Headphone Cable Measurements Part One

Tyll Hertsens's picture

When all you have is a hammer, everything starts looking like a nail.
I'm about to start some cable listening tests. There's a bunch of cable makers out there, but I went with two fairly well known headphone cable makers because I mainly want to make the point that cables do make a difference, but not a big difference. (I think people are well served by communicating with other enthusiasts and the cable makers themselves to get a feel for which ones will best suit your particular application.) I find the changes made by cables subtle, yet often worth while. Once you have a source, amp, and headphones you like, the last thing you can do is get a gentle tweak in a preferred direction by changing the cables on the headphones. Audiophile icing on the headphone system cake, if you like. But there's a problem...well, many problems really.

I measure headphones all the time, and believe there's a fairly strong relationship between measurements and what I hear. So, the objectivist in me wants to see wants to see identifiable features in the data that correlate with my listening experience. Cables are a bit of a buggaboo though, in that I don't have the proper equipment to measure them well. The right tools for that job would be capacitance meters, time domain reflectometers, and stuff like that. I've got enough experience measuring things that I know measuring the differences cables make on my headphone measurement system is just the wrong way to go about it. However, I get the request to measure different headphone cables all the time, so I figure at some point I just needed to do it.

Another problem with measuring cables on a headphone measurement system is that the differences between cables using that measurement method are bound to be very small. When I swap cables on the headphones I have to remove the cans from the measurement head to replace the cable, and then have to put the headphones back on the head. This will result in a slightly different position of the headphones on the head from the prior measurement. These positional changes will cause changes in the sound measured, and those changes are likely to be significantly larger than the effects of the various cables.

Lastly, knowing with relative certainty that I was going to get a result that would tend to indicate that swapping cables made no measurable differences, I know I'm likely to just give fuel for objectivists to throw on the fire claiming that cables don't make a difference. I kinda don't like to do that because I do believe cables make a difference. Oh well...I guess I just have to let the chips fall where they may.

How I Conducted the Test
I used a pair of Sennheiser HD 650 headphones of recent manufacture. I have six cables to use in the test: stock, Cardas Headphone, Cardas Clear, Moon Audio Black Dragon, Moon Audio Blue Dragon, and Moon Audio Silver Dragon. I took the head out of the chamber and put it next to the tester and headphone amp as I didn't want to have the headphone extension cable I normally use in the experiment. (The silence the chamber provides is really only critical for THD+noise tests. These tests were performed with 90dBspl in the headphones, well above the roughly 50dBspl room noise level.)

Once I put the headphones on the head and adjusted the headband for proper fit, I taped the headband to ensure that setting remained the same. When I placed the headphones on the head, I had a mark on the top of the head to position the headband, and then I would slide the earpieces forward gently until I felt the ear just touch the rear of the cushion. This seemed to work quit well and repeatably.

For each cable I would take five frequency response and impulse response measurements. Frequency response measurements should give a good idea of any tonal changes, and the impulse response should give some idea of changes in time alignment. I removed and replaced the headphones on the head for each measurement. I also measured the stock cables twice to see if those measurements agreed more closely than when swapping cables.

Once the data was in a spreadsheet, the five measurements were averaged together for each of the four data sets (left and right frequency response, and left and right impulse response). The reason for doing this was to try to average out any small changes due to the positional changes of the headphones on the head. After each cable had been measure five times, I would swap to a new cable and repeat the process.

Once all the data had been gathered and numbers crunched, I copied the final results for each cable onto a master spreadsheet. There, any slight vertical offset difference in frequency response was compensated for by off-setting each curve such that all curves went through the same value at 800Hz. The impulse response curves don't need this as they naturally have 0 volts as a reference.

Okay, turn the page to see the results.

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KikassAssassin's picture
Blind testing

 

I seem to remember you saying in one of the discussions you had with Steve Guttenberg about audio measurements that you don't like blind testing, but I still have to ask, have you tried doing double blind testing of the headphone cables to see if you can still make out any differences?

