Proof that speaker cables make a difference

[win]

https://www.psaudio.com/article/the-sound-of-speaker-cables-an-analysis/

the importance of cable construction for optimal characteristic impedance matching

 

[Universal Cereal Bus]

Isn't transmission line theory only applicable when the wavelength approaches the size of your circuit components? I.e., at frequencies way, way above 20 kHz? I seem to recall only needing to care about impedance matching in my microwave class.

 

[wwenze]

They are using Zo to refer to the capacitance / inductance of the cable, which themselves also define Zo. These have these effects shown in the article when presented with low frequency signals. But we are certainly not dealing with reflections which is when we would use the number called characteristic impedance.

Take note that for example, double the cable length will double the total capacitance / inductance, but does not change the characteristic impedance of the cable. Hence I'm not really sure if the author's comment that paralleling multiple 50-ohm characteristic resulting in 8.2 ohm characteristic impedance is correct or not.

Staff at Townshend Audio have known this since 1978 when they introduced the first Isolda cable comprising six 50-ohm coax cables connected in parallel to give a characteristic impedance of 8.2 ohms.

At least for RF frequencies, this is definitely wrong because the reflection is determined at the impedance boundary, so six 50-ohm cables in parallel reflect like six 50-ohm cables in parallel, not a single 8.2 ohm cable.

 

[LTig]

https://www.psaudio.com/article/the-sound-of-speaker-cables-an-analysis/

the importance of cable construction for optimal characteristic impedance matching

... plays a major role in high frequency applications, let's say above 1 MHz. If the complete audio chain (microphone to speaker) would be able to transport signals that high, and your ears would be able to hear these signals, then yes - good vs bad impedance matching might be audible. Luckily neither is the case so no need to worry about this. Just ensure the cable's resistance is low enough (meaning when in doubt then err on the thicker side).

 

[BDWoody]

https://www.psaudio.com/article/the-sound-of-speaker-cables-an-analysis/

the importance of cable construction for optimal characteristic impedance matching

Of course it makes a difference... It's just generally not going to be audible. If it is, get better cables.

Proof that anyone should be concerned would involve controlled listening tests. Until then, you are presenting marketing propaganda disguised as something meaningful.

 

[RayDunzl]

I got as far (with a lot of skipping) as the seven wire chart with decibels.

What does 0dB represent (for someone who didn't skip that designation, assuming the author did not also skip it)?

 

[LTig]

They are using Zo to refer to the capacitance / inductance of the cable, which themselves also define Zo. These have these effects shown in the article when presented with low frequency signals. But we are certainly not dealing with reflections which is when we would use the number called characteristic impedance.

Yep. And what they forget is that for complete impedance matching (to prevent reflections) the power amps output impedance must be the same as the cable's wave impedance and as the speakers load impedance, and this for the full audible frequency range.

Another consequence of impedance matching is that the power amp can create only half the power compared to one with close to zero output impedance (same voltage, twice the load, hence half the current), and another 50% of this remaining power is wasted in the power amps output impedance (half the voltage) so there is only 25% available for the speaker.

Now show me a speaker with constant impedance - and if you really did find one, then show me a power amp with identical constant impedance - and then find the matching cable ...

 

[A Surfer]

More slight of hand BS. It is hard to believe that there is such a lack of critical thought. Measurable does NOT mean audible. When it comes to our hearing, the only thing that matters is audibility. A fool and their money is soon parted.

 

[DonH56]

An excellent example of the misapplication of science in the pursuit of marketing.

 

[egellings]

For audio, R, L and C determine what the cable will sound like, if the differences are large enough. As far as transmission line theory goes, it does not apply to audio frequencies traveling living room distances over wires, and impedance matching is not accomplished anyway between a power and preamp, or between a speaker and power amp. It's just not difficult to get a cable completely competent for audio use.

 

[Blumlein 88]

Yep. And what they forget is that for complete impedance matching (to prevent reflections) the power amps output impedance must be the same as the cable's wave impedance and as the speakers load impedance, and this for the full audible frequency range.

Another consequence of impedance matching is that the power amp can create only half the power compared to one with close to zero output impedance (same voltage, twice the load, hence half the current), and another 50% of this remaining power is wasted in the power amps output impedance (half the voltage) so there is only 25% available for the speaker.

Now show me a speaker with constant impedance - and if you really did find one, then show me a power amp with identical constant impedance - and then find the matching cable ...

Pre ribbon Maggie's were very, very close to 4 ohms. But know we don't need characteristic impedance matching even then.

 

[egellings]

Yup! Impedance matching is just not an audio problem, unless you are using output transformers and the like.

 

[Doodski]

More slight of hand BS. It is hard to believe that there is such a lack of critical thought. Measurable does NOT mean audible. When it comes to our hearing, the only thing that matters is audibility. A fool and their money is soon parted.

The last speaker cable comparison that I did was on 3 different cables that where gifts from reps. Some ~22G solid silver core flat cable meant to go under carpets, some 16G Monster Cable and some 12G Monster cable too. Me and my buddies could hear no difference whatsoever. The speakers where a homebrew KEF with 107.2 tweets and 104.2 midrange with KEF woofers in a transmission line design large cabinet.

 

[richard12511]

.Luckily neither is the case

Yet...

Just wait till we get our cyborg ears.

 

[RayDunzl]

The apparent "winner" showed up in this older thread:

https://www.audiosciencereview.com/forum/index.php?threads/townsend-isolda-cable.7109/

 

[escksu]

haha, here we go again......

My stand on cables are very simple. Cable is like a religion. IF you think and believe it makes a different, then it does.... If you think it doesn't, then it doesn't.

 

[win]

thanks for everyone's replies, I knew it was bogus but wanted the propeller heads to educate as to precisely why

 

[Helicopter]

I saw this too. I knew it was BS when, in the intro, they assert that everyone knows cables make a difference and this has been accepted by experts since the 1970s.

I was a little surprised when I calculated the resistamce of my 16 AWG lampcord with tinned lead ends and realized 18 or 22 AWG probably would have been fine.

At some point I will probably go to some twisted high strand count locking banana 12 AWG with tech flex, cable pants, etc. Maybe I will find some Belden type E silver plated aircraft cable. That will look and feel nice and silver has good corrosion resistance. I don't have any illusion I will ever be able to tell a 15 to 20 foot run apart from 22 awg lampcord in a blind test.

 

[egellings]

I agree with escksu-belief in cables is much like belief in a religion or a politician's promises. Hey, if you believe that the exotic cable sounds good to you, then by all means use that cable and enjoy. You don't, however, get to force upon the science based community that your preferred cable is better due to some sciency sounding techno-bable. Cables do make a difference in extreme cases for audio, like a single strand of 28 Gauge magnet wire vs. 16 Gauge lamp cord for a speaker cable. It's just that going from the 16 gauge to the exotica over a short living room distance will not have a difference proportional to what you wallet will get taken for.

 

[egellings]

I'm done ranting on this 'cable' topic; it's all politics with no engineering at all. This whole election season has me in a bad mood anyway, and I do see parallels there.