Great Plains Audio 515-8C
Best box: 92.8 L sealed · Fc 64.8 Hz · F3 67.1 Hz
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Comparable 24.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Great Plains Audio 515-8C 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 321.9 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.
- Large enclosure volume (200.1 L) requires extensive internal matrix bracing to prevent panel resonance.
Textbook Bass Reflex — not recommended
PORT NOT BUILDABLE| Net Box Volume (Vb) | 200.1 Liters |
| Tuning Frequency (Fb) | 34.5 Hz |
| F3 (-3 dB Cutoff) | 38.3 Hz |
| F6 / F10 Extension | 32.0 Hz / 27.4 Hz |
| Port Inner Diameter | Ø 60.8 cm |
| Port Physical Length | 321.9 cm |
| First Pipe Resonance | 53.0 Hz |
| Estimated MOL @ F3 | 115.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 92.8 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 64.8 Hz |
| F3 (-3 dB Cutoff) | 67.1 Hz |
| F6 / F10 Extension | 51.2 Hz / 38.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 27.8 Hz |
| Total Q (Qts) | 0.3 |
| Electrical Q (Qes) | 0.311 |
| Mechanical Q (Qms) | 8.25 |
| Equivalent Volume (Vas) | 422.5 Liters |
| Diaphragm Area (Sd) | 45275.6 cm² |
| DC Resistance (Re) | 6.46 Ω |
| Efficiency Bandwidth Product (EBP) | 89.3 |
| Linear Excursion (Xmax) | 5.1 mm |
| Thermal Power (Pe) | 150.0 W |
| Nominal Diameter | 24.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Great Plains Audio 515-8C?
A simple ported box is not recommended for Great Plains Audio 515-8C: the textbook alignment (200.1 liters tuned to 34.5 Hz) needs a 321.9 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 Great Plains Audio 515-8C be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 92.8 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 67.1 Hz.
What port dimensions should be used for Great Plains Audio 515-8C to avoid port chuffing?
A straight 60.8 cm port would need 321.9 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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