 

I know you've worked with NwAvGuy on your amp measurements, so I'm curious if you've read his blog posts on the subject of blind vs sighted testing, and what your current thoughts are about it. He seems to make a pretty bullet-proof argument that sighted testing of audio gear is extremely problematic because it's impossible to overcome placebo and confirmation bias if you know which product you're listening to, no matter how experienced a listener you are, and blind testing is the only way to reliably remove that as a factor. In one article he even demonstrates a situation that shows blind testing to be a better way of picking out subtle differences than sighted testing (listeners weren't able to tell the difference between two black boxes--one of which was a straight wire, and the other added distortion to the signal--until they did a blind A/B/X test, where the differences became obvious).

Impulse's picture
I'm all in...

I'm all in on ABX testing, but I don't think you can draw far reaching conclusions off it... Trained ears will hear different, ears accustomed to one headphone/setup and not another will also focus on different aspects, etc etc. Basically ABX testing's great if you can participate yourself, otherwise I'm not sure it's much better than a general consensus of subjective opinions...

KikassAssassin's picture
Yeah, someone else doing ABX

Yeah, someone else doing ABX testing obviously won't tell you whether you'll like a product or not, because that's always going to be a matter of personal taste, but in the case of something like cables where there's no measureable difference, blind testing can tell you whether there's an audible difference or not, whereas sighted testing really can't.

Steve Guttenberg's picture
If you can't hear the difference...

Hey, I'm Mr. Subjective, so if you try a set of cables and YOU think they sound better, buy them. If YOU can't hear a difference, don't. If you don't believe cables make a difference, don't even bother listening, your mind's made up. One thing's for sure, you'll save a lot of money!

ultrabike's picture
Believe

"If you don't believe cables make a difference, don't even bother listening, your mind's made up."

I have believed many things, proven wrong, and have accepted that I was wrong. I also feel that if there is a difference, it would be nice to know why.

I have yet to experience unexplanable cable sonic improvements/degradation, and it's hard to figure out gravity objectively if the apple doesn't fall down from the tree subjectively.

Cami's picture
Why exclude or disregard blind testing?

Blind testing is based on subjective perception, and what makes it interesting for the so called "subjective crowd", is that the conclusions that you draw from it are ultimatively and only subjective. It is subjective perception that proves or disproves itself, not measurements or anything external to the listening experience.

Excluding or disregarding blind testing only makes the case for the cable market and cable manufacturers, as blind testing can challenge the assumption that there are substantial and clearly audible differences between cables. It only appears far to indulgent and suspiciously convenient for cable manufacturers.

If you want to advocate for the right of consumers to decide for themselves, you can't limit the tools - like blind testing - that consumers can use in order to decide on a purchase, especially if that tool is based on their subjective perception, and not an external nor "objective" reference or influence.

If what you preach is that we should be allowed to decide based on our subjective perception, then don't favor the exclusion or disregard of blind testing, otherwise you're just dictating the terms under which we should decide, and which appear too convenient for those who sell expensive cables based on the sole assumption that there IS a substantial audible difference between cables.
 

Limp's picture
Toothfairy

Once upon a time I believed in the toothfairy, now I don't. I know I can't prove a negative, but I've decided to suspend my belief until I get a proven positive.

Seth195208's picture
Objective or subjective?

I feel strongly about it both ways! And that's final!

mrcuriosity's picture
Headphone Amplifier Measures

 

Hi Tyll, very interesting experiment u did there! How about doing a similar experiment with headphone amplifiers? I always find it difficult to hear the extravagating differences many reviews claim on different amplifiers(especially those expensive ones Tongue)

ultrabike's picture
Two birds one stone

Measurement repeatablity and cable frequency response impact. Thanks Tyll.

I don't think the difference lies in distortion, but I could definitively be wrong. As far as using a TDR, I don't think it would yield any different results than what you already have with impulse response. It may capture reflections due to impedance mismatch, but I thought that was not a problem in the audio frequency range for the cable runs in a typical headphone application. I think capacitance should also show up in the impulse response.

I honestly don't know what could account for the differences, and have yet to hear music through Cardas (or other similar) cables. If available I'll make it a priority to give them a try in a meet.

Limp's picture
"…differences between

"…differences between cables using that measurement method are bound to be very small. When I swap cables on the headphones I have to remove the cans from the measurement head to replace the cable, and then have to put the headphones back on the head. (…) These positional changes will cause changes in the sound measured, and those changes are likely to be significantly larger than the effects of the various cables."

