This is a special order item, please allow 2-4 weeks for delivery.
The
USM 69 i stereo microphone has two separate dual-
diaphragm capsules. These are mounted vertically and rotate against each other. The
directional polar patterns can be selected separately for each
capsule. The capsules operate independently from each other.
Applications
The
USM 69 i condenser stereo microphone is a studio
microphone for intensity
stereo recording. It is suitable for
XY and
MS recordings.
Construction
The
microphone consists of the
amplifier section and the
capsule head. The
amplifier section contains two
microphone amplifiers operating independently from each other. They have an extremely low
self noise.
Two completely separate
microphone capsules are positioned closely above each other within the
capsule head. Their diaphragms are made out of gold-sputtered polyester film. The upper
capsule rotates against the lower one over a range of 270. Color markings on the lower
capsule system help to identify the angle by which the upper
capsule has been rotated.
When
sound waves reach the
microphone capsules from different directions they will generate
audio signals with different intensity only, but not with time differences, since the capsules are in close proximity and the
sound arrives at both capsules simultaneously. The result is an intensity
stereo signal that can be summed together for excellent
mono compatibility without causing interference.
Polar patterns
The
USM 69 i has two built-in rotary switches. The five
polar patterns of both capsules can be selected at the
microphone itself. Therefore, no special
AC power supply units or powering adapters are necessary.
The two outputs attach directly to any 48 V phantom powered connectors.
In addition to the usual
polar patterns:
omnidirectional,
cardioid, and
figure-8, we have added a
hypercardioid and a wide-angle
cardioid pattern.
A built-in
DC converter generates the required
capsule polarizing voltages.
Electrical features
The amplifiers feature high output capability and extremely low
self noise. Distant
sound sources, as well as very loud
sound sources at close range can therefore be recorded without any problem.
Each
amplifier has an active
filter. It effectively suppresses subsonic interference as caused by wind or structure borne
noise. At the same time, the
filter prevents the output transformers from overloading through very low
frequency energy.
Use as a mono microphone
The microphones may also be used as completely independent
mono microphones. There are many applications when it is important to have a
second mono microphone as a backup, or when the outputs of microphones with different polar response characteristics must be available simultaneously.
The outputs of the two
microphone channels can be linked (cascaded). In addition to the individual
directional patterns, other characteristics are available through the combination of both channels.
Operational safety
Both
microphone systems operate completely independent from each other.
The
second amplifier will be unaffected, even in case of a faulty
ground of the supply
voltage for one of the channels, or a short circuit in one of the outputs.
The
microphone is reliable in
mono usage, even if only one of the systems is operated and connected. Its simple and redundant circuitry guarantees a low failure rate.
Should the
DC converter ever fail, a diode circuit within the
microphone ensures that both systems will remain operational. The
cardioid pattern is automatically chosen. The
sensitivity is reduced by 3
dB.
Features:
- Switchable stereo microphones
- Two pressure-gradient transducers with double membrane capsules
- MS- or XY-stereophony
- Capsules rotary by 270
- Very low noise
- Aperture and pick-up angles freely choosable
- Directional characteristics reproducably switchable, omni, wide angle cardioid, cardioid, hypercardioid, figure-8
Specifications:
- Acoustical operating principle: Pressure gradient transducer
- Direct ional pattern: Omnidirectional, wide-angle cardioid, cardioid, hypercardioid, figure-8
- Frequency range: 20 Hz ... 20 kHz
- Sensitivity at 1 kHz into 1 kohm: 13 mV/Pa
- Rated impedance: 150 ohms
- Rated load impedance: 1 kohms
- Equivalent noise level, CCIR1): 24 dB
- Equivalent noise level, A-weighted1): 13 dB-A
- Signal-to-noise ratio, CCIR1) (rel. 94 dB SPL): 70 dB
- Signal-to-noise ratio, A-weighted1) (rel. 94 dB SPL): 81 dB
- Maximum SPL for THD 0.5%2): 132 dB
- Maximum output voltage: 3 dBu
- Dynamic range of the microphone amplifier (A-weighted): 119 dB
- Supply voltage (P48, IEC 61938): 48 V +/- 4 V
- Current consumption (P48, IEC 61938): 2 x 0.7 mA
- Matching connector: XLR5F
- Weight: 510 g
- Diameter: 30 + 48 mm
- Length: 293 mm