Why Dynamic Drivers for Speakers/Headphones/IEMs?

Audio Science
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Thinking aloud.

I come from the professional music/audio side, working or volunteering as an audio engineer for live events, or in a studio.

In that world, it is de-facto, if you want a really accurate representation, you do not use a dynamic microphone. You get a condenser(aka capacitor) microphone, and if you want a really accurate representation, you use a small condenser microphone, and if you want a really really really accurate representation, you use a very very small condenser microphone, such as the ones used as measurement microphones. Such as is made by Earthworks.

I understand that dynamic microphones, while they have desirable subjective, creative advantages, accuracy is NOT one of them. Case in point, lots of Youtubers love the sound of the Shure SM7 or SM7B, cos it boosts the low end, in a manner that is warm and cuddly, delivering that radio ready voice. But this is NOT an accurate capture, however desirable.

I understand that dynamic microphones, typically do not capture high frequencies well, e.g. in the Shure SM58 or Shure SM57- the worlds most popular microphones, but definitely not because of their accurate capture of the source audio, more for their durability and the character they add to the source audio, which is deemed pleasing.

I understand that dynamic microphones, will NOT have the most linear transient response, cos of the mass of the diaphragm, which has some ā€œinertiaā€, so it takes a certain amount of energy to get it moving, therefore it ā€œignoresā€ low level details, such as reverberation in a room, and one has to speak fairly close to a dynamic microphone. Which is great, for use in a reverberant room, i.e, the features of a dynamic microphone, that limit its sensitivity, have become an advantage, for recording in certain kinds of environments, with lots of ambient noise or reverberation.

Thinking aloud.

Why then do we use such a driver - the dynamic one, in so many transducers, in speakers, headphones, IEMs, when we know this kind of driver has well known limitations?

What is the loudspeaker driver equivalent, of a condenser microphone, in the speaker/headphone/IEM world, which would confer on such a speaker, the same kind of accuracy we hear in a condenser microphone.

Apologies to anyone looking for measurements. I have none. I do hope you can see my dilemma .
Just thinking from 1st principles, in one area of audio, we avoid using dynamic transducers for recording, yet we embrace them in speakers/headphones and IEMs.

For example it is almost impossible that we would find anyone recording an orchestra with a dynamic microphone. So why are dynamic drivers, so common place, in audio reproduction, i.e. playback of audio, when we avoid their use, in the accurate capture of audio?

I have no measurements, only what I hear, and you are welcome to put me down, for the next thing I say below. Its an open world - free speech and all that.

Ever since I heard a planar magnetic IEM, the ARRTI T10, Iā€™ve been struggling to explain the marked improvement over every other device I have heard - speakers, headphones, IEMs. Every time I switch back to the ARTTI T10, itā€™s like - wow, this is different, when I compare its Frequency Response, with other IEMā€™s such as the Zero 2, not too dissimilar, but upon listening, the Zero 2 and every other dynamic IEM I own, just sounds congested, and unnatural, especially when listening to the human voice, and a choir - which was where I heard the most difference. My dynamic driver IEMā€™s sound artificial in comparison, when listening to the reproduction of human voices.

I mention human voices, cos thatā€™s what we know best. Our own voice, and the voice of other human beings. So easy to know when we hear a human voice on a loudspeaker, we can tell that is a reproduction, and not a real voice. For some reason, I am hoping to get to the bottom of, the ARTTI T10, with its planar technology, just sounded so much more true to life.

And it set me thinking. Is there an inherent problem with the dynamic driver technology, similar to its limitations, in use within microphones, such that ideally we should not be using dynamic drivers, in speakers/headphones/IEMs.

I am asking WHY? Hope I get some conclusive answers. Cos if there is something fundamentally limiting with a dynamic transducer, why do we use them, for accurate reproduction?

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Is this the standard plastic case T10 or the professional version which is metal cased?

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The one I have is the original T10 - Whiteish/Creamish colour shell - with brushed metal faceplate, not the T10 Pro which was released recently, with a full metal shell - painted black, with a brushed metal faceplate.

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Because my wife will not allow a pair of Magnapan 3.7i or larger in the living room.

I tried.

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So love your honest candid admission. Thankfully with the head worn devices, for those who listen to these, it appears that the Spouse Approval Factor, is less of a consideration., as the alternatives to dynamic drivers, do not have to be significantly uglier or much larger, than dynamics.