 

As always, your work is much appreciated, but in this instance I must in particular commend your mastery of cognitive dissonance.

Because aren't you here saying that whatever difference you hear when comparing headphone cables with headphones on your own head, they are much more likely to come from the varying position of the headphones, rather than the cables themselves?

baten's picture
cables

One point in favor FOR different cables from me: when my Q701's had gotten faulty and emitted noise/crackling, with an aftermarket cable the noise was noticeably, repeatedly and consistently louder than with the stock cable. When the headphones were working properly I couldn't really differentiate the difference but attributed a subtle  boost to the aftermarket cable, I liked listening to it more. placebo? the prior mentioned made me believe there really was a difference.

DS-21's picture
Well, that's another case

Well, that's another case where there will be a difference: a defective part vs. a not defective part.

Steve Guttenberg's picture
What if they measure different...

So if Tyll does find measurable differences, and the wire/product can be picked out in blind testing, but YOU still can't hear the difference, what's the point? In the end, it's personal. Everyone hears differently, and has different preferences. Just because the measurements/reviewer says the product is great doesn't mean you'll like it. The Sennheiser HD 800 measures well, but I don't like the sound at all. Tyll has said the B&W P5 measures poorly, but he enjoys the sound. Personal preferences are personal, and measurements are no better at predicting outcomes than subject reviews.

Limp's picture
Revolution!

Well, for one it would be revolutionary, that has never before happened.

'Oohs' and 'aahs' would then be shared, before we started to demand an explanation for this cable's effect on the sound. Then it would be nice to know if this revolutiunary electric effect could be used in other parts of science, I'm certain CERN and DARPA would be intrigued.

DS-21's picture
That's a great company line...

...but it doesn't comport terribly well with actual reality. Sorry.

KikassAssassin's picture
I don't really disagree with

I don't really disagree with you on the point that, when there's a measureable difference, whether you prefer the sound of one product over the other comes down to personal preference. I mean, I adore my HD 650 headphones even though I know they aren't perfectly neutral--they have a bit of a mid-bass bump, and they're not the most detailed headphones around--but because I'm aware of the ways in which they deviate from perfect neutrality, I can make an informed decision about the kind of sound signature I prefer. I enjoy slightly heavier (but not too much) than neutral bass, and the HD 650's slight lack of detail and lack of any big spikes in the treble frequencies gives them a very smooth sound that's extremely pleasant to listen to without any listening fatigue over long listening sessions. All of this, btw, shows up in the measurements, so while you obviously can't tell everything about how a product is going to sound by looking at graphs, they can certainly help lead you in the right direction so you can narrow down your search.

If someone else can tell two components apart using blind testing, but you yourself can't, then that just means you get to save yourself some money while the other person might want to buy the more expensive product if it sounds better to them. So yes, just because someone else can tell a difference doesn't mean you're necessarily going to be able to (and vice versa), but that still doesn't change the fact that blind testing is a much more reliable way to evaluate audio gear than sighted testing is. And if the measurements don't show a difference, and blind testing doesn't indicate that there are any audible differences, you can probably pretty safely bet that you won't hear a difference, either. Neither reviewing method is perfect at telling you what you'll hear when you listen to it yourself, but I can at least have some confidence that a reviewer who evaluates audio gear using blind testing is removing their personal baises from the equation, which makes their conclusions far more valuable. No matter how experienced or well-trained a listener you are, you simply can't get around the fact that your brain is tricking you into hearing what you want to hear when you do sighted testing.

I also find it kind of interesting that when the subject of measurements and blind testing comes up, you essentially make the argument that your job as an audio reviewer is pointless. While I don't think that's strictly true, I do agree that you have to take anyone's opinion of an audio product with a gigantic grain of salt. I just wish more audio reviewers would take a more scientific approach to their reviews so we can reduce the size of the salt grain we need to take when we read them.

