AAW Halcyon
Headfonics 2020

AAW Halcyon Review

The AAW Halcyon is a tri-level hybrid universal or custom monitor featuring a quad-electrostatic, dual BA, and a single dynamic diver. It is priced at SG$1,999.

Disclaimer: The AAW Halcyon sent to us is a sample in exchange for our honest opinion. We thank the teams at AAW for giving us this opportunity.

To read more about AAW (Advanced AcousticWerkes) products reviewed on Headfonics click here.

Note, this review follows our new scoring guidelines for 2020 which you can read up on here. 

AAW Halcyon
AAW Halcyon
The AAW Halcyon is a presentation of possibilities. The use of a filter system combined with the dramatic changes with 3rd party tips makes a tricky monitor to pin down to one definite sound.
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The newly launched Halcyon is AAW’s second electrostatic hybrid monitor after the Canary but priced a little lower at SG$1,999 or roughly around $1500. If my discussion with AAW is accurate then despite the Halcyon now just entering the pre-order phase it has been gestating for a while now at the R&D and trade show feedback stage.

It first showed up as a potential custom IEM but although that is still an option, what we have here for review is the universal monitor version. The early version of Halcyon also did not have the new filtering system for the Halcyon that allows you up to 3 different signatures.

In any event, from what I am gathering, the universal Halcyon in its current guise is different from those heard at previous trade shows, especially now with the additional tuning filters.

AAW Halcyon
Copyright AAW 2020

Tech Inside


The Halcyon is a 7-driver hybrid consisting of no less than 4 electrostatic drivers, 2 balanced armature drivers, and a single 10mm graphene diaphragm dynamic driver.

The configuration is fairly straight forward with the dynamic driver acting as the sub-woofer for the lows, the BA drivers for the mids, and the e-stats for the highs using a 4 Way Passive+Acoustic Crossover. This is also reflected in AAW’s design of a triple bore tubing system for the driver groupings and as part of engineered phase control of the Halcyon.

Sonion Gen 2

Although this will be our 3rd quad-electrostatic driver monitor, (Empire Ears Wraith & Wavaya’s Octa), it is the first featuring the 2nd gen Sonion transformer.

Gen 1 would typically require a bit more power and damping to sound optimal. As a result, quite a lot of last year’s designs required more volume or current than you would have expected.

The 2nd gen transformer electrostatic setup is now more efficient than before requiring less damping for the quad array to shine. You simply do not need as much power anymore for the treble to sound, well, like treble should from an electrostatic driver. That is reflected in the 24Ω and 104dB SPL rating of the Halcyon which by most standards is reasonably efficient.

AAW Halcyon

BassFlow™ Control

This is the newer aspect of the universal monitor launch and has shades of 64 Audio’s APEX and Jomo’s ACU filter-based sound tweaking though not based on the same technology. Each filter regulates the air supply to the dynamic driver (venting) to alter both the response and timbre of the low-end of the Halcyon by up to 10dB.

The Halcyon comes with the Norm filter installed which is likely to be your reference point and has a base dB of 5dB. The Bass filter is 10dB and the Vokal filter strips it right down to 0dB. The extent of the upswing in dB on the dynamic driver is to the first crossover point of around 800Hz-1k.

Insertion and taking out are resistance-based with some tight rubber grommet rings keeping them in place and a small metal hexagonal disk to keep safe the filters that are not in use.

AAW Halcyon


I get a strong ‘Jeep’ or military vibe from the aesthetic of the Halcyon 3-piece universal build. It has a consistent anodized green finish with a bolted circular black ring layered on top of the faceplate. That black circular motif is matched by the similarly black-colored filter modules just below.

The underside of the green faceplates is also anodized black so quite the two-tone effect adding to that quasi-camouflage feel to the design. The quality of cutting is really good with intricate grooves on the rear and the semi-teardrop faceplate design. Nothing feels sharp or edgy in the finger or in the ear.


The materials used are CNC machined aluminum for both the body, faceplate, and ring motifs with metal straight Torx screws. Now, normally I would not be so tolerant of exposed Torx screws on an IEM design but this one seems to work and it does add a certain rugged appeal to the form factor.

The net effect is of a sturdy but lighter than expected aluminum monitor, (for 7 drivers) with a clean-cut right down to the nozzle tri-bore finish, including the tip ring.

AAW Halcyon


The filters mechanism or design is very easy to work with and requires no intricate screw-in or pliers such as the FLC micro-filters. These modules have little grommet circles that allow for a pressure-based insertion into that front hole of the shell rather than snap-in.

