Just search that question + reddit on google and you'll get dozens of the exact same thread, repeating the same arguments, with the exact same vitriol you would expect from audiophiles.

This gets really deep and there's been a lot of research on it. In short, Yes if two pairs of headphones had an identical Frequency response at your eardrum they would sound the same (ignoring factors like comfort, ambient noise, how the pads feel on your ears which all affect how we perceive sound).

The thing is, it's virtually impossible to make two pairs of headphones have the exact same Frequency response at your ear. Even from two models of the same headphones there will be differences you can't EQ in.

The frequency response graph you see from measurments is best used for comparisons, but it doesn't represent the frequency response it will have in your own head, and even headphones that measure very close on a rig, can have large differences in the frequency response when it's on your head due to difference acoustic impedance.

The best way to look at it is, yes everything does come back to frequency response in headphones, but it's just the end result and not something you can EQ one pair of headphones to match another. So in a way, "Technicalities" does exist as a part of frequency response, and you need to listen to them to get the full picture.

Technicalities is basically everything that isn’t FR so yeah it exists. You don’t need to put alot of stock into them. It’s little things you pick up along the way. Or larger things Like note weight and imaging and stage. So it’s not A thing. It’s thingS. An iem doesn’t live or die on them

Oh look, it's this question again.

Now in theory, for a headphone that acts like a minimum-phase device (and most headphones do), everything is encapsulated in (note the wording here) in frequency response and distortion. All of the technicalities and transient-response-related phenomena are reflected somewhere in the FR. In other words, you cannot change the technicalities of a headphone without also changing some aspect of the FR. The problem right now is we don't have a way to directly link technicalities to any parts of the FR with accuracy. Detail isn't just treble, but it's more like the balance of specific frequency ranges in the FR. Over-boosting the treble can actually hurt detail, as you're then masking other frequency ranges.

BUT, and this is a pretty significant but, don't trust graphs to tell you everything about a headphone's FR. Graphs don't take into account everyone's individual HRTF, so what you actually hear will deviate from what's shown on the graph. Secondly, FR in reality is a very fine-grained metric, which graphs (and especially target curves) do not represent well. So no, you cannot EQ any headphone to sound like any other headphone. That's just not possible, especially just by going off of a graph. I've had some success with EQing one headphone to sound like another when I had them side by side so I could EQ the treble by ear, but it's very complicated and time-consuming to do so.

There's another metric, distortion, that can sometimes play a role, but it's not always clear what that role is, or if it's really noticeable. Distortion basically sets the upper bounds of what a headphone can produce, because you can't EQ out distortion characteristics. Same goes for things like group delay, which is a metric that can be measured, but there's no consensus on what those metrics mean or how they relate to headphone performance.

Now, technicalities are definitely a part of the subjective experience of listening to a headphone. Imaging, resolution, dynamics, that's all part of what we experience. So I think it's fine to rate headphones by those metrics, because the experience is what matters. But I have yet to see any conclusive proof that those things are not influenced by FR in some way.

Very interesting, 2 models of the same headphone have different FR, I heard about this, but isn't it so small, that one person can't distinguish by his ears? About pads and comfort I agree, all this affect Frequency Response, but for example we have Focal open-back headphones that already have so much similarities between each other, can you take Clear pads(housing is basically 99.9% the same) and use some EQ to get actually sound like Clear? With this I don't know <0.1% of difference that can be even between two models of the same headphone

Btw, what about IEMs? Here fit, comfort and eartips usually are very close to be the same

One more sincere question. What do you mean by saying that you can't EQ one headphone to sound like any other. I'm asking because I'm not an engineer and also not good at physics, but how do manufacturers make so many headphones(of one model) to sound the same or 99.9% the same? It because of what? Can we call this 'hardware' EQ and not digital, because digital EQ have it's limitations, while 'hardware' EQ doesn't?

FR is by far the most important aspect of a headphone, and “fixing” FR with digital EQ, even if the fixing occurs at 192khz, which almost no consumer offerings could dream of doing, is not the best solution.

So, unit variation is a thing, and it's unlikely that any 2 headphones of a given model will sound exactly the same. Tight manufacturing tolerances and mechanical testing is generally how good consistency is achieved.

But I was talking about EQing one model of headphone to sound like a different model of headphone, like EQing a Hifiman to sound exactly like a Focal or Sennheiser. That's not possible.

Also, you can physically modify headphones by changing their earpads and other parts of their construction (hardware EQ as you put it) to change their sound, but that is actually less precise than digital EQ.

What you call technicalities in engineering we call nonlinearities. Frequency response is also called a linear distortion. It's the kind of distortion that doesn't change with drive level (how much power you're putting in). Nonlinearities in are very important in any audio transducer. You want them as low as possible. That's because music is a continually changing drive level. Things get quieter and things get louder all the time. That's where the fun is The most important nonlinearities are the ones that happen to loudness of a particular tone, also known as amplitude modulation. Your hearing system is very sensitive to that. Amplitude modulation suffer the most from compression which is an inherent quality of any audio transducer. Basically as the diaphragm wobbles it has increasing tensions in it's suspension as well as decreasing motor strength, the further away the diaphragm is from it's resting position. This means that the stronger the wobbles, the less accurate it becomes and also the less sensitive it is. This is very bad for sound quality and it's a universal mark of driver's limitation to properly reproduce sound.

