4.3 KiB
HubAudio System Architecture
- Status: Draft
- Date: 2026-08-01
- Document Type: System Architecture
1. Overview
HubAudio is a modular digital audio platform designed around a centralized audio processing architecture.
The system separates three main functional domains:
- Control Domain
- Audio Domain
- Time Domain
Each domain has a clearly defined responsibility.
The architecture is based on the principle:
ESP32-S3 manages the system.
ADAU1467 manages the audio.
The clock domain synchronizes the orchestra.
2. High Level Architecture
HUBAUDIO
CONTROL DOMAIN
ESP32-S3
WiFi / Network / UI
|
|
SPI
|
+---------------+---------------+
| |
ADAU1467 Si4684
Audio Processor Radio Receiver
|
|
|
AUDIO DOMAIN
|
+-------+-------+-------+-------+ | | | | |
ESP32 Si4684 BT RX Optical Other
|
ADAU1467
DSP / Routing / Mixing
|
+-------+-------+-------+
| | |
CODEC BT TX Optical Out
|
TIME DOMAIN
|
Audio Clock Tree
|
MCLK / BCLK / LRCLK
3. Functional Domains
3.1 Control Domain
The Control Domain is responsible for system management.
Main component:
ESP32-S3
Responsibilities:
- network connectivity
- streaming services
- user interface
- configuration management
- firmware update coordination
- device supervision
Communication:
ESP32-S3
|
SPI
|
Audio peripherals
The Control Domain does not transport real-time audio.
3.2 Audio Domain
The Audio Domain is centered around the ADAU1467.
The ADAU1467 is responsible for:
- DSP processing
- audio routing
- mixing
- digital effects
- format conversion
- audio synchronization
Audio sources:
ESP32-S3 Si4684 Bluetooth RX Optical Input
Audio destinations:
CODEC/DAC Bluetooth TX Optical Output
The audio transport uses:
I2S
3.3 Time Domain
The Time Domain provides the synchronization reference.
The ADAU1467 is the audio clock master.
The clock distribution provides:
- MCLK
- BCLK
- LRCLK
Clock distribution:
ADAU1467
Audio Clock Master
|
|
Clock Buffer
|
+-----------+-----------+
| | |
CODEC Si4684 BT
4. Component Roles
ESP32-S3
Role:
System Controller + Audio Source
Functions:
- network audio streaming
- system management
- configuration
Inside Audio Domain:
I2S Source
ADAU1467
Role:
Audio Domain Master
Functions:
- DSP
- routing
- mixing
- clock generation
Interfaces:
SPI -> Configuration I2S -> Audio Clock -> Synchronization
Si4684
Role:
Digital Radio Audio Source
Functions:
- FM reception
- DAB/DAB+
- digital audio output
Interfaces:
SPI -> Control
I2S -> Audio
Bluetooth Modules
Role:
Wireless Audio Interfaces
Bluetooth RX:
BT Audio
|
I2S
|
ADAU1467
Bluetooth TX:
ADAU1467
|
I2S
|
BT Transmitter
Digital Converters
Optical interfaces are handled through dedicated conversion stages.
Input:
SPDIF
|
DECODEC
|
I2S
|
ADAU1467
Output:
ADAU1467
|
I2S
|
ENCODEC
|
SPDIF
5. Design Philosophy
HubAudio follows a distributed intelligence model.
The ESP32-S3 provides connectivity and supervision.
The ADAU1467 provides audio intelligence.
Dedicated peripherals provide specialized functions.
The architecture avoids making the microcontroller responsible for time-critical audio processing.
6. Expansion Strategy
The architecture allows future integration of:
- additional audio sources
- additional DSP processing
- microphones
- sensors
- alternative wireless interfaces
Expansion follows the same principle:
Control:
SPI
Audio:
I2S
Synchronization:
Clock Domain
7. Summary
HubAudio is structured around three independent but coordinated planes:
CONTROL PLANE
ESP32-S3 | SPI
AUDIO PLANE
ADAU1467 | I2S
TIME PLANE
ADAU1467 | Clock Distribution
This separation defines the fundamental architecture of HubAudio.