But the cable debate still isn’t over.
As most audiophiles know, the debate over whether expensive cables actually improve sound quality has raged for decades.
The skeptics have long dismissed it as nonsense, claiming any perceived differences are just in people’s minds. But a recent scientific study might just be the new evidence we’ve been waiting for.
This offers compelling evidence that cable construction and materials can indeed have a measurable impact on a system’s sound.
Scientific Evidence of the Effect of Cable on Sound Quality
Kunchur’s study takes an objective, scientific approach to the cable debate. Here, he moved beyond the usual reliance on subjective listening tests. Instead, he focused on often-overlooked factors like time-domain effects and noise measurements.
This was done through a series of seven experiments on three types of cables:
- High-end cable (~$500): Made with high-quality materials and typically sold through specialty audio dealers.
- Mid-range cable (~$50): Commonly found in appliance and electronics stores.
- Generic cable (under $5): Basic cables included with inexpensive electronics.
Across these detailed experiments, Kunchur reveals clear disparities.
Here are his main findings:
- Basic Electrical Properties: Kunchur measured fundamental properties like resistance (R), inductance (L), and capacitance (C). The differences in resistance and inductance were minimal. But capacitance showed big variations, especially in lower-grade cables.
- Signal Transmission: Since the way signals reflect inside the cables can affect sound quality, he also examined how signals travel through the cables. The higher-end cables showed fewer signal reflections, translating to a cleaner, purer sound.
- Frequency Dependence: By testing how the cables handled different frequencies, the study found that the generic cable’s capacitance fluctuated greatly with frequency. This is far from the more stable performance of the high-end and mid-range options.
An oscilloscope screen where the slanted lines clearly show the phase differences. (From: SC.edu) - Transient Response: This test looked at how quickly the cables could respond to rapid signal changes. The high-end cable shone here with smooth, predictable responses. In contrast, the generic cable struggled with irregular and prolonged responses.
- Signal Speed: The study measured how fast signals traveled through the cables. As expected, the high-end cable had the fastest signal speed.
The waveforms showing the signal speed differences of the three cables. (From: SC.edu) - Signal Reflections: The experiments identified signal reflections, which can introduce unwanted noise. Again, the high-end cable performed best here, with the smoothest decay and least reflections.
- Noise Measurements: Finally, Kunchur measured the noise pickup from the environment of the cables. The high-end cable had the lowest noise levels, followed by the mid-range and generic options.
These detailed measurements prove that the electrical performance of cables can vary a lot based on design and construction. Based on these differences, Kunchur suggests that cables can shape the perceived sound quality in high-fidelity audio systems.
But that’s not all. Kunchur also delved into the world of microphonics and triboelectric noise.
He found that, unlike loudspeaker cables, interconnects are less prone to microphonic effects due to their high impedance and low current characteristics.
Sure, triboelectric noise from internal motion could theoretically degrade signal quality. But it’s estimated to be a whopping 180 dB below typical signal levels, making it unlikely to have an audible impact.
Audio Science Review’s Criticism of the Study
Of course, in the world of audio, no stone goes unturned.
Amir Majidimehr from Audio Science Review (ASR) has taken Kunchur’s study to task.
In a detailed video, he argued that while measurable differences may exist, they don’t necessarily translate to audible improvements.
His main critiques target the following:
- Methodology: Amir criticized the use of a digital storage scope with a 10 GHz bandwidth. He claims that such high-frequency measurements are overkill for the audio frequency range of 20 Hz to 20 kHz.
- Cable Selection: He pointed out that Kunchur didn’t specify the cable brands tested, making replication difficult. Amir also challenged the categorization of cables without clear criteria.
- Use of 4 ns Pulses: According to Amir, audio signals don’t contain such high-frequency pulses. So, the study’s focus on transmission line effects and non-ideal capacitive behavior doesn’t align with the real world.
- Non-Ideal Capacitive Effects: He also debunked Kunchur’s claims on non-ideal capacitive effects.
“Capacitors take time to charge and take time to discharge. And, audio signals are extremely slow in the world of frequencies. So nothing is changing fast in the audio world to say that the capacitance of the cable is instantly changing. Therefore, we should go measure those instant effects.” he says.
“This assumption is just totally, totally wrong. Nothing in your audio system would work if this assumption is true.”
- Noise Claims: Amir challenged Kunchur’s assertion that noise impacted what people heard in his previous study. He said no cause-and-effect relationship was proven. Thus, he suggested that Kunchur’s noise measurements were likely due to improper measurement techniques. Even if accurate, Amir maintained that the noise levels were still too low to be audibly concerning.
The Researcher’s Defense of the Study
But Professor Kunchur is no pushover.
In response to Majidimehr’s critique, he has strongly defended his work, emphasizing that his research underwent rigorous review by four independent experts before publication.
First, Kunchur stressed that his study carefully documents the tested cables:
- a StraightWire Virtuoso
- a $50 appliance store interconnect
- and a generic cable from general stores.
Then, he provided detailed rebuttals on technical aspects that Amir emphasized in his critique. This includes the time-domain measurements, noise correlation, and the relevance of high-frequency signal propagation.
He argued that high-frequency measurements are important for capturing a cable’s full performance picture. And, he clarified that Amir’s notion of digital temporal resolution equaling ~T/2^(n-1) (T=sample period, n=bit depth) is nonsensical.
According to his response, it corresponds to the shortest detectable shift in a waveform’s edge, not the resolvable fineness of waveform features. So, it is actually limited by the sampling period T.
He didn’t stop with the content of his study, though.
Kunchur also criticized Amir’s understanding of fundamental concepts in electromagnetism and audio signal analysis.
He pointed out that Amir’s lack of journal publications and conference invitations weakens his credibility in critiquing peer-reviewed research.
“Mr. Majidimehr seems to have a juvenile understanding of oscilloscope measurements. He thinks that they are limited to 8-bits of vertical resolution. ” he said.
“For repetitive signals, the resolution can be expanded through triggered measurements at multiple ranges, as was done for the IOSR paper’s Fig. 6(b) and (c). This is similar to shooting a static scene with a camera on a tripod at multiple exposure settings, a technique known as HDR photography.”
So Where Does This Leave Us?
The debate surrounding the audibility of Hi-Fi cable differences is far from settled. But, Professor Kunchur’s study provides compelling measurable evidence of these variations.
As an audiophile, I find his rigorous, scientific approach refreshing and thought-provoking.
Of course, the ultimate test will always be our own ears.
But, Kunchur’s work suggests that you shouldn’t write off the importance of high-quality cables in your next upgrade. They might just be the secret ingredient your system needs to truly sing.