639B
| Brand | Altec, Altec Lansing |
| Manufacturer | Altec Lansing Corporation, LTV Ling Altec, Inc., Ling-Temco-Vought, Inc |
| Function | Microphone |
| Produced | 1965 |
| Country | United States |
| Form Factor | Stand Mounted |
| Signal Path | Passive Hardware |
| Dimensions | 8.6 × 19.1 × 11.2 cm (W × H × D) |
| Weight | 3.25lbs |
| Frequency Response | 40Hz-10kHz |
| Elements | 2 |
| Element Types | Dynamic, Ribbon |
| Directivity Patterns | 6 |
| Directivity | Cardioid to Dipole to Omnidirectional |
| Output Impedance | 30/50Ω |
| Output Level | -52dBm/10dynes/cm² |
| Hum (Ref.: 10⁻³ Gauss) | -120dB |
| Finish | Instrument Gray |