[AmericanSpirit]

Some Brief Thoughts on Individual HRTF and IEM Preference

Hey everyone, I wanted to share some comments on the relationship between individual HRTFs and IEM preferences. I'm not an expert or anything of the sort; these are just some of my thoughts on the subject. Disclaimers aside, I see a lot of talk about how "everyone's ears are different and YMMV", to the point of which it often comes off as sort of a platitude. Well...at the meet-up yesterday, we took measurements of the Everest. This was done using an in-ear microphone with the headphones over it and playing a sine sweep through REW. The interesting thing about this is that this measurement procedure is dependent on the bodily anatomy of a listener unlike an external coupler with IEMs. Most industry headphone measurement rigs also use a set ear for consistency. Anyways, all four of us took turns taking measurements with the Everest on our respective heads.



(Green - Juan, Dark Blue - MRS, Light Blue - Me, Red - Evan)

I can't show the rest of the measurement as the project is still under wraps, but pictured above is the pinna compensation region. For those who might not be familiar with the term "pinna compensation," your body has natural resonance peaks that a headphone or IEM must account for, as these transducers bypass many of them. That in mind, the use of "pinna" in the term is not technically correct; it's just become somewhat colloquial.

You'll notice something interesting with the measurement above, though: the pinna compensation region is different for all of us. There were no broken seals here, as all of us measured identically up until around 1.5kHz. The above (disregarding measurement variation, placement, and other confounding factors) basically shows that all four of us have inherently different pinna compensations. What follows is my totally unscientific theory.

Juan (green) and MRS (dark blue) have noticeably more elevated pinna compensations, which implies that their perception of neutrality is based on a higher degree of pinna gain. We know that IEMs bypass the pinna; therefore, IEM manufacturers have to effectively "guess" at what the ideal pinna compensation is for a given listener. This might explain why MRS and Juan enjoy more "shouty" IEMs. They adore the Moondrop SSR, for example, because the SSR's high pinna compensation gets them closer to what they normally hear in real-life. These types of IEMs might not even sound shouty to them! On the other hand, we can see that my pinna compensation (light blue) is lower than both of theirs. All the IEMs that I regularly use - the 64 Audio U12t, CFA Andro 2020, and Sennheiser IE900 - have what would qualify as more relaxed pinna compensation. I find these IEMs more pleasing, and closer to my neutral, likely because my requirement for pinna compensation is inherently lower. Evan's measurement is more of a wild card, as his favorite IEM is the Shure KSE1200. The KSE1200 does have quite the dip after 2kHz, though, which is reflected in his measurement (he has the greatest dip after the pinna, moving into 4kHz).

I think this illustrates why an IEM that might sound "shouty" to one person might not to another, and why a more "muted" IEM might not sound so for one person but will for another. Now, I know, I know. This probably isn't anything groundbreaking (or really even new), as it mostly serves to corroborate what we already know. This also isn't an excuse for why some stuff sounds and objectively measures like trash. That said, it's stuff like this which might help to explain some broader listener preferences, and it's what really gets my head ticking because I want to learn more about this stuff.

Best informative piece of observation that I read on headfi for entire 2021!
Can I request your consent to link this post under my signature?
I had personal guess for main drivers of HRTF are the resonance peaks pinna/concha and maybe higher harmonics, and this piece of experiment is very valuable finding of supporting that! I generally simply put “peak spot hitter” or “conservative” under my cross referencing notes which specifically referred to gain spot approach of each IEMs to my individual HRTF.

 

[Precogvision]

Can I request your consent to link this post under my signature?

Go for it haha

 

[AmericanSpirit]

Agree with your points, though there was actually an official lawsuit that was conducted in the US: https://www.usitc.gov/secretary/fed_reg_notices/337/dn_3409_notice_08292019sgl.pdf

The lawsuit was opened in the august 2019 period and the judge officially ruled to support Knowles finally in the end June 2021 period: https://www.businesswire.com/news/h...s-in-Trade-Secret-Theft-Case-Against-Bellsing

So seems Bellsing lost the case. Knowles actually opened a few TOTL and branded IEMs specially to show that the insides were using Bellsings and used this to support their case. Supposedly, the judge ruled that audio gear can't bring Bellsing containing drivers into the US, but in practice how are the customs gonna check every IEM that comes in? Most audio gear are made in China BTW, and I suspect a lot of budget sets will use Bellsings.



