Crosszone CZ-8A

A technical marvel of a headphone attempting “speaker like” sound

The Crosszone CZ-8A is a closed-back headphone from the Japanese company Crosszone, specifically known for its innovative approach to spatial audio in headphones. Built to create a natural and expansive speaker-like soundstage, the CZ-8A uses some very interesting technologies that deliver a lifelike, out-of-head listening experience by simulating a stereo speaker setup.

Originally priced at $1700 this is premium headphone but while researching this review I came to appreciate that there was some extreme R&D cost required to build their headphones, so I have added a section below to explain some of their technical design.

The CZ-8A is one of the most interesting, though not necessarily the best sounding headphones, I have had the pleasure to listen too for an extended period of time. During my time with this headphone, I did notice a few things both good and bad, that I thought I would share in this review. I also think I have a “happy ending” as ultimately I got this headphone to sound the way I think it was meant to sound.

So if you are interested read on to find out, but first I think some background on this headphone is required:

Crosszone’s unique headphone configuration

So Crosszone describe themselves as the one company providing out-of-head localization in headphones with entirely acoustic / analog technology. I have played around (as many others have) with “digital” Crossfade which typically might be available in some high end DAC with various PEQ and filtering options. Well Crosszone believe they can provide an enhanced version of this effect using just analog technology built into the headphone.

So they effectively send both Left and right channels to both ear-cups, delaying the alternative channel (i.e. delaying the right channel’s signal on the left earcup) and then use a very sophisticated multi “driver” setup to deliver effectively that “in room” experience where ears would expect signals from both speakers with a slight delay from the more distant speaker to each ear, depending on the drivers configuration in each ear:

I think the speaker driver layout explains how they have “solved” this problem better than I can:

Note: as someone who has also reviewed a lot of IEM’s including many hybrid configuration it did strike me as strange (especially after listening to the CZ-8A for long periods) that this technique has not been tried with IEMs as it would almost certainly solve that “inside your head” sound that even the best IEM’s cannot properly escape, especially in an era of “usb-c” based IEM where I imagine a delay “buffer” could be utilised in the “dongle” to simulate this effect rather than the “analog” approach which Crosszone have taken.

Build quality and accessories

Since I am borrowing the CZ-8A I did not get the original retail box, instead I received the CZ-8A in its case and with a separate bag with the various cable options. I believe there is also an “enhanced” version of the CZ-8A which has a more premium box for its unboxing.

But the Crosszone CZ-8A retro style case does hint at luxury, in a retro 1970’s type fashion:

Opening the case reveals the CZ-8A and some cables:

Note: I did find this photo online of how the headphone might be found within the retail box (though this was from a japanese website and may be an exclusive packaging of this headphone):

I believe the complete retail box includes:

• Crosszone CZ-8A headphones
• Two OFC cables:
  • 1.5m cable with a 3.5mm plug
  • 3.5m cable with a 6.3mm plug
• User manual and warranty card

The cables, like the headphones, feel premium and durable, but due to the unique design of the CZ-8A’s these cables do not have left and right channel as both channels are fed to both ear cups:

One minor negative about this headphone is the typical things you might replace or upgrade like the cables or as you will see the earpads are unique and so difficult to find 3rd party replacements.

Design and Comfort

True to its Japanese heritage, the Crosszone CZ-8A is a meticulously crafted headphone that combines high-grade materials with ergonomic design.

From above:

The 3D-molded ear pads are carefully contoured to create a snug fit, comfortably accommodating various head shapes and sizes:

Crosszone has also considered the shape of the head and ears by designing angled ear pads that maintain sound stability and minimize pressure.

The headband and hinge system allow for easy adjustments and ensure the headphones stay securely in place.

While the headband was reasonable comfortable I have seen more comfortable designs as there is not allot of flexibility in the top of the headband:

Earpads

The earpads have a unique rounded triangular shape which are fairly comfortable though I do think makes the headphone a bit “positionally dependent”, i.e. move the headphone to a different angle on your head will greatly affect the sound much more than a more symmetrical or rounded earpad:

Later on you will see in the measurements you will see slightly different seating’s can change the bass response especially. I also think with this ear pad design it will be harder to find replacements, but as I mentioned they are very comfortable.

