Megatest speaker cables – 32 cables listened to and measured!

The findings!

Anyone who expected speaker cables and interlinks to work the same, is mistaking. While we did not expect this, we also did not expect the differences to be so large. Speaker cables work fundamentally differently from interlinks.

Impedance!

What turns out to be absolutely crucial is impedance. The lower the impedance, the better the power amplifier can do its job and the more grip the amplifier has on the speaker. After all:

Damping factor= load impedance / output impedance amplifier

So for example: 8 Ohms (speaker) / 0.1Ohms (output impedance amplifier)

So the influence of the speaker cable is quite large if you consider that it is sometimes more than four times higher than the output impedance of the amplifier. And in this test, difference between the best and worst cable is more than a factor of 1000!

Suppose we have a cable with an impedance of 0.4 Ohms (yes, those exist – even 0.6 we measured!). Then we end up with: 8 / 0.5 = 16. Surely this is a dramatic deterioration of the damping factor.

If we then take a speaker cable with an impedance of 0.1 Ohm, we arrive at an damping factor of 40.

Now you may think: but my amplifier has a damping factor of 500! So that doesn’t matter! Yes it does: because the cable has an enormous influence. Let’s take a look at the Bryston. It has a damping factor of 500. So that would be – in case of 8 Ohms – an output impedance of 0.016 Ohms. Ideally over 8 Ohms you then come to a value of 500.

If we take the 0.6 Ohm cable, we are immediately back to a damping factor of 12.98. This is because the cable adds a lot of impedance and thus kills the control over the speaker. (Yes… long live active speakers!)

The difference in response is very well visible in the response measurement we do on the speaker. Cables with a higher impedance, clearly show larger swings. And that gives coloration … These swings in response depend on the impedance curve of the speaker and the damping factor of the amplifier. We estimate that in most cases it will be audible mainly in the low range. However, it depends on the speaker and amplifier how bad the coloration is.

Now impedance and inductance are closely related. So it is important for a manufacturer to keep inductance in a cable low.

The wacky thing is that Audioquest with its Zero technology again shows that it doesn’t always have to be the case. The Firebird measures excellent in response, but does have quite high inductance. There are more exceptions by the way, but there is a close relationship, as this heat-map shows.

(We put all the data in an AI to find and visualize correlations. This heat map was the result.).

What this heat-map shows even more is that inductance (and thus impedance) and propagation variation have a mild correlation and capacitance and propagation time idem.

So we may say that a manufacturer ideally makes a cable with low capacitance, low inductance, low impedance and super-high conductance. I see something that is impossible for the time being. But who knows, maybe one day we will get there.

Shielding

We have both shielded and unshielded speaker cables in the test. We tested, as with the interlinks – shielding by connecting them to the scope and seeing how much noise is picked up.

It turns out there’s quite a difference. And yes: Audioquest’s DBS system also affects the noise patterns. It can be seen in this rudimentary set-up that DBS affects the noise in the cable. Whether it is lower is hard to say, but the pattern of the noise does change. And probably so does the sound and experience of the music.

Is noise audible? Of course it is. In our experience, a cable that measures “quiet” also sounds more ‘black’. Virtually all speaker cables that we have labeled “quiet” and “black” or quiet also show low(er) noise. Consider the Kimber 8PR and Kimber 8TC. Those are remarkably quiet.

However, it is not the case that all of these cables are also shielded. Some just have clever geometry applied. So think Kimber with the 8TC and PR. The C8 is an exception. It does not measure as quiet and also sounds totally different from its brothers. However, that only confirmed the relationship between the measurements and what we hear. (Fiew!).

Response

We have already explained that low impedance is quite crucial for flat response. The higher the impedance of the speaker cable, the lower the damping factor of the amplifier becomes and therefore the less grip the amplifier has on the speaker. That’s just how it works. In some cases it won’t matter very much, and you can also like the effect very much of course.

Phase

We also looked at how cables shift relative to each other in time/phase. We did not test all combinations because that is simply impossible. We have posted ten examples above.

We see sometimes quite large differences and sometimes virtually no difference. We expected this to have to do with propagation time, but it doesn’t seem so, since the Van den Hul Inspiration has a propagation time of 24ns and the Nordost Red Dawn is at 17ns (the Nordost Frey2 is even faster at 13.95ns even… Nordost usually has very fast cables).

In this test, the sinuses are practically on top of each other. In contrast, the difference between the Van den Hul Inspiration and the Driade Flow Reference (16.3ns) is very large. Again, these do show quite a difference in inductance and impedance. That could explain the difference.

What this test shows is that there is a difference in the phase behavior of cables. And that should eventually be audible, since in many cases this will also be frequency-dependent, since capacitance, inductance and thus impedance are frequency-dependent. Cables that show a lot of variation there will therefore show greater variation in phase shifts.