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Manufacturer: Midiland Inc
Min OS X: Any Version    Requires: Minijack Audio Port


Midiland IRS-F1
July 9, 2003 | Greg Gant
Pages:12


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Wireless is always a tricky feature to implement because the wireless device still require a power supply. Many wireless speakers use RF (radio frequency) transmitters but need to be plugged into a wall socket since amplifying a full sized speaker by battery would be very impractical. Fortunately for wireless headphones, a set of AAA batteries is adequate. Wireless headphones are fairly popular for home theater purposes since it allows you to have more freedom of movement and headphone cords generally arenít long enough to reach across a room. The major disadvantages of wireless headphones is that they cost more than regular headphones and have a much lower signal to noise ratio. Because of these drawbacks, wireless headphones are targeted toward home theater buffs rather than audiophiles. Still, you can find some exceptional wireless headphones support audio formats such as ProLogic, Dolby Digital and DTS.

The Midiland IRS-F1 comes equipped with an IR receiver/transmitter, a pair of wireless IR headphones, and a three-foot optical cable (rechargeable AAA batteries must be purchased separately). The base station has a built in NiCD/NiMH AAA battery recharger that can charge batteries anytime the base stationís power is on. The transmitter has an array of IR transmitters that give the headphones 24-foot (7.3 m) range and a coverage angle of up to 90 degrees. As with all infrared devices (such as remotes), the headphones must be in the line of sight of the base station for transmission. The transmitter also performs basic receiver functions and can have two devices plugged in at any given time: one via RCA and one via optical. The combined system has a low signal to noise ratio of 60 dB so a constant "hiss" is always present when listening. The headphones also have a 1% total harmonic distortion and a 20 Hz Ė 20 KHz frequency response.

Virtual 5.1 Sound
The most interesting feature of the Midiland headphones is "virtual 5.1 surround sound". Headphones cannot physically contain five speakers so surround sound Ďphones must emulate multi-channel audio on two speakers. I assumed that the headphones supported Dolby Digital because the receiver sported an optical port, but I noticed the manual had no mention of Dolby Digital or even Dolby ProLogic support. A quick test confirmed that the receiver indeed did not support Dolby Digital. The optical port only supports standard PCM audio so if itís connected directly to a DVD player, it might require some configuration in the DVD playerís hardware settings.

The headphones support two modes 3D modes: "surround sound" and "multi-channel". Many generic 3D surround sound decoders process Dolby ProLogic content. Iím not a patent expert but from my understanding, 20 years after a patent is filed, people may reverse engineer and sell products that perform the patented process. However, they cannot use the patented productís name since the name itself is a copyright which lasts much much longer. I noticed that the IRS-F1's "surround sound" function decoded ProLogic content so I suspected this to be the case. The multi-channel setting uses a four channel analog input. This means you need an external decoder such as a receiver with multi channel out sound or sound card like the M-Audio Revolution 7.1 (with Circle Surround II enabled) to decode the content to four channels.



Pages:12




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