What is it

The Esparagus Audio Brick is a high-fidelity, modular audio endpoint built for makers, smart home integrators, and audio enthusiasts. It combines an ESP32 core, the TAS5825M DAC/amp, and robust connectivity (Ethernet/WiFi) into a DIN-rail-mountable board that supports stereo, mono, bi-amp, or subwoofer configurations. With over-the-air updates, full DSP control, and an open software stack, it bridges the gap between DIY audio and professional installations. The Audio Brick is optimized for DIN-rail mounting and modular expansion. Thermal management has been improved for enclosed installs, the power stage has been reworked for efficiency, and the design has been cost-reduced to make multi-unit deployments more practical.

It comes in two models: a standard Single DAC model for standard 2-channel installs, which can also be configured into a bridge mode, where both channels can drive a single low-impedance load, typically a subwoofer. The Dual DAC variant of the Audio Brick's main feature is a second TAS5825M DAC that is connected to the same I2S line (so it is perfectly synced with the primary DAC), but allows flexible configuration as either an additional two channels of audio, a more powerful subwoofer channel, or even a bi-amp configuration, with each DAC driving one speaker (one driver per channel).

Single DAC	Dual DAC

It can be used both with Wi-Fi and Ethernet (to make sure bad Wi-Fi would not interrupt the stream)

Motivation

For the last ten years or so, I've been building a home audio system for my own home. Starting with off-the-shelf parts and second-hand audio gear, I got into modifying them, making them smarter and more integrated, more accessible for family members and automations. Every device I did is designed to improve my experience, based on my own use and community feedback, coming from people around the world.

After using a Raspberry Pi-based setup for more than 10 years, I do believe the ESP32 platform is finally at the point where it offers the same level of experience at a much lower price, and, more importantly, much more reliability and longevity. Latest changes in the Home Assistant world, including new Sendspin protocol development, allow incredibly lightweight and service-free installs that offer just as much as much bigger and more complicated setups based on Linux SBCs and even commercial setups. An open and developer-friendly ecosystem allows incredible possibilities for automations, integration with other smart devices, and cost-free upgrades in the future.

Furthermore, what takes Audio Brick apart from many other projects is built-in DSP support for the TAS5825M DAC. If you ever asked yourself how come JBL or Marshall tiny speakers sound so good for their size, or even why pro-studio equipment is so much more expensive than home-audio equipment, it is DSP that makes the difference. And with Audio Brick you're in full control; you define the sound you get from the speakers, based on your own space and taste. And new features are being developed to allow even more DSP settings to be adjusted to get the best sound your speakers are capable of.

Features

	Louder Esparagus	Esparagus Audio Brick	Esparagus Audio Brick Dual DAC
MCU	ESP32-WROVER-N8R8	ESP32-WROVER-N8R8 or ESP32-S3-WROOM-N8R8	ESP32-S3-WROOM-N8R8
DAC	Stereo I2S DAC (TAS5805M) with built-in D-Class amp	Stereo I2S DAC (TAS5825M) with built-in D-Class amp	Dual I2S DAC (TAS5825M) with built-in D-Class amp
Output (4Ω, 1% THD+N)	2x 32W	2x 45W	4x 45W
Output (8Ω, 1% THD+N)	2x 23W	2x 30W	4x 30W
Output (Bridge, 4Ω, 1% THD+N)	1x 45W	1x 53W	2x 53W
IR reader	✅	❌	❌
RGB LED	✅	✅	✅
I2S Microphone	❌	✅	❌
OLED screen (128 x 64px)	✅	✅	❌
TFT screen (320 x 240px)	❌	❌	✅
Flash/PSRAM	8MB/8MB	8MB/8MB	8MB/8MB
Connectivity	WiFi + BT4.2 + BLE + Ethernet	WiFi + BT4.2 + BLE + Ethernet	WiFi + BLE + Ethernet
Case	88 x 38 x 100 mm Aluminum case	90 x 90 x 40 mm DIN-rail mountable case	125 x 90 x 40 mm DIN-rail mountable case
Power requirement	Generic power adapter 5..28V or USB-PD capable power adapter	Generic power adapter 5..28V	Generic power adapter 5..28V
Software support
Squeezelite-ESP32**	✅	✅	✅
Snapclient***	✅	✅	✅
ESPHome (HA)	✅	✅	✅

⚠️ ** Squeezelite-ESP32 support for the ESP32-S3 is an experimental feature and is not fully stable; for styable operation, 'classic' ESP32 is recommended. Please refer to the original repo for up-to-date support information

⚠️ *** Snapclient support for the ESP32-S3 is in beta and not fully stable as well. For best results, 'classic' ESP32 is recommended.

