Free acoustic tool and 3D print generator

Parametric Subwoofer Port Calculator
& Watertight 3D STL Generator.

Tired of straight PVC pipes that chuff at high SPL? Calculate precision acoustic end-corrections, verify laminar airflow limits, and download watertight 3D-printable STL files (Aeroport & Salvatti-Roozen Continuous Venturi) ready for your Bambu Lab, Prusa, or Ender 3D printer.

Parametric Reflex Port & 3D STL Generator

Instant CAD · 0 Non-Manifold Edges
Internal chamber volume (Vb)
Helmholtz resonance frequency
Internal airway diameter
Aerodynamic profile shape
RMS power for velocity check
Curvature transition radius
Rigid 3D print shell (e)
Enclosure mounting interface
3D Printer Print Bed Height: If your print bed is under 250mm, choose 2-piece split mode to print both halves flat.
Calculated Length Ltot
373.5 mm (37.4 cm)
Includes acoustic end-corrections
Port Air Velocity @ Fb
19.5 m/s
Silent (< 15 m/s)
Mouth & Flange Ø
Ø 150.0 mm (Flange Ø 186.0 mm)
Cutout clearance dimensions
Port Volume Displacement
2.93 L
Deduct from gross enclosure volume
📐 Real-Time CAD Cross-Section Blueprint (In Scale) Coordinates in millimeters (mm)
Throat Ø 100.0 mm · R_throat: 1993 mm → R_mouth: 272 mm Flange Ø 186.0 mm Mouth Ø 150.0 mm 4x Ø4.0 on PCD Ø168.0 Flange th: 6.0 mm Inner Mouth Ø 150.0 mm Wall e: 3.5 mm L_tot: 373 mm · Center split: 2 × 186.5 mm
⬇️ Download Watertight 3D STL (.stl) Free · Ready for Cura / PrusaSlicer / Bambu Studio

Which Subwoofer Driver Fits this Port & Enclosure?

You have sized the port for 45.0L @ 32.0Hz. Don't guess which driver will perform best: Load Forge Bass Match™ scans 8,000+ catalog drivers to find which subwoofers reach maximum SPL (MOL @ F3) without bottoming out past Xmax.

Find Best Subwoofers for this Enclosure

The Aerodynamics of Port Chuffing: Why Hardware Store PVC Fails

A loudspeaker port is an oscillating acoustic mass. When airflow exceeds Reynolds critical thresholds, boundary layer separation causes audible noise (chuffing) and dynamic compression.

❌ Straight Cylindrical PVC Pipe

• Chuffing Threshold: Only 15–17 m/s (5% of the speed of sound).
• Acoustic Behavior: Sharp 90° edges at duct terminations cause immediate vortex shedding and turbulence.
• Dynamic Compression: At high volume, effective acoustic mass collapses, causing the enclosure tuning to shift upwards and bass to sound flat.

Flared Aeroport (R 25mm)

• Chuffing Threshold: Up to 28 m/s before turbulence detachment.
• Acoustic Behavior: Quarter-circle bellmouth gradual expansion gently slows air molecules at entry and exit.
• Physical Length: Flare curvature reduces effective mass reactance, shortening physical duct length by ~10–15% compared to raw pipe.

Salvatti-Roozen Continuous Venturi

• Chuffing Threshold: Unlocked up to 34 m/s — double the ceiling of straight PVC!
• Acoustic Behavior: Continuous hourglass power profile with zero straight sections. Eliminates sudden velocity transitions across the entire duct length.
• Manufacturing: Impossible to build with standard hardware pipes — 100% designed for Additive 3D Printing.

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Need Pipe-Organ Resonance Elimination & 260-Iteration Enclosure Synthesis?

In Load Forge Studio, acoustic engineers model sealed, bass reflex, passive radiator and 4th/6th/8th order bandpass loads, and run full Compass Pareto optimizations across 8,000+ drivers with real-time port geometry constraints.

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