1950s HECO Speakers with Sonos Drivers & Active DSP Crossover

Background:
I acquired a set of three vintage 1950s HECO speaker cabinets. They were in rough shape—infested with insects and containing thin, "canny" sounding drivers that seemed like they were from old cinema equipment. This project documents the build of the first of the three, converting it into a modern, active mono speaker.

Objective:

• Clean and restore the vintage HECO cabinet for the first unit.
• Replace the original internals with a modern woofer/tweeter set from a Sonos speaker.
• Create a compact, all-in-one active speaker perfect for an office or bedroom, serving as the template for the other two.

Hardware Components (per unit):

• DSP/Amp: Raspberry Pi 3A+ with a DigiAmp+ HAT (2-channel).
• Power Supply: Mean Well GST90A19-P1M (19V, 4.74A).
• Drivers: Woofer and tweeter salvaged from a Sonos speaker.
• Filament: Carbon Fiber PLA (PLA-CF) for custom parts.
• Software: Pre-configured Beatnik Pi SD card.

Signal Path:
Snapclient -> ALSA Loopback -> CamillaDSP (Crossover/EQ) -> DigiAmp+ (2-Ch) -> Woofer/Tweeter

Build Process:

1. Cabinet Restoration: Gutted the cabinet, disposed of the infested original driver, and thoroughly cleaned the wood.
2. 3D Printed Adapters: Designed and 3D printed custom mounting plates for the Sonos woofer and tweeter using PLA-CF.
3. Active Wiring: Wired the woofer and tweeter directly to the two output channels of the DigiAmp+.
4. DSP Configuration: Set up CamillaDSP to function as a 2-way active crossover, routing low frequencies to the woofer and high frequencies to the tweeter.

Result

The first unit is complete and the project was a success. The speaker isn't meant to be a flawless audiophile reference, but it nicely fills a single room (like an office or bedroom) with clean, detailed sound.

Next Steps

The goal now is to embed this functionality into the Beatnik Controller App.

Check our subreddit for more information on the progress:  https://www.reddit.com/r/beatnikAudio/