*WHITE PAPER* The Sound of Music - How & Why the Speaker Cable Matters

Rule of thumb says that cable becomes transmission line (reflections from impedance boundaries) when signal propagation one way is longer than 1/8 of the fastest transition time.  When perfect square wave is applied all cables behave like transmission line, but it doesn't happen in real life.  Rise time of the signal is roughly 0.35/BW, being 17.5us for 20kHz bandwidth.
17.5us/8=2.188us  a propagation time of 437.5m  (assuming speed of 5ns/m).   Designers do this calculation in any digital design to determine if wires or traces need termination.  I would worry about transmission line effects in audio when using speaker cables longer than 437.5 meters, unless I'm missing something?

(Another commonly used test is to compare length of the cable to 1/10 of the signal wavelength.  20kHz audio signal has wavelength of 10km, assuming signal speed of 200,000km/s.  1/10 of it is 1000m)

It correlates because spreading wires apart increases inductive reactance that is dominant factor here. The idea that 7m speaker cable is a transmission line for audio signals is insane, IMHO. For 20kHz signal you will need about 1000m long speaker cable (1/10 of the 20kHz wavelength) to even start becoming transmission line. In such case reflections would be inaudible because they are in MHz range (and because speakers are 1000m away).  Why not to use 20kHz sinewave for the test? It is the highest audio frequency component of interest in the cable.  Please show me reflections of 20kHz sinewave in 7m cable.  Any cable.

Let’s forget nonsense about reflections at audio frequencies and concentrate on frequency response. Increased characteristic impedance is not the reason for the signal attenuation at the high frequencies - increased inductance is. Same attenuation can be achieved by increasing capacitance. Higher dielectric constant insulation (same geometry) will increase capacitance, but inductance will stay the same. That way we will get bigger attenuation at high frequencies at lower characteristic impedance. Finding correlation between characteristic impedance and frequency response is pretty much like saying that tattoos are causing motorcycle accidents. Correlation, a very dangerous tool, assumes that if B happens when A happens, then A has to be causing B. It completely ignores the fact that both can be caused by C. In our case increase in characteristic impedance and increased attenuation at high frequencies were both caused by increased inductance.

Is it just coincidence that the traces track characteristic impedance quite closely?

Characteristic impedance always depends on inductance but taking false conclusions and writing papers on it is pretty bad.  I'm sure your cables sound wonderful, but please stop this "scientific" nonsense.

US spending on science, space and technology has 99.79% correlation with suicides by hanging, strangulation and suffocation.

http://www.tylervigen.com/spurious-correlations

Townshend-audio, It appears that you joined our audio forum only in attempt to place free advertisement for your product. It is dishonest IMO and I wouldn't buy anything from you. Audio2design attempted to explain to you why using square waves in audio is nonsense, but you don't get it.

Administrator please remove townshend-audio posting. We don't want it here. You want to advertise? - pay like everybody else.