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Articles Tagged Bill Whitlock

  • Wednesday, July 09, 2014
    whitlock
    Bill Whitlock 07/09/14 02:45 PM,
    Electromagnetic interference, often referred to as EMI, is a degradation of the performance of a piece of equipment or system caused by electromagnetic radiation. Electromagnetic radiation is the travel of alternating electric and magnetic fields through space at 186,273 miles (about a billion feet) per second, or the speed of light. A wavelength, as shown in Figure 1 below, is the physical distance traveled by a wave during one cycle. When the equipment or system is closer than about a… View this story
    Filed in: AVFeatureStudy HallAVInterconnectPowerSignalWireless

  • Wednesday, June 11, 2014
    power techniques
    Bill Whitlock 06/11/14 12:05 PM,
    When a system contains two or more pieces of equipment that are grounded, whether via power cords or other ground connections, a “ground loop” will likely be formed. (See Figure 1, below.) Although ground loops often involve power line safety ground connections, disabling them is both highly dangerous and illegal. However, devices called “ground isolators” can be inserted in the signal path to break the loop safely. This approach attacks the problem at its fundamental roots, while tampering with safety… View this story
    Filed in: AVFeatureBlogStudy HallAVInterconnectPowerSignalSystem

  • Thursday, May 01, 2014
    jensen
    PSW Staff 05/01/14 11:00 AM,
    Jensen Transformers president Bill Whitlock is presenting “Effective Audio Grounding Design,” a tutorial focusing on proper audio grounding techniques to keep systems quiet and problem-free, at the upcoming Sound Marketing Tech Expo on Tuesday, May 6, 2014 at Moraine Valley Community College in Palos Hills, IL, just outside of Chicago. Specifically, Whitlock will present effective audio grounding and signal interface design to keep systems free from hum and buzz. “I firmly believe that the technical concepts in this class are… View this story
    Filed in: AVLive SoundRecordingChurch SoundNewsTrainingAVEducationInterconnectPowerSignalTechnician

  • Friday, August 09, 2013
    ac grounding
    Bill Whitlock 08/09/13 04:45 PM,
    While hum and buzz are often blamed on “improper grounding,” actually, this is rarely the case. Properly installed, fully code-compliant AC power distribution systems will develop small, entirely safe voltage differences between the safety grounds of all outlets. These normally insignificant voltages cause problems only when they couple into the signal path at a vulnerable signal interface. Let’s look at why unbalanced interfaces are extremely prone to this coupling and cause noise problems even when no safety ground connections exist.… View this story
    Filed in: AVFeatureBlogStudy HallAVInterconnectPowerSignalSound ReinforcementStudioSystem

  • Friday, May 31, 2013
    image
    Bill Whitlock 05/31/13 11:56 AM,
    The idea that “dirty” power causes audio system noise problems has a nearly irresistible intuitive appeal - and there are dozens of companies ready to cash in on this widespread but mistaken belief. For example, here is a quote from a well-known manufacturer of power conditioning products: “Today’s residential systems contractors face unprecedented challenges where high resolution, trouble-free operation is required. From inducing AC ground loops, video hum bars, static bursts, damage from AC line surges and variable audio and… View this story
    Filed in: AVFeatureBlogStudy HallAnalogAVInstallationInterconnectMeasurementPowerSignal

  • Tuesday, April 16, 2013
    image
    Bill Whitlock 04/16/13 05:01 PM,
    “A cable is a source of potential trouble connecting two other sources of potential trouble.” The humor in this statement may be lost on those who regularly assemble sound systems. But a reality of sound systems is that a signal accumulates noise as it flows through equipment and cables. And once noise contaminates a signal, it’s essentially impossible to remove it without altering or degrading the original signal. For this reason, no system can be quieter than its noisiest link.… View this story
    Filed in: AVFeatureBlogStudy HallAVDigitalInstallationInterconnectPowerSignalSound ReinforcementSystem

  • Thursday, September 06, 2012
    system power
    Bill Whitlock 09/06/12 04:56 PM,
    An analog audio interface may be unbalanced or balanced, depending only on the impedances (to ground) of its two signal conductors. In balanced interfaces, both conductors have equal (and non-zero) impedances. A balanced interface also requires that driver, line, and receiver all maintain balanced impedances to ground. They are therefore extremely potent in preventing all kinds of noise coupling, in fact, so powerful that many systems, such as telephone networks, use them instead of shielding as the main noise reduction… View this story
    Filed in: AVFeaturePollStudy HallAVInterconnectSignalSystemAudio

  • Monday, April 30, 2012
    a/v
    Bill Whitlock 04/30/12 01:37 PM,
    If electrical wiring, from main breaker panel to outlet, consists of Romex and plastic J-boxes, an “isolated” or “technical” ground system is already in place. This is the case In most, but not all, residential wiring. However, when wiring consists of metallic conduit and J-boxes, as in most commercial buildings, an isolated safety-grounding scheme can sometimes reduce audio system noise. It is most applicable in situations where conduit may come in contact with building steel, water pipes, gas pipes, or… View this story
    Filed in: AVFeatureStudy HallAVPowerSignal

  • Wednesday, March 21, 2012
    unbalanced inputs and outputs
    Bill Whitlock 03/21/12 05:33 PM,
    Based on my years of helping customers solve interfacing problems of all sorts, connecting unbalanced outputs to balanced inputs, and vice-versa, certainly ranks among the most common and confusing of tasks for system integrators. Basically, two issues must be dealt with. The first involves the different signal operating levels between unbalanced (consumer) and balanced (professional) equipment. The second involves making the actual connections to transfer the signal while avoiding “ground loop” noise problems. Signal operating and reference levels are significantly… View this story
    Filed in: AVFeaturePollStudy HallAVInterconnectPowerSignalAudio

  • Monday, June 06, 2011
    audio system power
    Bill Whitlock 06/06/11 01:41 PM, 0 Comments
    A ground loop can exist in any system that contains two or more pieces of grounded equipment, whether via power cords or other ground connections. An isolator is a device that passes signal while interrupting the path for the ground loop current. They are not filters, and must be inserted in the signal path at a specific location, which is found through troubleshooting to be effective. A properly installed isolator virtually eliminates hum, buzz, or other noises caused by ground… View this story
    Filed in: AVFeaturePollStudy HallAVInstallationInterconnectPowerAudio