This article is part of an ongoing series examining electromagnetic field theory and its application to high-fidelity audio reproduction. The engineering framework described here has been developed, tested, and refined over thirty-three years of product development at Synergistic Research—and has been the subject of extensive public discussion on my personal Facebook page, where the physics, the mechanisms, and the results have been debated, challenged, and defended in front of audiences exceeding 700,000 readers per month. The original discussions, the data they reference, and the community that has formed around them can be found on my Facebook page under Theodore Walton Denney III.
Every debate about whether cables matter in audio is conducted as if the listening environment is a constant. As if the electromagnetic landscape a signal propagates through is the same today as it was in 1975. As if the blind tests conducted in a pre-WiFi world tell us something definitive about a post-5G one.
They don't. And the reason they don't is the subject of this article.
The ambient electromagnetic environment of a listening room has changed more dramatically than any component in the audio chain over the past seven decades. Every blind test, every measurement study, every "cables don't matter" conclusion from the pre-digital era was conducted in an electromagnetic environment that no longer exists. The conclusions don't transfer because the conditions don't transfer.
Understanding why requires understanding two things: what signal actually is, and what changed in the environment it propagates through—decade by decade, technology by technology, contamination vector by contamination vector.
What Signal Actually Is
Before the history matters, the physics has to be understood. The simplified model taught in electronics courses describes signal as electrons flowing through a conductor—current driven by voltage, measured in resistance, inductance, and capacitance. This model is an approximation. It is reliable enough for pass/fail circuit design—does the signal arrive within spec, yes or no. It is completely blind to what signal actually is.
Signal is an electromagnetic field propagating around the conductor. The conductor is not the medium—it is the waveguide. The wire guides the field's propagation pattern the way a riverbank guides water. The energy travels in the field, through the dielectric, through the space surrounding the conductor—at near the speed of light. The electrons inside the copper barely move—fractions of a millimeter per second. They respond locally to the field's arrival. They don't carry the signal. They react to it. This is described by the Poynting vector—S = E × H—which quantifies the direction and magnitude of electromagnetic energy flow. It points through the space around the conductor, not through the conductor itself.
The signal is an electromagnetic field propagating around the conductor. The conductor is not the medium—it is the waveguide.
This distinction is not academic. It is the reason the electromagnetic environment matters. If the signal were electrons flowing through copper, then only the copper would matter—its gauge, its purity, its resistance. Nothing outside the conductor would affect the signal because the signal would be inside the conductor. But the signal is in the field—and the field propagates through everything around the conductor. The dielectric. The air. The floor. Adjacent cables. And every source of electromagnetic energy in the room.
When high-frequency noise—from WiFi routers, cell phones, switch-mode power supplies, LED lighting, and every digital device in the home—rides on the same conductor as the audio signal, it is superimposed on the same electromagnetic field. The noise and the signal share the field. The noise reshapes the signal's field structure—altering the phase relationships that encode spatial information, smearing the harmonic envelope that defines timbre. You cannot hear the MHz-GHz noise directly. But you hear what it does to the audio-frequency waveform while sharing the same conductor and the same field.
The speaker at the end of the chain is a transducer. It converts whatever electromagnetic waveform arrives at its terminals into mechanical energy—the movement of a diaphragm that moves air and creates the sound you interpret as music. The speaker reproduces whatever it receives. Faithfully. If the waveform was clean, the sound is clean. If the waveform was reshaped by high-frequency contamination riding on the same field, the speaker reproduces the reshaped version—and the listener hears a compressed soundstage, high-frequency artifacts, unnatural timbre, flattened spatial depth, and sibilance that cuts instead of breathes.
The speaker doesn't know the waveform was contaminated. It doesn't fix anything. It reproduces exactly what arrived. The damage—or the preservation—happened upstream, in the field, on the cable, shaped by the electromagnetic environment the signal propagated through.
This is why the history of the electromagnetic environment matters. The field that carries your music has always been shaped by its environment. What changed is the environment — from the electromagnetically silent living room of 1955 to the broadband-saturated battlefield of 2026. The physics is the same. The contamination is not.
The 1950s-1960s: The Quietest Era
Vacuum tube electronics defined this era. Tubes operate with relatively low-frequency switching characteristics. No high-frequency clock oscillators. No switch-mode power supplies. The audio system itself was electromagnetically quiet—the components generated minimal RF contamination internally. The signal chain produced almost nothing that would interfere with its own signal.
The domestic environment was equally benign. No digital devices. No computers. No wireless communication. No LED lighting. Incandescent bulbs, analog telephones, tube radios. The electromagnetic environment a signal propagated through—both inside the system and outside it—was as clean as it has ever been in the modern era.
