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USB DI-VC |
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With the development of software for digital music, more and more artists and performers (e.g. DJ, or electronic band) are taking products like P.Cs and Macs and using them as musical instruments at live shows. However, a variety of Livehouse Venues use high impedance sources instead of balanced XLR (Cannon, Alcatel, Neutrik and others) as the interface, so instruments like acoustic guitar, electronic organ etc. must then use a professional DI BOX as the impedance adapter. Usually the sound with a DI BOX adapter is ideal, although the Mac and Notebook computers have the less than perfect signal output quality of the audio soundcard. Besides, most notebook computers only have a 3.5mm output socket, which requires that you use a 3.5mm to 6.5mm (¼") Jack Plug cable to be compatible with a DI BOX. This can cause noise and distortion and intermittent signals. Apart from the internal sound card audio outputs, one common solution for Artists is to use an external connected audio card for signal outputs. However, they are usually expensive and do not offer an XLR interface, so we still have to use a DI-BOX impedance adapter. But, under the principle of "more things, more troubles", using an externally connected audio sound card is the best choice. The ideal solution would be for an external sound card, with the DAC powered from the USB Port, and the DAC output also offering DI BOX like functions. Standard 300 Ohm adapters for impedance match Before the manufacture of the ARX AudiBox USB-DI VC, I was unable to find a suitable product. Of course the APOGEE MINI DAC could be used as a USB DI BOX, but the USB Interface option has been discontinued. However, after the manufacture of this USB-DI VC, not only the author, but also all the performers who use Macs and PCs to produce music around the world will benefit from and be interested in this product. The ARX AudiBox USB-DI VC will become the saviour of performances using Macs and PCs as the digital instrument at live shows. This product uses a heavy duty steel chassis and is finished in blue powder coat, and has all the appearance of a Professional Audio tool. There is USB socket on one side and Gold plated XLR output terminals with a volume level control knob on the other. Shown as a schematic diagram next to the USB terminal, the working theory of the ARX AudiBox USB-DI VC is simple. The USB Audio Stream is converted to Analogue by the DAC; the two-track audio signal is then level controlled and impedance matched before being balanced and isolated by the output transformers. This is the most basic and professional method way of dealing with the audio signal. However, the author has experience in using some other DI products without this simple theory. Some of these didn't have Balanced outputs or ground isolation. For the purpose of this review the author removed the unit's lid and made careful investigation of its internals. First receiving the signal from USB port is the SONIX SN11113F USB Audio Controller and then a VT1612A AC'97 Audio Codec, which converts the digital signal into 16bit/48kHz two - track audio signal. Two separate output transformers then offer signal balancing, impedance matching and isolation of the signal. Finally, the gold XLR output terminals offer a professional termination. This ARX USB-DI VC product is manufactured to a high industrial standard and is of a high quality. Low background noise and perfect sound During trial use, the author connected the USB DI to the USB interface of his Notebook computer with the Windows operating system. With this product the most impressive thing is that the S/N ratio is high and free from noise. The sound is clear and when listening to high frequency sampled tunes, sounds full and free from harshness. The full frequency response is free from distortion and even with high density samples the sound was distinct and clear. As for the musical quality, this product gives a full sound that is clean and without any audible artifacts. As for the range of sound, both the high frequency and low frequency excelled. It seems this product was designed to solve the problem of bad performance of high frequency sound with USB interface, and it did. In conclusion, the ARX AudiBox USB-DI VC is a remarkable and unique USB DI in terms of current or performance. ARX, a Professional Audio brand from Australia, has a low profile in Taiwan but it is a famous brand in overseas markets. The author has good impression of this product from its first use. Apart from recommending this product to people needing Mac or PC interface the author suggests you to go online to the ARX website www.arx.com.au , or contact the local ARX agent Taiwan High-sky, to get a all-round understanding of ARX and their products. (Taiwan High-sky: 02-2693-1018)
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