Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm
Best box: 276.5 L bass reflex tuned to 31.4 Hz · F3 31.6 Hz
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Comparable 21.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm 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
- Large enclosure volume (276.5 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 276.5 Liters |
| Tuning Frequency (Fb) | 31.4 Hz |
| F3 (-3 dB Cutoff) | 31.6 Hz |
| F6 / F10 Extension | 27.9 Hz / 24.4 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 20.2 cm |
| First Pipe Resonance | 850.0 Hz |
| Estimated MOL @ F3 | 122.6 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 123.7 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 56.0 Hz |
| F3 (-3 dB Cutoff) | 58.4 Hz |
| F6 / F10 Extension | 43.5 Hz / 32.5 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 27.6 Hz |
| Total Q (Qts) | 0.33 |
| Electrical Q (Qes) | 0.341 |
| Mechanical Q (Qms) | 10.7 |
| Equivalent Volume (Vas) | 444.0 Liters |
| Diaphragm Area (Sd) | 1735.0 cm² |
| DC Resistance (Re) | 5.4 Ω |
| Efficiency Bandwidth Product (EBP) | 81.1 |
| Linear Excursion (Xmax) | 11.0 mm |
| Thermal Power (Pe) | 1000.0 W |
| Nominal Diameter | 21.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm?
Load Forge's calculated alignment puts Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm in a 276.5 liter vented enclosure tuned to 31.4 Hz, reaching an F3 cutoff of approximately 31.6 Hz.
Can Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 123.7 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 58.4 Hz.
What port dimensions should be used for Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 20.2 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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Not sure if PSS555-8 21" Pro Subwoofer with 4.5" Voice Coil 8 Ohm fits your physical space?
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