Cable design was genuinely less critical in this environment—not because the physics was different, but because the environment didn't contain the contamination that cable design now has to manage.
The simplified model of signal propagation—the electron drift approximation, the R/L/C lumped-element model—worked. Not because it was complete, but because the environment was simple enough that the model's blind spots didn't matter.
This is the era the simplified model was built for. And within that era, it was sufficient.
The 1970s: The First Transition
Solid-state transistors replace vacuum tubes. This is the first fundamental shift in the electromagnetic character of the audio system itself. Transistor circuits switch faster than tubes—introducing higher-frequency noise inside the audio system for the first time. The signal chain is no longer electromagnetically silent. It generates its own contamination.
The domestic environment remains relatively quiet. No digital devices. No switch-mode power supplies in consumer equipment. CRT televisions and incandescent lighting are the primary external sources of electromagnetic interference. The noise floor of a listening room is still dominated by power line harmonics—60Hz and 120Hz. Manageable. Predictable. Low-frequency.
The THD wars begin during this decade—manufacturers competing to produce the lowest measurable total harmonic distortion. They succeed spectacularly on paper. They also produce some of the worst-sounding equipment ever made—gear that "won" every measurement and lost every listening test. Gear that has zero collectibility and zero resale value today. The THD wars are the first large-scale demonstration that the simplified measurement model can declare a product excellent while the product sounds sterile, lifeless, and wrong.
They also produce some of the worst-sounding equipment ever made—gear that "won" every measurement and lost every listening test.
The simplified model appears adequate during this era—but the cracks are forming. The system itself is generating internal noise that tube circuits didn't produce. And the measurement framework the industry relies on can't tell the difference between a technically flawless amplifier and one that sounds like music. The model's blind spots are becoming audible, even if the model can't see them.
The 1980s: Digital Enters the Signal Chain
The compact disc arrives. For the first time, a consumer audio system contains a digital device with a high-frequency clock oscillator operating at MHz frequencies—sitting inside the signal chain, connected to the same power supply, radiating into the same physical space as every analog component in the system.
This is a categorical change. The contamination is no longer external to the system—it's inside it. The CD player's clock oscillator, its digital processing circuitry, and its power supply are all generating broadband noise at frequencies the analog signal chain was never designed to encounter. And that noise is conducted through shared power lines and radiated through proximity to every cable and component in the rack.
Early switch-mode power supplies begin appearing in peripheral devices. They're smaller, lighter, and cheaper than linear supplies—and they generate broadband switching noise at frequencies that couple onto every conductor in their vicinity. The noise environment is shifting from low-frequency power line harmonics to a broader spectrum that includes the kHz and low MHz range.
The external environment remains relatively quiet by modern standards—no WiFi, no cell towers in most areas, no smart devices. But inside the audio system, the electromagnetic landscape has changed permanently. The signal chain now contaminates itself.
The 1990s: The Ambient Environment Begins to Climb
Personal computers enter the home. Early WiFi appears. Cell phones become common. For the first time, the domestic environment contains multiple sources of MHz-GHz electromagnetic radiation that have nothing to do with the audio system—but share the same physical space and the same electrical infrastructure.
This is the decade of the Richard Clark amplifier challenge—the most-cited "proof" that amplifiers sound identical. Clark level-matched amplifiers to fractions of a decibel and challenged listeners to identify them in ABX testing. The challenge ran from the early 1990s to approximately 2006. Nobody won consistently.
The challenge is still cited in 2026 as definitive evidence—conducted in an electromagnetic environment that was already changing but hadn't yet reached modern saturation. The ambient RF floor of a 1995 listening room contained a fraction of the broadband contamination present in a 2026 room. The test conditions that produced the null result no longer exist. The null result is still treated as permanent.
Cable differences are audible on resolving systems during this era—as they have been since the first purpose-engineered cables were designed. I entered the industry in 1992 selling cables that sounded materially different from each other, one design to the next, on every resolving system. The blind tests that produce null results during this decade do so because of their methodology—rapid switching, low-resolution systems, undocumented listeners—not because the differences don't exist. The simplified model appears to hold—not because it's correct, but because the tests being used to validate it are structurally incapable of detecting what they claim to evaluate.
The 2000s: The Threshold Crossing
WiFi becomes ubiquitous. Smartphones arrive. Bluetooth proliferates. Smart home devices begin to appear. Every charger in the house contains a switch-mode power supply radiating broadband noise into the electrical infrastructure and into the ambient field.
