Soundz Avant Review featured image

Soundz Avant Review

Select Comparisons

The following comparisons to the Avant were made using a HiBy RS8, Chord Electronics’s Mojo 2, and the Cayin RU7 as our main sources. All chosen comparison units are custom-designed with their stock cables.

The Avant was also compared using the Edge total block filter installed for all 3 comparisons and Immersive Mode turned on, (bass switch ) for the Maven Pro and Anole VX comparison.

Unique Melody Maven Pro

The custom format Unique Melody Maven Pro was launched towards the end of 2022, with our review published at the start of 2023. you can read our full review of the Maven Pro here.


Both of these custom monitors use 10 BA drivers, however, the Maven Pro goes one step further with an additional dual EST driver array for the ultra-highs. The Maven Pro also uses non-vented BA drivers and I believe the Avant’s Sonion drivers are vented which may well be a factor in its bass response.

The precise BA configuration is almost the same for both IEMs using 4 BA for the lows, 2 for the mids, and 4 BA for the highs.

However, with the use of EST drivers for the ultra-highs, the Maven Pro’s treble BA configuration is going to target more of the audible treble range up to around 8-10k, rather than air and headroom. 

There are no bass switches or filtering technology for the Maven Pro though bear in mind the Avant filtering system is highly dependent on the quality and size of the molds you submit so it is not always possible to get them fitted.

The Maven Pro has an impedance rating of 30Ω and 112dB SPL @1KHz so a slightly higher load but more sensitivity on paper than the Avant’s 16.2Ω impedance and 105 dB/mW @1kHz for SPL.

In our real-world testing with the RS8, I didn’t find a huge difference for volume matching purposes using a low gain SE output using Turbo mode. 

Unique Melody Maven Pro Review


Both are custom designs and by default, I normally say things can be very different. However, in this case, there are some substantial differences with the Maven Pro sample here using a dense and robust all-black titanium shell as opposed to the lighter Avant resin format.

The fact that UM is able to 3D print a shell from titanium is commendable but the degree of accuracy on top is truly excellent. It is a good fit, in short, with great passive isolation.

Still, the smaller Avant resin print seems more detailed to me which isn’t surprising since it’s a material of choice for most custom designs out there. Its fit is even more accurate and the seal is better when using the Edge total block filter but less so with the Edge Ambient filters attached.

The Avant Flex Fit Pro material keeps the comfort levels high with its better temperature control in the ear. The titanium shell of the Maven Pro can be an icy cold feeling in the ear for a short while and it does feel heavier in the ear also.

The Maven Pro’s UM Copper M2 cable is a step up for me over the Avant’s Ethos MKIV stock cable. both are 4-wire but the M2 uses a larger 24AWG gauge OCC copper 4-wire in a stealthier braided black PVC jacket and very modern ergonomically shaped barrels for good grip. 

The Litz Type 5 4-core 28awg UPOCC silver-plated copper wire Ethos MKIV is lighter and easier to manage but it’s going to be a little more resistive in terms of performance with that smaller gauge and uses old-school carbon fiber printed silver barrels. 


These two sound signatures are shaped very differently. The Maven Pro sounds warmer and darker in its timbre with a denser more rounded note. The Avant offers substantially more pinna gain and vocal presence plus higher levels of contrast though it will sound leaner through the upper bass and lower mids.

Save for a gentle nudge around 7-8k, the Maven Pro does not have the same treble presence and that creates a bit of difference in both relative headroom and light high-pitching spatial cue awareness.

For example, a track with a crescendo of hi-hat or cymbal energy is going to make its presence felt a lot more on the Avant than the Maven Pro which, in turn, fleshes out the body of bass guitars plucks in a more appreciable fashion. 

A number of FR differences contribute to that synopsis above. The Avant sub-bass with the total block filter and Immersive Mode on is more powerful sounding compared to the Maven Pro’s already beefy low-end.

However, the Avant cuts the bass shelf a little quicker and harder with more dip in the upper bass and lower mids which prevents a lot of potential warmth bleeding into the mids timbre. The Maven Pro is gentler in this region, creating more presence but also more bloom and warmth.

The second key difference is the 1-4k range which is a focus point for the Avant showing a lot more gain and presence. Vocals are very much to the fore whereas the Maven Pro sounds comparatively subdued and lacking in air with its weaker elevation and 3-5k dip.

If you like a forward vocal and percussion along with a beefy fundamental then the Avant is your pick. If you want something more relaxed and warmer then the Maven Pro is more suited.

qdc Anole VX

The qdc Anole VX was launched back in 2019 and is still available today to buy in both custom and universal formats. This version is the custom format, reviewed in the latter half of 2019 and received high praise from us. 


Like the Avant, the Anole VX uses 10 balanced armature drivers though the precise grouping is not outlined on their website.

In our review, we presumed that it was 4 for the lows, 2 for the mids, and 4 for the highs with its listed 3-way crossover but I am not 100% sure of that.