I've read a lot of discussions among audiophiles about how the high-end audio market is stuck in a tiny niche, and asking how we can get more people interested in high-end audio. I think one of the major barriers to high-end audio's acceptance among the general public is all the pseudoscience and snake oil that exists in the industry. If we want more people to take high-end audio seriously, we need more high-profile people in the industry to take a stand against all the pseudoscience and weed out the snake oil salesmen that have taken over the audiophile market. If you tell someone that a product will improve the sound quality of their audio system when that product makes no measureable difference and has no scientific basis whatsoever about how it could possibly make any difference, how is that person supposed to take anything else you say seriously? They're just going to assume you're full of crap, and since that kind of thing is so prevalent in high end audio, they'll just assume all of high-end audio is full of crap, so they'll just write off the whole thing entirely.

Willakan's picture
So, what you hear is the only thing that matters?

Absolute subjectivity - what you perceive personally is the only thing that matters - would be a perfect solution, were it not for the fact that the rainbows it chases are wasteful and elusive...and the slight catch that nobody actually believes in it.

If what you hear is the only thing that matters, then what exactly is wrong with an amplifier manufacturer offering a $500 "upgrade" service where they change one resistor (so the amp's volume is slightly different, to encourage the perception of differences) and then ship it back to you, declaring that the sound will be vastly improved?

If they don't make any claims beyond sound improvement for the listener (careful to not mention what they actually do in any detail), and that sound improvement is delivered upon listening (as extensive literature on the subject suggests it invariably will), where's the scam? Who cares if the difference isn't 'real' as such? It's real to you...right? Right? Guys?

@Tyll: If you want to establish differences between cables, why not try some null tests? They should catch any difference in existence, and shouldn't require any specialist equipment.

AsSiMiLaTeD's picture
I have not listened to all

I have not listened to all the cables tested, but I do have the Cardas cable for my HD600.  I can clearly hear a difference between the two cables, and can do it in a blind test with 100% success. 

I don't give a rats ass what the measurements show, if I can hear a difference in a blind test every time then there's a difference, simple as that.  Maybe not everyone can hear it, and maybe you can argue if the cost is justified to replace the cable but the difference is there.

Willakan's picture
There's another guy on

There's another guy on DIYAudio who claims to have blind-tested silver and copper cables...there's another who claims to have done the same with power cords. There are multiple examples of tests finding ESP to function under controlled conditions (remote viewing, that sort of thing). In fact, there are considerably larger number of tests supporting ESP versus magical audio stuff. Thank god for Occam's Razor.

The simple assertion that you have done a blind test isn't really enough to satisfy anyone about anything.

sp0525's picture
No explanations..

I'm not a fan of blindtesting (human being is very difficult to be experimented.). Never a measurement fan, either. However, I don't believe in the cable magic.

I generally believe something if that is supported by some explanation that 'sounds' reasonable enough. Unlike amps and CDP/DAC's, cable manufacturers (or cable advocates) have never tried to explain the magic of difference sufficiently in my opinion.

OldRoadToad's picture
Cables...

People will "hear" that which they desire to hear.  Unless of course they do not desire the truth, then they will ignore it.  So it is with cables and their affect upon sound.

 

Measurements clearly indicate zero genuine, measurable influence.  Ahhh...But the mind of the "sound addict" is a terrible thing to mess with.  No one wants to really do the double blind test, or at least no one that is addicted to sound or rather, sound as they perceive it.

 

It is kinda sorta like religion in that faith is there in the absence of proof with the caveat that cables are not there to save your soul, much less your sanity.  Personally I think that these "high end" cables are beautiful to look at but in truth make no difference in what you are really hearing.  I have yet to meet anyone that can discern the difference with any degree of consistency.

 

Years ago I had a friend that used HO Scale train trestles to keep his speaker wire off the ground.  I took my garage  Yorx stereo and hid it behind the "good stuff".  I was playing Jazz 88.3 through the Yorx but he thought it was coming through the Marantz and Onkyo (admittedly not nose bleed high end to many out there, but nice all the same!) equipment and remarked upon the smoooooooothness of the Marantz tuner and Onkyo amplifier.  Not nearly as good as his set up, but better than most at the local DOW Stereo shoppe he would regularly go hang out at and deride lesser equipment.

 

Their "signature" sound was clearly apparent, if you will.  .Being a semi- heartless fellow, I did not allow him to further shame himself and immediately showed him what I had done and he was shocked.  And pissed off.  He had praised my pauper's set up to make me feeeeeel better and in truth, he was just being kind.  I told him to get over it and just be happy with  what he had and allow others to be happy with what they had (and could likely afford).

