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PureAudioProject Trio15 Coax10 open-baffle speakers Review

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The hopeless truth (or fascinating reality)

They say wisdom is recognizing how little you know, that the more you learn, the more you realize how little you know. With each high-end audio system I assembled, and there have been hundreds, the feeling grows in me that I know less and less of the absolute extent of the HiFi performance spectrum. It’s not for lack of trying or of hearing good systems. I estimate the number of systems I’ve heard at residences, dealerships and shows at perhaps more than a thousand. This uneasy feeling that I do not have a handle on the enormity of the spectrum of sound is not for lack of experience but a growing humility that is reinforced by the uniqueness of each system. Perhaps the humility is similar to that experienced by astronomers who have learned that stars appear to be forming ten times faster than previously thought, or that there are ten times more galaxies than previously known. If you wish to learn more, search for articles about the Five-hundred-meter Aperture Spherical radio Telescope.

Audiophiles with scant experience like to categorize HiFi systems penultimately and speakers ultimately as if they are types of vehicles, but with little nuance as regards the particular characteristics of sound that are sought, the equivalent of inferring all roadworthy vehicles serve the same purpose. As people favor pickup trucks, sport sedans, or motorcycles, certain audio systems or speakers are said to be the best, as though they would be the best for every listener. High efficiency and horns are the best. No, says another, panels and heavy class A or A/B amps yield the best. Music Lovers (aka analog fans, who are typically mediaphiles) intone systems with the favored source, namely turntables, are the best. Wrong, wrong, wrong. These perspectives are too simplistic to accommodate the available experiences. The truth is that audio systems are nearly as myriad and unique as individuals.

The proper way to see HiFi is to consider it as personality of a system, not merely as a set of data points resulting in a ranking as the best. I used to do a lot of poring over the data in an effort to get the best result, the best system for a price point. Building hundreds of systems blows a Grand Canyon-sized hole in that philosophy. Audio systems are as distinctive as people, and their unique sonic structures are not cookie cutter but are as unique as a person’s personality. Here’s the truth: the manufacturer, dealer or reviewer cannot tell you, the readership, with any certainty what will result when you get your aggregate equipment home and hook it up to a random speaker. The best we can do is guess, just like you. Oh, there are specifications and measurements that get us into the ballpark, but the idiosyncrasies, the nuances of personality, are unquantifiable. Like a new acquaintance, you meet a system for the first time when you have not heard the precise assemblage.

If there can be four distinct personalities in speakers from one brand such as PureAudioProject, each one unique, what of the plethora of speakers available from all brands? Add in the bewildering variety of technologies and products that come to you as components, and you have a mystery only slightly less appealing to me than the question of Origins. I get to know a little about each product, from whence it comes, but whither it goes is a ripe unknown until I turn it on and hit PLAY. It’s the same with you. We know so little of the actual performance spectrum, we are like children arguing over whose Hot Wheels car is the coolest.


The sixth round

Given the above, it takes great care to provide a guide in terms of selection of components and speakers. One of the reasons I build several systems when I review a component is to chip away at the vast variables of how a component or speaker will perform given the pool of potential systems. It’s a miniscule sample, but at least it’s better than putting up one system, or perhaps two, and pretending to know how the product is expected to perform universally. Heaven knows I have written plenty of articles that, if not outright suggesting such, at least hint at it. I’ll try not to do that here, while still giving some general guidance for those interested in a really nice, affordable speaker system. Here goes…

This is my fourth round of working with a PureAudioProject speaker, namely the Trio15, and my second round working with the Quintet15. What can I say? PAP must conclude that I can tease out some understanding of the personality of their speakers, as they keep sending me new primary drivers. I have heard distinct differences between them and in order to not rehash the extensive discussion in regard to the general design of the speakers and the PureAudioProject (PAP) philosophy of speaker design, I direct interested parties to the following reviews:

Trio15 Tang Band

Trio15 Voxativ (AC-1.6 driver)

Trio15 Horn1

PAP-C1 active analogue crossover (for active bi-amping)

Quintet15 Horn1


Perusing both the Trio15 and Quintet15 speakers with the 10” coaxial primary driver is the next pair of articles. I am learning not only the PAP way but the ways of each of these speakers fairly well. Sincerely, I wish to help you as an audiophile, but consider that I am seeking to avoid dozens of eager questions from enthusiasts around the world asking particular questions about their systems and one of these iterations of the speakers. Almost universally my answer is, “I don’t know. I can only reinforce what has been said in the article.” I cannot tell you if you would like your source, pre, amp, integrated, cables, etc. with any given PAP iteration more than another. Until now.

