Yesterday I saw a press release via the Premier Guitar Twitter feed announcing Dean Markley Blue Steel instrument cables. Promising all kinds of magical tonal benefits due to the cable receiving a brief blast of liquid nitrogen. I say it’s pseudo-scientific nonsense. Dean Markley say that’s just my opinion. Well, this is how I arrived at that opinion…

First let me point you to their press release:

Lets quote some of the claims Dean Markley make about these cables…

“…wider and more dynamic range with smoother, more refined highs and deeper and more articulate bass. Players will immediately notice the super brilliant tone…

They can be used with both analog and digital gear to produce organic, three-dimensional sound quality.

Sounds very impressive. How are they supposed to make this happen?

“…a quick blast of liquid nitrogen that tightens the cables’ molecular structure, removing transient material that produces harsh highs and muddy lows.

If you take the time to play the video accompanying the press release, you’ll notice that any difference between the cables is small at best and in no way warrants the claims they make.

Now, if I am wrong in what appears below, I will happily put a retraction at the top of the page in bold text. But I challenge Dean Markley to publish justification for their claims with appropriate real data that can be verified. Dean Markley are making the claim here. The burden of proof is theirs, not mine to disprove.

Now, let’s first point out that we are talking about a very specific electronic operating regime: musical instruments with passive electromagnetic circuitry. Audio frequencies are LOW in the grand scheme of things, no higher than 20 kHz, which is the generally accepted limit of human hearing. Most adults can’t hear much above 16 kHz, and that decreases with age. FM radio typically doesn’t broadcast above 12 kHz. The speakers in guitar and bass amplifiers generally don’t produce much above 8 kHz to 10 kHz. For guitar and bass guitar, anything over approx 2 kHz is regarded as high frequency, anything below about 300 Hz is bass. Electrical engineers designing signal transmission lines deal with much higher frequencies, into the MHz range, where cable characteristics can be critical. But instrument cables are not rocket science. There are only three parameters we need to worry about to know how our guitar signal will be transmitted. They are; resistance, capacitance, and inductance. That’s it, that’s all. In principle if we know about the materials and cable dimensions we can calculate the resistance and capacitance and inductance. But it’s not necessary. With instrument cables we can simplify things even more…

Our instrument cables typically plug into a very high resistance at one end: the amplifier or effects pedal, which typically have in input impedance of 500 kΩ or 1 MΩ. At the other end of the cable is our instrument which may have 250 kΩ or 500 kΩ control potentiometers in parallel for volume and tone control and of course 6 kΩ-12 kΩ pickup coil resistance. The resistance of our cable is in the single ohms region. Clearly cable resistance is many thousands of times smaller than anything else in the circuit. We can ignore cable resistance completely.  A quick blast of liquid nitrogen can briefly reduce it further but we already don’t care.

The same is true of inductance. Our instruments contain a “pickup” coil which have an inductance usually somewhere in the 2 H – 6 H range (the ‘H’ is the unit of inductance called a “Henry”). The cable inductance is typically very tiny, measured in millionths of a henry. Again, we see the cable contribution of inductance to the circuit is so small that we can completely ignore it. No short blast of liquid nitrogen will make a significant change to the cable inductance.

So, for passive electric guitars and basses, capacitance is the ONLY relevant characteristic of the cable that relates to how our guitar sounds. And it does make a difference. Like inductance, cable capacitance is a function of the insulator material and cable dimensions. Instrument cables typically have a capacitance around 30 pF/ft – 40 pF/ft (90 pF/m – 120 pF/m), sometimes higher, sometimes lower. I think it’s a reasonable guess that many guitarists and bassists, given a side-by-side comparison, can hear the difference between two cables with a 20 % difference in capacitance. If a quick blast of liquid nitrogen could cause a permanent change in capacitance that large, and I don’t think it would, could it produce the changes and magical claims that Dean Markley describe? Absolutely not. Here’s why…

In instruments with passive electronics, cable capacitance interacts with the pickup inductance, volume pot resistance, and amplifier input impedance to shape the frequency response of our guitar. When we change cable capacitance we shift the resonant frequency of the circuit, typically in the range 2.5 kHz – 3 kHz. In addition we have strong low pass filter (12 dB/octave) attenuating all frequencies higher than the resonant peak. In general, cable capacitance is not good thing for passive pickup electric guitars and basses, we usually want to avoid that high frequency loss. We often call it “tone suck” and it can get worse as we as we reduce the volume control on our instrument.