That would closely mirror the grouping for the Avant though which uses a similar 10 BA grouping but I am fairly sure that the Avant Sonion drivers are newer tech. qdc never revealed if they used a mix of Sonion and Knowles in the VX but given it’s a 2019 creation, the drivers are likely to be of an older variant, at least in the sample I have here.

Now both have sound shaping options with the Avant using a switch for its ‘Immersive Mode’ to allow you to add or decrease the presence of warmth and bass. You also have the potential for filter technology depending on your mold shape and quality that does open up or reduce the amount of air and bass definition.

The VX goes a lot further with a triple dip-switch option giving you up to 8 tuning profiles allowing you to focus on bass, treble,  vocals, or go neutral depending on your preferences. It does not have any filtering options though.

Because of the dip switch, the VX resistance and SPL vary a little since the system has some resistance bias to achieve the sound signatures. Still, the VX rating is not too far off at 17-22Ω and 110-112 dB @1kHz 1Vrms compared to the Avant’s 16.2Ω and 105 dB/mW @1kHz.

Both were driven well from a Mojo 2 SE output with the Avant just slightly lower in volume but very marginal.

qdc Anole VX-S


The aesthetics go to the Anole VX whilst the intricacy of the design and fit go to the Avant. I suspect this is due to several factors.

In 2019, handmade was still the thing for custom monitors and I believe qdc still does handmade, or at least officially on their website they still do. The Avant is 3D printed and it looks really detailed in terms of how it captured my STL scans.

The VX is much bigger but is a little less detailed in the shell and softer on the curvature. It still fits wonderfully well but you can tell it’s purely for sedentary audiophile ears and not for active stage ears as the nozzle is somewhat shorter than the Avant version.

When you slot the more compact Avant into your ears you just know it is going to stay tight and in there no matter if you have an open or closed jaw stance or how much physical movement is involved. Key attributes required for pro audio artists.

The additional Pro Flex Fit helps seal the deal also in terms of tight fit and comfort, rare combinations at times in the custom monitor world.

Now aesthetics is very much for qdc and that is where handmade can have a distinct advantage over 3D printing. The Avant is very clean and well-made, do not get me wrong there but the pop from the glittery flake design of this VX finish is beautifully detailed and frankly breathtaking. 

Last but not least cables and the VX reversed polarity, the signature termination of qdc models. You need an adaptor to cable roll for the VX and roll you will because the stock cable is a bit cheap looking for me compared to the Avant’s Ethos MKIV. 

Tuning Setup

It is extremely difficult to give you a short summary of the differences here due to the 8 different tonal signatures of the VX.

So, instead, I will compare with all the switches turned on which maximizes the presence in all areas of the VX performance, and compare to what I feel is the most hard-hitting of the Avant’s options, using the Edge total block filter with the Immersive Mode turned on.


With these settings, you get some contrast in how they perform with the VX offering a slightly warmer and richer tone compared to the lighter higher contrasting sound of the Avant.

To be clear though that lighter tone comes through the mids and highs of the Avant rather than the lows where both are quite strong and powerful sounding.

The Avant sub-bass is maybe 1-2 dB lower and though both do have some dips to cut out the bleed the VX seems less emphasized carrying more warmth into the mids.

The VX mids tuning has a small shelf from 800Hz up to around 3k that introduces some nice presence and fleshes out the warmth of vocals but I would still classify it as a neutral imaging quality.

The Avant bass to mids separation is more emphasized with its dip higher at around 700Hz and a stronger 1-4k pinna gain which creates emphasis below 100Hz and above 1k leaving the lower-mids behind a bit. That takes some warmth with less richness in the vocals but still quite a natural tone to the mids timbre.

The VX does have some lift in the upper treble but it’s finely balanced with the mids neutral imaging so you won’t hear too much in the way of sibilance or percussion harmonic dissonance.

The Avant doesn’t either but its treble tuning is more relaxed to prevent treble overtones from popping up too much on that stronger 1-4k tuning. 

One area the VX excels in is its soundstage. This is an enveloping sound with excellent width and a slight mids emphasis but otherwise quite balanced. The Avant is more bass and upper-mids-centric with vocals and power to the fore and everything else tucking in behind it.

Westone Audio ES80

The Westone Audio ES80 was launched in mid-2017 with our review coming in 2018. At the time it was using some innovative tech and pitched to pro audio and audiophile alike so we do see some similarities in the approach with the Avant.


Like the Avant, the ES80 drivers are entirely balanced armature but this time we have 8 instead of 10.

Although not specifically mentioned in relation to the ES80, Westone Audio is also known to heavily favor Knowles drivers whereas the Avant uses the latest Sonion drivers. Unless the receipt has changed since 2017, the ES80 drivers will be non-vented also.

The precise grouping inside the ES80 is dual driver BA for the bass, dual drivers for the mids, and quad drivers for the highs using a 3-way passive crossover.

