Why Dynamic Drivers for Speakers/Headphones/IEMs?

Technical Discussion
21

I don’t know if this has relevance to IEMs. But there is another difference between the planar magnetic and dynamic drivers in some headphones that’s probably also worth noting. Some moving coil dynamic drivers will have a more flexible surround, and a more rigid diaphragm, like on a loudspeaker. While others will have a fixed edge, so the diaphragm literally flexes and distorts its shape as the coil moves.

I’m not up on all the very latest dynamic driver techs used in headphones, but I think most of the better dynamic drivers probably use a more rigid diaphragm, with either a flexible surround, or some variation of this general idea.

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22

Appreciated.

Another member here had also pointed me to this frequency response “test” web site, which you mention.

Planning to devote time for this, in a few weeks, from now, when I have more time to give it my full attention.

I read this earlier today(thanks to a post earlier), and it did make me wonder how significant driver technology is, in the grand scheme of things. Kind of like - diesel vs petrol vs electric, where at the end of the day, there is no real winner, each having their own unique advantages. Cos there is good and not so good implementations of each of these approaches.

One question one may not be able to answer, even if there is a measurable difference between some intrinsic behaviour of different driver technologies, is, is it audible, or rather how audibly distinguishable is it. For example two DAC are measurably different, but beyond a certain threshold of good quality, the difference in DAC’s becomes academic/subjective, partly aso because. if one is listening in the real world, with ambient noise, such differences between DAC, if they were audible in an anechoic chamber, become even more difficult to distinguish in real life.

From what I have observed, which is of course limited, in the evolution of dynamic drivers, from the KZ business (Knowledge Zenith), over a few recent years, as I have bought a number of their IEMs, all single dynamic drivers, here’s my own opinion, from what I have heard.

  1. Especially for IEMs, there are other factors which play their own part.
  2. Over the years, one can clearly hear the improvement in sound quality, from one product to another., as they improve whatever it is, that makes it sound good.
  3. There may also be a relationship between with the kind of shell used in the IEM, plastic vs metal rigid shell. The metal shell products seem to sound more accurate to my ears, of course this can be placebo, cos I’m not measuring. I do recall there’s a maker of professional studio speakers - Genelec whose casings are metal, to reduce resonances.
  4. So here’s this KZ manufacturer, in their single DD IEMs, improving something, and one of their more recent single DD IEM’s, the SAGA, just sounds really good to my ears., definitely better and more natural than previous products.
  5. Therefore, it may be - not so much an issue of the driver type, but the quality of implementation, whatever the driver type.
  6. Meaning that the only way one could tell if there was a difference, is certainly NOT at the budget end, but at the top end of the market, comparing the very best Dynamic Driver implementation, with the very best of other kinds of drivers.

So at the budget end, which is where I am likely to remain, for a while, in my interest in speakers/IEMs/Headphones, for my use case, the driver type used, at the budget end of things, may not be that relevant, cos there are so many other things to take into consideration.

In the case of IEMs, my current interest, these factors would be, eartips, fit in the ear, potential for resonances of one kind or another - due to kind of shell used, as well as the quality of implementation of whatever driver design was chosen, and the driver type itself, may no longer be that significant a factor, especially at the budget end.

So answering my own original question, based on information recently gathered, the answer may be - It depends, on how good the driver implementation is, rather than just driver type as a factor.

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23

Thanks. Lots to think about.

From all the info, at this time, I consider that, there has to be an - it depends. Especially in the budget category,

The type of driver used, in the budget category, may not matter that much, if one is not getting the best implementation of the driver type. i.e while it is an interest titbit, for marketing and product feature lists, it may be far more important to assess the device by its results, rather than assume that the driver type confers on it any advantage, cos all manner of corners may have been cut, in the budget range, to fit the product to a price bracket.

So for the foreseeable future, I’ll ignore driver type, when I’m buying budget gear, and focus more on - exactly how good/transparent does it sound to me, cos especially in the budget category, driver type is more unlikely to have any material correlation with audio quality - real or perceived.