Compression can get suddenly tragically worse with phase issues. FamouS examples are Sennheiser hd820 and buchardt s400. Both have severe compression at resonances that cause phase cancellation and consequently notches in frequency response.

Last thing is the time delay spectrum. It's frequency response taken as a 'lump'. Basically one very smart guy discovered that our auditory system catches short sounds like transients as lumps of sound. You can't hear how long they last. Instead, your hearing tells you that a longer sound is higher in intensity than a short one. This lead to development of time delay spectrometry, today known for example as waterfall plots. They are particularly useful in medium and high frequencies, because they allow us to find ringing that doesn't show up in frequency measurements. It is a crucial driver behaviour and measurement for sound quality and spatial effects.

How do manufacturers make the tuning of their particular headphones? With 'physical' EQ, if digital is not ok? Like changing pads can easily change sound, so they are changing sound by pads/diaphragm/something more?

>2 models of the same headphone have different FR, I heard about this, but isn't it so small, that one person can't distinguish by his ears?

Yes, but this is difficult.

>what about IEMs?

In the IEM world this is more easy, you can EQ a 7Hz Salnotes Zero to be really similar to a Thieaudio Monarch MKII or a UM Mest MKII (I tested both IEMs, it's not the same because of the differences in your own ear, but it's very similar), yes. In the headphone world, because of the pinna interaction, it is very difficult to make one headphone sound similar to another headphone.

You can improve the EQ using a sine sweep, this can improve things like "imaging" or "detail" because you are reducing some peaks and dips that happen with ear interaction, this makes the headphones clearer without auditory masking or "veils", but it's very boring to do the process.

Thank you for explaining about IEMs, because there are some IEMs that I am interested in and would like to use EQ to try their frequency response with my Variations. I can do this easily by software on my Mac, or do I need Quedelix 5K with it's parametric EQ?

I don't know, sorry, I don't use Mac. A Qudelix is ​​a very good thing, I recommend it.

Understood, thank you for extensive response, what about EQ not HiFiman to Focal, but Focal to Focal, especially interested in Clear/Elex, because their similarities is already very large, Utopia do have a bit more physical differences, but still looks like they are times more insignificant that for example Sundara/Ananda. They definitely have different pads, and voice coil in Clear are copper, while Elex is copper/aluminum, so can pad swapping and digital EQ make both headphones close to the 'same' sound, that most people will not even recognize the tiny differences?

The reason why peeps talk about frequency response and frequency response only is threefold:

First, headphones are tragically bad at it. Tuning a headphone is a nightmare as opposed to tuning a loudspeaker. They are often off by something like 10dB and it's not considered weird, that's how difficult it is to get that line flat. By comparison a reviewer's standard for a recommended loudspeaker is +/-1.5dB.

Secondly it's the only feature of sound that you, the user can affect. You can't change compression or ringing without comprehensive training in engineering. However you can push the sliders to make an EQ curve.

Lastly it has been shown that frequency response is very important. It's the most fundamental measurement that we have and our hearing agrees with the results of this measurement to the highest degree. Not 100% but still more than with anything else.

As a bonus I'll add that it's the easiest thing to measure. It doesn't require any special equipment or knowledge. The simple graph is also easy to understand. If I posted a waterfall graph instead, a common person reading it would be lost and had no idea what to make out of it.

Yes; the driver’s initial output, coupled with the housing design, acoustic fabrics/materials, and swappable parts like different earpads … all contribute to the FR of any headphone. Some better manufacturers include multiple earpad variations in the box, to adapt the FR depending on each user’s desired sound signature…

>First, headphones are tragically bad at it. Tuning a headphone is a nightmare as opposed to tuning a loudspeaker. They are often off by something like 10dB and it's not considered weird, that's how difficult it is to get that line flat. By comparison a reviewer's standard for a recommended loudspeaker is +/-1.5dB.

This is really interesting. As a non-engineer, can you explain why it is that tuning headphones is so practically difficult? Intuitively I know it to be true (hence all the substandard headphones, etc.), but have no sense of why it's so difficult.

Frequency response is far and away the most important thing.

But frequency response curves are highly smoothed graphical representations of the response to a sine wave sweep, intended to give information about tonality. They aren't designed to measure everything.

And there are other things that can be measured, including some of the things you mentioned. To some degree we can measure distortion, speed (or delay), and also things like mismatches between L/R drivers in phase response, frequency response, and amplitude. All of which are above audibility thresholds in at least some headphones.

Qualities like soundstage and imaging on the other hand may have no one direct measure, but are impacted by both frequency response and some of these other measurable factors, in ways that can be difficult to precisely define.