Unique Features

The Crosszone CZ-8A stands out for its unique approach to creating a spatial sound experience that mimics the feel of stereo speakers, addressing the common issue of “center localization” (where sounds are perceived within the head).

As I presented earlier the unique design of the driver configuration is the key to this localization:

Zooming into an individual earpad:

And into a specific angled driver:

Crosszone achieves this with several proprietary technologies:

Acoustic Resonance Technology (ART)

The ART system utilizes acoustic lenses and delay chambers to control the wavefront, guiding sound to the ears in a way that simulates a speaker setup. This technology helps avoid the typical “inside-the-head” sound of most headphones, creating an expansive and realistic soundstage.

Acoustic Delay Chambers (ADC)

Incorporating an Acoustic Delay Chamber (ADC) in each ear cup, the CZ-8A adjusts the timing of soundwaves to each ear, enhancing the spatial feel. This unique approach delivers the sensation of sound coming from outside the headphones, helping to simulate an out-of-head listening experience.

Tri-Driver Setup

The CZ-8A features a three-driver configuration: a 40mm woofer, a 23mm tweeter, and a 35mm cross-feed driver for each ear cup. Each driver is beryllium-coated for stability and detail, with a brass ring around each driver to minimize vibrations. The combination of multiple drivers with precise acoustic tuning offers clear and detailed sound across the frequency range.

Sound Quality

Note: While I did ultimately switch to listening with my EQ (as presented later) these sound impressions are based on the out of the box sound profile.

The Crosszone CZ-8A takes a distinctive approach to sound reproduction, aiming for a natural open sound rather than a conventional closed-back profile. The result is a headphone with good bass, mostly natural mids, and a recessed treble, combined with the time domain changes in the FR to provide that spacious and immersive soundstage.

Bass

The CZ-8A delivers full and deep bass, with excellent control and minimal distortion. Low-end frequencies feel natural, supporting the sound without overwhelming the mids or highs. Tracks like “Royals” by Lorde showcase the CZ-8A’s ability to render bass with both depth and accuracy, lending a strong foundation to the sound without excess bloom.

Midrange

The mids are not as balanced as I would like, this makes some vocals sound unnatural, these problems can easily be solved with EQ but one of the strange tuning decisions with the CZ-8A that keep it from being an extraordinary headphone. But the ART and ADC systems do enhance the sense of space, allowing vocals and instruments to occupy distinct positions in the soundstage. On acoustic tracks like “Fast Car” by Tracy Chapman, the CZ-8A captures the warmth of the guitar and the texture of the vocals with remarkable clarity.

Treble

The treble is slightly recessed which can sound a bit laided back for some people but will perfect for those who might be continuous of Sibilance. The beryllium-coated tweeter ensures that high frequencies remain articulate, allowing cymbals and strings to shine without sibilance. The treble extension is clear but controlled, avoiding the piercing highs that can cause listening fatigue.

Soundstage and Imaging

The soundstage of the Crosszone CZ-8A is remarkably wide for a closed-back design, thanks to ART and ADC technologies. The wavefront control system allows sounds to be positioned with depth and direction, providing a three-dimensional listening experience. This quality makes the CZ-8A feel more like a speaker system than a headphone, enhancing the presence and depth of the audio. Imaging is equally precise, making it easy to locate instruments and vocals within the soundscape.

Specifications and Measurements

• Type: Closed-back, over-ear
• Driver Configuration: 40mm woofer, 23mm tweeter, 35mm cross-feed driver (beryllium-coated)
• Frequency Response: 10 Hz - 50 kHz
• Impedance: 60 Ω
• Sensitivity: 98 dB/mW
• Weight: 480g (without cable)
• Included Cables: 1.5m and 3.5m OFC cables with 3.5mm and 6.3mm plugs

The CZ-8A’s frequency response provides an even balance across the spectrum, with slight elevation in the bass for a natural, full sound. The high sensitivity of 98 dB/mW ensures compatibility with a range of sources, though the 60Ω impedance suggests it may benefit from an amplifier to bring out its full capabilities.

