Soundqubed HDS3.3 Series 15" Subwoofer 1,500 Watts RMS D2/D4

SoundQubed HDS3.3-15 — 1,500W RMS Daily/SQL 15" Subwoofer

The SoundQubed HDS3.3 Series 15" subwoofer is the largest driver in the HDS3.3 lineup — a high-value, daily-driver and SQL-focused 15-inch subwoofer built for enthusiasts who want maximum cone area, deep infrasonic bass extension, and the kind of low-end presence that fills a vehicle from front to back. Rated at 1,500 watts RMS and 3,000 watts peak, the HDS3.3-15 is powered by a 160 oz magnet, a 3-inch diameter voice coil with a 40mm coil length, and a motor assembly tuned for controlled excursion and musical accuracy. Available in Dual 2 Ohm (D2) and Dual 4 Ohm (D4) configurations, this sub wires cleanly into a wide range of mono block amplifiers — making it an ideal choice for daily builds, SQL setups, and anyone who wants serious low-end output without stepping up to a full competition driver.

With an Xmax of 13mm (±) and Xmech of 27mm (±), the HDS3.3-15 delivers controlled linear cone travel across its massive 805 cm² cone area (SD) — the largest in the HDS3.3 series — producing deep, authoritative sub-bass extension down to a free-air resonance (Fs) of 28.7 Hz (D2) / 28.5 Hz (D4). With sensitivity ratings of 86.5 dB (D2) / 85.7 dB (D4), the HDS3.3-15 is the most efficient driver in the lineup, getting seriously loud on moderate amplifier power while delivering the kind of chest-thumping, room-filling bass that only a 15" can produce.

Why Choose the SoundQubed HDS3.3-15?

• 1,500W RMS / 3,000W Peak Power: Plenty of headroom for daily and SQL builds — pairs perfectly with mid-range mono block amplifiers in the 500–1,500W range.
• 160 oz Magnet Assembly: Solid motor force delivers BL of 19.2 N/A (D2) / 23.7 N/A (D4) for controlled, accurate cone movement across the full excursion range.
• 3" Voice Coil, 40mm Coil Length: Larger coil diameter improves thermal management for sustained daily use without voice coil fatigue.
• 13mm Xmax / 27mm Xmech: Well-tuned excursion for a 15" daily driver — deep, clean bass without over-excursion at moderate power levels.
• Dual 2 Ohm & Dual 4 Ohm Available: Wire D2 to 1Ω or 4Ω, wire D4 to 2Ω or 8Ω — compatible with a wide range of amplifier impedance ratings.
• Low Fs (28.5–28.7 Hz): Tuned for deep infrasonic bass reproduction — ideal for ported enclosures targeting 28–34 Hz tuning frequencies.
• Ported Enclosure Optimized: Recommended ported volume 3–6 ft³ and sealed 1.88–2.08 ft³ — versatile for any build style.
• 86.5 dB Sensitivity: The most efficient driver in the HDS3.3 lineup — gets seriously loud without demanding every last watt from your amplifier.

Amplifier & Enclosure Recommendations

The HDS3.3-15 pairs best with a mono block amplifier rated between 500–1,500W RMS at your wired impedance. For the D2 (Dual 2 Ohm) variant, wire the coils in parallel for a 1Ω final load or in series for 4Ω. For the D4 (Dual 4 Ohm) variant, wire in parallel for 2Ω or in series for 8Ω. A Class D mono amp stable at 1Ω or 2Ω is the most common pairing for this driver.

For enclosures, a ported box in the 3–6 ft³ range tuned to approximately 28–34 Hz will maximize low-end extension and output — the ideal setup for the HDS3.3-15's large cone area and low Fs. A sealed box in the 1.88–2.08 ft³ range delivers tight, accurate bass for SQL and daily listening where space is a constraint.

Electro Acoustic Specifications & Thiele Small Parameters

Mounting Dimensions

Enclosure Suggestions

Frequently Asked Questions

What amplifier do I need for the SoundQubed HDS3.3-15?
A mono block amplifier rated between 500–1,500W RMS at your wired impedance is ideal. The D2 wired to 1Ω or the D4 wired to 2Ω are the most common pairings. Any quality Class D mono amp stable at 1Ω or 2Ω will work great.

Should I choose the D2 or D4 version?
Choose D2 (Dual 2 Ohm) if your amplifier is stable at 1Ω (parallel) or 4Ω (series). Choose D4 (Dual 4 Ohm) if your amp is stable at 2Ω (parallel) or 8Ω (series). D2 is the most common choice for single-sub builds.

What size box does the HDS3.3-15 need?
For ported, use 3–6 ft³ tuned to approximately 28–34 Hz for maximum output and deep bass extension. For sealed, use 1.88–2.08 ft³ for tight, accurate daily bass where space is limited.

Is the HDS3.3-15 good for daily use?
Absolutely — the HDS3.3-15 is built for daily driving and SQL builds. Its 86.5 dB sensitivity means it gets seriously loud on moderate power, and its 805 cm² cone area delivers the kind of deep, full bass that only a 15" can produce — without the power demands of a full competition driver.