The Story: Helios
Welcome to ‘The Story:’, a series of blog posts where we discuss the design process behind our IEMs. We look at the Symphonium Helios; our first ever high-end IEM. Priced at US$1099 and armed with 4 balanced armature drivers, the Helios represents our idea of the perfect reference-class IEM.
Why The Helios?
Prior to the Helios, we released the Mirage (1 Balanced Armature IEM) and the Aurora (2 Balanced Armature IEM) in 2018. The focus was to tune both IEMs to have a warm and relaxed tuning without compromise on its clarity. The vocal range of singers were tuned to be sweet-sounding and their guitars intimate and pleasant.
Fast forward 2 years to 2019, we started to conceptualise the idea of the Helios. While the Mirage and Aurora had an easy-going and pleasant sound, we wanted to design something incredibly technical sounding in its stereo separation and also had a reference-class tone. We felt that the market lacked a true reference-class monitor. IEMs out there always seemed to have a flaw one way or another - either incompleteness in the bass, midrange or treble frequencies or a colored tonality unsuited for reference use.
Keep in mind that the market was vastly different in 2019 - most flagships then had a bloated bass and treble too peaky and elevated. Hence, we had to select different drivers and also use a complex crossover system to tune the Helios to sound much ahead of its competition.
Key Design Parameter: Reference-Class Tuning
The Helios would need to present music in an uncolored way, providing the deep subbass extension that IEMs are typically weak at, while at the same time controlled in its midbass response to avoid bass bloat. Vocals and guitars had to be accurately reproduced in the recording, as if the user heard it right in the studio. It would also need to have wide and deep stereo imaging that accurately tells the user where the instruments are placed.
We set out to design and create a earphone that has deep yet clean bass presentation, uncolored midrange and treble frequencies so clear it makes audiophiles question whether they have been accepting compromises in high-end IEMs.
A Generational Leap
Coming from the Aurora and Mirage, we had to do something very different and something we were not used to. We had to reinvent ourselves to gain a competitive edge in the high-end earphone market that we were new to. Halfway through our R&D, we decided to work with Subtonic to collaborate on new technologies and tuning methods so that we could make Helios a truly excellent reference monitor.
Our collaboration with Subtonic allowed us to develop new tuning methods to adjust the bass to sound like a carefully tuned subwoofer in a treated room. New proprietary acoustic solutions also gave the Helios incredible treble extension that has never been seen (or heard!) before in a reference monitor.
In addition, the ‘FLAT’ technology developed in-house with Subtonic will circumvent any issues that arise from source impedance mismatches; the Helios will sound unimpeded and consistent throughout all devices.
Our true 4-way electrical crossovers are also complex yet effective with each driver armed with a crossover. That has allowed us to fine-tune our earphones to exactly how we want it to sound with the help of high quality capacitors and resistors we use in all our earphones, akin to how good speakers are designed. Each driver would have a crossover to optimise the frequency bandwidth it plays and eliminate unwanted resonant behaviours with the drivers when interacting with each other. This must always be done to enhance sound quality and to ensure maximum driver performance.
4 Balanced Armatures?
Another key design parameter for the Helios was that we wanted to use 4 balanced armature drivers. We wanted to keep the number of drivers low yet produce stellar results with the use of a complex and effective true 4-way crossover.
Designs with a large number of drivers must also be met with sophisticated crossovers to fully optimise the use of all the drivers. Hence, to keep the Helios cost-effective in its price bracket we chose to use 4 drivers: 1 for subbass, 1 for bass, 1 for the midrange and 1 for the treble region.
Disproving Stereotypes Associated With Multi-BA Earphones
Audiophiles tend to associate BA drivers to be incapable of producing well extended and deep hitting bass frequencies. Hence, we wanted to make something so good to disprove this stereotype often found in multi-BA earphones.
The reason why BA tends to have weak bass is because they are often hampered in tuning (or the lack thereof) - the typical application found in most BA earphones causes subbass roll-off as well as bloated midbass frequencies.
Our true 4-way crossovers and proprietary acoustic tuning methodology unlocks the potential of balanced armature bass (or rather, how balanced armatures were supposed to be tuned). As a result, the Helios’ bass sounds like a carefully tuned subwoofer speaker in a treated room - and dare we say, better than a typical dynamic driver bass implementation in IEMs.
The treble frequencies have also been completely reimagined - our proprietary tweeter design sports strong upper treble extension that helps the stereo image to sound extremely wide and precise in localisation, solidifying the Helios’ place as a true reference-class IEM that can pick apart the minute nuances in recordings.
An Interesting Experiment
Prior to the Helios’ release, we collected over 30 individual user feedback/trials to gauge where the Helios stood in the market. An overwhelming majority of users actually mistook the Helios’ bass for a dynamic driver’s, which further reinforced our belief that most balanced armature woofers are not tuned well enough. Another common piece of feedback was that the Helios’ treble response is absolutely stellar - extending to the highest audible frequencies and providing accurate pinpoint imaging with a wide stereo image.
Note: We measure the Helios with 8500hz resonance as it is designed to be worn deep-fitted. We use the B&K 4195-Q (IEC 60318-4) for IEM measurements; it is not 100% comparable and compatible with other IEC60318-4 measurement rigs.
The Helios’ frequency response tracks the Harman Target generally well. However, we tuned the treble frequencies (3000hz-10,000hz) more conservatively relative to the Harman Target as we felt that Harman Target has too much presence in that region, which causes an overhyped treble response that is unrealistic and fatiguing.
The 10,000hz-20,000hz response of the Helios is also elevated relative to the Harman Target, as the Harman Target does not prescribe a target (for the 10,000hz-20,000hz region) due to measurement inaccuracy of the IEC 60318-4 standard in the 10,000hz-20,000hz range. The treble extension of the Helios allows for the pinpoint imaging it is well known for.
We are incredibly happy with how the Helios sounds and we are very excited for more audiophiles and engineers to try it. Two years worth of hard work has cemented the Helios to sound completely neutral with a wide and precise image. We definitely pushed the limits with the Helios.
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