MP S.R. 4b
| Brand | Martin Persson |
| Manufacturer | Ingenjörsfirma Martin Persson A/B |
| Function | Speaker |
| Country | Sweden |
| Form Factor | Bookshelf / Stand Mounted |
| Signal Path | Passive Hardware |
| Dimensions | 33 × 65 × 43 cm (W × H × D) |
| Frequency Response | 22Hz-20kHz |
| Treble | 2.5cm Dome |
| Midrange | 11.5cm Paper Cone |
| Bass | 26cm Paper Cone |
| Impedance (Nominal) | 4Ω |
| Crossover Frequency | 500Hz, 5kHz |
| Enclosure Type | Sealed |
| Enclosure Type | Bass Reflex |
| Enclosure Volume | 65l |