THE M4
| Manufacturer | Acoustic Research |
| Function | Speaker (Holographic Series) |
| Produced | 1990 |
| Country | USA |
| Form Factor | Floorstanding |
| Signal Path | Analog Hardware |
| Manufacturer | Acoustic Research |
| Function | Speaker (Holographic Series) |
| Produced | 1990 |
| Country | USA |
| Form Factor | Floorstanding |
| Signal Path | Analog Hardware |