ODA Hesperus A300 is a recent IEM by One Dot Audio, a relatively new player in the audiophile earphone market. I reviewed their budget model the Dolphin D100 recently.
Featuring a 3-balanced armature driver design, the Hesperus is positioned to compete in the midrange of the audiophile market. It currently costs $269, which fits in the stereotypical mid-fi category for portable audio.
Balanced armature drivers have been widely used in IEMs because of their smallness in size and the ability to produce articulate details. However, BAs are known to have thin timbre and bass. With the 3-BA design, One Dot Audio aims to address these issues through the unique tuning and customization of their Balanced Armature drivers.
For the bass, they have used subwoofer BA drivers which try to amplify the lows. Two BA drivers were also used to ensure mids extended treble, bringing out detail and air.
A unique offering from the A300 is its custom mid-frequency drivers that aim to give a natural timbre in the midrange region. The A300 also features a 3-way comprehensive passive crossover system, which ensures a smooth transition across various frequencies.
Upfront, the shell is a simple smooth blue color with a natural stone textured faceplate design. A molded shell for an ergonomic fit is also evident, observing how it’s curved across all dimensions. It’s nothing out of the ordinary, but very professionally finished.
Wearing the Hesperus A300 is comfortable even for long periods, despite the weight of the cable and drivers combined. It fits perfectly in the ears, thanks to the ergonomic contouring on the shell design.
While wearing the A300, outside noise is blocked out, making it easy to hear minute details in various tracks.
One Dot Audio did not skimp on the cable. It’s made up of 4 core ultra-pure grade oxygen-free copper which offers excellent conductivity for clean sound transmission.
From the outside, it’s a 1.2 m four-braided core laminated cable with a grey tint that compliments A300’s shell. It is terminated with a gold 2-pin 0.78mm and has a 3.5mm gold plug.
Stock cables add a noticeable weight when moving around. However, the effect on microphonics was subtle and was not bothersome. The wire sits comfortably at the back of the ears, with good memory retention, which adds a layer of secureness.
What’s in the box
Inside the box, we will find 6 pairs of ear tips with wide bore and double flange types in 3 different sizes, and an OCC 4 core cable that has a grey color that matches the in-ear theme. The cable has a 3.5mm termination and a metal Y-splitter. Overall, they are packaged quite well and feel premium for the price.
Hesperus A300 earphones
2-Pin 0.78mm to 3.5mm 1.2 meter Cable
6 Pairs of ear tips
Premium leather storage case
Drivers: 3 x Balanced armature (BA) drivers on each side
Sensitivity: 119dB SPL/mW
Impedance: 8 Ω
Frequency response: 20-20000Hz
Noise isolation: 26dB
Earphone type: In-ear
Monitor plug：3.5mm connector
Earphone end plug: 2Pin (0.78Pin)
Cable: 4-strand copper plated sliver plus high pure copper
Faceplate: natural stone
I would like to thank One Dot Audio for providing me with the review sample of Hesperus A300.
This is a V-shaped sound signature, with an emphasis on the bass and treble regions, and a recessed midrange. A300 has impactful and rich lows. To bass heads’ attention. Hesperus A300 inherits the distortion control power in the bass at a higher volume.
The sound is energetic, dynamic, and fun, but it may not be suitable for those who prefer a more balanced or neutral presentation.
The lows of the Hesperus A300 are a highlight, characterized by deep, impactful bass reproduction that is not only heard but also felt. The A300’s tuning offers substantial energy in the low range, creating a stimulating sensation for bass-dominant genres like hip-hop and EDM.
Testing on the SMSL DO300EX the bass sounds effortless and punchy with an elaborated decay. By feeding it with more power on the FiiO Q15, the bass gets firmer and faster but remains slightly shy on the very low end.
The tuning matches well with pop and rock with its big and bold bass image and elaborative harmonics, which sounds very engaging with live music especially ones with a lot of drumming and acoustic elements. The bass line is also rhythmic, and the upper strings of the bass guitar are clearly defined.
On the other hand, the bass transients on the Hesperus A300 are quite dependent on the source. Faster and more powerful amplifiers will strengthen the resolution, but even when powered with smaller DAPs and dongles such as the FiiO KA13 R2R player, it doesn’t sound veiled or blurred.
The bass response seems to mimic dynamic drivers and is airy and relaxing, instead of extracting every bit of the details in the track and pushing some frequencies for clarity, compromising naturalness.
The mid-bass on the Hesperus A300 is full-bodied, favoring low-pitched and powerful voices. You can hear the vocal line on top of the bass instruments, presented naturally with a hint of warmth adding to the vocal authority.
The separation power is satisfactory and when paired with a cooler-sounding or powerful source the vocal will cut through the mix more prominently. The Hesperus A300 works well with streamed content which often tunes up the bass and upper mids for clarity and stronger dynamics.
When testing with the FiiO Q15 it sounds more controlled and tightened, bringing more power to the upper mids. Resonating vocal harmonics are well captured too as such older blues and pops with stronger vocal effects from the 80s-90s are a joy to listen to on this pair.
The A300’s treble is vivid and energetic, delivering sparkle and crispness without inducing fatigue or sibilance. It beautifully reproduces high treble, with effortless extension to the top octave. The resolution and transparency in this region are impressive, ranking among the best in the thousand-dollar price bracket.
The high-end of A300 is energetic. ODA leaned into a tuning which creates a sound that’s resolving. The highs are elevated, stopping just short of sibilance. Cymbals and upper harmonics resolve beautifully usually reserved for the background, and pop forward surprisingly. It’s crisp, detailed, and etched in its presentation.
While some may find the treble emphasis a bit exaggerated, it adds an extra layer of resolution and vibrancy, benefiting a majority of popular genres. The excitement and vividness of the A300 are attributed to both its bass and this particular range.
Overall, the A300’s sound is a fun-focused, crowd-pleaser tuning that also excels in technicalities which we are going to talk about next.
As the vocal penetrates through the mix and stays on top, the Hesperus A300 brings the listener closer to the performer and has its bass slightly elevated such that vocal works sound intimate and immersive.
The vocal image is elaborative, as are acoustic guitars which are well-weighted and it works best with songs that don’t have too many instruments backing the track.
You can feel the presence and picture where the acoustic guitar radiates from as if the performer is pointing the wood cabinet to you a few feet in front.
The cozy, unintrusive tuning does not overly stretch the headroom and it sounds natural with air and harmonics delicately captured. The treble has decent control and even at high volume instruments are still well-defined without blurring all over.
In conclusion, the One Dot Audio Hesperus A300 stands out as a remarkable choice for any audiophile, offering an immersive and dynamic presentation across various genres, thanks to its enhanced bass, rich midrange, and crisp treble.
The A300 is not only technically proficient but also immensely fun, offering a listening experience that keeps you hooked.