American Bass Audio
Box & Port Calculator
Calculate enclosure volume and port length for your subwoofer build
Enter Dimensions: You know your box size or have space constraints. Enter width, height, and depth to calculate volume and port length.
Net Volume
0.00ft³
After all displacement
Port Length
0.0in
For 32 Hz tuning
Port Area: Good
Velocity: Quiet
Fit: Port fits inside box
Enclosure Dimensions
External measurements in inches
Width (External)
Measure the outside left-to-right span of your box. This is typically the longest dimension.🚗 Trunk tip: Measure your trunk or cargo area first — leave at least 1" clearance on each side for fitment and airflow. Common trunk widths are 30–44".
in
Height (External)
The vertical measurement of your box from bottom to top.⚠️ Common mistake: Don't forget to account for carpet/trim if the box sits on the trunk floor. Measure from the floor to the lowest obstruction (rear deck, seat fold, etc.) and subtract 1–2".
Rule of thumb: 12" subs need at least 13" of height; 15" subs need at least 16".
in
Depth (External)
The front-to-back measurement of your box.⚠️ Critical: Your sub's mounting depth + at least 1–2" of rear clearance must fit inside this dimension (minus 2× wood thickness). Check your sub's spec sheet for mounting depth.
For ported boxes: More depth gives the port more room to fit inside the box, reducing the chance of a "port too long" warning.
in
Material Thickness
3/4" (0.75") MDF is the industry standard for most builds. It's dense, acoustically dead, and affordable.When to go thicker: Use 1" MDF for enclosures over 4 ft³ or for high-power SPL builds (1000W+). Doubles panels on the baffle (front face) for extra rigidity.
Avoid: Particle board (too weak), plywood under 3/4" (resonates), and OSB (poor acoustic properties).
in
💪 Bracing Recommended
For enclosures over 3 ft³, add internal bracing to prevent panel flex. Use 2-3 braces made from the same material. This adds approximately 0.02-0.05 ft³ of displacement.
Target Volume Mode
Enter your desired net volume, get suggested dimensions
ft³
in
in
💡 Suggested Dimensions
32" × 14" × 16"
Subwoofer
Select size or enter custom displacement
Subwoofer Size
Selecting a size auto-fills a typical displacement value for that cone diameter. These are averages — your actual sub may differ.For best accuracy: Choose "Custom" and enter the exact displacement from your subwoofer's spec sheet (listed as "Vd" or "driver displacement").
Typical ranges:
• 8" → 0.03–0.05 ft³
• 10" → 0.04–0.07 ft³
• 12" → 0.06–0.15 ft³
• 15" → 0.10–0.20 ft³
• 18" → 0.15–0.35 ft³
Driver Displacement (Vd)
This is the physical volume your subwoofer's motor, magnet, and cone assembly occupy inside the box. It gets subtracted from gross volume to give you net volume.Where to find it: Check your sub's spec sheet or product page — look for "Vd," "displacement volume," or "driver displacement."
Why it matters: Ignoring displacement on a large sub (like a 15" or 18") can throw off your net volume by 5–10%, which changes your tuning and output noticeably.
ft³
1
Enclosure Type
Choose sealed or ported design
🔒 Sealed
Tight, accurate bass
🔊 Ported
Louder, deeper bass
💡 Sealed Box Tips
Sealed enclosures provide tight, accurate bass with excellent transient response. Consider adding polyfill (1-1.5 lbs per ft³) to make the box appear acoustically larger and smooth the response. Sealed boxes are more forgiving of volume variations than ported designs.
Daily
35 Hz
Balanced
32 Hz
SPL / Low
28 Hz
Slot Port vs. Round Port
Slot Port: A rectangular channel typically built into the box using wood panels. Provides more port area per inch of width, handles high power well, and is easier to integrate into tight builds. Most competition and high-output builds use slot ports.Round / Aero Port: A pre-made circular tube (like a PVC or flared aeroport). Simpler to install — just cut a hole and glue in the tube. Best for smaller or simpler builds. Flared ends reduce turbulence noise at high volumes.
Bottom line: Slot if you want max performance and can woodwork; round if you want easy and clean.
Tuning Frequency (Fb)
This is the resonant frequency of your port — the note where the port produces the most output. It's the single most important decision in a ported build.Higher (33–40 Hz): Punchy, responsive. Great for rock, country, and daily listening. The box plays louder in the upper bass range but rolls off faster below tuning.
Lower (26–32 Hz): Deep, extended bass. Ideal for hip-hop, EDM, rap, and SPL builds. You'll feel the lows in your chest, but you need more box volume and port length.
⚠️ Don't guess: Check your sub's spec sheet for the manufacturer's recommended tuning range. Going too far outside it can damage the driver or sound terrible.
Hz
Slot Port Width
The narrow (shorter) dimension of your rectangular port opening.Sizing guide:
• 2–2.5" — OK for low-power 8–10" subs
• 3–3.5" — Standard for most 12" builds
• 4"+ — Needed for 15"/18" subs or high-power setups
Trade-off: Wider port = more port area (less noise) but requires a longer port to reach the same tuning frequency. Watch the "Fit" badge to make sure the port still fits inside your box.
in
Slot Port Height
The tall (longer) dimension of your rectangular port opening. For most builds, this should match your box's internal height, since the port usually shares the top and bottom panels of the box.How to calculate: Take your external height, subtract 2× wood thickness. Example: 14" box with 3/4" MDF → 14 - 1.5 = 12.5" internal height.
Pro tip: Port height × port width = your total port area per port. Bigger area = quieter port at high power.
in
1
Port Velocity: ~15 m/s
Quiet operation - no port noise expected
Calculation Results
All measurements for your build
Gross Volume
0.00 ft³
Sub Displacement
0.00 ft³
Port Displacement
0.00 ft³
Port Area
0.0 sq in
📋 Build Sheet
Enclosure Type
Ported
External Dimensions
32" × 14" × 16"
Internal Dimensions
30.5" × 12.5" × 14.5"
Net Volume
0.00 ft³
Tuning Frequency
32 Hz
Port Dimensions
3" × 12"
Port Length
0.0"
✂️ Cut List
All pieces needed to build your enclosure
Enclosure Panels
Port Pieces
AMERICAN BASS AUDIO
Subwoofer Enclosure Build Sheet
Enclosure Specifications
Enclosure Type:
External Dimensions:
Internal Dimensions:
Wood Thickness:
Gross Volume:
Net Volume:
Subwoofers:
Port Specifications
Tuning Frequency:
Port Type:
Port Dimensions:
Port Length:
Port Area:
Number of Ports:
Cut List
Disclaimer: This calculator provides estimates for educational purposes only. Always verify calculations independently before building. Results may vary based on construction methods, materials, and environmental factors. American Bass Audio is not responsible for enclosures built using these calculations. Measure twice, cut once!