508d: 150w to 400w – 8 Inch Power Tuned Subwoofer
| Speaker Size (In): | 8 |
| Watts RMS: | 150 - 400 |
| Watts Peak: | 1200 |
| Impedance: | D2 / D4 |
| VCD (In): | 2 |
| Piston Diameter (In): | 6 3/8 |
| Fs (Hz): | 37.68 |
| Qms: | 5.858 |
| Qes: | 0.491 |
| Qts: | 0.453 |
| Vas: | 8.813 |
| Xmech (MM): | 64 |
| Xmax (MM): | 10 |
| Frame OD (In): | 8 5/16 |
| Frame OD w/Gasket (In): | 5 1/2 |
| Mounting Diameter (In): | 7 3/16 |
| Mounting Depth (In): | 5 |
| Motor Diameter (In): | 5 1/2 |
| Motor Depth (In): | 2 |
| Woofer Displacement (CuFt): | 0.06 |
| Sealed Enclosure (CuFt): | 0.35 - 0.6 |
| Ported Enclosure (CuFt): | 0.75 - 1.25 |
| Shipping Weight (Lbs): | 14 |
| Price (USD): | 219 each |