I definitely agree with you and @Precogvision that sound is the most important. If for example the Campfire engineers can tune a Solaris to sound excellent with Bellsings, so be it, as long as there is no false advertisement involved. Campfire never said they were using Knowles drivers in the Solaris, but said on their spec sheet that it was using "custom balanced armatures". FWIW, I've heard some IEMs using supposedly gourmet ingredients like Knowles and Sonion driver or purported beryllium drivers that weren't that great sounding, so I guess tuning and implementation is of more importance than the driver type or brand or count.

The issue of these summitFI brands charging big money for using supposedly perceived less premium parts is another story though. But it is a business after all, and which business doesn't want to be profitable? Willing buyer, willing seller.

I think a second bigger issue is also the ethical component, that Bellsing infringed on copyrights/patents from Knowles. Actually, just 3 - 4 years back, a multi BA driver IEM would be costing anywhere from $300ish USD and a single BA set at around $100 USD. It is actually partially due to the rise of Bellsing that prices were depressed and consumers didn't need to sell a kidney to get some BA CHIFI IEMs, as the Bellsings were more commonly used in CHIFI instead of the more expensive Knowles drivers. At the end of the day, I think we consumers did benefit in a way from Bellsing actually, although piracy and patent infringements are not ethical.

Maybe another reason we see “Brand Custom BA”

 

[291079]

Speaking about historical relevance for the professional world, stuff like westone and Shure really haven't innovated much.

yes, i notice that their products get talked about a lot less these days. sad, i thought the westones were real comfy

 

[Musicoflife]

Maybe another reason we see “Brand Custom BA”

If a given BA can be tweaked to sound a little different (and why not?), I think Bellsing is likely competent enough to be able to do it, and do it with consistency. If so I won't dismiss the possibility that the various brands have indeed 'custom BAs' from Bellsing.

 

[Precogvision]

Symphonium Helios Impressions

It's becoming increasingly rare that I get excited about an IEM these days, but this is one I've been eager to hear - enough that I probably refreshed the DHL tracking about a hundred times throughout the day waiting for it to arrive yesterday! (And yes, DHL conveniently decided to deliver at nearly 8PM which is why these impressions are going up today). But I digress. I think it's only proper that I lend some context about Symphonium, a brand that most readers have probably never heard of before. Symphonium is a small Singaporean brand, and the Helios is their 4BA flagship IEM. Yup, you heard me right. A humble four BA drivers, and it's very reasonably priced at $1100 too.

In the interest of transparency, the Helios was also developed with consulting from Subtonic. Subtonic is an upcoming Singaporean audio brand; a partnership between several audio enthusiasts that includes @toranku of Head-Fi fame. I regularly converse with Toranku and would consider him a good friend and someone who inspired my style of reviewing.

Spoiler: FR Graph

I had already seen the graph of the Helios, and it wasn't ever really a question of whether the Helios was going to be well-tuned given the individuals at the helm. Nonetheless, this can be considered neutral with bass boost; I'll also give a quick run-through of the overall tonality as well as some possible weaknesses.

The first thing that strikes me about the Helios is its bass performance. I praised the 64A U6t for its BA bass not too long ago, but the Helios is just as much a winner in the BA bass department. This is partly due to its tuning which is concentrated almost solely in the sub-bass regions, therefore emphasizing a high degree of cleanliness. But the Helios is no less a slouch in the intangible department either. It actually slams, so much so that I wouldn't mind putting it up there with my beloved 64A U12t. I still don't find it quite as "organic" - the Helios' bass texture leans more dry than the U6t and U12t, perhaps due to a lack of mid-bass - but the Helios sets the standard at a kilobuck for BA bass. Yes, I think prefer it to the Sony IER-M9's bass (certainly at least tonally) from memory.