12 Responses to PureAudioProject Trio15 Coax10 open-baffle speakers Review

  1. Waldo says:

    I like the way you think but after 40 years of system building I’ve learned to appreciate simplicity. I get over 90% of what you’ve built here for less than 10% of the price using Lii-15 full range drivers in simple open baffles, a Dayton 12″ sub, a super simple hand wired 2 watt SET amp and a Topping E30 DAC attached to my good old Oppo – 103D. With Blue Jeans Cables, the total cost was under $2K

  2. Douglas Schroeder says:

    God’s Peace,

    Thank you for the compliment! And thank you for sharing your system details.

    It appears your comments are subjective endorsement of how much you enjoy your system, and not a comparison of the two speaker systems in the same room and with the same equipment. With such vast differences between a 2 Watt SET and the Legacy Audio i.V4 Ultra, for instance, I do have thoughts in regard to the expected performance of your system, but I will not comment as I have not heard it.

    It is obvious you adore the sound of your system, so kudos on reaching pleasing performance!

    Douglas Schroeder

  3. Jim Widgren says:

    Your comment is much appreciated Waldo; I too believe that simplicity is a virtue (next to cleanliness and Godliness). I am going your rout and will order the Lii F15 today; I already have a Janis subwoofer for the bottom octave and many high-quality amps to play with. If I may ask, what SET amp design did you build? with what output tubes? Many thanks again for the purist & perhaps ascetic viewpoint!

  4. Paul Maier says:

    These speakers started out several years ago at around the $4000 mark. Now, just a few years later, they are running $8000+. Personally, I’d go DIY, or if not–Spatial Audio.

  5. Douglas Schroeder says:

    God’s Peace,

    You make a general statement in regard to the speaker without critical distinctions such as referencing the main driver and the crossover. The Coaxial 10″ is a fundamentally different speaker than the Tang Band version I reviewed six years ago or the Horn1, which is a two-way. The parts used in the crossover for the three-way Coax10 are higher quality than the original crossover and it is a more involved crossover to produce.

    Without a direct comparison preferences mean little. People can feel free to pursue a design with dual 15″ woofers and an approx. 1″ tweeter, which is closer to the Trio15 Horn1 version, but this should not be seen as equivalent to the fundamentally different Coax10 version. Persons who pursue any design using twin 15″ drivers and an approximately 1″ tweeter will NOT get performance in several parameters similar to the Coax10. Having heard in my room a two way Emerald Acoustics design which more closely modeled the Spatial Audio, in my use and recollection such would not compare well with the Trio15 10″ Coaxial in terms of frequency smoothness, midrange bloom and macro-dynamic capacity overall. I could have bought the EP speaker, but returned it for those reasons. I have no plans to part with the Trio15 Coax10 because it performs holistically superior.

    In my assessment of the comparison of the Coax10 design to ones that have twin 15″ and 1″ drivers I do not have to hear the competitor speaker to make my general assessment, as it is based on hard design and physical performance limitations (i.e. drivers) of speakers’ designs. Going beyond such analysis, however, without a direct comparison, is unwarranted. Audiophiles can make whatever claims they wish, but the readership should understand that often they are unsupported.

    The primary grievance which surfaces regularly in such reviews is about the cost. It’s pretty simple; if you build it yourself, you have all but assured you threw your money away in terms of recovering it at resale. You also likely lack the means to build a speaker as aesthetically fine as a manufactured unit. Some people do not care to have a garage build in their living room. Finally, given that in all likelihood there would never be a direct comparison between a home made speaker and one such as the Trio15 Coax10, the suggestion that the DIY speaker would perform as well is a fantasy without basis.

    I am not interested in a protracted discussion about the merits of the Trio15 Coax10 or of DIY. My assessment of performance based on the differences between the two designs is more widely applicable regardless of brands.

