hmmmm is placeboo also hearing a clear difference between the demo unit that has been burned in for around 100hrs with no one wearing to break in the pads and a freshly bought unit?
Esp with dynamic drivers, bass tends to be quite abit heaver and slugish along with peaky upper mids. Dont have much experence with planars since for most part that isnt my kind of sound.
For the record, yes both brain burn-in and driver break-in are real things that have nonzero impacts on how we perceive audio. Which has the bigger impact is highly contextual.
On the subject of using measurements to verify or disprove driver break-in (or any other audio measurements for that matter), there’s a big elephant in the room that no one really talks about: there is an inherent limitation in using a thing to measure itself. Allow me to explain…
When making a good measurement, if at all possible we want to use a standard that is of a different nature than the thing being measured. If we want to measure a person’s height, we don’t use that person as the unit of meaure, we use feet and inches (if you’re a stubborn American [gulity]) or meters and centimeters. If you used the person themselves, you get a meaningless answer: they are one themselves tall. If you use another human to measure the original person’s height, you get a little bit better idea, but there is still lots of uncertainty in what that means. For example, I might be about 0.83 Shaquille O’Neals tall. But, there is a lot of estimating and approximating in saying that, and it’s still not very clear.
Audio signals are alternating waves of energy travelling as oscillating electric and magnetic fields. To measure such things we have to use the effect that those changing electromagnetic fields have on other electromagnetic fields. So, we use like things to measure each other. Given our current technology, it’s the best we can do, but even what we consider to be very accurate (and useful!) measurements come with some inherent uncertainty as a result. To measure frequency response, we use a changing EM field to set a membrane in motion and create a compression wave. That compression wave then travels to another membrane that vibrates as those compressions hit it, adn then that device turns those vibrations into a wave of changing EM fields, which get measured by another gizmo using EM fields to measure those new EM fields. It’s using the thing to measure the thing, in essence. Sometimes doing so is unavoidable. But, we have to be clear on the limitations of doing so. Our brains and ears are a type of measuring device, if you will, and of a different type that they can be useful for perceiving things that are not captured because we use changing EM fields to measure changing EM fields.
Food for thought. Either way, if you find a headphone/IEM/speaker you love, hold onto it and enjoy the hell out of it, don’t let anyone else tell you you can’t.
In machining, when you need to take accurate measurements, you use a surface plate (slab of granite), a gauge blocks and then use indicators to measure the difference between the gauge blocks and the work piece.
Could also mount a mirror to the driver and use a michelson interferometer. Is a relatively simple photonics experiment to build an “optical microphone”.
True! We need accurate measurements in a great many things. Using EM fields to measure EM fields usually works well enough for most day-to-day purposes. I’m just pointing out that there is reason to believe the humain brain is good enough at recognizing patterns that it may detect differences that get missed in the “zone of uncertainty” (for lack of better expression) created by using EM fields to measure EM fields.
Hmm. Seems like that would add mass to the driver. Even a tiny amount can change its vibrating behavior.
You would be surprised how small mirrors that work for interferometry can be made. Where Biologists and Physicist meet, is where things get weird and interesting.
Burn-in. For cables? Meh, I personally have not heard a difference in the sound hours/days/weeks after the cable(s) were installed. I bought a higher end set that actually said they would sound their best after 150 hours of burn-in. I’m sorry, I’m calling bullshit on that. Did they sound good? Hell yeah they did, and that’s why I bought them. But they didn’t sound any better after the 150 hours.
Having said that, The Focal Elegia’s did settle in and improve over time. I have had tubes that got better over time. DACs stabilize and get good over time.
I also think brain burn-in is a real thing. It’s difficult to identify, but I am quite sure it has happened to me. And that’s OK. It’s an unavoidable part of the human condition.
To add complexity (as if more is needed) to the situation, when I have a new IEM, DAC, Cable, Amp, etc., and press “play” on a musical track, which I have great familiarity with, I have prior expectations of what it “should” sound like. I’m not sure about sound, but in vision, our prior experiences account for a majority of what we “see”. I wouldn’t doubt that sound is the same.
Brain burn-in is, I would say, largely reformatting our prior expectations. This is why new audio equipment sounds, both better and worse, weeks after we bought it and have stopped A/B testing it.
In my experience “burn-in” is mostly used as a synonym for “justifying my purchase”. I don’t discount it completely in audio, whether it be brain or equipment burn-in, but I am a cynic when it comes to more than say a few to maybe 20 hours.
