Aurai Audio Z215 Review: My Journey

I started writing this review in November 2021. Initially I thought it would be fairly simple and quick. It turned out to be neither. Listening to my room and my system through these speakers has turned out to be quite an education. It started at what I would consider to be a college sophomore stage, and through the months of changes to the system, I am now feeling more like a graduate student of Aurai University.

About Aurai Audio

Alain Pratali made his name in audio when he designed several products for Oracle Audio. The 1000 and 2000 CD players and amplifiers were his designs, and have been highly regarded products. He has designed several award winning loudspeakers under his brand Aurai Audio. The M1, M3, Lieutenant Capitain have all been featured in Sixmoons and given rave reviews by non other than Srajan himself.

The Z215 is one of his new Z Series loudspeakers. All are 2 way designs featuring a proprietary high frequency driver, time aligned and mounted atop a uniquely tuned enclosure featuring a Supravox full range driver. The Z 215 incorporates the 215mm Supravox, the 245 incorporates the 245mm driver, and the 285 uses the (you guessed it) 285mm Supravox.

The Z series explores higher efficiency designs, as all possess sensitivity beyond 95dB.

They are offered as a stand mount design, or can be configured to sit atop a matching powered bass module.

Aurai Speaker Philosophy Design

Along with the usual goals of a flat frequency response and uniform dispersion, Alain focuses on impulse response times and in-phase transient response. In other words, drivers that are fast, don't ring, and a speaker with time and phase coherence. Those aren't necessarily unique, but do lend themselves to a speaker that can reproduce very fine harmonic complexity, image like crazy and paint a huge, 3-dimensional soundstage.

Part of Aurai's "Special Sauce" lies within their proprietary polymer high frequency driver. A tweeter whose mass is only .12g. It uses a "floating" system, whereby no screws or extra glue are used to hold it in place. The net result is it works without tension and far fewer unwanted mechanical resonances. The polymer tweeter is then loaded into a horn which reduces frequency related lobing (ex. sound changes when you stand vs. sitting) issues common to every high frequency driver, and it keeps the energy (output) constant over it's pass band. When matching the tweeter to a woofer, Alain has incorporated an ingenious method of using a magnet to give up to 6dB of tuning capability WITHOUT the use of resistors in the high frequency driver's signal path. In the case of the Z215 however, the tweeter does not need any attenuation, as the woofer is several dB more efficient.

To attenuate the output of the Supravox woofer, the Z215 he incorporates an autoformer with several taps that allows one to tailor it's output relative to the tweeter. I received the Z215 with the autoformer set to attenuate the woofer by  -5dB. I ultimately settled on the -4dB down setting for my system and taste. Instead of turning the tweeter level downward, in this case I turned the woofer up. This created a warmer, richer balance with highs that were silky smooth but not lacking in speed or resolution.

The 215mm Supravox driver.

The Z215

Making a departure from the M Series, Z series are higher efficiency two way designs centered around the Supravox full range drivers, and the proprietary horn loaded high frequency drivers. The Supravox were chosen because of their sound and specifications within the envelope of performance Alain was looking for. 

The Z 215 utilizes a 215mm (8.46 inch) Supravox Midbass driver in what is called a Tapered Quarter Wave Tube. This creates a physically deep cabinet with a large opening on the back. I mean, large.  This clever design does several things:

1. It extends the bass response of the driver without reducing the speed of the bass. You get a useable response into the 60Hz region.
2. It creates a quasi-dipole speaker. The large opening in the back, coupled with the dipole tweeter, radiates sound in a dipole fashion. 
3. It keeps the enclosure from building up internal pressures and resonating. All that air escapes out through the TQWT opening with no buildup of pressure. 
4. It eliminates back waves (from reflecting off of the back of an enclosure) from radiating back through the driver

The rear of the Z215, showing the large TQWT opening.

TQWT with the grille removed.

Bass modules are available, but I chose to have a stand mounted monitor and pair with optimally placed subwoofers delivered. More on why I made that choice later...

The enclosures are high grade 1" Baltic birch plywood veneered in cherry with a high gloss finish. No MDF here. Since the speakers are made to order, the choice of veneers is nearly limitless if your budget allows.

