7Hz Eternal Review

7Hz Eternal review featured

7Hz is celebrating its 10th anniversary and has created an IEM to mark the occasion. Today I’m reviewing the 7Hz Eternal earphones. The Eternal has a large 14.5mm Liquid Crystal Polymer (LCP) dynamic driver, a sapphire optical glass faceplate and a CNC aluminium cavity. It’s priced at $249.

Disclaimer: This sample was provided by Linsoul for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

7Hz Eternal Review
Warm and earthy yet detailed and dynamic, the Eternal has a great tonal balance.
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Smooth, organic presentation
Tonal balance
Unique design
Comfortable fit
Might not be suitable for bassheads
Slightly attenuated upper treble
Our Score

7Hz Eternal

  • Resistance: 30ohm
  • Sound pressure level: 109db/1khz
  • Frequency response range: 10-20000hz
  • THD: <0.2%/1khz
  • Driver: 14.5mm moving coil
  • Product weight: about 6g single earbud
  • Connector: MMCX
  • Price: $249

Package and Accessories

7Hz once again provides a solid unboxing experience with an abundant accessory bundle. Here’s what you get in the box:

  • 7Hz Eternal IEM
  • Detachable MMCX SPC cable
  • 11x pairs of silicone eartips
  • Aluminium carrying case
  • Documentation & warranty
What's in the box


Taking inspiration from the 7Hz Timeless, the Eternal’s shells are almost identical in design. But there are some key changes here. First of all, the Eternal is bronze in colour. Secondly, the Eternal has a distinctly different faceplate design.

Where the Timeless has an aluminium plate with concentric rings, the Eternal has a sapphire optical glass faceplate with a spiral design beneath. The faceplate gleams with a blue sheen and makes the IEMs look even more unique.

7Hz Eternal design

There are 3 small vents on the inner side of the shells, just near the MMCX socket. Another small vent can be found near the base of the nozzle. Internally, the Eternal houses a 14.5mm Liquid Crystal Polymer (LCP) driver.

The Eternal is a really comfortable earphone despite its large shells. I can wear this IEM for hours at a time without discomfort. When it comes to passive noise isolation, the Eternal blocks out more noise than your average IEM, making it a good choice for use during transit or in noisy environments.

Included with the earphones is a single crystal OCC silver-plated copper cable. It has a coppery brown glossy sheath that matches the colour of the earphones. The straight plug, Y-split and connector housings are all matching bronze colour and there’s also an aluminium chin slider. It’s a little stiff but the cable handles well and it does not get tangled.

Eternal stock SPC cable


Gear used for testing includes the xDuoo Poke II, Shanling UP5 and Topping DX7 Pro.

The 7Hz Eternal has a lovely, musical tone and wasn’t what I was expecting coming on the heels of the Timeless. It sounds organic, natural and slightly on the warmer side of neutral.

Eternal has great tonal balance and one that is more musical than analytical. However, that’s not to say that it lacks in technicalities but it has a smooth and inviting tonality. It might not wow you on the first listen but you’ll appreciate it more as time goes by. The Eternal shows you that you can have details, resolution and soundstage and be musical at the same time.

7Hz Eternal frequency response graph
7Hz Eternal frequency response.

The bass is mildly boosted but is balanced with the midrange and treble. The sub-bass extension is good and the Eternal delivers satisfying rumble when needed.

The mid-bass sounds natural and weighted with just the right amount of thickness combined with medium-paced attack and decay. It’s a bass that gives the impression of power and authority and lends some warmth to the mids without any smearing or blanketing.


Eternal’s midrange is smooth and lush. Instrument note size is slightly rounder than neutral, giving the midrange a natural, earthy tone. Vocals are lush and silky but still articulate and nuanced.

The midrange is the focus of the Eternal’s presentation. It’s warm and rich yet maintains a high level of transparency. The mids blend cohesively with the bass and treble resulting in an engaging and pleasing tonal balance.


The treble is neither forward nor laid-back but clear with a touch of sweetness. It’s a safe, non-fatiguing treble with a hint of added warmth. Eternal creates slightly rounded treble notes with natural decay and a measure of airiness.

The treble is resolving but smooth and free of any sharpness. There’s no sibilance either, so treble-sensitive people shouldn’t be comfortable with this IEM. The level of detail retrieval is good but an attenuated upper treble means some micro-details are harder to distinguish.

Soundstage and Technicalities

The soundstage has fairly large dimensions and is wider than it is deep. Stereo imaging is good but depth layering could be improved. Eternal’s detail retrieval and clarity are good, especially for something with a warmer tone. The separation and overall resolution create good clean space between instruments and prevent congestion.

7Hz Eternal IEMs


7Hz Timeless
7Hz Timeless review featured

The 7Hz Timeless (review here) has a 14.2mm planar driver. There are some similarities in the presentation of these 2 IEMs but to my ears, the Eternal sounds warmer and more natural.

Timeless has more bass depth and authority. It also has a deeper sub-bass growl compared to the Eternal. The Eternal, on the other hand, is lighter in the bass region and focuses more on the midrange.

The Eternal’s midrange is thicker and more natural compared to the cooler Timeless. But the Timeless is easily the most resolving, not only in this comparison but in its general price range.

The Timeless has a drier and more elevated treble, giving it an edge in detail retrieval. In comparison, the Eternals treble is smoother, less metallic and less fatiguing.

Both IEMs have a wide soundstage but the Eternal has more depth and naturalness. The Timeless presents a rigid two-dimensional wall of sound with excellent spacing but a slightly unnatural presentation.

7Hz Eternal with carrying case


The 7Hz Eternal is a uniquely styled and well-crafted IEM. It delivers an inviting yet detailed and resolving sound. Eternal will suit anyone looking for a quality mid-centric IEM with a comfortable, non-fatiguing sound. It might not have the same crazy level of resolution as the Timeless but to my ears, the Eternal’s overall sound is superior.

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