It also begs the question. If I can have a planar magnetic IEM, that is no larger than a dynamic driver IEM, why canā€™t we have desktop computer speakers which are 100% planar magnetic, or 100% electrostatic.

I admit for loud playback, the bass may need to be driven by a dynamic driver, for ergonomic reasons. but with small speakers, like a desktop, or small bookshelf, we should be able to have them as 100% made from non-dynamic drivers. These may already exist, and I just happen to not know about them.

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You can.

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My headphones- at least the major ones

ZMF Auteur Classic - Dynamic - spousal gift
Rosson RAD-0 ā€“ planar
Hive (Nectarsound) ā€“ E-stat
Hifiman HE-560 v2 ā€“ planar ā€“ spousal gift
GRADO RS1e ā€“ dynamic
Sennheiser HD-6xx ā€“ dynamic
STAX SR5n ā€“ E-stat

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Thank you.

Now that is impressive. Looks promising. I will find time soon enough to revisit the speaker options, which do not use dynamic drivers. I accept that in some cases, there may be the need to compromise with a low frequency dynamic driver.

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Thank you.

That is a wonderful collection, you have there. And in particular, each of your listed listening devices is NOT a hybrid, and uses only one driver, which makes for a good opportunity to compare based on driver type and you have at least 2 each of Dynamics, Planar, and E-Stats. So a really good sample set, I think.

Please would you compare the resolution, and perceived clarity, of these listening devices, and does the driver type, confer any correlation, to what you hear?

i.e if we attempt to take Frequency Response out of the equation, cos each manufacturer will have their own ā€œhouse soundā€, for each device, do they sound different. And if they sound different in perceived clarity and resolution, is there any relationship with the type of driver used.

I recognise that this is asking for a subjective opinion, but itā€™s an opportunity I would not wish to lose, to ask from someone who has a good collection of diversely driven listening devices.

Apologies to anyone who is bothered, that Iā€™m asking for a subjective opinion, in a section of this forum, where objectivity is the watchword - i.e the Technical Discussion section. One has to ask a subjective opinion, cos hitherto, I have not yet come across a conclusive objective measurement which can differentiate the result of transducers based on driver type. My hunch is, there is probably such a test, but I am not aware of it yet. Happy to be corrected if Iā€™m wrong.

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You can find this info on google, needless to say, the entire post and all of these assumptions are incorrect. Dynamic drivers are consistently the most natural sounding ones, theyā€™re not the least detailed either, an HD800s is going to put a planar Sundara or Maxwell in the dirt, detail-wise.

Iemā€™s are not headphones or speakers nor do they work the same, they are less detailed by nature. Planars like the Arti have a quick decay and lack transients.

You canā€™t compare microphones types to speakers and headphones, they are quite literally the opposite function.

In general man, this is all over the place, youā€™re connecting dots that donā€™t exist. If you want impressions between drivers, again, there are thousands of youtube videos and written impressions. I suggest you watch some videos on the difference between each type or read the ones that are already on this website:

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Nobody in this forum will be upset about a subjective opinion. Not even in the technical discussion section. Itā€™s hard to take FR out of the discussion, because particularly with my old STAX headphones, there isnā€™t much bass, certainly not much low bass. I can say that the e-stat headphones do stand out in terms of perceived clarity and resolution. They always have. I used the STAX since they were new in the 80s, often for chamber orchestra and small combos, both Jazz and classical. Iā€™ve always felt that I was there with them. Cymbals had proper air without being harsh or annoying. Timbre of horns and woodwinds always spot on - whether I was driving them from my old amplifier through the adapter, or now through a proper electrostatic headphone amp.

In their day, there wasnā€™t a lot that could compare with them, although for bass heavy music, they were not the optimum choice. The Nectar Hive is all-around a better e-stat, many have compared it to the STAX SR-007, which I have not heard. But there is that same clarity - a feeling that there is no driver, just a window to the performance.

I donā€™t know why, but I suspect that it is because in the e-stat, the entire thin membrane is acted on uniformly. Perhaps someone with more design experience could eulcidate. My understanding of Planars is that the membrane between magnets is integrated with very fine wires on the membrane. Therefore not only is there an electrical conneciton for the wires, but the vibrating membrane is less of a free uniform surface than on an electrostatic.

The ZMF Auteur Classic is an interesting case. I feel that it has the technicality and resolution equal to but different than an e-stat. However other things in my chain - like the OTL tube amp I use with the ZMF may influence my perception.