Specs

• 60Hz-20kHz
• 96dB
• Supravox Paper Full range driver crossed at 3000hz
• Proprietary super light polymer horn loaded tweeter with a floating suspension
• Dimensions (with stands):
• HxWxD: 41" x 12.25" x 21 3/4"

The Z215 Frequency response at 1 meter

Z215 Frequency response at 2.5 meters

Build Process & Delivery

A very well packed pair of speakers

I was surprised that is only took about 4 weeks for Aurai to build my loudspeakers. Alain himself was in constant communication with me. Since he does not speak English and I do not speak French, we made heavy use of Google Translate, and communication was excellent. The speakers were packed in a single heavy duty crate, with metal reinforced edges and a thick foam internal cocoon. The crate was too large for a single person to carry, but I simply disassembled the crate with my trusty cordless drill and the speakers were easy enough to carry into the studio individually. The disassembled crate was easy for me to store since it now could be laid flat and put on a large shelf. I bagged the foam padding just so it wouldn't accumulate dust or insects while in storage.

Well foamed speakers and stands

The stands were unassembled but were easier to put together than an Ikea chair. All that was needed was a rubber mallet to gently coax the precisely fitting cut joints together. No gluing necessary.

The Z215 on stand, ready to play.

The fit and finish were first rate, as they should be for a speaker of this price. Alain's cabinet maker did a top-notch job with routing driver cutouts, assembling, and finishing the speaker.  The packaging and finishing of this caliber just makes the experience of buying a speaker so enjoyable. Yes even from a dealer perspective, the experience matters. Alain and Antoine are reliable, exceedingly competent and pleasant to work with. That is hugely important to me.

Placement

For placing the Z 215's, I relied on the New Record Day LOTS Placement method to work well in my room. I've also taken measurements at the listening position. I have one room peak I cannot get rid of that is at about 150 Hz. This speaker placement system, and my subwoofer positions, do not exacerbate the existing resonance, so I feel I have things pretty well dialed in.

Even though this is a monitor design, it can play like a big speaker that loves space and can scale.
I had solid, useable bass response down to 60Hz. One could use these as a full range system, and the sound would be warm and satisfying, albeit fairly lightweight. For real sonic heft, a subwoofer is required.

Tweaking out

This part was really interesting, and at times frustrating. At times I heard things that were negative, and blamed the speakers. But clearly as the frequency response curves indicated, they were not the cause, but they were the "amplifier" of what errant tweaks or cabling were doing. Yes, the Tweek Geek says that you can over tweak things. I was compensating for other speakers when I put the tweaks in, and the Aurai's revealed that I had gone too far. I removed many little tweaks here and there. The biggest gain was made from swapping out my wall outlet from the Furutech GTX D NCF to a QSA Violet. The QSA was a whole league above the Furutech in terms of naturalness, holographic imaging, and huge soundstaging. I also removed two of the three power conditioners I had running. Leaving only my prototype Bybee Stealth (soon to be V4, as soon as I can get a custom chassis for it). These speakers will tell you if something is amiss immediately. Its funny though. Usually speakers that do this will also shred your ears with less than stellar recordings. These did not once everything was in balance.

Cabling up

Cables were rotated in and out, with the performance being very dependent on them. Specifically speaker cables and interconnects. I started with my own speaker cable, which despite it's 9awg build was a little lean and dry in the midband and upper ranges. From there I tried Audience Studio One which allowed the speakers to provide more detail and more dimensionality, but I found the speakers revealed a little boost in the warmth. The FrontRow from audience was next up, offering even more detail, and better dynamics than the Studio One, but still a teeny boost in the lower bass/upper midrange area. At least on this speaker. It was still very, very good. I listened with the FrontRow for over a month before trying the Silversmith Fidelium. The Fideliums were designed to minimize phase shift. With the time aligned design and resolution of the Z215 this created some incredible holography. It also revealed the slightest harmonics, reverb effects, and brought more clarity to the high frequencies. The overall tone with the Fidelium cables on this speaker was darker, less sparkly, and less lit up at the highest frequencies. But the information that was coming through was astonishing. So, a little less sparkle, but I can't say the speakers sounded closed in or that the soundstage collapsed. I still had an enveloping soundstage with so much texture and subtlety.   

Last cable swap was with the latest cables from Stein Music. Their 3X, 4X and 8X power cords, along with the Silver Matrix interconnect. Here is where my journey ended, for now. The sound was  more refined, slightly laid back, creating for me what was an immersive, wonder inducing listening experience.

