Planar Magnetic IEMS - An emerging segment?

Hi everyone! I am new here in the community and I am from a startup called Danico Labs from Singapore. We are newcomers to Planar Magnetic IEMS segment.

Recently, been quite some interest in this area with models such as the Unique melody ME1 and RHA CL2. There are even new technologies such as planamic IEMS from MEE and magnetostatic IEMS from Earbridge. Has anyone auditioned them and what is your experience with these planar magnetic IEMS?

Also, if anyone is interested in the engineering aspect/challenges of these, ask away. I can offer up some of my humble experience in the area. I am not an expert in any sense, but do have experience in developing a planar magnetic IEM for my company.

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I’m curious as to the technical point of (i.e. benefits or reasoning for) using a planar-magnetic driver in something with a driver as small as that would feature in an IEM.

I get that, with large drivers, the idea is that having the motive force for the driver be active over the vast majority of the driver area leads to the driver acting more like a perfect piston, reducing smearing, blurring, and other distortions that would otherwise arise from break-up modes as the surface of the driver deforms under acceleration.

That would be a much smaller problem in the relatively tiny drivers (8-10mm seems common for IEMs with a dynamic driver in them). It’d be interesting to know, if that’s part of the rationale, how much of a difference in distortion performance, at audio-relevant frequencies, there is.

I know there are also benefits in terms of linear impedance/frequency response. And a single driver avoids coherence, crossover, phase and other issues, but that’s true for a dynamic driver IEM as well.

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I did a review of the RHA CL2 recently: https://www.youtube.com/watch?v=Yv5pVlN-Suo

I was fortunate enough to be on the review tour. I think generally there’s promise with this tech in IEMs, as was demonstrated by the performance (speed and resolution), but it’s likely that implementing it still poses some challenges, given the constraints of a closed shell-design that’s ideal for IEMs. The tuning of these is way off. There’s a 3-5khz peak that both sounds and measures poorly and hopefully that’s not deliberate, but rather a limitation of the tech. I know that other planar IEMs have similar issues, so I’m willing to give RHA the benefit of the doubt here.

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I’ve owned the iSine 10 and now own the Unique Melody ME1. I really do think they sound better than my favorite BA/Dynamic IEMs and have a good clean sound that is easier to work with EQ if needed than the other types.

I’ve since reshelled my ME1 to be a custom IEM and that’s been extremely great for me. I use them quite often at work and occasionally at home. I am definitely interested in this market segment, but have yet to try the CL2. Some of my more trusted reviewers werent so happy with it and looking at the FR curves, I can see why.

I’m pretty curious as to how some of the low budget Planar IEMs sound - e.g. the Senfer and Toneking models that came out recently.

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@Torq That is a really interesting point and I have to agree with you on that. From a standpoint on scaling down these drivers, when we look at the X and Y dimensions being reduced, we can expect that the stiffness of the membranes increases as the driver becomes smaller. In a sense, the dynamic driver does become like a piston as you have mentioned. However, another aspect which has to be considered is the shape of the dynamic driver, which is normally a “cone” shape. As the stiffness of the membrane increases, the more “cone-like” the driver also becomes, possibly introducing distortion to the sound. In a full sized driver, this cone effect is not as significant, as the membrane is relatively flexible in comparison to the size of the driver. Of course, the membrane can be made thinner in a dynamic driver, but there is a limit to how thin it can go before it starts deforming under its own, or the weight of the coil attached, as there is relatively little tension to the membrane. The sound produced by a cone vibrating would not be the same as that of a planar membrane. Our philosophy is to use a planar membrane without any additional surface geometry in order to produce sound that is as distortion free as possible. However, I would have to admit that we don’t have enough data as of yet to conclusively prove performance superiority and… this is a new driver we are developing as well, so there is still finetuning to be done. Now that you have mentioned this, it will definitely be on my to do list, for a head to head comparison of the existing drivers vs a planar IEM driver.