Going further, it could also be said that any deviation from the original frequency response is really some form of distortion. But there are many types of distortion, and we really don't have one good measure that can reliably account for all distortion and differentiate between what distortion is or isn't audible in different cases. It ends up being very difficult to define meaningful audibility thresholds for some of these measurements.

But there does seem to be a significant correlation between price and measurements of non-linear distortion. On the other hand, there is very little relationship between price and frequency response, which is still more important.

And even if higher priced headphones do tend to be better on technicalities, it still becomes very difficult to say at what point these differences should be inaudible. It's very easy to find things clearly above audibility thresholds in many headphones < $100, for example. But once you get to ~$300-$500 range, I think it really become debatable. And then when you are comparing Elex vs. Utopia, I have no idea whether there are any measurable differences which could even be audible.

So for now, I would say that if there is a strong consensus amongst listeners who have actually used these headphones, then likely there are differences, whether we have fully figured out how to measure them or not.

I think the vast majority of what people describe as "technicalities" are just facts about a headphone's frequency response, as perceived at the eardrum, and colored by non-audible qualities that feed into one's perceptions, like price. But that doesn't mean that these differences are, realistically, measurable or correctable. FR measured on a test rig with a plastic ear is useful to a point but very much secondary to how it sounds filtering through your ears and sensory system.

Let me give you an example.

The FR of Susvara and Nan-6 is almost the same. In fact, there is more variation between different units of the same model than between them. And yet they sound completely different. Yes, they sound very similar in tonality but that's literally the only thing that's similar between them. The spatial qualities, resolution, or dynamics aren't things you can read from the FR graph.

These talks about headphones being minimum phase systems and that FR is the only thing that matters are all just theoretical. In practice, the FR graph doesn't tell you anything but tonality. And even the tonality is only relevant to the specific measurement rig, headphone unit, and position on the rig.

That's also why headphone measurements by ASR are not very reliable because Amir only measures 1 position. And that's also why 5128 is the best rig ever only theoretically. It's so incredibly sensitive to positional variation without having stable resonations it's more practical just using Gras...

I've heard that the Elex is very close, like 90-95% of the OG Clear. I've also read that the Elex and Clear use the same earpads too; the Elex is an Elear with Clear pads based on what I've read.

So assuming you are listening at volumes that don't encounter the driver clipping issues that all Focals have (and the different driver on the Elex might make it more susceptible to clipping than the Clear), you are more likely to be able to EQ an Elex to sound just like a Clear, but again, you can't accurately do that with just a graph. The only way to you can accurately EQ the Elex to sound like a Clear is to have both headphones side by side, and EQ one to sound like the other by ear.

I've used and experimented with EQ a lot, and it's easy to destroy technicalities via EQ, but it's hard to improve technicalities with EQ. My experience is that technicalities are linked to relative levels of very narrow bands of frequencies throughout the audible range. "Correcting" small tonal problems via EQ also affects technicalities that are linked to those frequency ranges. EQ, even digital EQ, is not precise enough to accurately shape the needed frequencies without also messing up nearby frequencies. If you're really focused on technicalities, then I would suggest going for the Clear, as then you don't have to worry about EQ.

I'm not sure why you asked about whether "most people" could tell a difference. In audio, what "most people" think is irrelevant. Your ears are not anybody else's ears. Your preferences are not exactly the same as anybody else's preferences. Things that bother some people don't bother others. Will there be differences after EQing the Elex to sound like the Clear? Almost certainly, they won't sound exactly the same. Whether that matters is something that only you can answer for yourself.

Well, except the FR is not the same at all. I'd expect the overall tonal signature to be be fairly close, but all those little squiggles are audible qualities of the sound, with some fairly low-Q >3dB differences exactly where your ear is most sensitive.

But what are you going to do about it, have some kind of EQ with dozens of high-Q filters that would be completely different on your particular cans/ear or even headphone seating? Ultimately the FR measurement is only useful to a point.

Short answer: Frequency response is not all. It’s a very, very important part that can tell a lot, but “technicalities” do matter and exist.

More Treble does not mean more detail. It MIGHT mean more perceived detail, but it’s not that simple. I’ve heard dark tuning headphones that absolutely resolved information better than some sharp ones and provided more texture and detail, despite it’s dark tuning.

Thanks for the info on Time Delay Spectrometry. I did some searching on the keyword and found a paper by Richard Heyser (1973) and another later one by Mark Fitzgerald (1989). Is the Heyser paper the one that started the practice? Or is there another one that came earlier?

The psychoacoustic effect of a longer chirp being interpreted as louder by our brains helps explain a few cases I've experienced where a part of the spectrum sounded louder to my ears than the graph would suggest, but was fixable via EQ.

I wonder if there is a way to incorporate the auditory effects of "lumping" into the FR graph. Like it adds to the parts of the spectrum where there is ringing to represent the audible effects of that ringing. It would no longer be a pure FR graph, but it might be helpful in some cases.

