Down4Sound Level-6-18-m6-D1
Best box: 14.2 L sealed · Fc 56.4 Hz · F3 58.9 Hz
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Comparable 15.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Down4Sound Level-6-18-m6-D1 does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- Straight vent would be 303.1 cm long: not physically buildable as a simple tube. Use a passive radiator, a folded slot port or model a 3D folded duct in Load Forge Studio.
Textbook Bass Reflex — not recommended
PORT NOT BUILDABLE| Net Box Volume (Vb) | 32.1 Liters |
| Tuning Frequency (Fb) | 30.4 Hz |
| F3 (-3 dB Cutoff) | 33.4 Hz |
| F6 / F10 Extension | 28.1 Hz / 24.1 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 303.1 cm |
| First Pipe Resonance | 57.0 Hz |
| Estimated MOL @ F3 | 120.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 14.2 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 56.4 Hz |
| F3 (-3 dB Cutoff) | 58.9 Hz |
| F6 / F10 Extension | 45.2 Hz / 34.5 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 27.6 Hz |
| Total Q (Qts) | 0.343 |
| Electrical Q (Qes) | 0.364 |
| Mechanical Q (Qms) | 5.73 |
| Equivalent Volume (Vas) | 46.3 Liters |
| Diaphragm Area (Sd) | 815.0 cm² |
| DC Resistance (Re) | 4.77 Ω |
| Efficiency Bandwidth Product (EBP) | 75.7 |
| Linear Excursion (Xmax) | 32.0 mm |
| Thermal Power (Pe) | 4500.0 W |
| Nominal Diameter | 15.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Down4Sound Level-6-18-m6-D1?
A simple ported box is not recommended for Down4Sound Level-6-18-m6-D1: the textbook alignment (32.1 liters tuned to 30.4 Hz) needs a 303.1 cm port, and no nearby retune stays buildable without a bass hump. A sealed box, a passive radiator or a folded duct is the practical choice.
Can Down4Sound Level-6-18-m6-D1 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 14.2 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 58.9 Hz.
What port dimensions should be used for Down4Sound Level-6-18-m6-D1 to avoid port chuffing?
A straight 20.0 cm port would need 303.1 cm of length, which does not fit a practical cabinet. Use a passive radiator or a folded/3D duct instead of a straight tube.
Shareable Acoustic Card for Forums & Social Media
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