A Word On Bass Augmentation

If you wish to go lower than 60Hz, there is an optional matching powered subwoofer that can act as a stand for the Z215. As for me, I preferred to use the minimalist stand, keeping the front baffle area small, and utilizing multiple subs placed optimally within the room. In my opinion, one rarely finds a placement for a full range speaker that produces a reasonably level bass response and optimal imaging. Compromises must be made between optimizing bass performance and imaging. By having the ability to separate the low frequency reproducers from the mid and high allows one to more optimally place the main speakers for best imaging, and optimally place the bass drivers for best in room performance of the lower frequencies.

The open baffle servo sub tower next to the Z215.

For sub-woofage I chose a dipole (open baffle), servo controlled subwoofer. This design came out of a partnership between GR Research and Rythmik Audio. GR had a special 12" bass driver made of lighter, stiffer paper (better for music) and Rythmik Audio supplied the servo controlled power amp for the GR drivers. I purchased the "enclosure"  as a flat pack and assembled it myself. I have 2 of these subs, each with 4 12" drivers, powered by 2, 2 channel subwoofer amps. That's 8 12" subwoofers powered by 4 channels of amplification. But in all honesty, 8 open baffle subs is equal to about 4 12" sealed box subs in terms of room pressurization. But the quality of bass from the 8 OB subs is better. The servos correct for driver overshoot, allowing the drivers to stop instantly, even in free air. The response of the subs goes down to 19Hz, but more importantly, they are fast, accurate and very tuneful. The drawback is that the OB subs need space to the front and rear. They need to sit out in the room a ways. They can sit closer to side walls because their output to the side of the woofers is next to nothing. It's a null. But front and back, give them some breathing room.  I highly recommend the OB subs if you have the space for them. If you don't have that option, the next best thing is a sealed version of the servo sub that Rythmik Audio manufactures. After that a high quality sealed subwoofer is the next best thing. No ported subs please. You need speed to keep up with the Z's.

Playback Equipment

• Innuos Phoenix Switch - receives streaming data from the router, reclocks it, then sends it on to the streamer.

• Innuos Statement - Streaming Qobuz, Tidal, and my own collection of music

• Merason DAC 1 - Non oversampling DAC

• Modwright KWA225i (Class AB, Zero Negative Feedback 225 watts) and Qualiton X200 (KT150, EC88, E88C tubes, 100 watts, ) Integrated amplifiers. The Qualiton was preferred after a very long audition of both. But honestly the jury is still out on that one. The Modwright had more sparkle, the Qualiton more romance, inner glow...

• Audience frontRow interconnects, power cords, and speaker cables. Silversmith Audio Fidelium speaker cables. Steinmusic 3X, 4X, 8X power cords, Silver Matrix interconnects (available July 2022).

• Dark Matter Stealth Power conditioner

• ADD-Powr Sorcer X4

• Steinmusic Shuman sine wave generators (2)

• Stein Harmonizer System with 4 Harmonizers and 2 Blue Stones

• QSA Violet wall receptacle

(Partial) Playlist

• Anouar Brahem - Al Birwa from The Astounding Eyes of Rita, ECM Records. 
• Radiohead - Weird Fishes, from In Rainbows
• Ry X - Shortline
• Nick Cave and the Bad Seeds - Higg's Boson Blues from the album Push The Sky Away
• Prince - It's Gonna Be Lonely from the self titled album
• Pale Green Things by The Mountain Goats
• Sarah Bareilles - Gravity from the album Brave Enough
• Oliver Nelson - Stolen Moments from Blues and the Abstract Truth
• Kenny Burrel - Chitlins Con Carne from Midnight Blue
• Cecile McLorin Salvant - I Didn't Know What Time It Was from Woman Child
• Theme from Jurassic Park by Hans Zimmer

Lows

Since the speaker has limited low frequency operation, I will focus on speed, impact, definition, tonality and tunefulness. The Z215 revealed to me mid-low frequency detail, punch, tone and harmonics in many familiar recordings that I hadn't heard before. With string bass there were plucks, strums, and slaps that had impact. You could hear the body of the instrument, and feel the room it was in. Drums were tonal, clear, and sharp. There was the strike, the note, and the decay of the skins. if the drums were heavily damped, you could hear that too. They started and stopped with incredible immediacy.

Mids/Vocals

Vocals are scary present, textured, intimate when called for. I will paraphrase Srajan of Sixmoons with his review of the Aurai Lieutenant in that the depth of high harmonics in the upper midrange went well beyond what one normally gets from paper cone drivers. The Z215 dug down deeper into a tone's harmonic layers without becoming slow or syrupy. It made sense out of complex passages where most drivers compress and sounds start overrunning each other to become one homogenous mess of noise. If you are familiar with Radiohead's "Weird Fishes" from their album In Rainbows, you know that there are so many layers, with such divergent sounds, that it can turn to mush. Especially around the 4 minute mark. The Z215's kept the layers layered, the sounds individual enough, and everything together created this fascinating whole that was simply a treat for my ears.