 

For the record, I do not listen to equipment, I listen to music.  If the music is poorly reproduced, I will know it, not "perceive" it.  It will be painfully obvious to anyone and not just an "audiophile".  If I wanted to "be there", I would buy a ticket to a concert.  

 

The Toad

Cami's picture
Great comment

Especially the parts about enjoying what you have and can afford, and about enjoying the music. Those are two very sound reminders about the purpose of audio gear: to enjoy the music that makes you tick in the best possible way, without posing a threat to your economy and household, nor creating an outlet for uncalled agression on forums and blogs. I mean, where's the joy and happiness in that?

I personally know I can't possibly afford a pair of Stax SR-009, a Blue Hawaii or a Resonessence Invicta, unless I sell my car and start buying crap food at walmart. That, however doesn't take the bliss and joy out of my Violectric V100, my Dacport LX, my Q701s and my HD800s, and the music collection I've managed to amass for over 30 years now.

I also think that if I could afford equipment worth 10k-20k or more, I'd rather spend it on one, or more likely several, great vacation trips with my family, or maybe a new house. In that sense, you are lucky if you are single and can dish it all out on yourself, but then again, I wouldn't change the people I love for a couple of OP amps and DAC chips.

Getting your priorities right and keeping your feet on the ground, helps a lot when you start feeling that your equipment has to be upgraded, and that you are missing out on something so important you forget to enjoy the music you got the gear for in the first place. We probably all started enjoying music intensely long before we got to spend considerable amounts of money on exotic gear, and started paying attention to brands, reviews, manufacturers, magazines and blogs.

I would love to see a music section in this blog, even if it didn't mean giving Tyll more work than he has already got, but to share our good mood as well. The great mood we are all on when we listen to our favorite stuff and eagerly just want to share it, and when we for a moment forget that we don't have the best gear available out there, but nevertheless the joy of listening to music, which is priceless.
 

DS-21's picture
Of course wires CAN make a difference!

Wire-swaps can result in sonic differences, but ONLY when the RLC values are sufficiently deviant so as to modify the frequency response of the loudspeakers/headphones/IEMs. For example, consider the Etymotic Research ER-4S and ER-4P. The only difference between the two is the resistance of the cable, yet they are quite different-sounding IEMs. Now, when some feckless charlatan (to give two examples, Cardas and Moon Audio) markets a wire that doesn't offer significantly different RLC, well, I suppose pointless wire-swapping is a healthier habit than blow and hookers...

Denis's picture
Difference - yes and no

I have tested lots of different cables - OFC, OCC, SILVER, different diameters, different shielding. Is there a difference - yes and no.

Normally if I test different cables on the same headphone one can hear subtle differences - OCC is bigger sounding and silver is brighter sounding when I'm using the same volume level on my O2/ODAC.

But are there any differences really? I would say NO - because it is like you get the same sound characteristics at different sound levels. If I use a lesser cable(stock cable compared to expensive cable) and just turn up the volume it will sound like the bigger sounding OCC cable, so all you hear is your headphone at different volume levels. As you all know a headphone sounds different at different volume/sound levels (some distort a lot at higher volumes and doesn't sound good).

Some more thoughts about this subject:

I believe if you would measure headphone cables that are very long; say 100 meters then the measurements would show something completely different: more of a difference between different cable types because of RLC but at the lenghts one is using for normal use (1-5 meters) the difference is hardly there and thus you can't tell them apart easily.

timmyw's picture
Sorry Tyll not with you on

Sorry Tyll not with you on this one. Kinda. Personally no but....

I listen to music through my headphones every day. My perception of the sound of what I am listening to changes depending on varying factors. Whether I am sick, what kind of mood I am in, whether I have just eaten or had one of my favourite beers (Just as an aside, you Americans make the best (microbrew) beer in the world!) whether I have just had a shower, had sex... etc etc....

Now one thing I have noticed about audiophilia in general is it is about completionism more than anything really. The gear you get makes you feel great. I think that influences the sound of the music more than the actual gear.

The same goes with cables. In a way it's like putting a really hot set of wheels with the same dimensions as your previous set on your car. It just makes it look a lot better, and you feel differently about the car right away. Your perception of it changes based upon what it looks like. Suddenly it goes faster, performs better is just better in every way. That's how the brain chemistry of human beings work.

