The Debate: Can USB Cables Improve Audio Performance?
For audiophiles, digital interfaces in general and USB cables, in particular, cause much debate on whether they can improve audio performance in a home stereo system. The argument is that digital cables do nothing but transmit "ones" and "zero's," so there can be no audible difference among different cables. However, audiophiles who have tested different USB cables claim that USB cables do sound different.
The USB Standards Document is a lengthy and complex 650-page guide that outlines how USB cables function. Essentially, digital "data" is represented by electrical signals that meet certain conditions. In the case of USB cables, the data transfer is accomplished by using two electrical conductors, D+ and D-. USB defines "ones" and "zero's" as a difference between the two electrical signals transmitted by D+ and D-.
USB cables transmit electrical signals similarly to analog cables, but at a much higher frequency, up to 480 MHz. The integrity of the transmitted signal depends on the basic electrical parameters of inductance (L), capacitance (C), impedance (R), and crosstalk. To minimize harm to the electrical signal by these parameters, a cable designer's job is to reduce their deleterious effects.
Inductance is a phenomenon where, as current travels through a conductor, eddy currents form that try to push voltage in the opposite direction of the signal flow. Capacitance occurs when some of the energy escapes from the conductor and is briefly stored in the material adjacent to the conductor before being dissipated back into the conductor. Impedance or resistance is where voltage may drop over a given length of the conductor due to insufficient cross-sectional area of conductor material being used for a specific application. Crosstalk is the movement of energy from one conductor to the adjacent conductor. All four of these phenomena cause "jitter," which is a defect in the precise timing of data that is required to maintain the integrity of the data that is being streamed to the DAC, with crosstalk and capacitance being the biggest culprits.
In addition, the power transmitted from the host to unpowered USB devices can cause problems with the integrity of the D+ and D- signals if not properly isolated. External phenomena, such as radio frequency interference (RFI) and electromagnetic interference (EMI), can also introduce unwanted effects that will corrupt USB signals.
In conclusion, while many argue that there can be no difference between USB cables, audiophiles who have tested different USB cables claim that they do indeed sound different. The USB Standards Document is a complex guide that outlines how USB cables function, and the integrity of the transmitted signal depends on basic electrical parameters. Inductance, capacitance, impedance, and crosstalk can cause "jitter," which is a defect in the precise timing of data that is required to maintain the integrity of the data that is being streamed to the DAC. In addition, the power transmitted from the host to unpowered USB devices and external phenomena such as RFI and EMI can introduce unwanted effects that will corrupt USB signals.
The USB Standards Document is a lengthy and complex 650-page guide that outlines how USB cables function. Essentially, digital "data" is represented by electrical signals that meet certain conditions. In the case of USB cables, the data transfer is accomplished by using two electrical conductors, D+ and D-. USB defines "ones" and "zero's" as a difference between the two electrical signals transmitted by D+ and D-.
USB cables transmit electrical signals similarly to analog cables, but at a much higher frequency, up to 480 MHz. The integrity of the transmitted signal depends on the basic electrical parameters of inductance (L), capacitance (C), impedance (R), and crosstalk. To minimize harm to the electrical signal by these parameters, a cable designer's job is to reduce their deleterious effects.
Inductance is a phenomenon where, as current travels through a conductor, eddy currents form that try to push voltage in the opposite direction of the signal flow. Capacitance occurs when some of the energy escapes from the conductor and is briefly stored in the material adjacent to the conductor before being dissipated back into the conductor. Impedance or resistance is where voltage may drop over a given length of the conductor due to insufficient cross-sectional area of conductor material being used for a specific application. Crosstalk is the movement of energy from one conductor to the adjacent conductor. All four of these phenomena cause "jitter," which is a defect in the precise timing of data that is required to maintain the integrity of the data that is being streamed to the DAC, with crosstalk and capacitance being the biggest culprits.
In addition, the power transmitted from the host to unpowered USB devices can cause problems with the integrity of the D+ and D- signals if not properly isolated. External phenomena, such as radio frequency interference (RFI) and electromagnetic interference (EMI), can also introduce unwanted effects that will corrupt USB signals.
In conclusion, while many argue that there can be no difference between USB cables, audiophiles who have tested different USB cables claim that they do indeed sound different. The USB Standards Document is a complex guide that outlines how USB cables function, and the integrity of the transmitted signal depends on basic electrical parameters. Inductance, capacitance, impedance, and crosstalk can cause "jitter," which is a defect in the precise timing of data that is required to maintain the integrity of the data that is being streamed to the DAC. In addition, the power transmitted from the host to unpowered USB devices and external phenomena such as RFI and EMI can introduce unwanted effects that will corrupt USB signals.
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digital audio, usb
