Shure’s extreme wireless demo
By Julius Grafton
Shure’s new Axient digital wireless system has been turning heads in the upper echelons of audio since release – and also in it’s lengthy beta testing phase.
In September Shure flew a contingent of media to Chicago to see first hand the capabilities of its new digital wireless system. The demonstration was at Soldier Field, a 63,000 seat outdoor sport stadium close to downtown Chicago.
Wills Tower and the John Hancock Centre are two high rise buildings near by, each has a TV mast on top. The scan of wireless traffic at Soldier Field shows it is one of the more congested locations around.
The demo was shot on video earlier this year, here: https://www.youtube.com/watch?v=Jr8hM9nM7jo
What was remarkable was that in the demo, the system is running in HD mode, which opens up 46 active channels on one 6mHz TV channel. This is done at a much lower output power of 2 mili-watts. The normal maximum available channels are 19 – subject to frequency availability at any given location.
The video demo shows a guy up top of the furthest stand at the field, 220 yards from the receiver. He has a belt pack behind him, without line of sight. His signal strength is 3 of a possible 5, using HD.
A further demo video has an engineer walk in to the back of field tunnels. These are buried under the stands, with at least one foot of concrete walls and ceiling. The engineer walks and talks, around the curved tunnel, away from the receiver. This demo shows significant range.
At the press day, Shure recreated the video. They set the system up just before the press bus arrived, and didn’t have time to check much. The demo was identical – both the 220 yard HD transmission and the tunnel journey.
The four channel Axient receiver was connected to an antenna splitter to exploit Shure’s Quadversity feature. This combines four antennas. Two were placed at the tunnel opening, two were pointed up to the far distant grand stand.
A new body pack with internal antenna was shown, the ADX1M (where M stands for Micro).
The next demo was frequency interference detection and avoidance. Using an optional AXT6000 spectrum manager, the system deploys a control transmission on 2Ghz, and then each transmitter and receiver operates a pair of different MHz frequencies. If interference occurs the system switches to the second frequency within miliseconds. The demo was set up with a second system set to one of the frequencies in use. As soon as that transmitter was switched on, the system flipped to the alternate frequency.
Shure say that referee wireless is one of the classic uses where interference means running an alternately tuned beltpack onto the field, and having it switched over. It is also problematic at a show for a performer to switch out a beltpack. This feature alleviates the problem, and was shown to work flawlessly in the press demo.
The other notable features of Axient include ultra low latency, of around 2 milliseconds; and networked battery charging.
In a discussion about the development of Axient, Shure say that they assembled design engineers from the telecommunication industry, and also that a significant set of the features are subject to patent.
During the beta test program, various broadcast engineers took Axient to extreme locations, including buried in a slit on golf greens, where engineers have taken ambient mixing to a whole new level. To alleviate the long pauses and sometimes crushing boredom of golf coverage, they mix in crowd noises, or the sound of a ball rolling into a cup. One notable instance arose when rather than going to all the trouble, an editor inserted pre recorded bird sounds. Turns out that bird was not native to that area.
Shure’s Axient range has some market leading features, and the company are clearly very proud of what they have achieved.