The ZMF does have a forcefulness and punch that I do not get from the others, particularly when listening to electronica (Yello), The other dynamics, like the GRADO have a similar earfeel but less so, probably becuase of the smaller driver (I think driver size is also a determanent of any sound of the driver in headphones, and even perhaps in IEMs like the Audeze LCDi3/4)ā€¦ The Senn HD6xx just sounds like a normal dynamic headphone to me. I would never mistake it for any more exotic driver.

Itā€™s hard to pick out what youā€™re asking for - Iā€™m trying. There are similarites in sound between the Hifiman HE-560 and the Rosson, with the Rosson just having more clarity. Itā€™s also newer, and has fewer hours. The Hifiman is notorius for driver degradation, but there is no visible issue with my pair. The planars, particularly the Rosson approach that driverless open window to the performance (I really canā€™t find other words to describe it) that I get with e-stats, but donā€™t quite ever get there.

Note that I donā€™t always, or even that often try to pay attention to the technical minutia of the headphones or the drivers. I pick them up to listen to music - or in the case of the Senn, lots of times to movies or video. I like the 6XX a lot for SciFi series on Disney+. Although the Hive is handy and convenient for that also.

Perhaps itā€™s driver mass. Perhaps it isnā€™t . Iā€™ve got plenty of power for all of my headphone listening, so Iā€™m not getting artifacts and muddy bass due to insufficent power on the drivers. I know that Iā€™m not listening to square waves, but I do think about those old charts and graphs showing many e-stats starting and stopping more precisely than more massive drivers.

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Thank you. Highly appreciated.

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Thanks for posting this article by Resolve. This was an interesting comment about the differences toward the end of his article, that seems to capture the quality that OK1 is referring to.

I think the answer to the question of which driver type sounds more realistic may instead come down to the question of whether ā€˜realisticā€™ entails ā€œspeakers in a roomā€, or the way we naturally hear sound in the world. If itā€™s the latter, then perhaps planar magnetic transducers do actually perform better.

There are ways of correlating the differences between the two techs via measurments though imo.

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For me itā€™s NOT speakers in a room I listen to a reasonable amount of live music. Thatā€™s what I mean about the open window to the performance.

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The speakers in a room analogy is also flawed in some ways, since headphones donā€™t generally share most of the temporal or distortion characteristics of the former.

I also donā€™t want to suggest that all dynamic headphones will have one sound and all planars another. Because Iā€™ve heard many different sounding DD headphones. I believe there are some general trends that can be discerned in the measurements of the two techs (DD & PMD) that are different though.

How the audio content you listen to was authored or mastered might also play into the question of perceived realism/naturalness/fidelity.

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Now this whole thing is turned on its head. I have been so enthusiastic about the difference I was hearing in my ARRTI T10ā€™s which are planar magnetic, over every other listening device I own, which use dynamic driver.

I just received a single dynamic driver IEM - the KZ SAGA, and after a few hours listening, it has upset the apple cart.

It sounds so much more revealing than any other dynamic IEM I own, and even better than my cherished ARTTI T10.

So I who started this thread, have to go back to the drawing board, and based on what I have been hearing state, there does not seem to be any relationship between driver and perceived sonic quality/accuracy.

The KZ SAGA - mine is the balanced version, caveat, with third party eartips - the TRI Clarions, and a bit of EQ( High shelf rolloff, this is not essential - just needed to shave off a bit of brightness to my personal taste).

The SAGA sounds more precise, accurate, and true, voices are the most natural I have ever heard., spoken voice in particular, I could write a thousand words about the improvement in sound quality. Definitely worth getting. Cost $15 to $20, depending on where you buy, and sale discount available.

There is a SAGA Bass Version. Probably best to buy both, and see which you prefer, to avoid the need to EQ. Or depending on oneā€™s mood, or listening intention, switch between the SAGA Bass version and the Balanced version, on the day.

Obviously my sample size of IEMā€™s is pretty small, but at this time, I can conclude, its clearly more about the implementation. I.e within the budget range of IEMā€™s I own, it is possible for a single dynamic driver IEM, to sound even better than a celebrated planar magnetic IEM, which has received so many accolades from many online reviewers, whose opinions I respect.