Ultimately I have to now focus on - how does it sound, i.e listen for myself, more than anything else.

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24

Nah, it depends - period. I’ve tried all kinds of super expensive IEMs while I was at e-earphones in Tokyo, they’ve got all kinds of stuff from $20-$2000 for demo. I simply didn’t find any consistency in “audio quality” vs price. All kinds of stuff between $500-$2000 sounded really bad to me, and of course a few sounded excellent. But even at the sub $50 range my impressions were the same. A few sounded great and a few sounded borderline horrible. I didn’t find any consistency between having DD, BA, Planar, and multiple drivers. I was listening very hard for “detail” “dynamics” “sound stage”. Yes there are vast differences, but no I honestly didn’t feel like the more expensive products were categorically better.

I did find some correlation between price and IEMs. The more expensive ones are shinier, have more bling, usually made of better feeling materials, often are too heavy. My favorite ones were $20, 100, and $300.

I purposely didn’t name any of the products because I find that insertion depth and tip choice makes a huge difference in how IEMs sound to each person, and my impression will almost certainly not be applicable to yours.

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25

To dovetail on what Luke said, there are generalities that can be said about different techs. But they are just generalities that are certainly not always applicable. And you can probably find both good and bad implementations of all different techs at every price point.

It is also true that higher price points may give you access to some better materials, workmanship, QC, driver matching, build quality, etc. And in some cases, also better objective performance, based on measurements. If it doesn’t please your ears though, then it’s probably not worth the expense. So yes, I am also a big believer in listening and doing your own comparisons. Especially, when the comparisons can be done side-by-side, over shorter time spans.

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26

Thank you ever so much. Highly appreciated. Just what I needed. I concur on the points you made about tip choice and fit, from my own limited experience. Changing tips and getting the fit right, really improved the sound of every single IEM, I have used.

The one I sometimes forget, is the IEM insertion approach of extending the ear canal opening by opening the mouth like saying an Arrrrgh, inserting the IEM tip, then closing the mouth and the ear canal closes and clamps down on the tip. Such a simple technique, I learnt from a video, when I 1st got into IEMs, which I sometimes forget to use, but tried it again today on an eartip that was a bit loose, and after this, perfect fit, and best sound ever.

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27

100%. Thanks. Nothing like doing one’s own audition. Insightful.

28

One of the topics mentioned here was positional variation. I was aware of this from experience with headphones, moving them back and forward on my head, just did not figure out how much this applies to IEMs. So pretty much each time you put in an IEM, there is every chance that the sound will vary, and even while in the ear, as the IEM moves, the sound will change. also based on slight changes in the fit.

So much to learn, watched this today, never knew about a resonance based on the length of the ear canal, which I would interprete to be, the distance from the IEM to the ear drum. Makes sense, just like room modes with speakers. Just never occured to me that such was a thing with head worn devices.

Here was I concerned about driver types, when there are far more important issues, that are common to every single IEM, no matter what type of driver is used. The one that really shocks me is how eartip changes can make such a massive difference. And of course each eartip/IEM combination changes this distance. I’m hearing such massive differences between eartips, on the same IEM. There is an IEM, that I just got, and it has really impressed me - the KZ SAGA - Balanced version. But changing eartips on this IEM, results in such a huge difference in the frequency response and soundstage.

Amazing. More to think about. Interesting. Maybe one day there will be IEM’s which solve these problems by clamping somewhere firmly on part of the anatomy of the head, which will not move, and then we can adjust the fit precisely, with some sort of knobs, that set the position so accurately, that there is very little variation, from day to day. in how we hear the IEM. Hard to think of what the solution is, cos our heads have so many soft and squishy things and floppy on the outside, such as skin and hair that I cannot think of how one could securely fix something in place, every single time. Accurate to within 1 milimeter, or less. Nevertheless a nice problem to have, Hope someone solves this soon. - Constant distance from IEM to ear canal.

Then the second solution will be a way to establish the best seal for the airlock, having set the distance from IEM drivers to ear drum - at the most favorable distance, without changing the distance from the ear. A Universal eartip. that expands, to fit any size of ear canal. Wonderful, We can only dream.