I remember years ago when I bought the original Auralic Vega DAC. It was the flavour of the month in Audiophile circles for being detailed & resolving - which it was, but I found it fatiguing. The forum crowd told me it needed 250 hours of burn-in, I persevered and no change. Then people started saying that they were finding 500 hours to be more appropriate for a major change. Again I persevered and again no change. Then I started reading where people were quoting 750 & 1000 hours for transformational change!
My crazy person alarm was activated and I advertised the Vega as soon as I read that.
History now shows that the implementation of the ESS Sabre chip in that DAC exhibits a major IMD hump in the frequency response…nothing was ever going to change apart from human perception that was influenced by $$$ outlaid.
OK then, please be clear about it. Because I didn’t find your post clear.
Not sure how your feet an inches example is relevant. Are you suggesting that those measuring headphones are measuring them in units of other headphones??? Standardised unit of measurement exist, and are used in audio measurements. We hardly need to go all the way back to fundamentals here.
“To truly understand headphone cables, we need to consider the big-bang”.
Mmm, ok. So what’s your criticism of our current measurement systems? What deficiency have you identified?
Why only 2 options? I want to say “always believe” + “changes technicalities” + “already at 20h”.
I think it can be proven with measurements, I think Tyll has proven it with measurements even though his comments on his own graphs seem less convinced, and I think no one who claims to have disproven it with measurements can be believed if they haven’t tried it with cheap headphones that undergo the least testing at the factory, like Superlux older models (prime target would be the 668B). You test expensive headphones made out of the best materials, you’re not really giving the hypothesis a chance, IMO. I’d like to see 50-ish hours of frequency sweeps, and multiple measurements like FR, IR, SR and CSD to take an experiment seriously.
Interestingly, I’ve just bought 007mkii Stax and as I was paying, the chap said “don’t worry about running them in as that’s all done at the factory”
So Stax think it’s a thing apparently.
As does any other industry including but not limited to automotive, shipyards, electronic components, home appliances, construction equipment, etc.
I’ll take a swing at this! 
I got into IEMs about a year ago (dang HBB 
).
Of all the IEMs I’ve owned, or spent extensive time with, my Galaxy Bud + come the closest to the Harman Curve. This includes the Mangird Teas, Fir Audio VxV, Sennheiser ie900, Sony IER z1r and, my current daily driver, the UM Mest Mkii.
Any measurement system MUST have a standard. We don’t just say that something is “long” we say it’s 10 inches long and is LONGER than something 9 inches long. The same applies to “measuring” sound. Whether it’s THD, SINAD, Sensitivity, Frequency Response, Impedance, etc., if we insist on measurement we MUST do so against an objective standard. The problem, as it currently stands, is establishing an objective standard, like inches and pounds. And that’s all the Harman Curve (or any FR curve) is: inches and pounds. We aren’t anywhere close to an objective standard for sound. And this doesn’t even account for the uncontrolled variations in technique that occur among the many reviewers who do measure for FR.
Frankly, when it comes to music, my Galaxy Bud + sound like @ss compared to any other IEM I’ve owned. I only use them for listening to TV at night.
Anyone who accepts the Harman Curve (or any other curve) would have to account for why the Galaxy Bud + doesn’t sound as good as others that don’t adhere to the Harman Curve. That they don’t sound as good, I hope, is not controversial to this discussion.
(To be fair, the Galaxy Bud + don’t sound awful - just not as good as the others. As an old fart, I can remember the bad old days of the '70s and '80s and I would have walked over corpses to get something as good as the Galaxy Bud +)
Of all the things we could possibly measure in headphones, speakers, IEMs, etc, I think frequency response is probably the least interesting to me. Sure, we could hunt for a pair of cans with a truly “flat” FRC, or something that closely matches any “target curve” if we were so inclined. That’s only going to tell us how they respond in “from the factory” configuration, on “reference” source gear, measured on the rig of whichever reviewer did the measurements. Change the measuring device, dac, amp, pads, etc, and you’ll change the curve. That’s before even mentioning EQ.
For millennia, science was a semi-codified process of using our senses to observe the world around us. What’s worse, is the truth that the placebo effect can cause real physical manifestations. To a great extent, we hear what we expect to hear in much the same way we see what we expect to see (there’s a lot of new evidence coming out suggesting a huge percentage of our sensory perceptions are very heavily influenced or even completely controlled by the sum of our previous experiences). Further, with different ear shapes, ear canal shapes, etc. we don’t all hear the same sound the same way.
