Transcript
Whitepaper: The Fundamentals of USB Audio Your computer is capable of playing back the most incredible master quality recordings ever produced, often encoded in resolutions many times that of a CD. The computer itself is not bounded by the demands of audio, present and future applications included.1 The ubiquitous USB standard has been so successful and adopted on such a large scale that going to another standard is not likely. We must therefore work with what we have, and there are tremendous drawbacks to using a USB cable to transfer high resolution audio to your DAC or audio interface. The USB cable design is meant to transmit data from computer to peripheral, a specified amount of bits on the computer side is accounted for on the peripheral side. What time the individual bits arrive is irrelevant to the operation of the majority of computer applications. It’s a different story with streaming audio, because the audio is time dependent, it does not simply travel from A to B, it travels in strictly measured time. And that timing can be influenced by magnetic fields from proximate electrical conductors. The image below represents a typical USB cable, on the inside. The red wire carries the 5 volt power, the black is the ground, and the twisted green and white wires carry the data. The red wire is so physically close to the green and white data wires that the magnetic field produced by the electrons flowing over the red wire affects the timing of the data stream. It does not destroy data bits, it effects the cadence of the data transmission. Timing is absolutely integral to generating accurate spatialization.
The computer itself adds noise to the 5 volt power, noise from the EMI and RFI generated by the various circuits in the computer, and this noise may not only affect the cadence of the digital stream, it may also leak into the DAC and become audible.
More computer noise is transmitted to the DAC from the exterior metal fittings of the USB cable. From the diagram below you can see the four pins inside the USB cable, these pins connect to the four wires inside the cable.
The audible result of computer noise is a compressed sound stage, harsh and biting tones at times, the space between notes and instruments doesn’t render well, and an artificial loudness permeates the signal which is caused by the amplification of computer noise. All USB audio applications are affected. I have experienced firsthand the negative effects of computer noise in the most expensive digital systems, the problem is widespread and simply buying different DAC’s and amplifiers will not solve the problem. USB Disruptor and DaBigGeniusTM cables work together as a system to guarantee the digital stream isn’t molested on its journey from computer to DAC or audio interface. Our technology does three things to stomp out harmful interference, A. We physically separate the 5 volt power wire from the USB cable2, B. We cut out the computer 5 volt and its interference from the chain completely and replace it with a virtually noise free power source3, and C. We cut out the influence of the conductive outer shells of the USB cable by deactivating them. This solution is totally unique in the marketplace, nobody else does this, and the effect of these three taken together can be breathtaking in impact to even the most expensive and advanced computer driven audio systems. Our DaBigGeniusTM Audio Grade USB cables are USB 2.0 Certified. That means our cables can send around 50,000K per second of data. The data streaming rates for the most data rich recordings are currently around 9000k per second. It's important to note there are even more data dense recordings intended for studio use, these include Octuple-Rate DSD with a sampling rate of 22MHz. By my estimate the data stream rate for the 8xDSD at 22MHZ is just over 30,000K 1
per second. For high end home audio, USB 2.0 is future proof. By physically separating the 5 volt power lead from the proximity to the digital data lines removes the influence of the magnetic field produced by the activity of the electricity flowing over that 5 volt line. The magnetic field extends beyond the jacket of the 5 volt wire and bleeds over to the digital lines if they are too close together, like in every single USB cable, they are too close together for audio applications. But only audio seems to suffer because it streams rather than completes A to B data transfer. So for audio streaming you DO NOT want to have any power flowing down that wire at all. 2
The vast majority of USB devices need a 5 volt power source to function. It’s just part of the USB chipsets that are made for computers. Audio manufacturers don’t make their own USB chipsets, these are made in factories far away and by the millions. They cost pennies. They are designed to specifications that do not take high end audio streaming into account! So even if you remove the proximity of the 5 volt wire, you are still sending interference to the DAC via the dirty 5 volt power from the computer. Thus you must replace the dirty power with a clean source. So simply moving it is not nearly enough, you have to do both. 3