@Resolve Yes that is a good observation and these “peaks” are one of the challenges which we have faced in the engineering of our own planar IEM driver. Similar as to what I have mentioned above, when scaling down these drivers, the tension across the membrane also increases and the dampening characteristics of the driver also changes. This is because not only the membrane, but the effect of the frame on the membrane is also intensified when the driver is made smaller. Simply put, these drivers will become “over dampened” as compared to their full sized counterparts. What we have observed is that, we are not hearing a 3-5 Khz peak for example, but rather all the other frequencies have been dampened such that the 3-5 Khz region becomes revealed a “peak”. Therefore, in my humble opinion, chasing ways to reduce these peaks is chasing the wrong approach. Rather, the solution is to look into ways to relieve this tensioning and dampening issue… which is the philosophy that I have adopted and I am looking into ways in which to reduce this dampening issue so as to have a sound signature without harsh peaks. I think that planar IEM tech is still in its beginning stages and definitely more can be done to improve it.

@antdroid I am a planar lover myself and I am really happy to hear that there is more interest in this area and more companies throwing their hat into the game. Being located in Singapore, I have heard of Senfer and Toneking (but not yet have the pleasure of testing them). One thing that strikes me is that these designs are still open and semi-open, meaning that there will be an element of outside noise disrupting your listening experience. As a personal preference, I do like closed IEMs more (maybe because Singapore is a really crowded place…) and hope that more closed planar IEMs do get developed. It is for this reason that the IEMs we are developing are also closed planars. Of course, the closed design does bring about many other challenges.

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Hi @DanicoLabs , having owned the iSine 20’s I felt that being open gave that sense of for want of another word ‘openness’ which was one of its strengths IMHO. However with this came with the drawback of leaking sound and letting in a lot of outside noise. A few people I have spoken to equate planar iem’s with this open and expansive sound. Perhaps this is down to what has been on the market already. Won’t this be lost if it’s a closed back iem? What are the sonic benefits with going for closed rather than open planar iem’s?

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@prfallon69 Yes, this is indeed a good point. Presently, most of the offerings (if not all except, RHA) feature Planar Magnetic drivers using an open configuration. In my personal opinion, there is a difference between the experience of “airiness” and that of soundstage. I think that most people equate planar magnetics with spacious sound rather than it being exclusively being used in an open configuration. I believe it is still possible to achieve a wide soundstage in a closed configuration. What is lost instead, is the feeling of “airiness”. As a design philosophy, we do not want to loose the soundstage that is characteristic of planar IEMs and this is what we hope to achieve in the engineering of our IEMs. To do this, there are many things we can do in the design of the IEM, such as careful selection of chamber materials, shape, sound pathway, driver angle, etc.

In terms of the benefits of going for a closed design… First, we can achieve greater sonic clarity as well as driving efficiency, which is due to the isolation provided. Smaller planar magnetic drivers do not move as much air as that of the larger drivers of the iSine 20 (although there are tweaks can be done to improve this, but there is a limit). Secondly, the closed design allows us to accentuate certain frequencies in which planar magnetics are traditionally weak in, by playing with the materials and dampening of other frequencies. This provides a better listening experience when done in moderation.

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I’ve got to wholeheartedly agree with everything that you say. With regards to retaining Clarity and Soundstage. I am aware that there will be trade off’s when making something Closed back as oppose to Open back. I suppose the the hardest thing that designers and engineers have to do is to develop a Planar Magnetic Iem that still retains the great Planar sound but in iem form. Thanks for your feedback anyhow.:grin::+1:

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@prfallon69 I hope that we are the ones who are able to get that magic formula of planar sound in IEM form :smiley: By the way, when using the iSine 20, did you happen to run them single ended or balanced? In my experience, the sound in planars is really different when running in balanced mode.

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Unfortunately at the time I had the iSine 20’s I didn’t have a balanced rig or Dap. However I do now and run all my iem’s balanced. The benefits of running in balanced mode change from iem to iem IMHO. Some sound better than others.

With regards to the iSine 20’s the greatest difference in sound was brought about by using the Cipher cable. The difference was magical. Do you think that planar iem’s are benefitting from the extra power brought about by running it in balanced mode? I know overear planar’s benefit from a good amount of power to varying degrees is this still the case with iem’s and why?