It still begs the question, what measurements could one examine to correlate with this perception I just described? For now, Iā€™ll conclude that the best method we have at this time, is trial and error. We have to try them for ourselves, and ideally also own them also, so we can do our own listening comparisons. I do find the frequency responses graphs very useful, cos they correlate to the frequency response I hear. But definitely FR has, in my limited opinion and experience, has no correlation with the perception of clarity, detail, resolution, transient response, that I am aware of, at this time.

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If you are dwelling in the budget and mainstream consumer product tier, you will hear budget performance and serious compromises. Many vendors truly sort products by price. While some flagship models are wildly overpriced and still have flaws, they will open your ears about what is possible.

I recommend that you go to an audio show or local store to demo stuff in the middle and upper price bands. There are plenty of relative value items out there, but budget products remain budget products.

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That has to be a plan, to visit some stores or attend local events where I can audition more products. For now, no more buying. In particular, must pause IEM purchases. They are so dependent on the eartips, stock or otherwise, so thatā€™s two things one has to be bothered with, getting a good IEM, and also in some cases, where the stock eartips do not match my listening preference or provide a proper seal, thats a second issue to worry about and solve.

Headphones also have ear pad variations, and can be changed, and do alter the FR, but thinking I may at some point in time revisit. Over the Ear headphones. Right now, Iā€™m extremely pleased with the KZ SAGA _+ TRI Clarion eartips + some hgh frequency attenuation via EQ + making sure I push the tips in properly to get a good seal. Thankfully the end result is very comfortable, no pain whatsoever in the ear canal, and the sonic result is like I have never heard before. Happy quite happy.

Famous last words

But seriously, What Iā€™m hearing now is a massive departure from anything, Iā€™ve heard before.

Thanks.

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I donā€™t use or listen to IEMs, so my knowledge of them is limited. It may be that you need a little more experience with different techs and headphones though before forming conclusions about them. :slight_smile: Thatā€™s nuthin to be ashamed or embarassed about. Everbody starts somewhere in this hobby. And you seem to have some other experiences working with audio, to draw on in forming your opinions, which can also be helpful in some ways.

There are some measureable differences in the distortion and frequency response characteristics of dynamic and planar magnetic driver headphones, generally speaking. This was especially true when planars first started gaining some prominence, some 10 or so years ago.

Both techs keep improving though. So we now have some open dynamic headphones with better extension in the bass. And we now have planars with more neutrally tuned upper mids and ear gain.

My first real teacher on headphones and the technology behind them was Tyll Hertsens. You can still find most of Tyllā€™s articles and reviews for Inner Fidelity hereā€¦

https://www.stereophile.com/writer/15081

And his YouTube reviews hereā€¦

Tyll often went into the differences between different driver technologies in his reviews and articles. And he also did some lectures on headphone measurements for AXPONA which are also available on YouTube.

There are also differences in the distortion characteristics of the two techs. This is not true in all cases, and very dependent on the designs, but open-back planars magnetics have generally been lower in distortion across the board, and especially in the lower frequencies than open dynamic headphones.

Iā€™m less sure about this, but I suspect that planars are also (generally) less susceptible to modal breakup. This depends on the materials and design though of the driver and diaphragm. And the higher quality materials used in some more advanced dynamic headphones are probably much less susceptible to this issue than the plastic/polyester drivers used in some cheaper dynamic headphones. Corners can be cut in both techs though, and both can have better or poorer sound quality as a result.

The other big difference between the two techs is the shape of the diaphragm. As their name implies, the diaphragms in planar magnetics are a flat plane. Whereas most dynamic drivers are more dome-shaped, or employ variations on this type of shape. I think most feel that a flat plane is superior from the standpoint of distortion. And that is probably reflected in the distortion measurements. Most loudspeakers (as you know) use domes/cones though. So not flat planar drivers.

There are also some differences in the general distortion levels/characteristics of different types of transducers. Generally speaking, IEMs should have the lowest distortion. And loudspeakers should have the highest distortion. While the over and on-ear headphones should come in somewhere in between. When I refer to ā€œdistortionā€ in this context, I am of course referring primarily to the nonlinear variety.

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I know youā€™re not convinced at all for some reason, but run a 4000-16000hz sweep at 20 seconds http://owliophile.com/

Try that with all your headphones and IEMs. Note where each have different peaks and valleys, often times very dramatic and at very different frequencies.

After hearing that I think youā€™ll gain a new appreciation on why some of them could sound so different, even if they use the same, or different driver technology and are at vastly different price points.

EQing or not to flatten those frequencies is up to you, but at least give it a listen and write down the differences you hear.

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