    Douglas Schroeder

  6. Jörgen says:

    Great review !
    I might simply follow your footsteps relative to both amp and speakers.
    Now, I believe you were using a 4 channel amp … if so (and even if not) … could you bi-amp and introduce room-correction a la Legacy on the bass only ?

  7. Douglas Schroeder says:

    God’s Peace,

    Thank you for the compliment!
    It would be much simpler to do the passive bi-amp setup that I worked with in the review. The advantage of using identical channels is simplicity, the same output of the amp for all four channels, and the same resolution, tonal and soundstage characteristics for all the speaker inputs. When using a combination of two stereo amps to get four channels there is no predicting what result will occur or if it will be agreeable.

    As to the use of the Legacy Wavelet processor, I think in theory it could work as you suggest, but I would contact Legacy Audio to discuss that possibility. I have heard of others using the Wavelet with different brand speakers, so perhaps it could work in this situation.

    Douglas Schroeder

  8. Phil says:

    Doug, You cannot compare how Claytons Emerald Acoustics speakers from days past sound today with the new Spatial Audio speakers be it the Shappire series or X series. You need to review a pair so you have real knowledge of their performance, which was so good I sold my Quad speakers which I had for 10 years.

  9. Phil,
    God’s Peace,

    I was at AXPONA all three days and returned yesterday after the show. While there I heard the Spatial Audio Hologram briefly. Its sonic footprint was as I had expected and described above in general comparison to the PAP 10″ concentric, as would be expected by the design parameters. It immediately called to mind the older Emerald Physics design about which I made my comments above. At the show I heard at least one or two other designs utilizing a diminutive tweeter with larger woofer(s), and they also carried the sonic signature that I describe above versus the larger coaxial of the PAP 10″ Coax. That is a result of design and driver considerations, and those who are familiar with such do not need a direct comparison to know it. Above I was not suggesting that I have complete familiarity with the current models of Spatial Audio, but rather was discussing the performance characteristics of such designs.

    After listening for a few minutes to one of the versions of the Spatial Audio Hologram and hearing the distinctive characteristics I have mentioned above, I made the decision to not seek a proper demo and chose not to pursue it for a review. It is possible that had I conducted a proper demo, I might have changed my mind. However, I have no interest in debating my decision, nor debate over how closely the Emerald Physics and Spatial Audio designs compare.

    If you were the owner of vintage Quad speakers, I am not surprised that you sold them after hearing OB contemporary speakers. My long term conclusion in regard to the older Quads, after hearing them several times, is that they are in today’s market unimpressive. Aside from their undeniable nostalgia I would not own them. Unless, quite literally, someone wished to give me a pair. I have a set of the coveted Ohm Walsh Model F’s because they were going to be taken to the dump and someone recalled that I like gear. I saved and had a bit of work done to resurrect them, so I have those vintage speakers for fun, not for critical listening. I do not tend to keep vintage gear as to my ear it underperforms more contemporary designs. I heard the vintage Wilson WAMM at the show, which was a real treat! I appreciate the speakers, amps, EQ, etc. being brought in for the public! However, I knew quickly that I would not own it, for I would not listen to it, again, because it has what I consider fatal flaws in performance compared to what is done with larger towers today. The ’57 and ’63 Quads have serious performance compromises, among them pitifully low wave launch resulting in a sunken soundstage, and no appreciable low end extension. I believe that for most speakers that are compromised in bass extension the purported superior midrange is not actually superior, but simply stands out as there is no appreciable bass to consider. I have a similar effect that occurs when I use the Wharfedale Opus 2-M2 speakers with their glorious 3″ soft dome midrange. It is not difficult for contemporary designs to holistically outperform vintage Quads. The one important variable that could push someone to get the vintage Quad is the coherence combined with ESL sound. For some people, that is enough of a cause to own them.

    In terms of larger, far more capable ESL speakers, I prefer to use a full range speaker such as the King Sound King III. As to the larger Quads of several years ago, if I recall correctly, I contacted the distributor to arrange for a review but I never heard back. I will neither confirm nor deny the rumors of reliability problems, but I am content that I did not conduct the review. I feel my time was well spent on the review of the Sound Lab Ultimate 545.