The midrange of the Helios continues to follow the Harman target closely throughout the lower-midrange. Despite the more gentle approach taken to the pinna compensation and the upper-midrange, then, the Helios' note weight definitely skews slightly thin to my ears. Is this bad? Not at all, but this is where tonal preference will divide some listeners on the Helios' tuning. Personally, I think it could use with some more warmth. I also want to say that the Helios is almost too clean for its own good here. While I don't hear any exaggerated instances of sibilance on my usual test tracks like Girls Generation's "Flyers" at 0:46, transients seem to have a slight edge to them that makes even very small instances of sibilance, such as on Loona's "Voice" at 0:25 to 0:30, pop more than I'm used to. This is especially apparent when listening with the Azla Sedna tips.

My only real complaint with the tonality of the Helios would be its treble. It's something of a double-edged sword. I cannot deny that it is wonderfully extended and mostly smooth without any egregious dips or valleys in sine sweeps. But here's the not-so-favorable side of that sword: the treble of the Helios teeters on abrasive to my ears. I have to imagine that this abrasiveness is partly baked into excess air as, again, swapping off the Azla Sednas for the Symphonium tips mostly fixes this issue. But either way, the timbre of the Helios's treble seems somewhat distinct from the bass response which is surprising given that this is an all-BA IEM. This applies to the midrange to a lesser extent. At times, I could even mistake the Helios for sounding more like a hybrid than it does a BA IEM.

You might see where I'm going; the Helios doesn't sound as coherent as I'd like. As with IEMs like the Thieaudio Monarch and the Moondrop Variations, this feeling is ostensibly attributable, at least partly, to the tuning. From the Helios' razor sharp bass shelf, slight dip to the lower-midrange, and to its excellent treble extension, it all culminates in a more segmented if not clean presentation. I have to admit that my critiques of the Helios are, to some extent, because it's actually too damn good in one department or another. The midrange is too resolving, bringing out micro-detail I don't want, the treble has too much air resulting in slight harshness, and the timbral inconsistency is partially because the bass is so good for a BA. I'd say these are some of the better problems to have. Your average listener probably wouldn't pick up on the coherency issues, and the excess treble air would likely be a boon for most listeners.

It doesn't hurt that the Helios has a strong technical foundation with little to no weaknesses in the departments I usually index for. Detail is good. I hear that faint ring to the backdrop of Taeyeon's "I Found You" which usually only presents itself to me on my speakers. Imaging is slightly out-of-head and the Helios's layering chops are excellent. While not as holographic as the Andro 2020, the Helios edges out the Andro 2020 in terms of positional incisiveness in A/B. And as much has I like to complain about dynamics, the Helios is certainly not compressed for macro-dynamic contrast. Transients also lean fast, and I find myself glued to BoA's Deluxe album. Honestly? I'm hard-pressed to ask for more on the front of technicalities. You (or at least certainly I) wouldn't know this IEM toted a mere 4BAs if it wasn't in the product literature.

The million dollar question is whether the Helios is top-tier material. To be blunt...nah. Not quite. It lacks that last leg of refinement, perhaps special sauce, that would place it at the top amongst greats like the 64A U12t, Empire Ears Odin, and Elysian Annihilator. But for the price of a little more than a grand, I have zero qualms giving this my stamp of approval - at least on the basis of sound quality, as the shells of the Helios are comfortable but quite large and stick out more than I'd like. But I digress. Symphonium has released a highly competitive IEM for its respective price bracket, one that is definitely worthy of kilobuck gatekeeper status in my eyes. And as far as the bias scale goes, I think the score will speak for itself.

Score: 8/10

All critical listening was done off of the 2.5mm jack of my iBasso DX300 with the stock cable and the stock tips. I found the included Azla Sednas to be a tad strident for my preferences, so I swapped to the other included Symphonium tips.