Yes, the ideal headphone would be a minimum phase system. But manufactures go to a lot of trouble to design them to be as close as possible to minimum phase, and still come up short. For one, minimum phase systems don't have nonlinear distortion. Headphones do.

The "headphones are minimum phase systems" arguments tend to remind me of the old joke about the theoretical physicist hired to consult on how to improve milk production efficiency on a dairy farm. When time to report his solution to the farmer, he begins "First, we assume a spherical cow...."

In order to understand the difference, you need to know how a loudspeaker is tuned. A hifi loudspeaker has bare drivers on a flat baffle. There is nothing affecting the sound between the diaphragm and a microphone. A loudspeaker designer than has a full arsenal of tools to affect it. It's like working in a chemical lab, where everything is in clear glass with no contamination and all the tools to precisely dose chemicals. If you want to alter a driver, you make a precise virtual model in software and the software spits out it's response. You know for sure that this response will be very close to the real thing. You can for example put the tweeter in a waveguide and an app will help you iterate the design 20 times before you can get all the lines parallel. You don't need to make the thing 20 times. You're done with the baffle and the thing is still not flat? That's OK, you can compensate any problems in the electric domain. You open another program that lets you make a filter out of electronic parts. It simulates a notch filter here and a shelf there and with 20 parts you have finally linearized the response. The whole thing weighs a ton and barely fits in the enclosure, but hey it sounds great. Oh did I mention that AI does that last part for you? Yup, there is an app that does just that. You give it a measurement and it spits out a circuit diagram.

Now headphones... Remember when I said that you can design a waveguide? So with headphones you are already forced to work with one. The ear cup is a waveguide, a terrible one and there's not much you can do about it. Headphone's ear cup is like room that cannot be detached from the loudspeaker. You can't take it to an anechoic chamber. You need to work with the mess that it creates. Sound is like light except everything is a mirror. A lightbulb in a torch illuminates the surroundings differently than a lightbulb in a chandelier. A headphone is a lightbulb in a crumpled tin can. The result is a mess.

Headphones are tuned by covering holes on the driver with lossy materials. You poke a hole and see what happens. Each time you change it, something drastic happens, but it's difficult to understand what. I have personally no idea what tools or software do the big guys like Sennheiser have to aid them with it. I guess a headphone designer would shed some light on it, not me. But even if you get the driver tuning right, you change the earpads and it sounds differently. More than that. You put it on someone with curly hair and glasses and that makes a difference as well :D That's because the enclosure is lossy. Very lossy. I personally don't understand why we can't add passive filters to headphones. It used to be problem of source output impedance, but now that everything is measured and reviewed, we can predict how a filter would sound. So it would be cool to see filter PCBs for headphones. It won't fix all issues because the most appalling resonances in headphones are destructive, meaning that they cannot be fixed without physical change. It can be used to attack broad valleys and bumps though.

With headphones I have understood, that you really can't EQ 6xx to the Susvara sound, due to so much variables and differences between them, but still interested in Elex/Clear/Utopia case, because except pads, they all have same housing, and overall very very similar to each other

Also as I understand with IEMs it should be easier to recreate sound of one IEM to the other, even if one of them have 1 driver, and other 12 for example?

Understood, actually it's a pity, that you need still eq by your ears, having 2 headphones, I never have used any good EQ software, but I do want to try it(Qudelix 5K parametric EQ), I was thinking you just need to download some preset or press one button and get close to Clear sound with Elex, but now I understand the problem, because everyone's eardrum is different, so there will not be any universal preset that you can download for over-ear headphone and call it a day?

At least as I understand, after asking other people under this post, EQ with IEMs can be more effective to recreate close sound of another IEM

I have a Focal Elex with fenestrated sheepskins pads, so I think I should reply even if I haven't had the pleasure to listen to Utopia yet. With these pads and if I use something like MorphIt to EQ them with Utopia as a target, I would get very close to the real deal, but they will never match the speed of the beryllium drivers. So, yes technicalities are definitely a think when frequency response is determined by the physical properties of an unusual driver material.

I don't have the time or knowledge to answer for all types of headphones technicalities, but I can speak of slam or punch.

I believe slam is unrelated to the frequency response. It has to do with the volume of air the driver can move at once. If the whole audio chain from file format to DAC, amp then headphones is optimized to maximize dynamics, slam is definitely perceptible.

See this thread

or this post for more details.

I think you could get them to sound very close to each other in terms of their broad tonal signature, but the devil's in the details, which show up as those little narrowband wiggles in the FR plot. For the most part that stuff is simply not amenable to correction via EQ. The Utopia and Clear may be similar, but the drivers are made of different materials, they probably differ in the finer points of their driver/enclosure design. Some driver distortion mode may very well show up in an FR, but you can't really fix it without fixing the driver - at best you could reduce whatever frequency excites that distortion, thereby probably doing more damage to the sound.

It does make sense intuitively, doesn't it? I'd love to see it made. Heyser was the pioneer. A real genius. Today maybe Tom Danley is comparable of the guys that I've heard. Not that I've read much.