Measurements

Crosszone’s proprietary design actually makes measurements of this headphone both interesting and challenging. Since both channels are feed into both speakers a single Left or Right sweep is not good enough but since each earpad has a complex design it can be worth trying to how much of channel contributes to the overall sound signature in each ear cup.

Frequency Response

So due to the nature of the way each ear has multiple drivers and mixes both the left and right channels in a way that emulates listening to speakers in a room, there is not really just one frequency response or at least it makes sense to present both the left and right channel response separately and combined for each ear.

So there is a lot to see above from just the Right Ear measurements - what is most interesting is where the Left channel contributions to the Frequency Response i.e. Purple, specifically Crosszone have mostly pushed the midrange of the left channel into the right ear (and the opposite obviously happens on the other ear ) but what I thought was fascinating is that can see the expected phase cancellation with the combined measurement specifically in the 1-2Khz region.

But this graph also shows some of the things I didn’t like with the sound, for example a very recessed treble region and a muddy bass. My EQ recommendations which I will show later will try an alleviate some of the deficiencies, but having tried many EQ options I did leave that interesting 1-2Khz region alone.

The Soundstage “effect”

Just highlighting that specific region again where I believe the delayed Left channel audio is out of phase because of what Crosszone are doing to get that “speakers in a room” effect:

Here are some of my headphones that do try to diverge from Harman in that region to give that effect that seems to be a natural side effect of the delay introduced by Crosszone:

More Frequency Responses

So I thought I would show a little bit more of each of the separate Frequency responses.

First the “main” driver in each ear:
This shows reasonable good channel matching and a match to Harman except for the recessed treble.

Note: I did measure with different seatings including (with thin framed glasses) - the bass drops considerable:

Here is the FR of the opposite channels:

Distortion:

Here is main driver distortion - mostly pretty good other than maybe that increase in the 3rd harmonic around 1Khz:

But as a percentage it seems fine:

And given the driver playing the opposite channel has an easier job it shows very little distortion:

Group Delay:

The group delay shows some oddness in that 700Khz region:

And the combined group delay looks even messier:

EQ:

So if you get a good seal (especially without glasses) I think the main issue with the Crosszone is the recessed treble give it a dull sound, so after a couple of weeks I ended up using this EQ: This tidies up the bass response and mainly enhanced the treble. I did adjust that 1-2Khz region a little to make vocals sound more realistic without messing with that “soundstage effect”.

Preamp: 0 dB
Filter 1:  ON  PK  Fc 58 Hz  Gain 4.4 dB  Q 0.7
Filter 2:  ON  PK  Fc 130 Hz  Gain -3 dB  Q 1.7
Filter 3:  ON  PK  Fc 270 Hz  Gain -5 dB  Q 0.8
Filter 4:  ON  PK  Fc 1600 Hz  Gain 4.43 dB  Q 2.39
Filter 5:  ON  PK  Fc 2700 Hz  Gain -4.13 dB  Q 7.21
Filter 6:  ON  PK  Fc 4100 Hz  Gain 5.57 dB  Q 1.41
Filter 7:  ON  PK  Fc 7900 Hz  Gain 10.14 dB  Q 1.7

Rating

The Crosszone CZ-8A would receive a 5-star pragmatic rating for its innovative approach to providing a closed-back design with a much more open sound, but I did feel the default sound signature while incredibly spatious sounding was a little too dull and laid back for the price you pay, so I took away 1-star. But with EQ this headphone was transformed into something that is really special.

Conclusion

The Crosszone CZ-8A is an exceptional headphone that redefines what’s possible with a closed-back design. For those who appreciate an expansive, natural sound with meticulous detail and build quality, the CZ-8A is a unique and rewarding choice. With its focus on spatial accuracy and a lifelike sound field, it’s a standout for audiophiles and professionals alike who want an experience that blurs the line between headphones and speakers.

For audiophiles seeking an immersive listening experience with the convenience of headphones, the CZ-8A offers a unique take on high-end closed-back audio reproduction.

The CZ-8A’s combination of advanced driver technology, precision engineering, and acoustic innovation sets it apart from traditional closed-back designs, aiming to provide true spatial depth while maintaining clarity and detail.