Kef Uwireless Universal Wireless System
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We all hate cables running all over the floor, specially when they are not without apparent effort hidden. We just invested in a top-notch home theater system. We have a outstanding video monitor, an audiophile quality home theater receiver, and a lot of great speakers. So far, so good. Now it’s time to connect the rear channel surround speakers. Agh! Our scheme look was just degraded from Star Trek to Mad Max. This is an evident application for wireless, right? Actually, there are a heap of severe troubles with using wireless proficiencies for surround sound channels. Time Lag: Wireless surround systems have a processing/transmission time lag that makes the sound from the rear channels out of sync with the audio from the front speakers. The inherent time required to generate the signal, transmit it to the speaker, decode the signal, and finally, to amplify the signal for the speaker causes the time offset. Minimal audio processing latency is required for effective surround sound. The sound from the dissimilar speakers ought to be heard at the same instant. For most installations, the rear channels are closer to the listener than the front channels. For this reason, Dolby Digital and Dolby Surround Pro Logic schemes implement a delay of a few milliseconds for the surround sound channels. The timing is that critical. When persons listen the same sound from dissimilar directions, the illusion is produced that the sound’s source is a phantom emplacement amongst the sound’s sources. Recording engineers use remainder controls to simulate sounds throughout the sound field, permitting them to locate sounds to dissimilar sensed locatings throughout the sound stage. Timing is critical among surround channels where depth and emplacement data are to be determined by the ears, and ultimately, by the brain. Interference: The second problem with wireless surround schemes is interference. There are multiple technologies employed for wireless surround, and the source of interference is specific to the technology. Both Bluetooth and Wi-Fi gimmicks operate within the 2.4 GHz band. Bluetooth is the engineering science that is employed many times for wireless keyboards and mice, but the capability of Bluetooth systems is marginal for surround sound applications. A Bluetooth signal power is only with regards to 1 milliwatt. Dolby Digital requires a bandwidth of when it comes to 400 Kbps and Dolby DTS uses a bandwidth of regarding 450 Kbps for a 5.1 system. Bluetooth has a greatest or most complete or best possible info transfer rate of 433 Kbps, which is cutting it finelooking close. Another substitute for surround sound transmission is Wi-Fi 802.11b (also in the 2.4 GHz band, as is 802.11g ). An 802.11b signal is capable of 54 Mbps greatest or most complete or best possible throughput (30 Mbps in practice), which is more than sufficient for this application. However, there are significant roots of interference in this 2.4 GHz spectrum from cordless phones, other Wi-Fi instrumentation like wireless-enabled laptops, wireless game controllers, fluorescent lights, and even microwave ovens. Even bad electrical connections may cause wide Rf spectrum emissions. Bluetooth attempts to keep away from interference by “frequency-hopping”. If the signal is receiving interference, it will (hopefully) only be for a fraction of a second, because the system will tell apart the interference, and switch to a dissimilar frequency. Wi-Fi also has the capacity to keep out of the way of interference by altering channels, and by redundant loops of info transmission Many Wi-Fi merchandise assert to mange interference problems. Unfortunately, the productions are fixed by the capablenesses of the 802.11 chipsets, and the 802.11 protocol itself. IR (infrared), which is most ofttimes employed by remote controls, is yet another technology at times used for wireless surround. IR has a bandwidth capability of more than 100 Mbps. IR for info transmission was frequent on laptop computers a few years ago. More recently, it has been substituted by other wireless technologies such as Bluetooth, because they don’t need a direct line of sight (LOS). IR transmission is lost whenever there is a loss of LOS amidst the transmitter and the receiver, and, in addition, the signal is subject to interference from IR remote controls and ambient light. Power: A third problem is that the rear speakers will require a power source if they are receiving the signals wirelessly. They will need power not only for the actual speakers, but they will likewise need power for an on-board amplifier. If our goal is to eliminate all wires, this is a problem. Powercast (Pittsburgh, PA) has a engineering that will wirelessly supply power to little widgets like cell phones, but the greatest or most complete or best possible rate is 10-15 watts, not sufficient for surround channels. On a final note, if you determine to buy a wireless surround system, read the product traits carefully. I not so long ago assisted on an installation where a DVD/Receiver scheme was purchased with wireless capability. However, in this case, the wireless capability was for distribution to a second room for the primary channels, not a wireless capability for surround channels. |
