marantz’s brand language needed from a display medium. Conceptualise locked the porthole-as-display premise with the industrial design team. Visualise built the motion-rich GUI in TouchDesigner. Prototype rebuilt it in Qt against the HEOS platform. Integrate handed it to the Model 10 product team as production-ready specs.
Three design decisions carried through all four phases:
The prototype delivered seven canonical porthole states — brand mark, source, time, volume, VU meter, spectrum, farewell — in two chromatic variants so the industrial design team could choose their palette direction. The underlying GUI library was built in Qt against the HEOS-as-Platform vision, which meant the same display pipeline could extend to future Marantz and Denon products without a rebuild.
The Model 10 shipped with the Porthole display as its signature front-panel element. The design language we established — centred radial geometry, audio-reactive motion, warm-amber accent — now informs the broader Marantz hi-fi line.
Underneath the visible display sits the iceberg: the Qt-HEOS module, JSON-defined animations, IR remote command mapping, and the microcontroller glue that lets a prototype become a product. We designed and specified that whole stack, not just the surface.
The Model 10 was recognised as a new reference in high-end amplifier design the year it launched:
The Porthole work was part of a broader UX direction across the Sound United / D&M Holdings portfolio. Over the same window, the Denon side of the house saw its sound-bar and AVR categories climb hard in Japan:
Awards get published; market share compounds. Both landed inside the same UX direction era, and the Porthole design language is now the throughline between the flagship amplifier and the soundbar lineup underneath it.
“The porthole stays a window, not a screen.”
design principle · Model 10 Porthole proposal