Heyser basically found what everybody interested in audio wants to know - what is the connection between pleasure objective data. TDS is basically asking a driver to shut up and seeing how it complies. Spoiler alert - it doesn't. Complex diaphragms and motors have resonances that store energy and release it when there is no stimulus. These resonances rob us of silence! No other measurement finds that. There is a lecture on Heyser on YouTube and it captures all you need to know about the guy.

Most famously waterfall plots help us understand the smoothness of tweeter sound. Select people with enough money or DIY patience know that ribbon tweeters sound smooth and domes are harsh despite the fact that they're made of the same material. For a long time there was no graph to capture that, but waterfall makes it clear.

If you can hear non-linear distortion then the transducer is very low quality, excessive power is applied beyond what the transducer was designed for, or both. Most of this distortion is usually concentrated at very low frequencies. Decent transducers do not produce audible distortion other than the frequency response itself at normal listening levels.

Since most people who talk about technicalities do not measure nor talk about how the transducer creates distortion nor any technical aspect associated with distortion such as levels, their talks about "technicalities" can be dismissed as gibberish.

> waterfall plots

These plots which are nothing but a fancy and convoluted plot for resonances are can be very misleading and not very useful to meaningfully interpret data. Even more useless for headphones and iems.

By fenestrated sheepskins pads you meant original Utopia pads? Or it's from decony? Without eq, do you liked sound with these pads more than with Elex original pads? Or differences are subtle? Resolve says that Utopia pads significantly improved FR in Elear, but they cost half the price of my Elex, doesn't seem like a good deal

> By comparison a reviewer's standard for a recommended loudspeaker is +/-1.5dB.

In real life you almost never get a loudspeaker that produces a flat frequency response within +/-1.5dB . That's fantasy unless you listen to very high end speakers in a perfect anechoic chamber which is not happening. So more like +/10dB in real life. In that sense both headphones and iems can produce a smoother frequency response than most loudspeakers.

This right here is the best answer so far. In a way I think 'technicalities' is the wrong word, with all apologies to my good friend Crin on this topic. It should probably be something anchored more to just the subjective or unidentifiable aspects in FR on a graph.

There's a site called DIYAudioHeaven that does provide schematics for analog filters for certain headphones. And I've seen speculation that the Dan Clark Audio Expanse uses a passive filter to produce its bass shelf that would normally be impossible on an open-back planar-magnetic headphone. So it's not unheard of to use passive filters, but certainly not commonplace. I suppose people who use high-output-impedance amps on headphones with highly variable impedance curves are doing some passive filtering too.

It’s the only thing that matters to the guy who bought cheap headphones to EQ to match more expensive ones. And he thinks the guy who bought more expensive ones got ripped off or is an idiot.

Everything is FR but we don't have ways of interpret them and every headphone have their own unique FR, way of interacting with your face, ear. Then there is magnet, driver material etc which also shows itself fr graph but we don't understand it.

Technicalities exist to ear, not to measuring equipment. You can't EQ headphones to Utopia.

> that usually audiophiles love to describe it as: punch, slam, soundstage, resolution, separation, imaging, speed, decay, much more other.

That understanding of "technicalities" is very poorly defined and do not seem to have any correlation whatsoever with any measurable characteristic of the headphones. Chances are those are just figments of their imagination. Which is why nobody should take into account that kind of nebulous claims to make any purchase decision

> As I read again in comments somewhere, that usually impossible to recreate identical tuning, but I don't why and what science are behind it

The problem with headphones is that they sometimes create resonances (standing waves) that are very difficult to recreate with equalization and it would be futile to do so. Nevertheless, with the right measurement you can actually recreate the sound signature of any headphone, even if not identical.

Hifiman have almost identical tuning in most of their headphones but they sound quite different. Graph reading is just not the full picture as you said. It's a low resolution reading with a lot of cues we don't understand/interpret.

Pushing for thinner diaphragm, better material and stronger magnet, lighter and efficient overall design shouldn't be underestimated. Not every 20khz capable driver is same. I find ''technicalities'' proper term.

How much of Susvara's, LCD5's, electrostat's qualities come from acoustic design vs technology ? Susvara doesn't even have fancy CSD plot so i don't know how much acoustic treatment it got. We know how Audeze tried hard to get consistency with their thin planar development. A big headache for them, must yield some results in terms of ''technicalities''.

Thank you for elaborating. This was a good read.

They're from Dekoni audio. I would say that they improve details perception in the treble without any detriment to the bass or mid range. I should have the opportunity to listen to Utopia 2022 in a few weeks and I'm going to try to compare them to my Elex

What about IEMs? They are I suppose free from this resonances, so it's much easier to recreate identical tuning between similar sized/shaped IEM?

I think you may have just demonstrated your lack of understanding of how a driver works. I touched on it in the first post, so I'll begin where I left it. A transducer reproduces sound most accurately near it's resting state. This means that small amplitude vibrations are clean. The further away the diaphragm gets from the center, the less linear it gets and consequently the more the sound distorts. I think so far we are on the same page. So here's where your logic is failing - it's a fullrange driver. At the same time as it plays the lows that push it far from it's comfort zone, it simultaneously plays the highs, that are being reproduced in and out of that comfort zone. The small, high frequency vibrations are subjected to the same modulation of forces as the bass. This causes often audible distortion throughout the range.