The key difference here aside from the type of drivers used is the additional 2 BA drivers on the lows for the Avant and it does make a substantial difference to the performance. The Avant also states an electrical 4-way crossover which I presume to mean ‘active’ rather than passive.

There is a big difference in the rating of these two monitors. The ES80 has a very high impedance or load of 80Ω compared to the Avant’s 16.2Ω benchmark which is almost OTL amplifier territory for matching.

The sensitivity isn’t too bad though at 111 dB @1kHz 1 mW but even so, testing with a Cayin RU7 there was a big difference in volume matching with the ES80 running at least 10 steps higher for volume using the dongle’s SE output.

Westone ES80


Another gorgeous design but also one that uses similar technology to Avant’s Flex Fit Pro for the nozzle.

Westone calls their version ‘Flex Canal’ but it operates in a very similar fashion with a semi-soft nozzle material that reacts to body temperature to increase comfort levels upon insertion as well as give it that final shape ‘teak’ to enhance the seal.

However, the consistency of the material does feel slightly different with the Westone variant slightly softer on the squeeze compared to the Avant’s Flex Fit Pro design.

Just to note, the ES80 is hand-made if you want to use their Flex Canal technology. If you opt for their 3D printing process you cannot have a Flex Canal fitted. Depending on your mold quality it is possible to have both a 3D printed Avant as well as the Flex Fit Pro finish.

From the top down the ES80 is about the same size but it uses a much deeper shell and a shorter nozzle system.

The short spout has a more relaxed fit though I think the bulkier main shell has to compensate for that as it feels like it is bludgeoning your ear into shape compared to the precision fit of the Avant shells.

Isolation thus is very good on the ES80 but excellent on the Avant. Even with the Edge Ambient filter it isolates better than this ES80 sample. I suspect the enhanced accuracy of the Avant shell printing combined with the longer nozzle is giving it a stronger seal and a more secure fit.

The MMCX terminated cold pour shells on the ES80 are beautiful. Their copper flake design combined with that rough outer texture is truly unique. However, the copper design is not an option if you opt for a 3D-printed ES80.


I hope that Westone upgraded the drivers inside the ES80 because on almost every level and aspect the Avant is superior.

Now I normally refrain from saying catch-all statements like that because preference is a personal thing but you can tell the driver selection is from older tech with a ‘pitter-patter’ bass line from the ES80 symbolic of where BA drivers were in 2017. I doubt they are on the level of the new woofer drivers coming out into the market today.

As a result, the ES80 lacks staging depth compared to the Avant with instruments short of a convincing fundamental or warmth for that matter. There is only a mild sliver of punch and warmth coming in with a vastly reduced sub-bass presence compared to the Avant.

To be fair, the ES80 does possess great width, perhaps even more so than the Avant but everything is aligned on the X-axis so vocals are competing with instruments giving it a very flat neutral sound signature. As a result, the ES80 sounds two-dimensional.

The mids on the ES80 do have a very nice neutral-to-natural timbre when the bass is not being called upon with a treble delicately tuned not to offset that harmonic balance. The pinna gain is not as strong as the Avant so vocals, though with good body, are not pushing too far beyond instrumental imaging but do not block it out either. 

The Avant timbre just sounds more refined, even with its pushed mids the vocal tonal balance is smoother and more resolving.

The additional space and the more careful arrangement of instruments beyond as well as the better bass body just give a more interesting dimension to its staging capability. That and a much better level of PRaT give the Avant a distinct edge.

Soundz Avant retail box

Our Verdict

The Soundz Avant sort of bucks the latest trends in IEM tuning a bit for me. Less of those in-vogue relaxed mids, and more of the classic top-tapping vibe with vibrant vocals and surprisingly great bass performance from those Sonion BA drivers. 

As such it’s not a reference tool, it’s really a well-tuned monitor for enjoying music. It is the type of sound signature that aims for an emotional response, especially with the more powerful Immersive Mode presentation which I tended to be biased towards.

The custom design work in terms of technical skill is outstanding. The intricacy of the printing, the detail in the curvature, and the Flex Fit Pro nozzle produce one of the most accurate fits in a custom I have reviewed to date. Throw on that total block filter and it’s way better than ANC, I promise you that.

The downside is the limited range of design choices. I would like to see more work being done there to bring additional themes and complexity to the aesthetic. I have the same thinking for the cable finishing which is a bit dated.

Aside from that, the flagship Avant is fun to listen to, technically competent, and provides some of the best BA lows I have heard in a long time. Since the Soundz team comes from Greece, then kudos is perhaps a very apt conclusion.

Soundz Avant Technical Specifications

  • Driver Type/Count: 10 Sonion BA drivers per side
  • Driver Configuration: four bass / low-mids, two mid-high, four super high
  • Frequency Response: 5Hz – 24kHz
  • Sensitivity: 105 dB/mW @1kHz
  • Impedance: 16.2 Ohms
  • Crossover: Electrical 4-Way crossover
  • Bores: Three bores
  • Isolation: Up to -35 dB

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