  10. Jim Tutsock says:

    Douglas, I, for one, would appreciate a copy or at least a number for that patent you purport to hold. Those attorneys can be fierce.
    I’m slowly in the market for my 20 year changeout of equipment so I am enjoying my education and remain utterly and satisfyingly confused to this very minute. I guess I will have to get my butt to Capital Fest, but the last time ( 7 years ago ?) my ears gave out way before the minutes and seconds. I had a stapedectomy performed in each ear in the low 90″s and that will bring on tinnitus or so I was semi-recently told; enough concerts and the like (not to mention previous housebuilding, related construction work and now a certain medication) to bring it on anyway. Strangely I enjoy listening to music even more and think I’m better at it. You are in a top class of reviewers (if, where else, only for your patient and complete replies to commenters, sheesh!) and I have numbered many this trickle of years. 2 questions: Stand mount monitors at their best can easiest perform the disappearing act that I need for my enjoyment. Open baffles are supposed to be good at this but I don’t always see it addressed and I mention it here because I’m not sure you did or maybe I need to read all of the earlier reviews to find it. Also the coax driver (which for some reason I was always a big fan of back to my car stereo days) in these designs seems low in relation to ear height and I have read that this will make for reduced image height, even if it’s angled up to reach ear height, but I’m sure you would not have gotten to this far a traverse with this speaker arrangement if that was the case but still wondering…. lastly when Axpona spent one year in Atlanta (06 or 7) I heard the original Voxativ that they now do as a diy kit and boy was that something different and magical. They have come a long way and would like to hear PAP and them in the same time frame at similar $. (or $$+). Jim

  11. Jim,
    God’s Peace,

    “… that patent that you purport to hold.” I worked in collaboration with an IP attorney to get the patent. The patent has been issued, but I’m not interested in addressing questions which are on their face incredulous. I also have no interest in debating with anyone the technical or sonic merits of the Schroeder Method of IC Placement. There are those who try and those who talk. Those who try find it to work. For the record, here is the article:

    I also discussed it at length on Audiogon:

    FYI, I dropped all participation on Audio Asylum years ago, and Audiogon more recently as I found involvement to have diminishing merits over time. Ergo, I have no idea what the threads say recently, and I don’t care much.

    In the review here I didn’t address the topic of “disappearance” of the speakers because my perspective is that the ability of the speaker to disappear has far less to do with speaker type and far more with the complexion of the system and setup of the speakers. We may disagree on that, but it is one reason you do not see me saying of all sorts of speakers that they disappeared, as though it’s a mandatory phrase to have a good review. The audiophile is not building a very good system if the speakers do not disappear, and I have found that is true of every type of speaker and regardless of size. I have 5.5′ tall, 30″ wide King Sound Electrostatic speakers that disappear as well as any bookshelf I have ever used. So, I’m not in agreement with the characterization that bookshelf speakers inherently image better than larger speakers. I have reasons for that perspective beyond comparison of dozens of models, but I am not discussing it further now.

    You are correct in your assessment of the relative height of the coax, or any other primary driver in the Trio15 line. Angling the baffle slope back helps, which is why I suggested to PAP that I use hockey pucks under the front to address that somewhat. PAP took my idea and have their own special hockey pucks for that use. I’m flattered that my opinion mattered.

    That’s a pretty strong judgment, “but I’m sure you would not have gotten to this far a traverse with this speaker arrangement if that was the case,” which makes me think this is more of an issue for you. Conversely, many are not terribly bothered by the lower orientation of the midrange relative to the ears. Witness the plethora of sub 4′ smallish tower speakers. I prefer very sizable speakers when possible, but that doesn’t mean smaller ones are without merit. If the baffle slope solution is not agreeable, the alternative solution is quite simple; elevate the speaker. You can do so with the Landscape Orientation that I use extensively, which in my case required specialty Sound Anchor stands which are not cheap (however, PAP has changed the metal frame for the Trio15 which makes it a more difficult proposition), or you can find some base to set the speakers atop. It’s a simple way to change the orientation and gain the ear height, or even in some cases, slightly above ear height one might desire. Now, if one wishes to debate the efficacy of such a base, I’m not interested. Such things are not resolved from armchair discussions, but from trials. 🙂

    As nice as the Voxativ model I reviewed sounded, I holistically prefer the coax. It mates superbly with the twin 15″ woofers.

    Douglas Schroeder

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