The reason why opinions like the above circulate is because many people learn from basic theory and looking at graphs instead of using reasoning and insight. The distortion that you see in reviews is a so called THD or total harmonic distortion. Let's break down this cluster. HD or harmonic distortion is a measurement. It's not a physical property of a driver. It's an oversimplified measurement procedure that is older than sound reproduction itself. It wasn't adapted to your psychoacoustic model, and neither does it describe accurately the troubles of reproducing music. It is simply playing a SINGLE tone and seeing what other tones come out. Total HD is simply a way of presenting this data in even simpler form. No wonder you don't know how a headphone works, you're basing your knowledge on a simplification of an oversimplification. Real distortion test that's representative of sound quality is a multitone intermodulation torture test and a set of compression curves known from Klippel. There are plenty probably other flaws in your concept , but let's just stop and digest this. IMO the OP makes a great point. The basic measurements that we use dont fully describe sound quality. It may be enough for you, but that's just like your opinion, dude.

IEMs are not free from resonances but they are less prone to some resonances than most headphones.

Headphones create multiple sources of sound between the ear and the can, which can create more standing waves, out of phase cancelations and additions, etc. Some very sophisticated headphones got rid of this using acoustic meta-materials.

A good evidence of this is that the group delay for iems are usually much cleaner compared to headphones.

But resonances still exist with iems particularly at higher frequencies where the wave length is comparable to the length of the ear canal.

Nevertheless , if the measurement device is fairly accurate at higher frequencies then it would be easier replicate at least most of the sound signature, as long non-linear distortions are not significant.

Sadly, most measurements you find of the web were done with inferior couplers that make this task more difficult to do.

Hey that's cool. I'll check it out.

> multitone intermodulation torture test

I think you are missing the point here.

Even if it is true that the 'real and true' measurement for audible distortion is the 'multitone intermodulation torture test', absolutely nobody is using that to review headphones or iems to talk about 'technicalities' or 'sound quality' except perhaps for some obscure nerdy gnome in a cave.

Secondly, that 'multitone waterboarding test' is kinda silly because the overwhelming majority of the distortion is usually concentrated at very low frequencies, since that's where the drivers has to move more to displace air. That's where the non-linear distortions rear their ugly heads first. Something that can be more easily identified with a normal a total harmonic distortion measurement. If the transducer can't pass simple that test at decent loudness, I don't see what's the point to continue with more exotic tests.

> The basic measurements that we use don't fully describe sound quality

If people measure the headphone at 150db and is distorting like Death metal guitar of course that the frequency response is rather useless.

But if the traducer is not significantly distorted then I don't see what's the point that you are trying to convey here. If it matters then measure it and report at what level the distortion becomes audible. Then obviously, do not measure the frequency response when this is the case. Such a silly and moot point...

I feel like you didn't really read what I said and only implied an insult either to me or the OP with a malevolently worded ad populum. The fact that most people use THD instead of a more adequate form if measurement has nothing to do with your disdain and hateful view of this community. It's simply the easier thing to compare. THD is a standard, and Multitone tests are custom. You can't compare the results between different users who use different test procedures. The problem that I'm pointing at however is that you're not using THD for that. You use it to draw ignorant conclusions on working principles of transducers. Your reasoning only applies to multi way devices. A fullrange driver distorts in it's entire bandwidth. This is an obvious fact known to everyone who designs audio and a primary reason why it's worth to build multi way speakers. If a fullrange driver is playing bass, the vocals distort. That's just how it works. HD plots don't display that. Multitone tests do, because unlike HD, they were specifically designed for testing music reproduction.

Don't worry about it

lol got eem

Thank you so much for writing this out. This is what reddit is great for. Very interesting.

> Hifiman have almost identical tuning in most of their headphones

I think what's being said here is that they don't actually have the same tuning. They have the same general TREND of FR, but if you were able to get a good, accurate reading of them, there'd be a ton of differences that change the sound quite a bit.

Plus, our measurements past I think 10 khz aren't very accurate, if I recall. So it gets even worse once you start reaching the treble, which is where a LOT of detail is.

Just show that distortion is significant/audible beyond certain level, then do not measure/publish the frequency response beyond that level. At that point the whole discussion about "multitone intermodulation torture test " becomes utterly irrelevant to the frequency response . It is that simple.

True. I said the same thing.

Great response, just had to say your statement “a headphone is a lightbulb in a crumpled can” is perfect 😂 sincerely - a headphone designer after a long day.