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In my experience, I prefer running planar IEMs in balanced cables as well. I feel like the extra power is helpful. I have only noticed slight difference in sound.

As far as open vs closed, I have only tried out open-back planars, ovbiously, since I have not tried the CL2 yet. It’s on my list of things I’d like to listen to one day, but it’s price + signature doesn’t seem that appealing to me. The other IEM that has been talked about is the MEE Audio Planamics which I’m not sure if you want to call it a planar or a dynamic - it looks like a planar driver to me - and it also got mixed reviews for the opposite reasoning (too dark). I’ve yet to try out either one.

I do not mind using open-back IEMs. The good thing with IEMs is that the driver is not anywhere large enough to leak out any significant amount of noise in a normal work environment. I can see it being a little problematic if you walk outside and use them frequently or use it on a train or plane.

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Yes I looked into the MEE Audio Planamics and they really didn’t seem to go down too well. Like you I’ve only used open back planar iem’s and they worked really well. Though I you take them outdoors I can see the sound leak and noise intrusion can be problematic. I know that iem’s are supposed to be used on the go, in my circumstances iem’s fit my needs for indoor use too.

With regards balanced use with planar’s I can only guess that I may enhance listening given my experiences with other iem’s. Of course you either believe in balanced cables or you don’t.

@prfallon69 Thanks for the cable reccomedation! Perhaps I should see if they have an mmcx version and get myself a pair to audition :smile: From testing our own planar drivers, there is a great increase in performance in balanced mode as power is theoretically doubled because of the summation of the +ve (in phase) and -ve (out of phase) signals. If you compare a planar to a dynamic driver or even an armature driver, there is an dampening to the vibration of the driver from the rear (For the dynamic driver it is the voice coil and for the armature it is the armature itself). When power is doubled this increased vibration is more dampened because the coil/armature behaves like a spring (Force = -spring constant * vibration displacement). Increasing the power increases vibration displacement and thus this recoil force is increased. Planars do not have anything to the rear and so this is one of the reasons why the additional power from balanced mode tends to benefit planars more. This is of course also true in IEM form as the coil and armature is still present. Another school of thought might argue that in an IEM, the stiffness of the coil or armature can even increase (but we cannot exactly test this conclusively). Simplistically, we can model this as trying to bend a shorter and shorter rod at the centre. The shorter rod is harder to bend. It is for this reason that we are big advocates for balanced drive (we ship with balanced cables).

@antdroid Point taken a about the sound leak from open backed IEMs. Perhaps we should also release an open version in the future :slight_smile:

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That’s a great explanation thanks. It’s good to hear that you shop with balanced cables too.

For my own rig, ever since I bought a balanced DAP a year ago I have the fear of “missing out” and have been steadily recabling all my headphones to balanced… My latest was a recable of my ultrasone edition 8… Oh my wallet x.x

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Exactly, it’s an expensive endeavour. :grinning:.

I’ve bee doing the same but making my own cables which is much more cost effective

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@antdroid, just wondering, when you are making the balanced cables, does the length of the cables on both sides have to be very precise? Also, in your experience, does the material of the jacks/connectors affect the sound significantly?

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Some people prefer using copper wire and others pure silver or an in between hybrid of the two. It is said by some that the use of silver wire gives it a brighter edge over copper along with other slight differences. It seems to change from cable company to cable company. There are lots of spurious claims made regarding cables. It’s all subjective in my eyes. If you see a difference then great if you don’t then don’t shit on those that do. I like using balanced cables with my iem’s. Now whether or not it’s a measurable difference scientifically doesn’t matter to me. As long as people don’t go round shouting that it’s a scientific fact that such and such a cable will make your music sound 20 times better because it’s been made from angel tears.

Some cables can be extortionate prices I will only pay Upto a certain price point and then that’s it. If I could make my own I would. It would be far more practical and lots of fun. And probably much cheaper. All my own opinion of course. :grin:

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Would the same reasoning apply to STAX making their SR-001, SR-002 and SR-003? @bret had a pair of SR-001s when they came out, and they were good, if lacking a bit in bass.

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