PureAudioProject Trio15 Coax10 open-baffle speakers Review

PureAudioProject moves to a 3-way crossover

Ah, yes, the speakers… the move to a three-way crossover is transformative for these speakers. In vain I have tried over the years to convince some hobbyists that usually they lose out by trying to simplify too much, that is, to seek a smallish two-way speaker, as though by opting for simplicity they have won big. No, they haven’t. They have diminished their system substantially. They may have more clarity—maybe. But they have forfeited the grandness, the opulence of a more generous-sounding speaker. Is there an exception, a two-way speaker that can capture the fullness of a larger, multi-way speaker? In the vast majority of instances, no. Hobbyists think they have achieved that feat, but once a larger, multi-way speaker is brought into their room, they realize how short the two-way has fallen in terms of performance.

I remember the transition from using the Voxativ AC-1.6 driver in the Trio15 to the Horn1 driver. The speakers use different crossovers, both are built by Mundorf with the same crossover platform, i.e. screw-down resistors and capacitors, so I cannot speak absolutely about the drivers in isolation. The Voxativ was comparatively laid back compared to the Horn1 and had a bit wider center image. The Horn1 is a highly coherent driver that demands very precise positioning, perhaps as much as any speaker I have used. When dialed in the Horn1 is superb at hardening, that is, solidifying the center image, and so it is excellent for chamber music, solo instruments and voice. A speaker such as the Tannoy Glenair has a ripeness, a fullness and midrange bloom that evades the Horn1. The concentric Tannoy might be described as burlier and not as spritely, while the Horn1 is comparatively lithe and with relatively less weight or bloom in the midrange.

Now comes the Trio15 Coax10. Let the reader who is entranced by evocative names for speakers after rivers, planets, or animals not be put off by the colorless name for this model, as it is anything but colorless sounding! Things have gotten much better in respect to the Coax10. The generous-sized paper mid-bass driver is a thing of beauty, along with the polymer tweeter used in the Horn1. They both are Beyma drivers, but the tweeter sounds utterly different in the new application, and to my ear it is a very good change. The Voxativ speaker had a paper wave guide, but the 10” Coaxial uses a cast waveguide affixed to the basket of the 10” driver. I am impressed, as I love everything I’m hearing from this driver!

While I’m at it, the Mundorf-built crossover is top notch, with robust binding posts and oil-filled caps (one poly cap the exception). Ze’ev says it simply sounded better in that application than the oil-filled cap. Don’t scoff; I have heard several other designers say such things. PAP supplies a couple pair of resistors for challenging situations where particular frequencies need adjustment due to hearing issues or the system’s lack of conformity to expected performance. Screw down terminals for the resistors and speaker cables allow for experimentation. I’m sticking with the basics here so as to not give the impression that the supplied speaker cables are not good enough. Two facts that are not contradictory; they are good enough for me to be completely satisfied with the performance, and I will most assuredly explore upgrades to these wires over time. I am a maximizer, and I have a hard time leaving such things alone, but have to reach for the next level. Frankly, I did not expect such good sound as I am getting with the stock cables. Were they perceptually deficient, I would reach for an alternative wire, but have not. So, take that as an indication of their suitability.

In an awesome turn, this is the first crossover from PAP that I have used featuring the option of connecting four channels of amplification! It took me only a few minutes of comparison to firmly conclude the speakers will not be returned to two-channel operation, but four channels of the i.V4 Ultra will remain in use as long as these amps are here. Importantly, because of the coaxial nature of the primary driver, the coherence suffered not one bit from passively bi-amping. That is a luxury that most speakers cannot afford.

Improving by switching the DAC and cables

The system was improved by changing the DAC setup to the COS ENGINEERING D1 DAC + Pre-Amplifier and replacing the RCA interconnects with the Iconoclast sibling XLR cables, as the Legacy i.V4 Ultra accepts either connector for all channels. In this arrangement I used the Fixed output (maximum) of the SONORE Signature Rendu as operated through Roon’s software and used the internal preamp in the integrated COS D1 DAC, which increased the gain and allowed for the option of turning the Buffer of the D1 on or off. Over the years the performance of the Buffer setting has been system dependent, and in this case the sound was more robust and tonally balanced with the Buffer turned off. In an example of why all iterations should be tried with every new setup, defeating the Buffer of the COS D1 usually results in a more sinewy, thinner sound, but in this case, it was thicker, more robust! One simply does not know the outcome if the setting is not tried. The changes drove home the point that the 10” Coaxial driver had a lot more to give in terms of resolution, as is often the case with a new speaker. Usually, the first setup is not the best overall, and the onus is upon the owner to drive the changes forward to achieve a more preferred performance level.