It seems to me that the best measurement tool we have is probably still our ears. Yes, leaning on them poses some challenges. Eliminating, or accounting for all of the various biases and psychological influences is difficult to do. However, things like FRC, minute variations in timing, sound waves partially interfering with one another, etc. we probably won’t come up with more “objective” tools that can tell us which factors interact with one another in what way to make the resolving ability of one pair of headphones sound superior, but in a very small, intimate stage, while a second pair (of equivalent open / closed level design) could sound smoother, less resolving, but in a grand, wide, deep stage.
TL;DR - sound reproduction is a problem where a large number of variables interface and influence one another. It’s still too complex for the basic measurements we’re using to tell us much that is very useful. Our ears are still the best tool for the job.
It’s also interesting (and should not be left unchallenged or taken as a given) that we humans have this “urge” to convert sound into a Cartesian graph which displays amplitude and frequency in a VISUAL format.
The fact is that humans, like all primates, are primarily visual creatures. A significant portion of our neural apparatus is geared towards vision (unlike dogs/wolves, which are geared towards smell). We humans traded increased visual distance, due to the height of our eyes above the ground, for a reduced sense of smell - since most scent molecules are heavy and fall to the ground.
What does a frequency response mean to someone born blind? Teaching mathematics and geometry to those born blind poses serious challenges (Google it for more info. An interesting topic). Can a blind person not appreciate (or judge) the quality of sound of a transducer because they cannot see the FR? I actually heard on YouTube a reviewer (I won’t mention his name) say that he had a hard time judging a particular IEM because he didn’t have a graph…
Would anyone take seriously food recommendations reduced to X vs Y graphs measuring salinity, acidity, sweetness, sourness, umami, etc.? Certainly not. The reason we pay rapt attention to visual graphs is because we are visual animals.
Edit: I prefer to use my vision for it’s evolutionary adapted purpose!
First off, this is a completely different topic to the one I was responding to (above). As noted wavetheory wasn’t clear in his criticism, but if I had to guess I would say he was alluding to microphones being an insufficient device/technology for measuring sound.
I don’t think you are saying anything controversial, but I also feel like you are mixing the terms somewhat. Feet and inches are the units of measurement. Saying you should be 6 foot tall at least to join the army is a standard. We could describe you relative to that standard, but we would still measure you in feet and inches (or centimetres), and we would use a measuring tape (the measurement device).
A response target is a standard, expressed in 2 dimensions. Unlike the example above which is expressed in a single dimension (height).
You don’t enjoy an earphone which allegedly conforms well to a response target. Ok, I would say this is a common occurrence, which could be explained by many factors (eg unit variance, measurement / comparison problems, preference). I personally, don’t prefer Harman tuned headphones.
With regards to your other points, THD, SINAD, sensitivity, impedance again are not units of measurement, but dimensions upon which a piece of audio equipment could be measured. Some of these are quite predictive of performance. Sensitivity measurements, for example, can tell you if your amp can make them sufficiently loud.
This thread is about the concept of burn-in. I would expect performance changes related to burn-in is a measurable phenomena. In fact from what evidence I have seen on these measurements, we can often measure an effect, but find that the effect is inaudible. This would lead me to believe that our measurement devices are quite sufficient (for the subject at hand).
I would expect that food scientists formulating mass produced snacks, soft drinks etc would use this kind of information. And then they could establish through subjective measurements how those technical measurements relate to preference. With that that they could attempt to make some relationships, improve the product, test again… repeat.
The good audio products gets tested, so they notice possible flaws or production errors. Maybe even figure out what was wrong and in what component, if there are more similar incidents. They know there is flaw in production or material. They will fix or change that.
Products should perform at optimum levels before consumer buys them, so no changes happen in sound.
It something would happen, it’s not in the product you bought.
Well, more on this. I was on the Focal site and saw this while in the Elegia product page:
"RUNNING-IN PERIOD
So there you go. As previously mentioned, I did notice a significant improvement after several hours. I definitely think that in some cases, it is relevant, and in others, not so much.
In my experience it depends on the product. Some brands you don’t need to worry about burn in like Schiit which does that as a means of quality control inspection before shipping their products. Sometimes burn in varies like with Dan Clark products; sometimes it is barely noticeable and other times it is a huge leap. I have experienced a night and day difference with burn-in like with my Meze Liric and my friend’s Meze Elite after just 10 hours. 100 hours of burn-in though is preposterous and just nonsense.
To me it is a case by case basis. Besides if after 10 hours of burn-in I am not impressed then I’ll take advantage of the retailer’s return policy. All I can say is I wish the poll had a case by case option.