The ambient RF environment of a typical home crosses a critical threshold during this decade. The noise floor is no longer dominated by power line harmonics at 60 Hz and 120 Hz. It is dominated by broadband MHz-GHz energy from dozens of simultaneous sources—each one radiating an electromagnetic field that couples onto every conductor in the home, including every cable in the audio system.
This is the inflection point. Before this decade, the ambient environment was noisy but manageable. After it, the environment is saturated. Every conductor in the audio system—signal cables, power cords, ground wires—is simultaneously carrying the audio signal and acting as an antenna for broadband RF from sources the system's designers never anticipated.
The simplified model's inadequacy becomes undeniable during this era. The model assumes the only signal on the conductor is the one you put there. In a 2005 home, that assumption is indefensible. The conductor carries the audio signal, the Wi-Fi router's radiated field, the cell phone's emissions, the SMPS noise from the charger across the room, and the Bluetooth signal from the speaker in the kitchen. The model that says "just measure R, L, and C" can't see any of these interactions. The ear can hear all of them.
The 2010s: Saturation
5G cellular. IoT devices in every room. LED lighting with high-frequency switching power supplies in every fixture—replacing the electromagnetically benign incandescent bulbs that had been the standard for a century. Multiple WiFi access points per home. Smart speakers. Streaming devices. Smart thermostats. Smart refrigerators. Every appliance in the modern home now contains a processor, a wireless radio, and a switch-mode power supply.
The listening room is now saturated with broadband RF from every direction—radiated through walls, conducted through power lines, coupled onto every conductor in the audio system. The electromagnetic field environment is no longer a background condition. It is the dominant factor shaping what the audio signal looks like by the time it reaches the speaker terminals.
The LED transition deserves special attention. Incandescent bulbs were resistive loads—electromagnetically inert. They generated heat and light. Period. LED bulbs contain a switch-mode power supply in every socket—converting AC to the DC the LEDs require. Every LED bulb in the home is a source of high-frequency switching noise conducted onto the power line and radiated into the ambient field. A home that replaced thirty incandescent bulbs with LEDs didn't just change its lighting. It installed thirty broadband noise sources distributed throughout every room.
2026: The Modern Listening Room
The modern listening room contains more sources of broadband electromagnetic contamination than existed in the entire neighborhood in 1955. A typical home in 2026 operates WiFi 6E or WiFi 7, 5G cellular penetrating through walls, dozens of IoT devices, LED lighting throughout, multiple streaming devices, smart speakers, and switch-mode power supplies in every charger, every appliance, and every peripheral device.
Every conductor in the audio system—signal cables, power cords, ground wires, digital cables, USB cables, Ethernet cables—is simultaneously carrying the signal it was designed to carry and acting as an antenna for every RF source in the environment. The cable's job is no longer just to carry signal from point A to point B. It's to manage the electromagnetic field environment the signal propagates through—while that environment is being continuously contaminated by dozens of broadband sources the cable's designer can either address or ignore.
This is why cable design matters more in 2026 than it did in 1975. Not because the physics changed. The physics has always been the same—Maxwell's equations don't update. What changed is the environment the physics operates in. The signal field propagating around a conductor in a 1955 living room encountered a clean, quiet electromagnetic landscape. The same signal field propagating around a conductor in a 2026 living room encounters broadband contamination from every direction, on every frequency, from every device in the home.
The cable didn't change. The battlefield did.
Two Converging Vectors
The story of the electromagnetic environment is the story of two contamination vectors converging.
Vector one - inside the system. Vacuum tubes to transistors to digital processors. Each generation introduced higher-frequency noise into the signal chain itself. The system went from electromagnetically silent in the 1950s to self-contaminating by the 1980s. The CD player, the DAC, the streaming device—each one generates MHz-GHz noise inside the system, conducted through shared power supplies and radiated through proximity to every analog conductor in the rack.
Vector two - outside the system. The ambient RF environment of the home escalating from near-silent to saturated across five decades. WiFi, 5G, Bluetooth, IoT, LED lighting, switch-mode power supplies—each technology added another layer of broadband contamination to the electromagnetic landscape the audio system operates in.
Both vectors converge in 2026 to create the most contaminated electromagnetic environment any audio system has ever operated in. The system contaminates itself from the inside. The environment contaminates it from the outside. And every conductor in the signal chain—every cable, every power cord, every ground wire—is the interface between the two.
The cable is no longer a passive wire connecting two components. It is the boundary layer between the signal and the contamination. Its geometry, its dielectric, its shielding, its field management characteristics—these determine how much contamination reaches the signal and how much the signal field is reshaped before it arrives at the speaker.
