GR Research Tested My Concrete Speaker — Here's What the Measurements Showed

Danny Richie of GR Research just reviewed the Arcus — my mineral cast speaker — and spent the first several minutes on the one thing most people never think about: the cabinet itself. In this video, I break down his measurements, correct a couple of things, and show you exactly how (and why) this cabinet was built. I don't come at speakers from the audio side. I come from decades of manufacturing — cast composites, tooling, production parts. Cabinet resonance is exactly the problem the Arcus was designed to solve: a box that rings colors everything coming out of it, no matter how good the drivers are. Casting the main cabinet as a single, dense, curved piece pushes resonances up and out of the vocal region — and the spectral decay plot shows it. We also cover: Why "concrete" isn't quite right — this is industrial mineral cast, not driveway concrete 3D printed molds vs. hard production tooling (and why the printer is only for prototyping) The GR Research Neo3 planar magnetic tweeter with a waveguide molded directly into the cast face The M165 woofer and the crossover Danny designed and voiced specifically for this cabinet Frequency response, off-axis behavior, impedance, and the one measurement I care about most ⏱️ CHAPTERS 0:00 – Danny Richie Reviewed the Arcus 0:44 – Why Cabinet Resonance Makes or Breaks a Speaker 4:26 – The Problem This Cabinet Was Built to Kill 4:51 – It's Not Concrete — It's Mineral Cast 5:21 – Bracing, Panel Resonance & Cabinet Design 6:18 – 3D Printed Molds vs. Production Tooling 7:13 – Accelerometer Testing the First Prototype 8:24 – Going High-End: The Neo3 Planar Tweeter 9:44 – CAD to Cast: The Molded-In Waveguide 10:27 – A Word from Pale Blue Batteries 10:47 – The Part I Don't Do: Drivers & Crossover 11:41 – The Measurements, Explained 13:55 – Spectral Decay: The Number That Matters Most 14:23 – Next Time: Why Speakers Don't Have to Be Boxes 🔊 THE ARCUS SPEAKER Full technical specifications, frequency response measurements, and ordering: 👉 https://stonesonicaudio.com 📺 Watch Danny's full review over at GR Research:    • And Now For Something Different! Stone Son...   ‪@GRResearch‬ 🔗 RESOURCES GR Research: https://gr-research.com/ Neo3 planar magnetic tweeter: https://gr-research.com/product/gr-ne... Sponsor — Pale Blue Batteries: https://paleblueearth.com/collections... If you're into DIY speakers, cabinet design, or what happens when a manufacturing guy wanders into high-end audio — subscribe. Next video: cabinet shapes, why most speakers are boxes, and why they don't have to be. #ConcreteSpeaker #DIYSpeakers #GRResearch