Ten Driver Hybrid In-Ear
64 Audio’s Volür is a hybrid universal in-ear monitor (UIEM), released in September 2023. It’s made using 10-drivers, crossed over 4-ways, and our patented technology; including some exciting new innovations.
History and Legacy
Volür began as an exercise in improving our Nio UIEM, which has been wildly successful for us since 2020. Nio, being a 9-driver hybrid, is known for it’s deep bass and rich/warm sonic presentation. We wanted to take that rich sonic character and build on the quality of the bass and highs. Before we came up with a name, the project was actually designated Nio 2.
The primary requirement for changes to the low-frequency band (LF) was quality over quantity. With the new Isobaric tech we achieved both in a way; more on that to come. Our new tia™ waveguide improved the high-frequencies (HF) so much that we see it being used in future products. Although these seem like the only two major departures from Nio, integrating them meant that almost everything about this new UIEM had to be re-engineered. Volür may have started as a Nio 2, but quickly became an entirely new creation. As an homage to Nio, Volür carries over the signature abalone faceplate but in purple instead of blue.
Isobaric Bass
While trying to improve the LF response of Nio, our R&D team tried things like increasing the size of the dynamic driver (DD), adding a second DD in parallel, and even some odd polarity tricks. While these things all sounded good nothing lived up to, and surpassed, Nio; until we decided to try something entirely new.
First we need to define what is and, more importantly, what isn’t technically an isobaric design.
Two drivers, whether in standard or push pull polarity, firing into the same space are not isobaric. Drivers that are acoustically parallel and wired in parallel effectively double the output volume; where a true isobaric driver configuration wouldn’t increase your output volume. The key to isobaric is the air volume coupling the two drivers (acoustically inert coupling chamber) being fully sealed off with only one diaphragm exposed to the listener. Whether it is cone-cone, cone-magnet, or magnet-magnet (with the fully isolated drivers’ back pressure also being fully enclosed or vented independently of the iso-group) you’re effectively only hearing one of the drivers.
The Iso-Group
Since this doesn’t increase efficiency, like a standard dual driver setup, what are the benefits? In large scale speaker design it is mainly used to reduce cabinet space and increase power handling. In our application this design intrigued us mostly because of the sonic benefits. By doubling the moving mass we get lower distortion, better damping, twice the power handling, and deeper bass response. To further shape the sound we use a high precision textile mesh acoustic low-pass filter originally developed for Fourté Blanc.
This in-phase cone-to-magnet iso-group presented some implementation challenges. Since the drivers had to be wired in series, to maintain a realistic total impedance, this reduced their sensitivity. We worked with suppliers to develop a new custom 9mm driver, with an upgraded n54 magnet & 25μm PU/115°C + 19μm Ti Cone, to accommodate for the sensitivity change.
While Volür’s low-mid and high-mid section is identical to Nio, they’re assembled into an updated 3D printed housing with integrated acoustic tuning features. This was mainly a space saving update along with a decrease in shell wall thickness.
Improving Treble
One of the defining characteristics of our patented tia technology is the smooth and extended HF sound achieved by the direct-radiating driver in the IEM nozzle. To level-up the treble response of Volür we had to think outside the box, and we had very little physical space to do it.
Our new new tia waveguide increased the general amplitude of the highs. This increase was welcome, but required some taming. This is where the front and side diffusion windows were introduced, creating a smoother more balanced HF response. The waveguide also serves as a mounting mechanism, mating to the mid-driver housing, offering exact driver positioning during manufacturing.
The Sound
Wide Nozzle Silicone Tips/m15 Modules
The goal with the LF response was to increase quality, not just quantity, and the dual isobaric drivers deliver both beautifully. Due to its distinctive damping qualities, you hear more of the music and less smear, in a sense lowering the noise floor to a darker background between notes/beats and allowing details to shine. There’s a more palpable impact, with subtle sub-bass information revealing the artist’s true intentions. This head-filling bass also allows you to experience a full sound at extremely low volumes, especially with a more isolating module like m20.
The familiar Nio mids, known for their rich character, maintain that signature quality, delivering an almost tube-saturated presentation. Volür’s unique response curve enhances that experience with holographic center imaging that really shines with vocals, making them feel as if they are floating inside your head.
The tia waveguide plays the biggest role in improving HF response since our invention of the direct-radiating driver. The clarity presented by the HF band, and Volür’s unbelievably wide sound-stage, puts it in the same sonic resolution category as our flagship Fourté. This is a rare high-end audio product that bridges the gap between indulgent bass-loving and technical detail-oriented audiophiles.
The New m12 Apex Module
Originally released exclusively with U4s (included in all new Volür orders for a limited time) is our new m12 apex modules.
The m12 modules were developed for those who felt that the bass drop between m15 and mX was too drastic. Perfect for tracks where the bass is just slightly overpowering the rest of the spectrum. Increases mid-range punch. (reduction by 1db-4db at 130hz-20hz).
Tip Variations
Wide nozzle silicone
Staging is less localized with better panning blend. Hits target frequency response curve with m15 module.
TrueFidelity foam tips
Narrows the mix slightly and shifts high-frequency resonant peak down. The foam tips also offer a more secure fit.
Spinfit tips
Shifts HF resonant peak up. Best at handling microphonic and occlusion effects because the nozzle is decoupled well from the silicone touching the ear canal.
Volür Specs
- Transducer Type/Count: 2 Low DD – 6 Mid BA – 1 High-Mid BA – 1 tia High BA
- Freq. Response: 5hz – 22kHz
- Sensitivity: 103 dB/mW @1kHz @1mW (94mV)
- Impedance: 6.3Ω Impedance @1kHz
- Crossover: Integrated 4-way passive crossover
- Isolation: -20dB, -15dB, -12dB, -10dB
Air Pressure Exchange is a patented vent that releases air pressure in a sealed ear canal all while retaining standard IEM levels of isolation, enabling musicians and music enthusiasts to listen more comfortably for longer. This venting alleviates listener fatigue and allows for a much more realistic soundstage. Apex comes in four module variations for Volür: mX, m12, m15 and m20. While it looks similar to many of our UIEMs, the internal construction of the Apex system is redesigned to maximize space for the LF bore incorporated into the mid-driver housing.
Tubeless In-Ear Audio is a patented IEM design methodology that aims to reduce unwanted resonance and distortion for a transparent and lifelike sound signature. The tia system consists of three major elements: open balanced armature tia drivers, the tia single-bore design, and tia acoustic chambers. Volür features two major elements of the tia system: the tia driver and the tia single-bore design.
Linear Impedance Design (LID) is a patented circuit that corrects the non-linear electrical resistance of the multiple driver-sets comprising this 10 driver IEM. Varying source amplifier output impedance in devices like smartphones, body packs, DAC/amps, and DAPs typically results in varying frequency response, depending on the increase in resistance. Restoring proper interaction with the source and preserving the desired sound signature enables a consistent reliable sound.
The Reviews Are In
Tech Power Up | 64 Audio Volür In-Ear Monitors Review – Flagship Bass!
Headfonics | 64 Audio Volür Review
Headfonia | 64 Audio Volür Review
The Headphone List | REVIEW: 64 AUDIO VOLÜR