Sub-Zero Low-Frequency Extension System
Flagship-grade low-frequency control that puts 60 Hz underfoot
Sub-Zero is BitDiamond’s flagship low-frequency extension system. It compresses flagship-grade low-frequency control into a volume a desk can accommodate: a 5-inch FMLA carbon-fibre / PMI sandwich composite diaphragm handles mid-bass transient and speed, while two 9.5-inch ultra-long-stroke drivers supply the energy reserve below 60 Hz. All-digital direct drive (Power DAC) bypasses the conventional crossover network and the cascade of amplifier stages, holding the physical noise floor below 0.0005% and minimising the uncertainty that reaches the speaker terminals. The system supports Web-GUI and Web-Bluetooth mixer channels, as well as an in-house “perceptual bass” DSP plugin that compensates for the blind spots of desktop listening environments.
Specifications
- Mid-bass driver
- 5" FMLA sandwich composite diaphragm
- Ultra-low driver
- 2 × 9.5" ultra-long stroke
- Amplifier
- 700 W Class-D all-digital direct drive
- Physical noise floor
- < 0.0005%
- Total diaphragm thickness
- 50 μm
- Effective radiating diameter
- D_eff 125.0 mm
- Young’s modulus
- 180 GPa
- CIM inference latency
- < 45 μs
Carbon-fibre / PMI interlayer
Equivalent to 20 pairs of oversized subwoofers
Power DAC clean noise floor
No cascaded amplification chain
Effective mass of only 0.28 g
Standard 5-inch
Carbon-fibre outer skin
Compute-in-memory, 120 mW
Design notes
All-digital direct drive
Power DAC converts the digital signal straight into analogue drive, keeping the physical noise floor below 0.0005% and eliminating the cascading error of a crossover network and multiple amplifier stages.
Femtosecond-grade diaphragm process
The sandwich diaphragm — 50 μm total thickness, effective mass 0.28 g — is hot-pressed in AL7075-T6 precision tooling at 130°C / 0.6 MPa, with edge trimming accurate to ±0.01 mm.
VWDF-MLP dynamic sensing
Weight modelling and dynamic sensing algorithms adjust the low-frequency allocation in real time from programme content, avoiding the muddiness that dynamic overshoot produces.
Hot-swappable and expandable
A modular design on standard DIP-8 sockets means laboratory-grade DIY and self-upgrade work (such as Sparkos / OPA2134) needs no replacement of the whole unit.
Engineering diagrams