Mature speaker

The Trio15 Coax10 has matured beyond where I thought it could. Top down this driver sounds upscale in every parameter of performance. Its sonic character is reminiscent of fine models from Voxativ and Lotus Group heard at shows. I did not think the driver capable of the precision of the Horn1 version, but with the introduction of the COS DAC and Iconoclast XLR Interconnect Cables I changed my mind. The Horn1 does not have the bloom, the midrange presence, that the Trio15 Coax10 has. Those who wish for a skinny, more brisk sound might consider the Trio15 Coax10 to put too much meat on the bones. I am sensitive to speakers that sound bloated, overly warm and syrupy, and the Trio15 Coax10 does not elicit that reaction.

The Trio15 Coax10 fills a midrange gap between the Horn1’s primary driver and the 15” pair of woofers. The result is a sense of increased solidity in the bass, so much needed with an open baffle speaker, and softened top-end due to the filling of the midrange. Top to bottom, it has a more even and extended output across the frequency spectrum than any other PAP driver I have used.

Vocals are greatly enhanced by the 10” driver. I listen to lot of jazz female vocals, and instantly I registered a warming and thickening in the voices of artists such as Sarah Bareilles, Alyson Moyet (what a voice for jazz!) and Joy Williams. In female vocals I have tended toward alto voices partly because I am annoyed at the shrillness of some sopranos. The Trio15 Coax10 is masterful in moderating shrillness, whether instrumental or vocal. In your system, relative to the other PureAudioProject center drivers, the Coax10 will be warmer sounding and riper sounding. That is what a 10” mid-bass driver does. If you wish to read my analysis of the size of midrange drivers, look at my review of the massive Legacy Audio Valor Speaker System with its 12” midrange coaxial driver. I’m not saying here that the Trio15 or Quintet15 are holistic replacements for the Valor, but in terms of the warmth and generosity of the midrange, they are, to use Folgelberg and Weisberg’s album title, twin sons of different mothers.

Resolution and retrieval of nuances

Resolution directly influences the degree to which nuances in the music are heard, and that is so regardless of the brand or model of speaker. The speaker can only capture what the components and cables allow, so any judgment of a speaker’s capacity to be revealing is dependent upon the system upstream. It is one reason why visiting a show or showroom is not a complete experience in terms of the speaker’s performance capabilities.

I have done several things over the years to increase resolution in systems, including treating CDs before moving to file and streaming playback, upgrading cables, upgrading the DAC, and moving from traditional amps to class D. All of these have improved resolution, but often the system has to be re-tuned to achieve the desired tonal palate. The genre of speaker is hugely important in conveying a sense of openness, which can be exploited by making a rig with very high resolution. A belief that will trip up the audiophile is to think that certain genres of speakers, such as electrostatics, inherently have superior resolution capabilities. It is nothing more than preference to ascribe exceptional definition and resolution to any genre of speaker without regard to the rest of the system build. I have not found any genre of speaker that asserts itself as fundamentally superior in terms of resolution and retrieval of nuances in the recording while played via inferior components. For instance, a panel speaker, such as a Magnepan, will not allow for exceptional resolution if driven by average components. There are limits to the performance of a speaker based on the quality level of the associated gear.

The resolution and nuance retrieval capabilities of the 10” Coaxial driver are pleasantly beyond what I had expected! The larger mid-bass driver and the tweeter are able to send through to the listener as much information from the signal as I hear from the electrostatic, omni, or line source designs I have used. The more finesse a system has, the more the artistry of bass players, such as Marcus Miller, shines through. The Coaxial driver is so generous that it reveals the quickness in the fingering of the strings, and is plush enough to capture a wide range of detail, from the initial scraping and release of the string to the peak of its vibration. For the better part of twenty years, I have worked to get systems to present the bass line clearly. It is not easy to get an audio system to reveal the bass line distinctly. More typical is a rig that either flabs the bass and runs it all together or buries it under the rest of the frequency spectrum. In addition, speakers that are inherently incapable of hitting the sub-30 Hz range, or those with large drivers contained in boxy cabinets that bring cabinet-ringing distortion into the mix, have a difficult time of delivering pristine bass the way it would be heard in a recording session.

