Sonifex RB-OA3 3 Studio On-Air Switcher

Vendor: Sonifex
Sonifex RB-OA3 3 Studio On-Air Switcher The RB-OA3 is a unity gain on-air switcher that fits into a 1U rack and can move three stereo pairs across three studios. A smooth and uninterrupted...

Sonifex RB-OA3 3 Studio On-Air Switcher

The RB-OA3 is a unity gain on-air switcher that fits into a 1U rack and can move three stereo pairs across three studios. A smooth and uninterrupted broadcast from any multi-studio radio network is made possible by each studio's ability to manage the transmission path in addition to two peripheral paths for gear such a codec or hybrid. Additionally, a "Last studio to offer" bus is included. A "sustain" mode permits the broadcast to be managed by a sustaining system, like a PC automation system. It is possible to switch between numerous studios or stereo pairs by connecting more RB-OA3 devices together.

Relays are used for switching, except the "last studio to offer," which is switched by an analog switch. Latching relays are used for switching the transmission path. This implies that the transmission path will continue to be chosen in the event of a power outage in the unit. For electronically balanced audio signals, all studios are connected by 25-way D-types; for control, 15-way D-types are used to connect to an external control unit, such as the Sonifex S2-MTBS mixer control panel. To incorporate audio that is universal to all studios into the transmission path, a transmission mix connection is included. For example, this might be used for commercials or jingles. All connected studios can share control of a profanity delay thanks to the RB-OA3.

Every studio can provide the broadcast. The "last studio to offer" bus is used to send the transmission to the other studios after it has been offered. The transmission can then continue continuously if the next scheduled station fades in and accepts at the appropriate moment. For example, an automated studio can be programmed to play music overnight using the "sustain" option. The automated system will take over in this scenario, and station control will hold down the Offer button for a predetermined number of seconds, as established by a calibration program. This will choose the sustaining studio, designated as studio three, and return control to the other studios right away. After that, any studio may agree to start up regular transmission again.

Through the use of RJ45 serial connections, the RB-OA3 can be expanded to switch between up to 5 studios or up to 6 stereo pairs. Expanding in "studio" mode enables two more studios to assume control of the transmission path and extra equipment with the addition of a single unit. Three more stereo channels can be added if the expansion is done in "bus" mode. Six stereo pairs can be switched between up to five studios by connecting four RB-OA3 devices. Each unit's rear has dip switches that are used to customize the modes. The unit ID is managed by two dip switches, and the "studio" and "bus" modes are selected by two more switches. All communication between units is carried out by a master unit, which is identified by a predefined ID.

Key Features

  • Controls the offer/accept switching for 3 studios.
  • Switches 3 stereo bidirectional channels, e.g. studio output,codec clean-feeds, telco feeds.
  • Has a stereo transformer mix input, e.g. for playout system.
  • Continuity mode allows switching to/from a PC playout system.
  • Latching relay switching means transmission path remains intact on power-fail.
  • Can be expanded to switch 6 stereo channels between 5 studios.

Transmission and Peripheral Path:

Relays are used for switching these specific paths leading to a passive, transparent audio path.

LSO Path:

Input Impedance: >20kΩ
Output Impedance: <50Ω
Gain Range: Unity gain
Frequency Response: 20Hz to 20kHz ±0.1dB
Common Mode Rejection: < -66dB typically
Distortion: 0.01%THD @ 1kHz
Noise: -100dB unity gain, ref +8dBu

Mix Audio Transformer Specifications:

Common Mode Rejection: < -64dB @ 10kHz
Distortion: 0.5% THD ref 17dBu @ 40Hz
Bandwidth: ±0.5dBu 10Hz to 36kHz


Studio I/O: 3 x 25 way D type socket (female)
Transmission I/O: 1 x 25 way D type socket (female)
Dump/Delay Control: 1 x 9 way D type plug (male)
Studio Control: 3 x 15 way D type sockets (female)
LSO Expansion Port: 1 x 9 way D type socket (female)
Mix Input: 1 x 9 way D type socket (female)
Serial Ports: 2 x RJ45
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused, 9W maximum
Fuse Rating: Anti-surge fuse 2A 20 x 5mm

Equipment Type

RB-OA3: 3 Studio on-air switcher

Physical Specification

Dimensions (Raw): 48cm (W) x 15.8cm (D) x 4.2cm (H) (1U)
19” (W) x 6.2” (D) x 1.7” (H) (1U)
Dimensions (Boxed): 59cm (W) x 27.5cm (D) x 11cm (H)
23.2” (W) x 10.8” (D) x 4.3” (H)
Weight: Nett: 1.9kg  Gross: 2.5kg
Nett: 4.2lbs Gross: 5.5lbs