Highs

This is where the Z 215 really shines, and will also reveal any shortcomings in your system. The ultra lightweight membrane  and horn loading gives the driver incredible speed, delicacy and energy. The polymer material of the high frequency driver does not have the zip or ringing of a metallic ribbon as it is better damped. Transients and recovery from transients are incredibly lifelike. The speed helped to decode with clarity rapid cymbal or snare strikes unlike anything I have heard. Ever. This is one Bugatti class driver.

Resolution

This is where things can be challenging with the Z215. It is not as forgiving as some speakers of poor system or cable matching, and will quickly let you know that there is a mismatch. If only it could tell you where. For me it was the cabling, and  tweaks. I ended up with a QSA outlet at the wall, Stein Harmonizers, Stein Schumann generator, Stein interconnects and power cables. The speaker cables ended up being the Silversmith Fideliums. This combination worked for me. When I say "worked" I mean I stopped looking for things to improve.

Coherance

Another area where if things are not right in your system you will know it. When things were optimized, the sound eminated from spaces in the room in front of you. Not a flat plane, but the entire room. You could not hear one driver, let alone one speaker. Everything worked as a seamless whole.

Imaging/Soundstaging/Phase

Flat out superb. The phase coherent, time aligned speakers behaved as expected. Disappearing sonically, leaving a very expansive soundstage, and pinpoint imaging. They pressurized the room in a way that felt bigger than the room itself on certain recordings. Sound was everywhere, and you were in the middle of it. Now to be clear, the performers were still in front of you, but reverb, hall echos, etc. filled the entire room and surrounded you as they would in a live setting.

Dynamics

At 96dB, the Z215 is lively, dynamic and presents dynamic information extraordinarily well. Transient information is conveyed effortlessly with absolutely no overshoot or overhang. Vocal Transients on Muddy Waters album Folk Singer, track 1 "My Home is in the Delta" were shocking, uncompressed and had me startled in my seat. 

Complexities/Harmonics

If you listen to  complex music, be it orchestral, vocal, or well recorded rock and electronic music, the Z 215 can present musical complexity in a delicate, coherent, and natural manner without mashing sounds together. As you turn the volume up, they hold their composure, although your room may not. It makes a great argument for acoustically treating one's room.

Scale

Again, the advantage of a time aligned, phase coherent speaker is that phase information that gives the sense of the size of a venue (small club vs. concert hall) exactly as it was recorded. It can be jarring at times when going through a playlist that has a mix of such recordings. One goes from being in a concert hall, to a tiny club in the blink of an eye. This is felt almost as much as it is heard, that's how I explain it. 

When one is discussing power handling and output as a factor of scale, the Z215 definitely plays bigger than it's dimensions would lead you to believe. I drove them with 225 watts and they didn't break a sweat.

Conclusions

After living with the Aurai's for more than 6 months, I can now safely say that  the Z215 is one of the best loudspeakers I have had in my system to date. Not since the Vivid Audio Giya have I had such imaging, soundstaging, sheer output and musical enjoyment. The 215's do exceed the Giyas in that they are more natural sounding with my system and to my ears. That is very high praise indeed. When the recording and system setup are up to it, these speakers will disappear and throw a huge, wrap-around soundstage with pinpoint imaging, naturalness and "relaxed resolution" that will leave you reveling in the moment. There is an element of wonder that this speaker brings. A bit of what got me hooked on audio and music in the first place.  I suspect because of the way the speaker just seems "right" in so many aspects of it's portrayal of the musical event.  It is lively, textured, engaging, and energizes the listening space with emotion and  music.

With my final system setup, even the not so good recordings brought joy, and had elements within them that made them engaging and enjoyable. With many hyper-revealing speakers this is not the case. The Aurai's have pulled off a magic trick of epic proportions here. Enjoyable, engaging, and super-resolving.

When I want to listen, and melt into the moment, the Z 215's deliver. When I need to put my "analytical ears" on, for example when evaluating a component or tweak, the Z215 also allows me to precisely determine a product's effect in my system very quickly. It can be used as a microscope for hearing changes, but one has to be mindful of the task at hand or otherwise be caught up in to the music and out of analysis mode. Consider this your warning. :)