With the previously utilized center drivers, I had hit the outside limits of the bass performance of the Trio15. The bass line was clean but not overtly presented, and I thought this was due to the absolute limitations of the open baffle design. In fact, the lightness of the mid-bass due to utilization of the tiny horn coupled with the larger 15” woofers created a gap in the mid-bass, which the Coax10 has filled. Now, with higher power, the Coaxial driver, which is mated in a beautifully seamless fashion to the 15” woofers, brings forth the bass line obviously but not overbearingly. The frequency distribution in terms of performance with the Horn1 model I now see as shaped like a barbell, with emphasis at the extremes. However, with the 10” coaxial driver, the bulge has been moved inward such that the frequency distribution is more gathered —not obnoxiously, but slightly — into the middle, like a football. Another bonus of that redistribution is a more generous-sized center image, one that reaches further out from the center point toward the left and right discrete channel information. That also gives the listener the sense of more enormity of the artist who is center stage.

Further enhancement with new Iconoclast cables

As this part of the review was coming to a conclusion, Iconolcast sent me their new TPC Version 2 Speaker Cables, which are the first and lowest of three levels of a new design incorporating similar geometry to their sensational SPTPC top-of-the-line Version 1 Speaker Cables. The importance of this development is that Galen Gareis has now successfully split the function of the cable carrying the bass signal from the cable carrying the midrange and high frequencies. Iconoclast is building a reputation for impeccable sounding cables, and they captivate me, despite my handing several more costly brands.

This PAP speaker is superb at revealing the distinctions between these two versions of speaker cables. I had comparable 28” jumper cables of each as well, and I was able to reach from the crossover of the Trio15 to the input of the Legacy i.V4 Ultra Amp’s inputs, allowing me to replace the speaker cables with identically purposed jumper cables. The Version 2 Speaker Cables and Jumper Cables both squeeze out more vividness, resolution, timbral correctness and spaciousness than the former Version 1. As Iconoclast suggested, I preferred using the Version 1 (blue jacket) on the bass inputs and the Version 2 (red jacket) on the midrange and treble inputs. Galen had said the advantage point in using the Version 2 cables begins at about the 200 Hz crossover point, the same location as the crossover for the Trio15 Coax10! No wonder I heard the melding of the Version 1 on the bass and Version 2 on the mid/treble as ideal.

I said earlier that experimenting with the internal cables from the crossover to the drivers would intrigue me, but these cables are expensive enough so as to be harder to argue as a necessity for a speaker that starts at $8,250 U.S. I would not doubt that the sonic improvement over the stock cables would be significant. One obstacle to experimentation is the flat, slip-on tab posts for the tweeter only. The tab terminals on the tweeter do have a hole in them, and that might allow for a thinner wire to be threaded through and twisted tight, but it would call for using raw wire. I believe Iconoclast does not sell unterminated lengths, but Blue Jeans Cables, which does the terminations for Iconoclast, may have a budget-conscious option to try. For reassurance, the character of the sound with the provided cabling is excellent, and I suspect you will not be itchy for a change unless you have money to burn.

Listening experiences with the new driver

One of my lifelong favorite musical groups is the Alan Parsons Project, and I was pleased to see that there is a new live album from Alan Parsons, The NeverEnding Show: Live in the Netherlands, which is a gratifying listen with the new driver. I have a tendency to jack up the listening level on this album. I normally moderate the volume because there are treble artifacts that can come with different instruments, at times making them piercing to my ears. Not so with the beautiful Mundorf crossover work, as the treble is controlled nicely. It is a pleasure hearing the parade of vocalists work through much of the catalogue of hit songs, each voice crisply but not gratingly shining through the earnest band and symphonic accompaniment.

Johnny Cash has an unnerving piece called “The Man Comes Around,” in which he sings of the last Judgment of Christ. A low-level scratchy background gets obscured as his guitar and voice dominate, and he bluntly intones warnings such as, “It is hard for thee to kick against the pricks,” a phrase borrowed from the Apostle Paul’s recounting of his encounter with Christ (Acts 26:14-15). I remember a quote in which Johnny said faith isn’t for sissies, and he seems to stare me in the eye as he sings of the gore and glory of the End. His guitar and voice hang in the air as corporeal as if he was seated ten feet away. He ends by reading the passage from Revelation about the rider on the pale horse, and death following behind. Then it fades to the scratching once again. It is so intense that it gives me goosebumps.