 

[Sebastien Chiu]

Symphonium Helios Impressions

It's becoming increasingly rare that I get excited about an IEM these days, but this is one I've been eager to hear - enough that I probably refreshed the DHL tracking about a hundred times throughout the day waiting for it to arrive yesterday! (And yes, DHL conveniently decided to deliver at nearly 8PM which is why these impressions are going up today). But I digress. I think it's only proper that I lend some context about Symphonium, a brand that most readers have probably never heard of before. Symphonium is a small Singaporean brand, and the Helios is their 4BA flagship IEM. Yup, you heard me right. A humble four BA drivers, and it's very reasonably priced at $1100 too.

In the interest of transparency, the Helios was also developed with consulting from Subtonic. Subtonic is an upcoming Singaporean audio brand; a partnership between several audio enthusiasts that includes @toranku of Head-Fi fame. I regularly converse with Toranku and would consider him a good friend and someone who inspired my style of reviewing.

Spoiler: FR Graph

I had already seen the graph of the Helios, and it wasn't ever really a question of whether the Helios was going to be well-tuned given the individuals at the helm. Nonetheless, this can be considered neutral with bass boost; I'll also give a quick run-through of the overall tonality as well as some possible weaknesses.

The first thing that strikes me about the Helios is its bass performance. I praised the 64A U6t for its BA bass not too long ago, but the Helios is just as much a winner in the BA bass department. This is partly due to its tuning which is concentrated almost solely in the sub-bass regions, therefore emphasizing a high degree of cleanliness. But the Helios is no less a slouch in the intangible department either. It actually slams, so much so that I wouldn't mind putting it up there with my beloved 64A U12t. I still don't find it quite as "organic" - the Helios' bass texture leans more dry than the U6t and U12t, perhaps due to a lack of mid-bass - but the Helios sets the standard at a kilobuck for BA bass. Yes, I think prefer it to the Sony IER-M9's bass (certainly at least tonally) from memory.

The midrange of the Helios continues to follow the Harman target closely throughout the lower-midrange. Despite the more gentle approach taken to the pinna compensation and the upper-midrange, then, the Helios' note weight definitely skews slightly thin to my ears. Is this bad? Not at all, but this is where tonal preference will divide some listeners on the Helios' tuning. Personally, I think it could use with some more warmth. I also want to say that the Helios is almost too clean for its own good here. While I don't hear any exaggerated instances of sibilance on my usual test tracks like Girls Generation's "Flyers" at 0:46, transients seem to have a slight edge to them that makes even very small instances of sibilance, such as on Loona's "Voice" at 0:25 to 0:30, pop more than I'm used to. This is especially apparent when listening with the Azla Sedna tips.

My only real complaint with the tonality of the Helios would be its treble. It's something of a double-edged sword. I cannot deny that it is wonderfully extended and mostly smooth without any egregious dips or valleys in sine sweeps. But here's the not-so-favorable side of that sword: the treble of the Helios teeters on abrasive to my ears. I have to imagine that this abrasiveness is partly baked into excess air as, again, swapping off the Azla Sednas for the Symphonium tips mostly fixes this issue. But either way, the timbre of the Helios's treble seems somewhat distinct from the bass response which is surprising given that this is an all-BA IEM. This applies to the midrange to a lesser extent. At times, I could even mistake the Helios for sounding more like a hybrid than it does a BA IEM.

You might see where I'm going; the Helios doesn't sound as coherent as I'd like. As with IEMs like the Thieaudio Monarch and the Moondrop Variations, this feeling is ostensibly attributable, at least partly, to the tuning. From the Helios' razor sharp bass shelf, slight dip to the lower-midrange, and to its excellent treble extension, it all culminates in a more segmented if not clean presentation. I have to admit that my critiques of the Helios are, to some extent, because it's actually too damn good in one department or another. The midrange is too resolving, bringing out micro-detail I don't want, the treble has too much air resulting in slight harshness, and the timbral inconsistency is partially because the bass is so good for a BA. I'd say these are some of the better problems to have. Your average listener probably wouldn't pick up on the coherency issues, and the excess treble air would likely be a boon for most listeners.

