Here is a vintage 1955 RCA Type 77-DX velocity ribbon poly-directional microphone. This particular example, serial number 6549, is in very excellent cosmetic condition and works perfectly, so take advantage of this opportunity to buy an absolute studio necessity. Increbidly excellent for capturing sweet and smooth vocal performances, in addition to, being beautiful for translating delicate and soft signals into sublime sonics, the RCA 77-DX has become the quintessential ribbon microphone with respect to both operation and aesthetic.
This mic was recently purchased from a professional studio, where this mic was sitting idle in inventory. It was re-screened and serviced approximately 20 years ago, and remains in excellent working condition. The original brown XLR mic cable is deteriorating in several places, but there is still many feet of functional chord. We can easily address this and remove the worn portion on behalf of the buyer, but have decided extend this offer should the winner prefer.
The RCA Type 77-DX Poly-directional Microphones MI-4045-F and MI-11006-C are high-fidelity micro phones of the ribbon type which may easily be adjusted to obtain a variety of directional patterns. Since the MI-4045-F micro phone is primarily intended for broadcast use, it is finished in satin chrome and a low-gloss umber-gray enamel. The frequency response of a velocity microphone is essentially uniform when the sound source is at least three feet from the microphone, but the low frequencies are accentu ated when the sound source is closer to the micro phone. Speakers and singers are often required to stand close to the micro phone, and the low-frequency accentuation which occurs is undesirable except when special effects are wanted. To solve this problem, a jumper connection is provided on the micro phone terminal board that provides either of two degrees of compensation for close talking. When the jumper is in the M (music) position no compensation is provided, and the response is essentially uniform from 50 to 15,000 cycles per second, provided that the announcer or musical instrument is at least three feet from the micro phone. However, the announcer may move as close to the micro phone as 12 inches when the jumper is in the V1 position, or seven inches when it is in the V2 position, without causing objectionable low-frequency boost. (V1 -10dB shelf at 100hz, V2 -15dB shelf at 100hz) This particular example has been modified with a switch for easy switching between M and V. The plate is marked U, N and B, as symbols for the uni-directional, non-directional and bi-directional pat terns. Three additional markings L-1, L-2 and L-3 are used as reference points for other directional patterns which may be obtained.