⚠️ Louder boards will connect to passive speakers; you can't use headphones or an external amp

💡 Need to connect an external amp? Check out HiFi Esparagus and Amped Esparagus

💡 Don't need DSP capabilities? Check out Loud Esparagus

💡 Looking for a more cost-efficient version? Louder-ESP32 / Louder-ESP32-Plus

Which chip: ESP32 or ESP32-S3?

This board is available with either the 'classic' ESP32 or the newer ESP32-S3. They are not interchangeable for every use case, and picking the wrong one is the single most common support question — here's the short version:

• ESP32-S3 is the newer, more capable chip — more RAM headroom, a faster CPU, and native USB — but it has no Bluetooth Classic radio, so Bluetooth A2DP only works on the original ESP32.
• Squeezelite-ESP32 and standalone Snapclient: pick the classic ESP32. Neither firmware is fine-tuned for the S3 yet, and current S3 support is noticeably laggier.
• ESPHome / Home Assistant media player: pick ESP32-S3. The new Sendspin renderer runs much better on the S3's extra headroom.
• Voice assistant (wake word) in Home Assistant: ESP32-S3 is mandatory — the classic ESP32 doesn't have the RAM/CPU headroom to run it.
• AirPlay 1 & 2 (rbouteiller/airplay-esp32): both chips are fully supported; ESP32-S3 is preferred for its extra performance headroom.

Your use case	Pick
Bluetooth A2DP from a phone/laptop	ESP32
Squeezelite-ESP32 or standalone Snapclient	ESP32
ESPHome media player / Sendspin	ESP32-S3
Home Assistant voice assistant	ESP32-S3
AirPlay 1 & 2	Either — ESP32-S3 for more headroom

If none of that applies to you and you just want the safe default, pick ESP32-S3 — it's the newer chip. Only choose classic ESP32 if you specifically need Bluetooth A2DP, or plan to run Squeezelite-ESP32/Snapclient today.

Board Pinout

Please refer to pinout section of the docs.

Software Options

• Home Assistant smart home audio and notifications. Start from the web-installer; as soon as you configure WiFi, the boards will be discovered by the ESPHome add-in automatically. Dedicated configs can be found in the documentation for a simple and stable media player, experimental sendspin protocol, and experimental snapclient component
• Squeezelite-ESP32 Spotify Connect, AirPlay, Bluetooth, or Logitech Media Server. Flash directly from your browser using the web-installer. Configure WiFi using Hotspot (default password: squeezelite). Don't forget to exit Recovery mode when done.
• Snapclient multi-room audio streaming with snapserver. Flash directly from your browser using the web-installer; as soon as you configure the WiFi, the board will discover the snapserver automatically
• Snapclient (edge) - developer version. Developer's version of the snapclient, less stable and more feature-rich for those who cannot wait for new features to be released. Installed via web-installer, similar to standard snapclient
• AirPlay 1 & 2 with Sendspin, Bluetooth, and full DSP control. Native, actively developed AirPlay 1 & 2 firmware (rbouteiller/airplay-esp32) with PTP multi-room sync, an experimental Sendspin renderer, Bluetooth A2DP on the ESP32 revision, and full 15-band DSP control over the TAS5825M/TAS5805M from the board's web UI. Flash straight from your browser with the web-installer — no toolchain needed. See AirPlay 2 support below for details.
• Your own software. Use Arduino IDE or Platformio IDE and the provided software samples

AirPlay 2 support

Both Audio Brick revisions run rbouteiller/airplay-esp32, an open-source AirPlay 1 & 2 receiver you can flash straight from your browser via the web-installer — no PlatformIO or toolchain required. It's a separate firmware image from Squeezelite-ESP32 and Snapclient above, so flash whichever matches how you want to use the board.