Current practice with eartips, each one changes the distance from driver to ear drum, so even if you were to be able to identify the resonant frequency and deal with it by EQ or modding the IEM, in some way or DSP, you’d have to do measure that resonant frequency, each day, cos it changes.

Of course I’m speaking of - off the shelf IEM’s and - off the shelf ear tips.

Can imagine that maybe custom eartips, could deal both problems, of better airlock, and consistent distance from eardrum, by :

  1. Having a more predictable seal mechanism, cos of the individual moulding which would have a better fit, and placement of the IEM/Nozzle/tips, etc in/on the custom mould.

  2. Be able to work with the customer to identify the ideal distance from drivers to eardrum, and adhere to this distance, when placing drivers in the IEM.

So with enough money, and a supportive custom IEM business, which understood these issues well, this could be a non issue, cos by custom design, everything is set to perfection when the IEM is custom made, and due to the much better fit, the risk of some of the variation issues discussed earlier are minimized. Interesting.

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29

custom molded IEMs can help in this aspect.

Give it a try with a slow sweep and you’ll see how correct you are in this assumption for your own ears and tips. Like you’ve experienced, sometimes theory and practice are similar, sometimes not.

Even on headphones, some of them (especially closed backs) are quite sensitive to positioning due to minor changes in seal, and the wave interactions within the cup and the ear changes a few hundred hertz or +/- 6db… it can be pretty wild. Some headphones are much less sensitive in that regard, but it’s not always true that open backs are better either.

Obviously despite the variations in theory, in your experience some IEMs sound better than others consistently. So as much as the variations in fit and seal can change, it might not be dramatic or dynamic enough to conclude that it’s random or that EQ can’t be helpful.

You’ve made some great observations, I look forward to hearing what else you’ve learned and come across so I could also learn from your experiences.

30

Was watching the following podcast, and Brent B. mentioned another difference between dynamic and planar mag headphones I’d forgotten. Planar headphones tend to have a flat impedance response, whereas the impedance in most dynamic headphones tends to vary somewhat with frequency. This matters because the headphone’s impedance curve interacts with frequency, expecially when using a higher impedance amp. The video below is cued to this question.

31

Tired of planar, dynamic. You need to try some decent electrostatics.

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32

I’m willing to try one, but not own one. :slight_smile:

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33

I’d love to. Just have not found any in the sub $200 price bracket. And you need a dedicated headphone amp., which also costs extra. So main reason I have not heard or bought one, is cost.

Most stores where I could audition one, are a few hours travel away, so I tend to limit myself to buying and trying, and stick to the more well known, widely accepted favourites. Albeit I did take a bit of a risk buying an ARTTI T10, which paid off - great find. Sounds even better with Moondrop SPRING XL’s if you have larger ear canals. Must say, I am pretty pretty happy at this time, with the change of tips from the stock ones, to these, am extremely satisfied. So satisfied, I do not think they need any EQ. Balanced, detailed, and I think a very good representation of whatever I’m listening to, with nothing that say - this needs EQ. Amazing I no longer use EQ. I may play around with some, when I have a lot of time at hand, but feel zero need to EQ. This is the 1st time, I’ve experienced that with any listening device.

So main issue with electrostatics is cost. Hopefully the same thing that’s happening with planars, where finally we have good affordable one’s in the market, and IEM’s sub $100, which are very good, will happen to electrostatics, someday.

In the interim, I can with a whole heart recommend the ARTTI T10, and encourage the buyer to reserve about $30 to $40 to acquire a variety of tips, including the Moondrop SPRINGS, in a variety of sizes, to try out and see which of these improves the T10 sound, even more than the stock. The stocks sound OK, but the Moondrop SPRINGS, take it to a whole new level. I received my SPRINGS yesterday, and it is a whole new experience.

I hate to make this anecdotal comparison, but it reminds me of singing into a condenser microphone, compared to a dynamic, when I compare it with the 7 other dynamic IEM’s I own. Instant improvement in detail, and especially on the SPRINGS tips, this occurs with frequency extension at the bottom and top, with no added sibilance. Great combination.