What’s important to note is that everything below the resonant peak, what we call mids and bass in the guitar world, remains unchanged.  This means that all cables perform identically below the resonant frequency. This means that all cables of the same capacitance value sound exactly the same. (See here for a great explanation and demonstration of this at the Ovni Labs website.)

It also means there is nothing you can do to get “deeper more articulate bass“. There is nothing you can do to get “more dynamic range” or “organic three-dimensional sound quality“.  That’s all nonsense. There is only a simple, well-understood effect in the resonant peak and high frequencie loss which depends on the total cable capacitance. No other characteristic of a cable, e.g. brand, color, gold plating, oxygen-free copper, smell, or a short blast of liquid nitrogen makes the slightest bit of difference.

Could their cables have “smoother, more refined highs“? Well, first tell us what you mean by “more refined” in terms of frequencies because until you do it’s a meaningless term. How about “smoother“? I think most sound engineers would take that to mean as slightly reduced high frequency content. We know that’s possible, just increase the capacitance a little and presto! But Dean Markley also mention “super brilliant tone“. Brilliance in music and audio generally refers to additional high frequencies compared to something else, which suggests a lower capacitance compared to other cables. Have Dean Markley contradicted themselves here? Maybe, maybe not. Is there a magic sweet spot in cable capacitance? That’s a purely subjective question, only your ears can decide.

And let’s not forget cable length.

Cable capacitance, and therefore the frequency response of our circuit, depends on the length of the cable. That means that two pieces of the same cable of different length will sound different. Dean Markley’s 30 ft long cable will sound very noticeably less bright than their 10 ft cable, which already negates their claim somewhat. Somebody might well describe one cable as smooth or dark sounding and the other as brilliant. If Dean Markley would tell us the capacitance per foot of their cables we’d know how they compare to some other cables on the market at different lengths. Sadly, they don’t seem to offer that information. For me, all this magical verbiage in their press release tells me precisely nothing.

And then there is active electronics, as in effects pedals and instruments with active pickups. Active circuits have a low output impedance, a few tens or hundreds of ohms. Why? So that any high-frequency loss due to cable capacitance is avoided for cable lengths shorter than 30 feet or 50 feet. As we saw with the Ovni labs webpage above, all cables sound identical under these conditions.

Remember this from the press release: “”…a quick blast of liquid nitrogen that tightens the cables’ molecular structure, removing transient material that produces harsh highs and muddy lows“? Sounds impressive but I’d love Dean Markley to explain it. What sort of “molecular tightening” occurs that won’t undo itself when back at room tempature? What irreversible phase change could occur in a polymer or pure metallic copper due to a “quick blast of liquid nitrogen“? What is “transient material”? Most importantly, how much does all this change the cable capacitance and/or produce the results you claim? If you can’t answer these questions you can’t make the claim!

So, you see now why I describe this marketing as pseudoscientific bullshit? Monster Cable Inc do this too; their “time correct windings” and “magnetic flux tube technology” are somewhat based in real science but applied in a situation where it makes not one iota of difference.

And it angers me because it takes advantage of people, who through no fault, lack the specific technical knowledge necessary to know that these are empty promises. Most of these folks work hard to pay the costs of pursuing their musical hobby or profession and companies will blatantly lie to them to get the money. In my book that is immoral. Confirmation bias in audio is so ingrained in the human brain, so difficult to avoid, that “emperor’s new clothes” are a really easy sell: in the absence of an easily recognisable difference, we believe we hear what we expect to hear. This is a pervasive problem throughout the guitar industry, and pro audio, and has been for a very long time!

OK. Time to give Dean Markley some “benefit of the doubt”.

Dean Markley may be selling a really nice cable. All cables are not created equal: shielding, handling noise, and durability count for a lot. Maybe they’ve done a great cable design job here. Maybe they’ve bought a quality cable from a big cable manufacturer, dressed it and stuck their own name on it, which would be totally fine and what many companies do anyway. But I think they should do something important when they sell it…

Stand by your product for what it really is.

Guitar and bass players care about their tone. We know cables make a small difference to our sound, one the audience won’t notice, but it’s important to us. Don’t market to us a ton of bull. Tell us what we need to know. Tell us how the cable really compares to others on the market, in real meaningful terms. And don’t ever assume your customers are less smart than a marketing department with an ethical deficit.

Do that and you will win lasting brand loyalty and respect.