To elaborate slightly about the tools the various “big guys” use, there are a handful of mathematical methods you can use to predict/understand what sorts of changes to make regarding the variables of headphones, but it is quite messy. And a lot of the more boutique headphone places follow the “pole a hole and see what happens” approach. - which isn’t a bad thing, just one of many design methodologies.

technicality exist but mostly we cant measure them and it subjective because it kinda differs between ear to ear

but stuff attack and decay exist and we can measure that by using impulse measurment or square wave measurement

however the rest is mostly material and aerodynamic science stuff

Please correct me if I’m wrong, but FR graphs are also not pinpoint representations, correct? My understanding is that they smooth out the sample data.

E.g. LCD-5. It’s darkness is one of the main reasons I got it. After owning a dozen headphones before it, I realized I preferred dark headphones.

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/u/oratory1990

Really nice explanation even if I can't quite visualize it or understand it perfectly.

So I don't understand the whole phase thing but the part about phase cancelation and consequent dips made me go "aha, I see" because I have AKG K371 and HD560S that both have notches where they get really quiet but also one side gets louder (K371 much worse though) and I can't fix it with EQ.

Let me give you another example. 58X and 660S have the same signature with very similar tuning and spatial qualities. 58X has just more bass and treble. But even if you EQd them to have the same FR, 660S would still sound miles better in terms of resolution and dynamics.

This is technically an incorrect statement since technicalities is FR since again on minimum phase devices it is the most important thing by far before we go into other aspects like distortion which even then don't seem to matter as much as is often assumed on audiophile circles.

Good example would be the Moondrop Chu which is often considered technically mediocre due to "low bass impact" (Which I guess is true since they are a bit light on the bass but eh) so people speculated it was due to high distortion in the drivers yet distortion on them is fairly excellent in practice even compared to much more expensive sets.

Now though whatever or not we can correctly define what (to an extent subjective too) aspects of the FR (And that's talking about FR at your own eardrums and not FR graphs too) constitute "technicalities" is another matter entirely and that's without mentioning subjective bias you add into the discussion that doesn't have anything to do with the inherent properties of the transducer like price for example.

Yeah but people like to seperate it. Makes things easier to talk about and review the more we brake things apart. Even if they’re related

You sound like someone that bought an expensive pair of headphones and is extremely sensitive to perceived criticism

Technicalities are perceived elements of sound that are all effected by the frequency response (some perhaps are mostly related to tuning) and likely no single measurement can capture any of them. Our brains translate the combination of various sound elements into musical elements so we talk of slam, soundstage, detail etc because those are what we care about and understand. People also mean vastly different things with the same words and differ in what is good or bad even if they mean the same thing. FR is a huge thing, bigger than the average hobbyist thinks I believe, but there are meaningful things beyond that. This is where I'm at for now.

from an engineer's perspective what would you say are the brands that actually seem to know what they're doing, contrary to a lot of the hype or otherwise?

No, just a phenomenon I’ve witnessed over the years on forums. One guy was convinced his little Chane home theater speakers must sound better than Wilson speakers because of EQ.

You are not alone. No one understands phase. I think Scott Hinson wrote an article on this, but I have yet to read it. Phase is a very abstract term that means time. But it's not time measured in arbitrary units like seconds, but in waves. A wave can have any propagation time so saying 0.5ms delay doesn't tell you much. However if you say "the length of 2khz wave, which is at the same time half the length of 1khz" then you can start imagining what that delay is going to do to your frequency response simply knowing how waves combine. As I said it's an abstract term and consequently we can apply it to different situations. For example phase cancellation suggests that there are two sources. One makes positive pressure, the other makes negative pressure and they end up working hard and achieving nothing. These two things can be anything. For example two halves of a diaphragm. Grab a sheet of paper and hold it flat in one hand. Move it up and down slowly. The paper should flex a little but generally move with your hand. The suspended part of your diaphragm is in phase with your hand. Now as you speed up, it starts to bend. At certain very specific pace, the end of this sheet will flap up when your hand goes down and vice versa. It'll be out of phase. When your hand makes positive pressure the suspended paper makes negative pressure. When these pressure regions propagate, they expand into each other and to a large degree cancel. Here your hand is driver's motor and the far end is diaphragms edge or suspension. Other examples of a phase issue can be waves bouncing back and forth between the driver and the back enclosure, effectively impeding it's movement. It can be some part of the enclosure ringing also out of phase with the driver. In these cases the propagated sound coming back is the second source. Phase issues are deeply connected with resonances. A resonance can be out of phase with it's energy source. Engineers often use that to their advantage for example Helmholtz resonator is a phase reversing device that is used to extend bass in a bass reflex enclosure. The air in the port is out of phase with the back of a driver inside the enclosure, consequently in phase with it's front. We like when this happens :) The last phase issue that comes to my mind is quite tricky. It comes from driver being relatively big to the wave that it makes. It's called directivity because it works in such a way that depending on the angle from which you listen to the speaker, it's frequency response will change. It will change because there will be travel distance differences between various points on the driver. The far part of the driver makes pressure that has to travel more to reach you and by the time it reaches the pressure from the close part of the driver, they are out of phase (on some specific frequency or frequencies). This is especially a problem on expensive headphones with big drivers. In speakers we fix that with so called phase plugs - obstacles that force selected parts of the wave to take longer paths.

