7HZ AERO: Unexpectedly Good Sounding One

7Hz appears to be diversifying its product line-up as they released a flagship midrange set a few months ago and it received mostly positive feedback on that one on how it performs tonally with premium-grade inclusions with it as some high midrange sets do not have those contents with that kind of quality. And now they release a budget-friendly IEM for budget-conscious audio enthusiasts.

This is a 7Hz AERO and it is a single driver set-up IEM earphone. It was equipped with a dual-chambered N52-grade neodymium magnet along with a metal wafer diaphragm on its 9.2mm dynamic driver for less distortion, better resolution and delivers a full range sound. Then the driver was encased in a rounded shell chassis made of polycarbonate plastic in which it has a decent build quality in my opinion although its cable is fixed rather than opting for interchangeability.

The cable seems to be a decent one with a PVC insulating coating on its copper wire strands with a standard gold-plated 3.5mm single end on its termination plug. It is quite flexible and I didn't encounter any microphonic issues at all.

Regarding its wearability, the 7Hz AERO with its rounded teardrop-shaped design, offers an ergonomic fitting for almost ear sizes as it also seals well into my lugholes without any discomfort. It gives a passable isolation from unwanted noises from the outside surroundings.

The product packaging of this one is rather elementary in its presentation with just the essential contents inside, the IEM earphone itself and some extra silicone ear tips in different standard sizes.

This set is a bit tough to drive as normal gain mode on some devices in a medium volume level won't deliver that fullness and dynamic sound on this one. You need a dongle with a better than usual power output or if you have a DAP with two or three stages of gain mode, medium or high gain mode would be sufficient enough on this one.

As for tonality, the 7Hz AERO has a U-shaped sound signature with a warmish-balanced tonality that makes it more pleasurable on listening sessions for both casual listeners and experienced audio hobbyists.

(FR graph was provided by [USER=516219]@baskingshark[/USER] , credits to him)

LOWS/BASS:

The bass sections are fairly well-balanced on presenting the sub bass part and mid bass section as it delivers a rumbly, incisive and striking bass response while trying to keep under control any chances of mid bass smudging across other frequencies.

As the sub bass presence are clearly perceived its reverberating and rumbling nature that are produced by certain instruments like drum machines, synthesisers and low tuned bass guitars, its mid bass have an adequate texture to have some firmer note weight on certain instruments like bass guitars, double bass and bass kick drums, and also low octave male vocals like bass and bass-baritones. Bass guitars have a resonant sound, double basses have a sombre sound and bass kick drums have a sufficient fullness on its sound. Bass and bass-baritone vocals have a fairly deep resonant and reverberating voice with ample volume and darker tone.

MIDRANGE:

While it appears that it has tad notched midrange presentation on its overall sonic frequency spectrum, it has a proper warm to give a balanced note weight with a hint of energy to give off some translucency on its midrange tonality. Vocals of any type have an ample richness, fullness and clarity on their general sound characteristics while instruments have a well-nigh natural timbre of any kind.

When it comes to male vocals, baritones have smooth and warm voices, tenors have some graceful, ringing and brassy sound on their vocals and countertenors have sweet and tender on their light and agile voices. As for female vocals, contraltos have some rich and smoky sound from their usual chesty vocals while mezzo-sopranos have some fiery yet velvety on their versatile vocal range. Sopranos seems more silky and creamy with some added sheen to make it more cantabile and euphonic.

On instruments, strings like guitars, cellos and violin, they sound warm, lustrous and sensuous respectively while on brasses, trumpets sound full, trombones have these full and solid sound on them and horns sound ponder and tempestuous. As for woodwinds, concert flutes have a mellow and rich sound, piccolos have a clear sound, clarinets have throaty sound and saxophones have a round and warm sound. On percussion instruments, snares have hard and rustling sound, tom-toms have warm and sonorous sound, field drums have full and clear sound and kettledrums have resonant and booming sound. Pianos sound pretty balanced with rich and clear tones on them.

HIGHS/TREBLE:

The treble response of this one is relatively balanced and smooth but its airy extension is rather meagre in my opinion. There is a slight elevation on the upper-mids and presence parts just enough to give some definition and clarity on vocals and attack of percussives and rhythmic instruments. And I can assure that not a hint of sibilance nor harshness that I've encountered on this one that treble-sensitive folks will enjoy its tuning.

As I mentioned a while ago, it doesn't have an airy treble presentation and is also less sparkly. Cymbals have a lustrous sound while hi-hats have that short buzzing sound which sounds quite correct. Glockenspiels have a bell-like sound on them and the celestas have a mellow and velvety sound.

SOUNDSTAGE, IMAGING AND OTHER TECHNICALITIES:

To be honest, I don't really expect some good technical capabilities in this one but to my amazement, it unexpectedly executes pretty well. This set is able to project an above-average sound/speaker stage with a moderate width on its lateral span along with good height reach and depth of its sound field.

It projects a concave-like presentation of its stereo imaging where I was able to locate the placement of instruments and vocals in a not-so layered soundscape with just enough separation on it. Playing complex multi-instrumental tracks isn't that highly recommended on this set as I noticed some congestion and smearing of instruments on its playback.

Coherency is quite good as it is capable of delivering a nimble transient response without any issues like distortion or disjointed sound. On resolution capability, it has a solid macro-dynamics with acceptable micro-detail retrieval capability for a single DD set.