I discovered female vocalist Sarah Bareilles about two years ago, and she has become a favorite. Give a listen to her Brave Enough: Live at the Variety Playhouse, a particular favorite. Previously, I had missed the atmospheric “Satellite Call,” but found it a delicious performance with the Coax10. Especially with the open baffle design, the expansiveness of the piece is emphasized. Later on in the review period I slipped the Legacy Audio XTREME XD Subwoofers into the rig, and they took the commendable bass of the Trio15 in this iteration down further. The drum thwacks and piano notes at the beginning of this song are great for sensing solidity of imaging. The intent of the piece is to elicit a boundless propagation of the message, and the Trio15 Coax10 accomplished that admirably.

A year or so ago I stumbled upon the Voices Only and Voices Only Forte albums from Voices Only Productions. They feature a range of groups and musical styles, and as I work through my favorites once again, I am struck by how the performances are elevated by the 10” coaxial version of the Trio15. These performances are entirely acapella, but as heard through many systems the formation of particular treble, bass, and background effects seem generated by something other than a human. As the performances are opened up more via the new driver, the particularities of the formation of sound by the human voice box are revealed, and it adds to the enjoyment of the moment. How superbly members of these groups mimic machines as filler for showcasing the lead singers and chorus. Now, finally, I can hear the pulsing exhalation of the beat boxing, the interplay of tongue and teeth in generating the treble, and how closely the larger group’s harmonies are woven. Yet, these nuances do not distract from the group’s intonations.

Exceptional sub-$10k speaker

PureAudioProject does not advertise moon shot technology or cost-no-object manufacturing. It is a sensible design for reasonable people who are not hung up on fancy cabinets. But the Trio15 Coax10 sonically is closer to being an exquisite speaker than it is to being an average speaker. I have heard a lot of systems with full range drivers under 6” size, but as Shania Twain sings, that don’t impress me much. If you heard the Trio15 and thought it lacked oomph, or that there was a gap between the horn driver and the 15” woofers, such perceptions are addressed by the Trio15 Coax10. This is a new game and an entirely new result for this speaker. Top to bottom, it is a larger and fuller sounding experience without loss of intimacy. I predict it will bring a wide smile to those who pursue it, and while I anticipate using the Horn1 version as well going forward, this is the version of the Trio15 that will occupy my attention the most. In the forthcoming second part of this review, we will see whether the Quintet15 also performs as admirably as the Trio15 version.

ASSOCIATED COMPONENTS:

Source: Small Green Computer sonicTransporter AP I7 4T and SONORE Signature Rendu SE and systemOptique

Streaming Music Service: Tidal premium

DAC:  COS D1 DAC + Pre; Exogal Comet DAC and Plus upgrade power supply and Pulsar IR receiver; Eastern Electric Minimax DSD DAC Supreme with Burson, Sonic Imagery, Sparkos Labs, and Staccato Discrete Opamps

Preamp: TEO Audio Liquid Preamplifier

Amps:  Legacy Audio i.V4 Ultra (pair, totaling 9 channels); Exogal Ion (PowerDAC, used exclusively with Exogal Comet DAC)

Integrated: Redgum Audio Articulata; Kinki Studio EX-M1+

Speakers: Kings Audio Kingsound King III; Legacy Audio DSW Clarity Edition; PureAudioProject Trio15 Horn 1; Pure Audio Project Quintet15 Horn1; Kings Audio King Tower omnidirectional; Ohm Walsh Model F (refurbished)

Subwoofers: Legacy Audio XTREME HD (2)

IC’s: Iconoclast 4×4 “Generation 2” XLR and 1×4 “Generation 2 RCA”; Clarity Cable RCA with Audio Sensibility Y Cables; Schroeder Method Audio Sensibility RCA; Schroeder Method Clarity Cable XLR with Audio Sensibility Y Cables; TEO Liquid Splash-Rs and Splash-Rc; TEO Liquid Standard MkII; Clarity Cable Organic RCA/XLR; Snake River Audio Signature Series Interconnects; (Schroeder Method, self-assembled with Audio Sensibility Y Cables used with several brands)

Speaker Cables: Iconoclast by Belden SPTPC Level 2 Speaker Cables and TPC Level 2 Speaker Cables; TEO Cable Standard Speaker; Clarity Cable Organic Speaker; Snake River Audio Signature Series Speaker Cables;

Digital Cables: Clarity Cable Organic Digital; Snake River Audio Boomslang; Silent Source “The Music Reference”

USB: Clarity Cable Supernatural 1m

Power Cables: Belden BAV (Belden Audio/Video) Power Cord; Clarity Cable Vortex; MIT Oracle ZIII; Snake River Audio Signature Series; Anticables Level 3 Reference Series

Power Conditioning: Wireworld Matrix Power Cord Extender; Tice Audio Solo

Copy editor: Dan Rubin