Ignore them both- get Grados

Technicalities exist, and technicalities are what you should be looking for

FR graphs tell you the distribution of frequencies, ie. how loud each frequency is. Nothing more, nothing less. A frequency distribution you don't like can be fixed by EQ (though some devices degrade the audio quality after applying EQ), but you can't EQ your way into detail, timbre, imaging, speed, etc. Soundstage is the one thing where you can improve through EQing, but not by much. Material doesn't tell you any reliable information about the sound either.

The most important thing really, is to try the headphones yourself.

IMO, the utopia and 800s perform quite poorly (not just for the price), as with most headphones on the market. Two i really recommend trying are the Meze Empyrean and Susvara. Below that the Arya is decent for the price compared to other headphones, but is easily beat by IEMs at the same price.

Another thing to keep in mind for headphones is the DAC and amp, which makes a massive difference in sound. So much so that I wouldn't recommend buying anything unless you can try everything together at a shop

This is an interesting question. I was thinking for a while about it and came to conclusion that I haven't heard many headphones outside of the mainstream hifi. The ones that I've heard were way more deliberate that I could ever make them, except for Grado. The Grados I heard years ago were like hearing aid. I guess people with hearing impairment can have their hifi too.

Most pointless products that I bought however must be some multi-driver Chi-fi earphones. Really badly executed products from TRN and KZ. I keep them stored in hope that some day I'll retune them.

I was also disappointed with Shure. Not bad, not terrible, just uninteresting. You can see how many popular products in hifi were iterated even 10 times before reaching high status. Sennheiser is an example. I used to have their HD545 which was to a degree a precursor to HD600. You can see a clear direction of development there. They not only know what they are doing. They persisted for a long time. Same applies to KEF in the speaker world. Refinement takes time.

Most small manufacturers either make planar drivers, or use freeedge dynamic drivers found in Denon, Fostex and Creative. They're available online. You can have fun with them too and have a no-bullshit set of cans :)I'm personally happy with modded Fostex T40RP. Nothing too fancy, but gets the work done.

i'm here for those transients and psycho-acoustics. i want that "magic". otherwise i'd just get the cheapest pair of cans that can produce a harman curve and call it a day. nothing wrong with that either-- it's just not what i'm after.

That statement about the balance of frequency ranges vs simply boosting treble for detail is very interesting.

Using my Takstar Pro 82 as an example, these have an elevated and very peaky treble, they have a very zingy and sparkly treble that I perceived as very detailed back a few years ago when I was pretty new to the hobby, but it's so all over the place in the balance that it's the perfect example of "fake" detail in my collection nowadays.

Compared to my LCD-X and 400SE for example, which have a much lower overall level but smoother treble, the detail is not even close even though the Pro 82 has that zingy quality to it, it just sounds "wrong" and that fr range balance sounds like it could be a big contributor.

There's a term that one reviewer (Marcus at Headfonics) uses that I like very much, and that's "tonal contrast". In the reviews I was reading from him, he doesn't even use the term "detail". Elevated treble produces more tonal contrast, which the brain will easily pick up on (our vision is also highly dependent on visual contrast for object identification), and think it's detailed, because the contrast between tones is greater via the boosting of the harmonics. But more contrast doesn't really improve true detail retrieval, just like maxing out the contrast slider on your TV or monitor won't improve the detail that you get from that screen. Proper balance between colors is what produces good visual detail, and avoids colors being crushed.

The treble peaks on the Takstar (I had a HyperX Cloud which is based on that headphone) make certain types of sounds, like the trailing tones of cymbals and snare drums stand out with greater contrast (that sparkly sound), but when those tones are overemphasized, it starts to affect our ability to perceive other similar tones at the same time, so overall perceived detail suffers. I had an Audio Technica headphone that I modded with different earpads, and those headphones brought out cymbals like nothing else. Cymbals would cut through the mix, and if a song had cymbals or hi-hats, you would know that they were there. They were subjectively pleasing to me, but that emphasis on the air region in the upper treble would obscure details elsewhere in the treble.

Another great analogy with the visual one! That does make a lot of sense and I 100% agree with the assessment. Yeah the trailing tones getting overpowered seems to be my experience with peaky FRs as well.

I do also enjoy an airy treble subjectively and it is so incredibly hard to find a treble that sounds just right to me. Using the Dioko for example, very airy extended treble and it is detailed, but at certain points I do hear some obscuring of other treble details.

Thanks lots for the info!

> Imaging, resolution, dynamics, that's all part of what we experience. So I think it's fine to rate headphones by those metrics, because the experience is what matters. But I have yet to see any conclusive proof that those things are not influenced by FR in some way.

Are there any measurements at all for those properties? I haven't seen anything that does a reasonable job of quantifying them.

This is why back in the 90's people tried to make a smallest well tuned loudspeakers to hang over ear. ;P Bypass all the problems with having to deal with human imperfections.

> beyond certain level

At what frequency/frequencies?

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