The faceplate cavity is also very cleanly cut so I cannot see the filter edges getting worn down and losing their seal over time which would be a disaster.

Just a note on the white marking on the top of the filters which are different for each filter. For the Norm filter, it is a white line with two breaks in the line. With the Vokal filter is its 4 breaks and for the bass filter no breaks. This should make them fairly easy to distinguish from each other.

AAW Halcyon

Cable & Connectors

Given AAW’s close relationship with Null Audio, it was no surprise that the Halcyon comes with an above-average stock cable. This is a 1.2m 24AWG UP-OCC Cryo-silver Litz Type 5 wire with a 10% silver solder finish and 24k gold-plated pin contacts.

The Litz Type 5 bundling means each wire is individually insulated with a PVD clear coating to prevent oxidization or the dreaded ‘green effect’ which is just as well as the silver cable shines through a very soft and flexible insulator jacket. You really want that silver to shine consistently.

The braiding is perfect with a short-throw overlap and zero loose loops that could catch. It is incredibly pliant, memory-free, and also fairly lightweight.

I have to give additional brownie marks for the super-soft memory wrap just above the black 0.78mm 2-pin connector barrels on the Thera. It is barely noticeable both in your hand and on your ear but does a great job of forming around your ear.

AAW Halcyon


The Thera Monocrystalline is also not an exact duplicate of the $399 Null Audio Thera UP-OCC Cryo Silver, however. There have been some stylistic changes that blend in beautifully with the design of the Halcyon namely the military green and black splitter and jack barrels.

These are not glued on barrels either. These are mechanically assembled with some very unusual rotational ability between the fixed top and bottom plates for the jack barrel.

The splitter does not rotate but feels very lightweight for a CNC machined aluminum design. Both barrels have the same crew type finish as the main driver housing so they do make for a very complimentary visual aesthetic.

AAW Halcyon

Comfort & Isolation

Because of the exceptionally smooth finish on the CNC aluminum body, you are unlikely to feel any awkward pressure points in your ear when inserting and using the Halcyon.

However, being a machined design rather than the custom universal acrylic favored by the Canary its less of an exact mesh to the shape of your ear. That means there will be more emphasis placed on the tips in terms of a secure fit and the amount of seal or isolation. Particularly with the short nozzle and high tip lip which means much of the extension into your ear comes from the tip itself.

AAW Halcyon


AAW supplied two sets of tips with the Halcyon: foam, and single bore silicone. Both variations come in standard small, medium, large, and all packed in a foam tray that sites very neatly at the bottom of the Halcyon carry case.

Personally, the single-bore silicone does not really work for me as well as the foams for isolation and a secure fit. They do let in a bit more treble presence but if you do not get that sweet spot in your ear you can lose a bit of power and bass presence. The foam tips will warm up the sound, add some more bass weight but attenuate the treble down a little in the process.

I would roll the Halcyon with Final E tips personally. They make a huge difference with a much fuller low-end and a bit more treble shining through than the stock foams. They also deliver an airier soundstage and generally paint a livelier picture than either of the stock tips. They make a great pairing with the bass filter for low-end power.

I also tried some single bore silicone SpinFit tips with the Halcyon and like the Final E they did a great job fleshing out the low-end but not quite to the same explosive level as the Final E. However, they did create a bit more girth in the midrange with a smoother treble tone and for some the more balanced of the two tips.

AAW Halcyon

Packaging & Accessories

Oh gosh, impressive packaging and something which AAW has worked on quite a lot over the last few years. Gone is the singular blue leather-wrapped zipper case from the Canary and Nightingale.

Instead, we have a rectangular display case with a smaller blue leather carry case, IEMs, and the filter plate all neatly laid out in a velvet wrapped foam layer. Inside the full accessory line-up is as follows:

  • Thera Monocrystalline IEM Cable
  • Genuine Leather Carry Case
  • BassFlow™ Control Filters
  • 3 Pairs of Silicone Ear Tips
  • 3 Pairs of Foam Ear Tips
  • Cleaning Tool
  • Owner’s Club Card

AAW Halcyon

Most of this you will find tucked away inside the mid-sized blue leather zippered carry case which has a lovely lattice finish on the top and plenty of space inside for tips, cable, and monitors. The Owner’s club card also has an ID number which you can use to register your Halcyon online and get an additional 3 months warranty. Something I highly suggest you do.

The only critique I would have is based on my tip rolling experience. I would love to see a set of Final E or SpinFit tips inside the box as a 3rd tip option. They are much more dynamic sounding than either of the stock tips.

Click on page 2 below for sound impressions and comparisons

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