Would definitely like to do the same “experiment” that led me to the T10, with an affordable electrostatic IEM. If I can find one.

34

With hobbies it’s not how much you pay, but how much you can sell things for. Quite a few hobbyists buy stuff used, be it cars, watches, pens, knives, headphones, glassware, or dolls. If the used market is stable and the product doesn’t break, you can often get out for a 10% loss. Some of us actually made money when selling used items during the lockdowns too – there were lots of bored people with money to burn.

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35

Wow, this is something I never thought of, profiting from the items by selling. Just never occured. I do see your point. Interesting angle. Food for thought.

I’ll be honest, my primary interest is to hear audio at the highest quality possible, within what I can afford. The profit for me would come from my work, using the products in my profession, as a musician, music curator and audio engineer, to deliver the best value to my clients, by being able to hear better than others, in a similar position, cos I’m using better listening techniques, and better gear - within budget.

I engineer for a church, (audio), and last Sunday, I spent some time listening to the end result of my “work”, and it was the best feeling ever. Even if I say so myself, the sound was spectacular, every vocal, and instrument super clear and super audible, and allowed the singers and musicians and preachers to do their thing, effortlessly. The guitar player was beaming from ear to ear, as he left the church at the end of the meeting, obviously pleased with the sound of his guitar, which I had “worked on” a few weeks earlier, and taken it to another level of effortless clarity - lovely acoustic guitar tone.

And having a really good listening device, the ARTTI T10, was a major part of that achievement, cos I use it to check and “tune” solo channels on the mixing desk, or monitor the broadcast mix through it., cos I’m working in an open space, next to the congregation sitting area.

That’s my immediate objective with the interest in headworn devices and speakers. Really good sound. For me and others.

I went through decades of not being able to have this quality of listening, and just so glad it has now become affordable, not just for me, but for many others.

Next frontier would be to influence those in my community and sphere of influence, from what I have learned, to choose and buy the best listening devices, within their budget, and this adds to their enjoyment of life. I feel this is a missed opportunity, every human being (well almost all) have been blessed with hearing, and lots of us have good hearing.

Simply being able to hear recorded and broadcast or live music (such as a musician who uses in ear monitors to hear themselves play - without speakers on stage), and hear it properly, with good clarity, should be a universal human right.

Through good folks @ various sites, AudioScienceReview and Headphones.com, and reviewers on Youtube, I’ve through a rather tortuous journey, eventually arrived at a highly resolving listening chain, 13 months it took. Cos there are so many conflicting opinions, to sift through. Would be great if this hobby/passion led to millions finally being able to hear the music/audio with the kind of clarity that improves their quality of life, without having to spend too much money. If I could make money by enabling that to happen great, nice bonus.

Right now - listening to tracks in my playlists, e.g What’s going on - Marvin Gaye - music I’ve heard for at least 40 years, more like 45, but that music is older like 55 years old, and saying to myself - so this is what it is supposed to sound like. Awesome. And I wonder did Marvin Gaye himself ever hear his own music, with the clarity I am now able to have. Cos there has been so much improvement in transducers. That’s ample profit for me. Simply being able to HEAR, is such a blessing, and to hear well, via a highly resolving device chain - Nirvana.

So much great music has been made, and now we have the opportunity to hear it even better than those who created it. Cos we have better speakers, better headphones, and now IEMs that are also quite good, in my opinion. Good hearing should not be the preserve of the well heeled with deeper pockets - I sincerely hope.

36

May I say a huge public thank you to Luke, who pointed me in the direction of this tool, a few weeks ago. But I was so busy with other things, I only got round to trying it out today.

My take is this, it all adds up, every single refinement one makes, from the quality of the source audio itself, to the DAC, headphone amps, decent (note - I did not say esoteric) cables, the listening devices chosen, choice of eartips, placement, playing audio at the right level, etc, etc.

