Discussing whether audio cables change the sound often turns into a never-ending debate based on subjective impressions.
"Long RCA cables make the sound feel muddy."
"Silver wires add a glossy texture to the highs."
"Extremely long speaker cables lose their punch."
These anecdotes have existed for decades, but personal experiences alone don't reach a conclusion. Conversely, simple IDEAL circuit models often fail to explain what audiophiles actually hear.
That's why I decided to stop looking at the cable in isolation. Instead, I built a simulator that treats the entire signal path as a single physical system:
Physical characteristics of the cable
Interaction with connected equipment
Amplifier behavior
Response degradation in the time domain
Analytical metrics closer to human perception
The Project
GitHub: https://github.com/moe-charm/audio-chain-physics
Live Demo: https://audio-chain-physics.streamlit.app/
Zenodo DOI: https://doi.org/10.5281/zenodo.18898657
What I Built
Audio Chain Physics is a research-oriented simulator designed to handle the audio chain in stages. It models the following layers:
RLGC Model of the Cable: Moving beyond simple resistance.
Interface Interaction: Output impedance, input capacitance, and common return paths.
Non-linear Elements & Small-signal Stability: How the amplifier reacts to the load.
Dielectric Absorption: Approximating "trailing" responses.
Time-Domain Analysis: Group delay, impulse response, step response, and "TailRatio."
The core philosophy is not just analyzing the cable itself, but how the cable changes the operating conditions of the equipment.
For example, the propagation delay of a 3-meter cable is negligible. It’s too small to be an "audible difference" on its own. However, when you combine Output Impedance + Cable Capacitance + Load Capacitance + Amp Phase Margin + Complex Speaker Load, the settling time, group delay, and ringing change. This synergy is likely what manifests as a perceptible difference in sound.
What the Simulator Reveals (So Far)
The most significant result is that under extreme conditions, sound quality degradation can be clearly reproduced through calculation.
In scenarios such as:
Long, poor-quality RCA cables
Excessively long speaker cables
Amplifiers with high output impedance
The simulation clearly shows:
High-frequency attenuation or peaking
Distorted group delay
"Tails" in the impulse response
Ringing in the step response
Drop in Damping Factor
This confirms a solid starting point: If cables or connection conditions are handled poorly, the response of the entire audio chain will degrade.
What Still Remains Unexplained
To be completely honest, I haven't yet fully explained the more subtle audible differences I’ve experienced myself—those "nuances" that are hard to put into numbers:
The sense of "glossiness" or "air" in the highs.
Changes in "soundstage" or "depth."
The feeling of the sound becoming "thicker" or "denser."
While I can reproduce degradation in extreme cases, I cannot yet claim to have simulated those delicate nuances under "normal" high-end equipment conditions.
This is my current conclusion: While degradation due to extreme conditions is reproducible, explaining subtle sonic nuances requires further research. This feels like the most honest scientific stance at this stage.
Future Roadmap
There is still a lot of work to be done. My focus will move toward:
Validation: Comparing simulation results with real-world measurement data.
Complex Loads: Supporting measured speaker impedance curves.
Stochastic Models: Modeling RF interference, hum, and poor contact points.
Controlled Listening Tests: Correlating sim data with subjective perception.
I want to move from "degradation happens at extremes" to "explaining why we hear what we hear in everyday listening."
If you’re interested in the physics of audio, please check out the GitHub repo or the live demo!
GitHub: https://github.com/moe-charm/audio-chain-physics
Live Demo: https://audio-chain-physics.streamlit.app/
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