• AirPlay 1 & 2 — shows up natively in Control Center and any AirPlay app, with PTP-based multi-room sync
• Sendspin (experimental) — an open multi-room protocol renderer sharing the same output path, DSP, and volume control as AirPlay
• Bluetooth A2DP on the ESP32 revision — phones and laptops can stream directly whenever AirPlay is idle (the ESP32-S3 revision has no Bluetooth Classic radio)
• On-device display — the OLED (single DAC) or color TFT (Dual DAC) shows track metadata and progress for AirPlay, Bluetooth, and Sendspin alike
• USB audio (UAC) — the Audio Brick Dual also ships a ready-to-flash build that enumerates as a USB sound card to a connected computer, sharing the same DAC path and DSP; on the single-DAC revisions, UAC mode can be built yourself the same way
• Per-amplifier DSP — the TAS5825M/TAS5805M's on-chip EQ is fully exposed: 15 cascaded biquad sections per output, each an arbitrary peaking filter, shelf, high/low pass, band pass, notch, phase shift, or raw coefficients, plus a crossover builder and (TAS5825M only) full PurePath Console 3 tuning replay for tone, loudness, and DRC beyond the EQ page

TAS58xx DSP: full parametric EQ and crossover control

AirPlay 2 support above isn't just playback — it exposes the TAS5825M's/TAS5805M's on-chip DSP in full from the board's web UI:

• 15 biquad (BQ) filters per channel, usable as a full 15-band parametric equalizer
• Bi-amp filter configuration for 2-way speaker systems — split the signal between tweeter and woofer with independent filter chains per amplifier (and, on the Audio Brick Dual, per DAC)
• Low-pass filtering for subwoofer tuning and bass enhancement
• Generic filters for speaker and room equalization — peaking filters, shelf filters, and EQ sections with a configurable Q-factor, applied per channel individually or to both at once

A	B

Work in progress: REW (Room EQ Wizard) integration, to drive automatic room-correction algorithms directly from a measured response.

Using with Home Assistant

Both Esparagus Audio Brick versions were created specifically to be used with Home Assistant via ESPHome integration. For both boards, rich configs were pre-created with hardware configuration for common use cases. These include

• media_player component for simple and robust media playback and TTS announcements (with ducking effect)
• Sendspin media player – new experimental protocol for multi-room sync with media controls and more
• An experimental snapclient component that allows near-perfect multi-room sync and seamless integration with Music Assistant
• Voice assist config for the ESP32-S3 version of the Audio-Brick

Configurations are being actively maintained and upgraded, and new experimental components are being added for you to test and enjoy

Hardware

Please visit the hardware section for board schematics and PCB designs.

Boxed

The Audio Brick is designed with a DIN-rail mount option, making it suitable not only for hobby projects but also for structured and semi-industrial installations. By mounting directly in an electrical cabinet or distribution box, it becomes easy to wire, power, and manage multiple units in a clean and reliable way. Since each device drives two channels, you can scale simply by adding more Bricks — one per room, per zone, or per speaker as needed. This modular approach makes it practical for whole-home or even small commercial audio installs where consistency and neat wiring matter.

For added convenience, it uses plug-in connector pairs (not yet on the prototype), which simplify installation and allow quick replacement in case of maintenance or failure.

BTL and PBTL mode

TAS5825M DAC allows two modes of operation - BTL (stereo) and PBTL (parallel, or mono). In mono, the amp will use a completely different modulation scheme and basically will fully synchronize output drivers. Jumpers on the board allow both output drivers to connect to the same speaker. The most important step is to inform the Amp to change modulation in the first place via I2C configuration.

One can test audio with a single speaker connected between L and R terminals (plus on one side and minus on the other). Optionally, jumpers on the board will effectively connect the second driver in parallel, doubling the current capability.