It doesn't hurt that the Helios has a strong technical foundation with little to no weaknesses in the departments I usually index for. Detail is good. I hear that faint ring to the backdrop of Taeyeon's "I Found You" which usually only presents itself to me on my speakers. Imaging is slightly out-of-head and the Helios's layering chops are excellent. While not as holographic as the Andro 2020, the Helios edges out the Andro 2020 in terms of positional incisiveness in A/B. And as much has I like to complain about dynamics, the Helios is certainly not compressed for macro-dynamic contrast. Transients also lean fast, and I find myself glued to BoA's Deluxe album. Honestly? I'm hard-pressed to ask for more on the front of technicalities. You (or at least certainly I) wouldn't know this IEM toted a mere 4BAs if it wasn't in the product literature.

The million dollar question is whether the Helios is top-tier material. To be blunt...nah. Not quite. It lacks that last leg of refinement, perhaps special sauce, that would place it at the top amongst greats like the 64A U12t, Empire Ears Odin, and Elysian Annihilator. But for the price of a little more than a grand, I have zero qualms giving this my stamp of approval - at least on the basis of sound quality, as the shells of the Helios are comfortable but quite large and stick out more than I'd like. But I digress. Symphonium has released a highly competitive IEM for its respective price bracket, one that is definitely worthy of kilobuck gatekeeper status in my eyes. And as far as the bias scale goes, I think the score will speak for itself.

Score: 8/10

All critical listening was done off of the 2.5mm jack of my iBasso DX300 with the stock cable and the stock tips. I found the included Azla Sednas to be a tad strident for my preferences, so I swapped to the other included Symphonium tips.

Good stuff. Can't wait to try this boy out soon!

 

[KuroKitsu]

But the maximum bass setting is not good at all. On this setting, the Layla Aion sounds overly bloated with the farty quality that characterizes BA drivers having been pushed past their limits. As a whole, the sound signature brings to mind the dreaded descriptor of "mud-fi". Best to lay off the bass; personally, I chose to set the dial to the 12 o'clock position. On this setting, the Layla Aion's bass just sounds like normal BA bass; it has no slam, no dynamics. Pretty inoffensive for what it's worth.

But the midrange of the Layla Aion is an affront to any self-respecting weeb listener. Actually, scratch that: any listener with normal hearing. The Layla Aion's pinna compensation is non-existent, falling outside the scope of any academic target curve. You have a minor bump at 1.3kHz and then an abrupt dip after, where most IEMs would be rising. This is followed by a baby hump at 3kHz which has no place being there. The Layla Aion effectively has no upper-midrange; female vocals sound incredibly suppressed and diffused. Male vocals sound slightly more correct, but that's not a high bar. This IEM is effectively limited to a very specific subset of music - dark, slow, male vocal tracks - to sound passable.

You'll notice I said "dark" tracks, so let's talk about the Layla Aion's treble. Our perception of the treble frequencies is partially baked into the balance struck with the bass frequencies. But feel free to dial back the bass all you want - to the bare minimum - because it doesn't change the Layla Aion fundamentally having almost zero treble extension. Subjectively, and on paper, the Layla Aion's treble rolls off even earlier than 10kHz. Maybe JH Audio was going all-in on a more relaxed tuning, I don't know. But it's not an excuse. The Layla Aion still sounds fatiguing (even if it doesn't hit me at first) because of how off the 7kHz peak is contrasted to the rest of the treble response. There's also, like, $25 IEMs with better treble extension than this.

If you're wondering about technicalities, they're not good. As in "not good to the point of which I normally don't take the time to talk about it" not good. But the Layla Aion isn't some random, sub-$100 IEM. It's a multi-kilobuck IEM with expectations. Notes are blunted from head-to-toe. Staging is slightly better than average, but individual instrument lines are smushed and nigh impossible to discern from one another. The Layla Aion sounds incredibly compressed and boring; perhaps this perception is partly baked into its lack of extension. No matter how you cut it, there's no way you'd know that this IEM has 12BAs. There are 1BA IEMs, such as the Etymotic ER3XR, that handily out-resolve the Layla Aion.

Did you steal my real life chats with @riverground about the Layla? And generally JH's house sound too?

It's interesting how they use the 7 khz treble peak to compensate for the abyss known as the "upper mids", but it just doesn't cut it at all it seems. For you it's fatiguing, for me the fundamental base harmonics are missing for the upper mids.