This isn't some wild theory, this is genuine scientific knowledge. You have completed your set. Collected it all. Now you can just relax and kick back to the awesome sound. 

Here's the kicker. Even if a cable doesn't really change the sound, and you think that it changes the sound, for you it has changed the sound. @_@.

The chemistry in your brain has just changed as you get your fancy new cable. You get a dopamine injection into your brain cells carried there by receptors from the glands. This WILL change the perception of what you are listening to / looking at / eating etc... It's called a reward system. (Whether you own the cable or not just so you know). 

I've never personally heard a difference. Ever. Speaker cables... no. Headphone cables ..no. But if someone else hears a difference and they like it even if I know deep down that they don't make a difference well is that so bad? Who am I to judge?

listening to music is one of the most harmless things you can do, especially through headphones. It's not hurting anyone else in any way. In fact it's a great thing to do and there are so few ways to be happy these days I say go for it! Whatever floats your boat! 

The only problem I have with it all is the exhorbitant cost of some of these cables and the wild claims made by these.... constructors. The mark ups go well into the thousands and some times tens of thousands of percent above raw materials. THAT, IMO should be a crime. I won't mention any cable makers but really some of them should be ashamed of themselves. Or in jail for fraud.

Personally for me though.... no cables do not and will never make a difference. Perhaps I am one of the lucky ones, or maybe I am missing out on hits of dopamine or endorphins Sad.

SonicSavourIF's picture
Our perception may vary greatly

 

I often find, that my perception of the same equipment can vary strongly, depending on how I feel, how tired I am and so forth. I am sometimes able to here details in music or amplifiers I am not able to hear at other times. Sometimes when commuting home after a long day I am extremly sensible to treble or even to very low volume levels.  Different concentration at different times? Tiredness? My brain interpreting sound differently? Psychology? The point is, that we experience music through interpretation of our brain, which may strongly vary depending on your mood, concentration, tiredness, let alone such things as having a cold (sore, inflamed ear-drums), having pressure on your ear (planes, mountains) or even suffering from back tensions. Such differences in the perception make reliably evaluating sound and reproducing sound experiences very difficult. To eliminate such variation of hearing performance in blind tests one would have to repeat these tests under exact conditions over and over again at different times, in different moods etc. and average the results. That would be an interesting thing to do. I haven't listened to cables so I cannot comment on the effect, however as a scientist I remain very sceptical if nothing is measurable. And seriosly, 1400$ for a HD650 Cable 

(oh yes(!): http://www.stefanaudioart.com/Voice%20HD650%20headphones%20Single%20Ended.html)...

There comes a point, where it becomes insane. Where is the point in Hi-fi, when it remains something for the ultra rich...

 

Cheers, I highly appreciate your work Tyll

 

David

IgorC's picture
Thank You, Thank You, Thank

Thank You, Thank You, Thank You for debunking a stuff around  silver and gold 1,000$ cables.

One of my fellow  and me have tried Cardas cables for Sennheiser on HD 650 and 800. While he was saying  "this is warmer, that is lifeless". But  the same procedure with closed eyes was laughable.  He was just randomly  guessing "warmer", "cleaner", "better" and so on.

 

P.S. Probably all these variations were coming from a slight different sits of phones  on a head.

DanTheMan's picture
important decisions

Decisions that are easy to make are typically most crucial.  That's why this cable thing has gone on so long. 

miceblue's picture
If the effects of "cable swapping" were audible...

...wouldn't it make sense that there would be measurable differences in the sound "you hear" from a headphone?

If you claim "[you] find the changes made by cables subtle, yet often worth while", and "[you] measure headphones all the time, and believe there's a fairly strong relationship between measurements and what I hear", then the "audible" effects of cable swapping should be noticed in the headphone measurements, no?

That, or you're just hearing things as many objectivists point out in audio gear. Is it actually audible, or do you think you can hear a difference? If the measurements of cable swapping aren't measureable, try an ABX test to see if you can really hear a difference. If so, then maybe measurements aren't as reliable as people would like to think they are. Afterall, what measurement "measures" the soundstage and imaging ability of a headphone?