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Field Report: AEQ Eagle and Swing
The past decade has seen a total evolution of how remote broadcasts are handled. With ISDN phone lines becoming commonplace just about anywhere in the world, broadcasters have come to rely on them to deliver high-quality audio from remote locations and events back to their studio. Radio stations are broadcasting live from locations that were once out of the reach of their RPU transmitters, not cost-effective for satellite broadcasting, and too important for the low audio quality of dial-up and cell phone audio.
As usage increases, so do the demands on the manufacturers of the audio codec interfaces for better audio, more bells and whistles and universal compatibility worldwide. AEQ has stepped up to the plate with its Eagle and Swing ISDN codecs. The Eagle is a rack-mountable studio version, while the Swing unit is a compact and portable package for remote locations.Universal compatibility
Both units have direct inputs for the U.S. ANSI standard or the European ETSI ISDN standards. Typically, there is no need for an external terminal adapter. However, one can be connected through a V35 port on the back of either unit should you find the need.
The AEQ units can talk to most other brands of ISDN codecs by incorporating many common coding algorithms including G.711, G.722 and MPEG LII modes. The LII mode offers 64kb/s and 128kb/s mono or dual-stereo. AEQ also offers its own algorithm when connecting with another AEQ unit, which offers high quality (15kHz bandwidth) with low delay. When connecting to another unit, the codec will detect the operating mode of the remote end and automatically adjust for proper sync.
|Performance at a glance|
These codecs can also come to the rescue on those occasions where a spur-of-the-moment broadcast doesn't allow enough time to order an ISDN line, or when you arrive and the line is not working or you were given the wrong SPIDs. In this event, you can connect and broadcast over a standard analog POTS line. While it's not designed to be a POTS codec, it does offer a built-in frequency extension to improve the low end frequency response and pass signals between 50Hz and 3,750Hz. It gets you on the air, makes the phone line sound better and saves the broadcast. Two and four wire POTS connections can be accommodated.
Data channels can also be passed through the codec along with the audio. Easy Port connections provide a quick way to interface RS-422 data. A standard 9-pin D connector also offers RS-232 compatibility. A typical setup would allow mono audio and 64kb/s data on the ISDN B channel. Data rates can also be customized for individual needs up to 115kb/s. Audio quality may be reduced as higher data rates are desired. A computer can be connected using AEQ software to customize the data channel rate, or to allow remote control of the codec.
Both the studio and remote units can be customized for startup and user features. A built-in phone book allows storage of as many as 256 frequently called numbers, and can also be programmed to selectively accept incoming calls. Pre-programmed numbers can automatically connect, while other numbers can be programmed to ring only and be answered manually.Portable features
The features of a remote unit can make or break a product. The company did its homework and designed the Swing to be compatible with just about anything anywhere in the world. A built-in mixer allows direct connections of as many as three microphones, or the third input can be selected for line level inputs. Neutrik connectors allow compatibility with XLR or ¼" audio cables. The mixer also provides connections for two headphones. The headphone outputs provide a mix of local audio with the mix-minus return audio from the studio. Each guest has his own level and mix adjustments. The Swing even includes a built-in compressor and limiter to keep the audio level consistent. VU meters are easily visible for transmit and receive audio on top of the unit, and a digital display is used for setup and shows status and parameters. This display is small and can be difficult to read, though. A surprise feature was a built-in battery in the ac adapter. This can serve as a UPS to prevent disconnection when someone trips over the power cord or during a power failure. I was able to run the unit for two hours on a full charge.
AEQ has packed a lot of features into the single rack spaced, studio unit. Analog and AES digital inputs are available on the back panel, and an intercom IFB microphone can be connected on the front panel. The system is capable of accepting two calls from remote broadcast locations, and a front panel multiplex switch allows the receive audio from one line to be relayed on the send audio to the second location. Front panel switches allow you to mute or activate the on-air audio for each channel. This feature can also be controlled through a computer by connecting to one of two data ports on the back.Through the paces
The AEQ Eagle and Swing ISDN codecs tested well. The compatibility to other brands worked well, as did the direct connection between the two units. Audio quality is good and a variety of algorithms allow a trade off between quality and low delay times. Another notable attribute is the variety of connection types from the different ISDN standards, and the ability to connect RS-422 or RS-232 data. Also impressive is the ability to adjust the auxiliary data bit rates for custom applications.
While the conservation of rack space is appreciated, the single rack unit chassis creates a busy appearance on the front panel. At first glance, there are a lot of colorful buttons, which appear to be confusing, however they are clearly labeled and easy to decipher in a very short period of time. As in the portable unit, though, the rack-mount version uses the same small displays, which can make it difficult to read for someone with poor vision.
Fluker is the director of engineering for Cox Radio, Orlando.
Editor's note: Field Reports are an exclusive Radio magazine feature for radio broadcasters. Each report is prepared by well-qualified staff at a radio station, production facility or consulting company.
These reports are performed by the industry, for the industry. Manufacturer support is limited to providing loan equipment and to aiding the author if requested.
It is the responsibility of Radio magazine to publish the results of any device tested, positive or negative. No report should be considered an endorsement or disapproval by Radio magazine.
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