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Cable Pathways Between Audio Components Can Affect Perceived Sound Quality

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The arena of highest fidelity in music reproduction, sometimes referred to as high-end audio, has many controversial claims and contentious issues. One such controversy is whether the cables and topology used to interlink components together make an audible difference. There seems to be a disparity between anecdotal experiences reported by audiophiles and published formal scientific research as to theminimal changes in system configuration that can be audibly distinguished. With the motivation of bridging this divide—which may originate from differences in instrumentation and subject-listening conditions used by the two groups—this work utilized a high-performance audio system and extended-duration listening protocol that more closely resembles audiophile auditioning conditions. With these measures the present work was able to prove through direct psychoacoustic testing that two different analog-interconnect pathways can be audibly distinguished.

JAES Volume 69 Issue 6 pp. 398-409; June 2021
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Johannes Didden
Johannes Didden

Comment posted June 7, 2021 @ 15:58:31 UTC (Comment permalink)

I would like to congratulate Professor Kunchur with a very interesting and thorough research. The subject has been discussed, on and off, for more than half a century now and studies like this are few and far between.

I do have one question though, which concerns the measurement of the frequency response of the tested cables, results of which are presented in fig. 3. What were the source- and load impedances on the cables used in this measurement?

Ammar Jadusingh
Ammar Jadusingh

Comment posted June 8, 2021 @ 15:47:30 UTC (Comment permalink)

So called "High End" aka "High Prices" Audio is a devotion to archaic stereo reproduction.

The concept of "Fidelity" there to what exactly, is somewhat questionable. Dr Floyd Tooles "Circle of confusion".
Worsened by the fact that 2 channels can't possibly reconstruct a real soundfield.
Unclear how (possibly) detecting differnces in balanced/unbalanced cabling in a system helps here.

Roland Jacques
Roland Jacques

Comment posted June 9, 2021 @ 15:30:40 UTC (Comment permalink)

@Ammar Jadusingh: I'm afraid that the vast majority of audio producers and consumers only cares about the emotion of the music, and has little interest in physically correct wave fields. Quite on the contrary, many smart devices and smart speakers only deliver some vague spaciousness, or outright plain mono, often with compromised audio quality, along with a suboptimal listening environment. In comparison, a high-quality stereo reproduction is a revelation in spatial, tonal and dynamic accuracy. But I totally agree that especially in the cable business massive overpricing can be found, along with unscientific claims - therefore I applaud any solid, unbiased investigation into such claims, in order to support honest manufacturers who offer real, verifiable value.

Roland Jacques
Roland Jacques

Comment posted June 8, 2021 @ 15:47:39 UTC (Comment permalink)

Dear Prof. Kunchur, thanks for this very interesting article. As you point out, this field has been a controversial one for decades, sometimes bordering on metaphysical claims and beliefs. Any rigorous scientific approach is therefore highly appreciated, and very helpful for consumers, manufacturers and researchers alike. Upon studying your article, I had several thoughts:

First, regarding the choice of music program. As could be expected by the age of this particular recording, there is some rumble and hiss present, a quick analysis showed an SNR of only 40dB at peak moments, and only 17dB at soft moments. So it seems that the program noise was higher than any noise introduced by the cables, which leads to the question of the influence of the latter. A recording with less intrinsic noise might be better suited for the topic at hand. Also, a recording with stronger transient elements such as percussion or voice might be useful for analysis of the time-domain effects you mentioned. I would also suggest to, for some stimuli, increase the listening level above the 60dBA SPL average reported here.
Regarding the somewhat astounding noise floor figures: It seems to me that the reasons for this can be found in the setup as described below Fig. 4: Firstly, the 1 MOhm coupling probably makes the cables more susceptible to "antenna-like" EM induction than in the case of 10kOhm input impedance of the amplifier. Secondly, it is not surprising that the internal differencing applied to the +/- wires of cable A leads to effectively much lower noise, since this is the very goal of such a balanced topology (common mode rejection). Thirdly and most importantly, as you mention yourself, most of the noise is far outside of the audible spectrum; I'm not sure I can agree to the claimed "audible signature" due to "rectification-demodulation" of RF noise (I presume the input circuit of the amplifier is much more of a lowpass than a rectifier); most certainly not to the extent implied by your statement of 25.1dB effective SNR with the music program used here, which would be stupendous for a cable. I would suggest additional measurements to clarify these effects and their causes.
I also appreciate the thought which you put into the listening test design, and I can somewhat understand the concerns of fatigue and mental "overlap" when switching between the configurations too frequently, and the potential benefit of allowing time for building up a mental "image" of the music and its sonic properties. On the other hand, my experience in listening test design has taught me the very strong influence of the quickly diminishing auditory memory, combined with unavoidable fluctuations in the subject's mental and biological state. Therefore, the choice to have >5 minutes long segments, only 1 presentation per stimulus, and a pause of 40sec between them seems quite extreme to me, and I'm wondering whether the mental images of the sonic signature are really detailed and persistent enough to survive the quick decay of the auditory memory. This question alone would warrant a master thesis of its own, I think, and also allow for larger sample sizes and larger sets of stimuli.
I look forward to your insights on this, and of course to any further research in this quite relevant field. Thank you and best regards!

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James Hipperson

Comment posted June 10, 2021 @ 15:46:44 UTC (Comment permalink)

 "This DAC has two isolated buffered pairs of analog outputs — single-ended RCA and balanced XLR"

This to me sounds like a severe confounding variable in the experiment, unless it was the explicit intention to test balanced vs. unbalanced, which is not clear from the rest of the paper. 

The abstract says:

"the present work was able to prove through direct psychoacoustic testing that two different analog-interconnect pathways can be audibly distinguished."

I think a fairer and more specific summary of the experiment, was that it was demonstrated that listeners can distinguish between balanced and unbalanced interconnections, which is interesting in itself despite being less general than implied here. 

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