TAS5825M DSP capabilities

The TAS5825M DAC has a very powerful DSP that allows doing lots of data processing on the silicon, which otherwise would take a considerable part of your CPU time. At the moment of writing exposing the DAC features in active development, with a focus on the ESPhome component and controls exposed in the Home Assistant UI. What you have today is

• Flexible input mixer with gain corrections
• 15 EQs with pre-defined filter configurations (-15..+15dB)
• LF and HF 4th-order cutoff filters for subwoofer/satellite use with frequency presets (60..150Hz)

Currently in development

• Fully customizable BQ-filter configuration: Shelf filters, equalizer, cutoff filters, peaking EQ - with all parameters adjustable
• Loudness function using dynamic BQ configuration
• 128-tap FIR filter for phase-distortion-free precision filters
• Dynamic EQ (based on audio level)
• 3-band Dynamic Range Compression with flexible curve configuration
• Automatic Gain Limiter with flexible configuration
• Soft clipper

At this moment, it is very experimental. In the perfect world, you should be able to adjust all of those settings to make your speaker-enclosure setup work the best it can, and even apply your room factors into the equation. It is a work in progress.

Power considerations

The TAS5825M DAC can be quite a power-hungry device; simply using 5V over the USB-C would limit its power to mere 5W. It is recommended to use a 12- 26V power adapter, DIN-rail mountable in case of an industrial setup, but also generic power adapters will do just fine, as long as their rated power is at least 20% above what you want to get on the speakers. It is not recommended to go above 26V (although it is rated to up to 30V), since the DAC will report an overvoltage fault and eventually will go into protection mode, cutting the audio off

External voltage selection

The power adapter requirements depend on the speaker power rating and impedance.
Since the amplifier (DAC) operates at roughly 80% efficiency, use the following method to determine the minimum voltage and current required.

Calculate the Required Voltage (per channel)

1. Take the rated power of one speaker (e.g., 10 W for a 2×10 W setup).
2. Take the speaker impedance (e.g., 8 Ω).
3. Compute the RMS voltage needed to deliver that power: V_RMS = sqrt(P * R)

For a 10 W, 8 Ω speaker: V_RMS = sqrt(10W * 8Ohm} = ~9V

1. This RMS value is your minimum supply voltage per channel.

Calculate the Required Current (including efficiency)

1. Use the RMS voltage from Step 1.
2. Compute the output current per channel: I_out = V_rms / R

For 9 V RMS into 8 Ω: I_out = 9V / 8Ohm = ~1.2A

1. Adjust for amplifier efficiency (≈ 90%) to determine input current.
2. Multiply by the number of channels (e.g., 2 channels).
3. Round up for safety and headroom.

Example:
Two 10 W, 8 Ω speakers → ≈ 1.2 A per channel × 2 ≈ 2.4 A, rounded up to 3 A total.

Final Result

For a pair of 10 W / 8 Ω speakers, you need a power adapter rated for at least:

• Voltage: ~9 V
• Current: 3 A total
  
• Power: 25..30 W

It is not recommended to go far beyond the voltage your speakers can handle; otherwise, the amp will blow your speakers in no time. Using a 12V power source with a 9V requirement probably will be totally fine, but getting a 20V power source for 10W speakers is a waste of budget and added risk.

Restocking & Availability

New restock batches are regularly ordered from the factory, and I plan to keep all versions available at least until the next board revision is released. For current availability, you can also check the Crowd Supply or official reseller Elecrow.

USA shipping Update

Due to the new tariffs introduced by the Trump administration, standard shipments are temporarily on hold. However, shipping to the US has now resumed via UPS, though rates are currently quite high. I’ll fully resume regular shipping as soon as the restrictions are lifted. In the meantime, you may consider ordering through Crowd Supply or Elecrow

Sponsorship & Community Support

If you’re working on an open-source project, an educational initiative, or any pro-bono/volunteer effort, feel free to reach out for sponsorship details. I’ll do my best to provide discounts or even free boards.

Custom Design & Consultation

If you’re interested in a custom design based on, or inspired by, my boards, I also offer contract design work and consultation when needed.

Most orders are shipped the next business day morning. All shipments are tracked. Delivery time in the EU is 3-7 days, outside 2-3 weeks, depending on the distance. After 30 days, the package is considered lost - reach out for a refund or replacement.