I did not get too far with the use of the tool, it has many options and I only used a few, but this helped me identify a few areas in my listening which could benefit from an EQ adjustment. I ended up implementing only 3 filters in my DAW (playback app), not too precisely, but somewhat close to the EQ I had derived in the owl tool.

End result, there seems to be a “scratchiness”/sibilance at various points in my listening, one as low as 1 Khz which needed improvement, and it is a welcome improvement. Vocals are more forward, and the front to back image is improved. Like a veil/film or smokescreen or dust has been lifted. Vocals more natural. Intelligibility improved, music is now massive like I’m right there in the hall, with every element of the music. Right there with the vocalist, Definitely an improvement.

A very real improvement. that removes any residual listening fatigue, cos now I can listen a few dB louder, actually I am encouraged to listen a bit louder, which is a good sign in my book, means that there is less “distortion” in the audio chain. It will take me too long to explain, but in audio distortion gives an impression of loudness and tells us to stop increasing the volume. With some “distortion” removed, I have a few more dB of headroom, to push the level, cos I am no longer hearing the “distortion” that would have told me - this is loud.

In another few weeks, or months, I’ll try and see how much further I could take this.

I definitely think this approach has value, and hope it continues to be improved upon, especially made easier to use. This tool is definitely NOT for everyone, most people do NOT have the patience or time, to devote 30 minutes or more to identify their own EQ corrections, and another hour or more to run through test songs to discover if the correction works.

The EQ I manually derived in my DAW, from the EQ which I defined in the owl web site., is active, and I think I’ll keep it active, Wow, now everthing has a deep, wide and far image, and special mention goes to live strings. In every song with live strings, all of a sudden I’m hearing them, Where have the been before - buried?

What more can I say?. Luke - Thanks a million. Thanks indeed.

This works for me. Wow strings sound like I have never heard them before, on songs that I never recal hearing strings, I’m hearing them and in place - typically at the back of the “hall”, on pop music - like Whitney Houston’s last album. In the past I did not hear these strings, they obviously were there, I just did not hear them.

Very nice.

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37

You’re welcome, the tool for others who weren’t following is owliophile.com, basically a more sophisticated version of a tone generator/sweep generator with built in PEQ.

That is also what I realized after using a manual tone sweep tool, especially one like owliophile which allows you to drag on the graph back and forth and easily identify and mark peaks in the frequency response. Something about those sharper spikes always make sound scratchy/dry feeling.

I’m quite curious to what you’ll find (or even more interestingly, NOT find) with your other IEMs. In my experience, the ones that happen to sound amazing out of the box usually have fewer spikes for my own ears.

Also curious to hear what you think when you’ve largely eliminated the spikes on your different IEMs, that would make it easier for you to hear the difference (if it exists) between Planar and Dynamic drivers.

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38

I have come to a conclusion on other IEMs and headphones I have - which are all dynamic single driver affairs, not worth the effort. At this time I can no longer recommend any of them to anyone. No more. The minimum quality any human being should be listening to - is something like the ARTTI T10(with non stock tips such as the Moondrop SPRING), or better. If they cannot afford teh T10, the compromise would be the KZ PRX, which is also a planar magnetic, but the cost saving is only about $30. We live only once, that extra $30 is worth the investment so one can enjoy the ears God gave us.

What’s the point in saving money to feed our ears with quality that is far below their ability to resolve detail. We would not wear blurred spectacles, so why do we put up with this rubbish when it comes to dynamic driver devices, in the budget category. Now I have “seen the light”, I am cross, really cross. These cheap budget dynamic driver devices should be banned, they are unfit for human use.

I am also cross with lots of reviewers, who entice us to buy budget dynamic IEMs. Never again, now that I have heard better.

39

Just discovered there is a huge used market on ebay for headphones, iems and speakers - actually all kinds of audio gear. Interesting. Not that I am likely to want to sell anything I have bought, cos I generally only buy what I need, but good to know.

Which supports anyone who may be interested in disposing of surplus assets, or profiting from a marketplace demand, for what they own.

40

There are other specialty used audio sites too. Cannot cite now, as I’m on mobile.

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