PEER COMPARISONS:

KZ EDCX

• It has a modified UIEM-type shell design.
• Also has a non-detachable cable with an L-shaped 3.5mm single-ended termination plug.
• It also has a similar U-shaped sound profile with a balanced-warmish tonality.
• It has also a punchy bass response although the bass bleeding appears more prevalent on this one.
• It shares similar warmth and textured midrange as it delivers a natural sound.
• The treble response appears to be smooth and balanced just like the AERO but I noticed that it even has a lack of sparkle and air on it.
• It has a narrower sound/speaker stage size especially on lateral span width.

KZ LINGLONG

• It also has a fixed cable on its cylindrical-shaped transducers.
• It uses a smaller dynamic driver.
• It is quite pretty-well accessorised.
• It shares similar tonality and sound signature with AERO as it also has a balanced-warmish and also follows a U-shaped sound profile.
• Punchy and well-balanced bass response.
• Less warmer and a tad more recessed midrange presentation with less energetic female vocals and string instruments.
• Almost similar treble response as it also has a smooth yet less airy and sparkly one.
• On technical capabilities, it has a narrower sound/speaker stage and its stereo imaging appears to be more of a two-dimensional.

TANGZU PRINCESS CHANGLE

• Another set with a non-detachable in a cylindrical shell form but it has a more ornate design.
• Uses a smaller dynamic driver technology.
• Fully accessorised for a budget-level set.
• Like all the previous sets that were also compared with AERO, it also has a U-shaped balanced-warmish sound profile albeit it is a little bit leaner.
• Punchy and rumbly bass response but I noticed that it has less textured mid bass.
• While it has a sufficient warmth on its midrange, it appears that some instruments sound a bit hollowed.
• It also shares similar treble response with AERO as it also has sounds smooth, balanced and inoffensive.
• Compared to the AERO, It performs less impressively as it has a narrower soundstage and a two-dimensional stereo imaging.

As I concluded my review on this product, this is one of the few entry-level sets that impresses me in terms of tonal performance on how it delivers a sense of natural and analogue-ish type of tuning. While a non-detachable cable will be my main complaint on this one given that there are some ultra budget level sets that have those features along with too meagre of inclusions and a bit power demanding, those minor quibbles will somehow be outweighed with its sheer tonal balanced tuning which is the main selling point of this one that I actually prefer this one over that overhype entry-level set from the last quarter on the previous decade which supposedly an excellent sounding one.

And I hope that 7Hz will release a better version of this one later.

7HZ AERO is now available at LINSOUL, checkout the unaffiliated link below that I've provided.

LINK: https://www.linsoul.com/products/7hz-aero

SPECIFICATION:

MODEL: 7HZ AERO

IMPEDANCE: 27Ω

SENSITIVITY: 104dB

FREQUENCY RESPONSE: 5Hz - 20KHz

CABLE LENGTH: 1.2m

PIN TYPE: NON-DETACHABLE

PLUG TYPE: 3.5mm

DRIVER UNIT(S): (1) DYNAMIC DRIVER

PROS:

● The shell design is rather interesting as it has teardrop contours in a very compact size.

●  Its design choice is surprisingly pretty ergonomic and it offers an excellent fit.

● A well-done coloured sounding set as it has a warmish-balanced tuning.

● An analogue sound lover's delight on how the sonic qualities of this set conveys.

● Well-balanced bass response with ample punch and rumbling sub bass response.

● Warm and well-textured midrange with an almost natural sound on vocals and  instruments on their tonal colour.

● Smooth and inoffensive treble response.

● An above-average to wide sound/speaker stage projection.

CONS:

● Non-detachable cable

● Spartan inclusions

● Needs more power output to sound more dynamic and fuller.

● Not for neutral heads and analytical types of listeners.

TESTING TRACKS: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)

Alison Krauss -When You Say Nothing At All *

Jade Wiedlin - Blue Kiss**

Led Zeppelin - When The Levee Breaks **

Mountain - Mississippi Queen *

Queen - Killer Queen **

Guns N' Roses - Patience *'*

Eric Clapton - Tears in Heaven '*'

Sergio Mendes- Never Gonna Let You Go '*'

Pearl Jam - Daughter **

Roselia - Hidamari Rhodonite *

Assassin - Fight (To Stop The Tyranny)*

Celtic Frost- Visual Aggression *

New Order - Blue Monday *

The Corrs- What Can I do (unplugged version) *

Jimi Hendrix Experience - Voodoo Child *

The Madness- Buggy Trousers *

Metallica - Motorbreath **

Mariah Carey- Always Be My Baby *

Destiny's Child - Say My Name *

Malice Mizer- Au Revoir *

Mozart - Lacrimosa *

New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *

Eva Cassidy - Fields of Gold (Sting cover)*

Michael Jackson - Give In To Me *

Exciter - Violence and Force *

Diana Krall - Stop This World **

Debbie Gibson - Foolish Beat *'*

The Sisters of Mercy – Lucretia My Reflection**

Suzanne Vega – Luka **

Lauren Christy – Steep *

Ottoman Mehter - Hucum Marsi *

Diana Damrau - Mozart: Die Zauberflöte*

P.S.

I am not affiliated to 7HZ nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.

Once again, I would like to send my gratitude to MS. KAREENA TANG of LINSOUL for providing this review unit. I truly appreciate their generosity and trust towards me and other reviewers.