Despite how much I dislike their signature, I always take a step back to remind myself that JH is for stage/studio monitoring so if feels unfair to give an audiophile take on it.

Maybe in some parallel universe, JH will have a different tuning for audiophile aimed iems. But in ours, they just happen to advertise to audiophiles despite not even being aimed at them (for some off reason), and that's more on them when it bombs with reviewers that are more critical.

Transients also lean fast, and I find myself glued to BoA's Deluxe album.

You need to stop mentioning Asia pop that I also enjoy a lot! Otherwise my demo track list will be stratospheric at this rate

Also I had Deluxe playing on my 2ch while perusing this.

 

[Precogvision]

Despite how much I dislike their signature, I always take a step back to remind myself that JH is for stage/studio monitoring so if feels unfair to give an audiophile take on it.

Maybe in some parallel universe, JH will have a different tuning for audiophile aimed iems. But in ours, they just happen to advertise to audiophiles despite not even being aimed at them (for some off reason), and that's more on them when it bombs with reviewers that are more critical.


You need to stop mentioning Asia pop that I also enjoy a lot! Otherwise my demo track list will be stratospheric at this rate

Also I had Deluxe playing on my 2ch while perusing this.

Yeah, artists probably have different sonic requirements than us audiophiles. I still die a little inside whenever I check out Soundcat’s gallery of CIEMs on Instagram, though. So many K-Pop artists using the Layla haha.

On the other hand, 64 does seem to get quite a lot of big names too. Some recent ones I saw:

Spoiler: K-Pop Artist CIEMs

 

[riverground]

Yeah, artists probably have different sonic requirements than us audiophiles. I still die a little inside whenever I check out Soundcat’s gallery of CIEMs on Instagram, though. So many K-Pop artists using the Layla haha.

On the other hand, 64 does seem to get quite a lot of big names too. Some recent ones I saw:

Spoiler: K-Pop Artist CIEMs

Some of my favourite artists

BlackPink for example used EE Phantom for their Coachella performances (Except for Jennie that stuck with her Westone ES80). Before that, Jisoo used to use the A18t, Rosé had the A12t, and Lisa used the same ES80 as Jennie. With the “How you like that” comeback however, it seemed like they are all using 64 Audio IEMs, with only Rosé’ being confirmed to be A18t’s.

Maybe all of them are using the same ones now.

TWICE & BTS members’ majority are either using JH, UE, or 64. So it seems like those are the most used IEMs in the industry.

Also, funnily enough, one of the DREAMCATCHER members [JIU] ha 2 IEMs made for her in a span of less than a month. I wonder why?
(Ga Hyeon back in March was also using the UE11PRO as well)

From UE to JH…

This was posted July 22nd

And this was from August 19th.

 

[antdroid]

Helios is good.

 

[KuroKitsu]

Yeah, artists probably have different sonic requirements than us audiophiles. I still die a little inside whenever I check out Soundcat’s gallery of CIEMs on Instagram, though. So many K-Pop artists using the Layla haha.

On the other hand, 64 does seem to get quite a lot of big names too. Some recent ones I saw:

Spoiler: K-Pop Artist CIEMs

You have to admit that JH's designs are wild in comparison to say 64.

I took the plunge with 64 initially because so many of my western and asian artists were using them. Its interesting to see artists using JH because I feel that asian vocals are a horrible match even for stage use.

China's an oddball with QDC.

 

[riverground]

You have to admit that JH's designs are wild in comparison to say 64.

I took the plunge with 64 initially because so many of my western and asian artists were using them. Its interesting to see artists using JH because I feel that asian vocals are a horrible match even for stage use.

China's an oddball with QDC.

And then there's Japan with FitEar lmao

 

[KuroKitsu]

And then there's Japan with FitEar lmao

I've tried the 334 as its the only universal. The rest are a complete mystery to me. QDC does both for all their models.

 

[riverground]

I've tried the 334 as its the only universal. The rest are a complete mystery to me. QDC does both for all their models.

You heard the Monet17 too lol

Maybe once I have enough money again, I'll collect FitEars again.