Helix U 10A

Helix U 10A – ultra-compact 10″ active subwoofer

The Helix U 10A is an ultra-compact active subwoofer from HELIX, sold alongside the smaller U 8A. It is designed for vehicles with little mounting space and adds low-frequency punch to an existing car hi-fi system without a complicated installation – the especially flat housing can even be fitted under a seat.

An integrated Class AB amplifier with 180 W RMS drives a heavy-duty 10-inch / 250 mm driver with a very rigid aluminium cone and heat-resistant voice coil. The solid, low-resonance die-cast aluminium housing supports precise bass reproduction and dissipates heat effectively, while a continuously variable steep-slope low-pass filter and finely adjustable phase let the installer match the bass to the vehicle acoustics.

Key Features

• Integrated Class AB amplifier: 180 W RMS / 360 W max for punchy bass.
• Heavy-duty 10″ / 250 mm driver: Extremely stable aluminium cone for compression-free conversion of amplifier power into sound pressure.
• Die-cast aluminium housing: Solid, low-resonance enclosure for precise bass and optimum heat dissipation.
• High-level inputs with Auto Turn-on: 2-channel speaker-level input that switches the unit on automatically.
• Low-level inputs: 2-channel RCA input.
• Variable low-pass filter: Continuously adjustable from 50 to 150 Hz with a steep 24 dB/oct slope.
• Phase control: Phase switch 0°/180° plus continuously variable phase shift 0–180° for fine adjustment.
• Subsonic filter: Fixed 16 Hz, 12 dB/oct.
• Cable remote control: Remote volume control included in the delivery.
• Under-seat design: Flat housing, 78 x 245 x 345 mm (H x W x D), for space-saving installation.

Drivers & Construction

• Driver: 10″ / 250 mm heavy-duty chassis with aluminium cone and heat-resistant voice coil.
• Housing: die-cast aluminium, low-resonance, with good heat dissipation.
• Dimensions (H x W x D): 78 x 245 x 345 mm / 3.07 x 9.65 x 13.58″.

Inputs & Outputs

• 2 x RCA low-level input – input sensitivity 0.3–4 V, input impedance 10 kOhms.
• 2 x high-level speaker input – input sensitivity 1.2–20 V, input impedance 33 Ohms, with Auto Turn-on.
• 1 x Remote In.
• 1 x input for the included cable remote control.
• Auto Remote switch.

Power & Amplifier Section

• Amplifier type: Class AB.
• Output power: 180 W RMS / 360 W max.
• Frequency response: 40–150 Hz.
• Signal-to-noise ratio: > 92 dB (A-weighted); distortion (THD): < 0.4 %.
• Operating voltage: 10.5–16 V; fuse: 25 A maxi fuse (APX).

Filters & Sound Tuning

• Low-pass filter: 50–150 Hz, continuously adjustable, 24 dB/oct.
• Subsonic filter: 16 Hz, 12 dB/oct.
• Phase: 0°/180° switch and 0–180° continuously variable phase shift.
• Volume adjustable via the included cable remote.

Installation & Connectivity Notes

• The flat 78 mm housing allows mounting under a seat or in other tight spots.
• Two signal paths are available: 2-channel high-level input with Auto Turn-on and 2-channel RCA input, plus a Remote In connection and an Auto Remote switch.
• Protect the power supply with the specified 25 A maxi fuse (APX).
• Mounting material and cable remote are included.

Technical Specifications

Scope of Delivery

1 x Active subwoofer HELIX U 10A
1 x Cable remote control
1 x Mounting material
1 x Instruction manual