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7Hz Eternal Review


The 7Hz Eternal is an in-ear monitor (IEM) which uses a single 14.5mm dynamic driver with a liquid crystal polymer diaphragm. The Eternal was provided to me by Shenzhen Audio in exchange for my evaluation. The Eternal retails for $249.


I have used the 7Hz Eternal with the following sources:

  • Qudelix 5K
  • E1DA 9038S

I have tested the 7Hz Eternal with local lossless audio files and Spotify Premium. Visit my page to get an idea of what I listen to:

XenosBroodLord’s Library |


The 7Hz Eternal comes in a rectangular teal box with a red slipcover. Technical specifications for the Eternal are provided on the rear of the slipcover in Mandarin Chinese.

In addition to the IEMs and the removable MMCX cable, the Eternal includes a heavy copper-colored metal storage case with a magnetic lid. The lid is embossed with the 7Hz logo on the bottom right-hand corner. The Eternal also includes two plastic clamshell eartip storage containers and four different sets of eartips. In total, 22 eartips are included with the Eternal. In terms of documentation, a warranty card, warranty instructions, and a quality control chit are included with the Eternal. All documentation is provided in Chinese only.


The Eternal has aluminum shells in the same copper hue as the storage case. The Eternal’s most distinctive physical features are the large disc-shaped faceplates. These faceplates contain a decorative inlay designed to resemble a dynamic driver and are covered by sapphire-coated optical glass lenses. There are three circular vents towards the top of each inner housing, and one pinprick vent just above the driver. “L” and “R” indicators are printed in white off to the side of the three circular vents towards the front of the IEM. “7Hz Eternal” is printed in white text below the MMCX connectors on the forward-facing side of the housings. The nozzles have a significant lip to secure eartips. The nozzles are covered by mesh, over top of which a thin metal overlay cut with a whirlwind-shaped relief is set.

Each strand of the MMCX cable is jacketed in a burgundy-colored plastic sheath. The cable hardware is copper-colored metal with silver metal accents. There is strain relief above the 3.5mm jack. The cable uses preformed earguides without memory wire. The 2-pin connectors are embossed with faint markings to indicate left and right. There is a chin-adjustment choker.


The 7Hz Eternal is intended to be worn cable up. The nozzles have a shallow insertion depth and I consistently had to use larger eartips than I normally do to get a good seal. The Eternal is more comfortable than I expected given its shape. Secureness of fit and isolation are average.

The Eternal has significant driver flex, especially with silicone eartips. The driver flex is so severe that one can move the diaphragm out of position entirely if the IEM is inserted too deeply or forcefully into the ear canal. This will result in effectively nonexistent sound reproduction out of the affected earpiece. The listener must create suction to pop the diaphragm back into place for the earpiece to function correctly, which is an imprecise and frustrating process.


Measurements of the 7Hz Eternal can be found on my expanding database:

7Hz Eternal — Squiglink by Bedrock Reviews


The 7Hz Eternal is a warm-sounding IEM.

The Eternal has a sub-bass-focused bass tuning with a distinct if gentle sub-bass shelf. The shelf is moderate in magnitude but allows for substantial mid-bass presence. Sub-bass extension is good but not great. Impact and slam are prioritized over speed of articulation, which is merely average. The Eternal has excellent dynamics and satisfying note weight. These qualities are especially evident listening to quieter instrumental tracks and ambient soundscapes. The bass has better than average texture.

The gentle slope of the sub-bass shelf strikes a good balance between avoiding mid-bass bleed and imparting the lower midrange with warmth. However, the upper midrange is uneven, particularly for the musical genres I listen to most. Male vocals have body and grit but their intelligibility varies. While not shouty, male vocals can come across as hazy and oversaturated. Female vocals are even more overemphasized. Female vocals are very forward and breathy. There is too much presence for distorted electric guitar-driven musical genres. While not exactly sibilant, the attack of certain string and woodwind instruments can be a bit aggressive at higher volumes. On the other hand, both physical drum kits and synthesized percussion have a natural-sounding timbre. This combined with the bass characteristics described above means that percussion is a joy to listen to on the Eternal.

The treble response avoids harshness but is too muted and relaxed for my preferences. There is some lower treble but little mid-treble. Upper treble extension is poor. Detail retrieval is lacking for the price, and treble transient delivery is wispy and poorly defined. The soundstage is expansive for a single dynamic driver design, and instrument separation and imaging are excellent.


The 7Hz Eternal is hard to drive and requires a quality source device. I did not notice any hiss during my listening on any of my source devices.


SeeAudio Bravery Review

7Hz Eternal, SeeAudio Bravery — Squiglink by Bedrock Reviews

The SeeAudio Bravery is an IEM with four balanced armatures (BA) per housing which retails for $279.

The Eternal has more satisfying bass than the Bravery. The Bravery has more immediate slam and impact to percussion hits than the Eternal, but the Eternal has fuller, more resonant bass delivery. The Bravery sounds slightly hollow in comparison and the characteristic percussion compression inherent to many BA designs is evident. The Bravery’s bass is more agile than the Eternal’s.

The Bravery has a much more correct-sounding midrange than the Eternal. Heavy rock genres are much easier to enjoy as male vocals and distorted electric guitars do not sound like they are competing for the listener’s attention as they do with the Eternal. With the Bravery, male vocals have better intelligibility. Female vocals are still quite forward but do sound a bit more reined in than with the Eternal. The Bravery has fewer issues with sibilance.

The Bravery’s mid-treble is slightly overemphasized, so there is an excess of sparkle to cymbal hits, but the Bravery is head-and-shoulders above the Eternal in terms of detail retrieval. However, where the Eternal’s treble transients sound indistinct, the Bravery’s treble transients sound over-sharpened. The Bravery has a more expansive soundstage and superior instrument separation.

The Eternal is harder to drive than the Bravery.

The Bravery and the Eternal have very different physical aesthetics, but the build quality and variety of included accessories are comparable between the two. Both are what I would expect from a $250–300 IEM. The Bravery has more extravagant packaging.


The 7Hz Eternal is a fun-sounding IEM carried by the strength of its bass performance. The toe-tapping physicality of the Eternal’s dynamic driver is frequently successful in distracting the listener from the less-than-ideal upper midrange and underwhelming detail retrieval. With that said, there are better options at this price point for critical listening.

The 7Hz Eternal can be purchased here:

7HZ Eternal Earphone IEMs 14.5mm Dynamic Driver IEM HiFi Music Monit (




Hyperbole-free reviews of audiophile IEMs, headphones, digital source and amplification products, and other consumer electronics.

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