Why the Old Conclusions Were Wrong Then Too
The blind tests of the 1990s and 2000s didn't produce null results because the electromagnetic environment was quiet enough that cables were indistinguishable. I entered this industry in 1992. Cables sounded materially different from each other—one design to the next, audibly, repeatably, on resolving systems, in that era. The differences were real in 1992. They were real in 1998. They are more dramatic in 2026. But they were never absent.
The null results came from the same five methodological failures dismantled in the first article of this series. ABX rapid-switching protocols that chop the music into segments too short to evaluate spatial coherence, timbral decay, or dimensional staging. Low-resolution systems incapable of revealing the differences the test claimed to evaluate. Undocumented listeners. Undocumented rooms. And a publication ecosystem that treated forum anecdotes as data—including one that concluded mud is a valid audio conductor.
Those methodological failures produce null results regardless of the electromagnetic environment. They would produce null results in a Faraday cage. They would produce null results in 1955. They produce null results in 2026. The methodology is structurally incapable of detecting what cable design affects—and the null result is reported as proof that the phenomenon doesn't exist rather than proof that the test can't see it.
The men citing those old tests as proof that cables don't matter weren't right then. They're more wrong now.
The escalating RF environment doesn't change whether cables matter. It changes how much they matter. A purpose-engineered cable in 1992 managed conductor geometry, dielectric interaction, and field propagation characteristics that produced audible improvements on any resolving system. A purpose-engineered cable in 2026 manages all of that plus the broadband MHz-GHz contamination from every device in the home riding on the same conductor as the audio signal. The engineering challenge grew. The audible consequences grew. The differences I heard in 1992 were real. The differences in 2026 are larger—because the contamination the cable must manage is orders of magnitude worse.
What This Means for the Listener
If you're listening to a high-resolution audio system in 2026, you're listening inside an electromagnetic environment your system's designers never anticipated. Your amplifier was designed to amplify an audio signal. It wasn't designed to operate in a field saturated with WiFi, 5G, and broadband switching noise from thirty LED bulbs. Your cables were designed to carry signal. They weren't designed—unless they were purpose-engineered for field management—to handle the broadband contamination riding on every conductor in the system.
The consequence is audible. Compression of the soundstage. Loss of spatial depth. Timbral inaccuracy—violins that don't quite sound like violins, voices that flatten, instruments that blur into a two-dimensional plane between the speakers instead of existing in three-dimensional space. Not because the recording lacks the information. Because the electromagnetic environment the signal propagated through reshaped the waveform before it reached the speakers.
The man who says "I can't hear a difference between cables" may be telling the truth—about his system, in his room, at his resolution level. The man who says "cables can't make a difference because the tests proved it in 1998" is wrong. The tests didn't prove it in 1998 either. They proved that ABX rapid-switching on undocumented systems with undocumented listeners couldn't detect differences that were audible on every resolving system in the industry. The methodology was broken then. The electromagnetic environment has made the consequences of that broken methodology more dramatic now.
The Environment Changed - the Debate Didn't
The audio objectivist community is fighting a 2026 war with 1998 intelligence. The blind tests they cite were methodologically broken when they were conducted—and the electromagnetic environment has grown orders of magnitude more hostile since. The simplified model they defend was built for a world where the only signal on the conductor was the one you put there. That world never existed in practice—but the gap between the model and reality was narrow enough to ignore. It isn't anymore.
The physics didn't change. Maxwell's equations are the same in 2026 as they were in 1865. What changed is the environment those equations describe. The signal field propagating around a conductor in your listening room is navigating an electromagnetic landscape that didn't exist when the tests were run, the models were built, and the conclusions were reached.
Cable design matters more now than it ever has—not because cable designers discovered new physics, but because the environment demands engineering that the simplified model can't see and the old tests were never designed to detect. The contamination is real. The consequences are audible. And the men insisting the debate was settled in 1998 are defending a conclusion that was wrong when they reached it and is catastrophically wrong now.
The electromagnetic environment your music lives in is not the one the textbooks describe, not the one the tests assumed, and not the one the simplified model was built for.
It is the one you're sitting in right now—surrounded by devices, saturated with fields, and wondering why your system doesn't sound the way you expected it to.
Now you know why. The next article in this series will address what can be done about it.
Theodore Walton Denney III is the founder, lead designer, and CEO of Synergistic Research, Inc. He founded the worldwide high-end power cord industry in 1992 and holds nearly twenty patents in electromagnetic field management for audio applications. This is the second article in an ongoing series published at Positive Feedback.
