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PureAudioProject Quintet15 10” Coaxial open-baffle speaker system Review

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Systems and sound

As I have written extensively about the Trio15 and Quintet15 speakers in use with a variety of systems in my previous reviews, I will not discuss a similar number of setups in this article. From previous reviews I know the essential character of the speaker and its primary driver. Thus, once again I direct readers who wish to explore use of genres or brands of electronics with the Quintet15 10” Coaxial to my other reviews.

The systems I used to assess this version were more similar to one another than is typical for my reviews. Again, as I have spent considerable time using an assortment of gear discussed in the other reviews, I am not going to repeat all that work. For this review I used the system described below, and made changes to the number of amp channels, the DAC, interconnects, and speaker cables. These changes will be discussed below. Here is the initial system:

Small Green Computer sonicTransporter with SMG Linear Power Supply

SONORE Signature Rendu SE with systemOptique (current product is opticalModule Deluxe)

Clarity Cable Supernatural USB 1m

COS Engineering D1 DAC + Pre-Amplifier or Exogal Comet DAC with PLUS power supply

Iconoclast SPTPC RCA or XLR interconnects

Legacy Audio i.V4 Ultra Amplifier (either 2 or four channels)

Iconoclast SPTPC speaker cables

Belden BAV and Clarity Cable Vortex power cords in assorted positions


The most engaging aspect of the Coaxial driver is its luxurious character, which reminds me of experiences with Tannoy, Voxativ, and other speakers relying upon a single, or concentric, driver wavelaunch. Center imaging is exceptional with such designs, but often low-end extension and macrodynamics are anemic if the driver is smallish, i.e., 6” or smaller. If the concentric driver is larger, as in a 15”, there can be indistinctness associated with a large driver cone attempting to handle the bass and midrange on up through the upper midrange. PAP’s coax driver hits the sweet spot by being large enough to escape what I would call significant limitations of a moderately sized midrange driver. These struggle to achieve the same supple and full sound as a larger midrange driver on the order of the PAP. All kinds of designs have been made with smallish midrange drivers, but they just don’t get the job done the same way as a bigger midrange. In terms of midrange performance my two favorite of the dynamic speakers I have used are the Legacy Audio Valor speaker system and the variants of the PAP 10” Coaxial.

What changes when that 10” driver is transitioned from the Trio15 to the Quintet15 platform? Additional support from the lower bass to the midrange is in play. The Horn1 version of the Trio15 and Quintet15 might be likened to dumbbells, with perceived output elevated at the top and bottom of the frequency range. I believe it is due to the midrange of the horn driver being somewhat less colorful and warm. The 10” driver brings both color and warmth, which sounds like it blends much better with the 15” woofers, like a thicker bar connecting the end weights of the dumbbell. The addition of another pair of 15” woofers gives the impression that the variance between the ends and the middle has been eliminated entirely, as if the weight is one solid rod without constriction in the middle. Similarly, the move from the Horn1 driver to the 10” Coaxial relatively built out the midrange, and the transition from the Trio15 to the Quintet15 with the 10” Coaxial driver eliminated any vestige of incongruence between the top, bottom, and the midrange.

The experience reminds me of my review of the conversion of the Eminent Technology LFT-A to the LFT-B version, which involved changing the tweeter element. One might think only the high end would benefit, but it sounded as if the entire speaker was reworked. It seems the manipulation of one end of a speaker’s performance forces a brain reset such that it must approach the speaker anew, hearing it as a different device. In the same way, the seemingly localized changes to the low end of the Quintet15 10” Coaxial, adjusting nothing other than the larger coil, nevertheless is perceived as a much different speaker. I know nothing changed regarding the upper midrange to treble in terms of measurements, but the sound relative to what was changed strikes me as better. I love the comfortableness of the speaker, how it engages me with crisp but not sharp treble, full midrange without tube-like bloated syrupy coloration, and firm but not fuzzy low end.

Music moments

Turing to listening sessions, I enjoy a few albums from Marc Cohn, particularly Listening Booth:1970 and The Very Best of Marc Cohn. From the former album, “Maybe I’m Amazed” and “After Midnight” are representative of Cohn’s work. I was pleasantly surprised when I discovered an older album by smooth jazz artist Jeff Golub, whose work could be summed up as inoffensive and uninspiring. I tend toward quieter, melodic jazz, but much of Golub’s work is close to elevator music. After I bought a couple of Avenue Blue discs decades ago, I was not interested in adding more to my collection. As I was out of touch with his work and it cost only the monthly fee forTidal’s upper tier of streaming music, I happened across Soul Sessions, a most pleasant departure from Golub’s earlier work. No, it is not sizzing, nor trend setting, but it’s livelier than I had heard previously. Marc Cohn sings on the track “Isn’t That So,” a vocally looser blues piece that showcases both men’s talents.

As with other male vocals, the Trio15 has enough driver acreage to keep Cohn’s voice from being devoid of weight. I would not choose to hear him through smallish towers or bookshelves with a 5” or 6” woofer and smallish tweeter because I would miss a great deal of the appeal of his voice. The Horn1 does not have the capacity to undergird and solidify the midrange as much as the 10” Coaxial. While a person who hears the Trio15 may think they have reached close to the limits of fully rendering a male vocalist, they would be mistaken. A substantial move toward that full rendering of male voices — and female for that matter — comes with the Quintet15. The improvement is not only in information retrieval or resolution, but in timbre and fullness.The Quintet15 makes the 10” driver seem more complete in that not only is the voice more easeful, but more tonally saturated.

To grasp the effect I am speaking about, consider paint coloring. Tinting paint means to add white in order to lighten up the color and is how pastel colors are made. Without the white the color is deeper and perhaps perceptually richer. Similarly, the Quintet15 10” Coaxial would be akin to viewing a color that has not been tinted, while the Trio15 version retains the same basic character, but with lightening or “tinting” of the tonality.

That primarily happens on the lower mid to bottom end of the speaker. The Trio15 is therefore less weighty and prodigious than the Quintet15, as would be expected. That weightiness and prodigiousness of the Quintet15 is not without limitation despite having four 15” woofers. Open baffle designs simply do not, generally speaking, yield as much dynamic impact or perceived weight to the bass as do larger dynamic speakers with cabinets and large woofers. But, relative to the Trio15, the larger speaker is notably more prodigious.

Line source speakers have a distinct characteristic of discernible multiple wavelaunches due to the use of several identical drivers. Multiple wavelaunches from the flanking 15” drivers is discernable when listening to the bass of the Quintet15, but it is not obvious with the Trio15. The additional pairs of woofers are distinctly heard if you know how to hone in on them. The same characteristic is found in all large multi-woofer designs, such as the Legacy Audio Whisper. It is not as easy to achieve the wall of sound experience with dynamic speakers having fewer woofers. Some listeners enjoy the perceived fullness that the additional woofers create despite the slightly additive effect of the multiple wavelaunches. Having switched dozens of times from speakers with a minimal number of drivers to those having multiples, I have never experienced a line source type speaker that does not have slightly less precision in the bass due to the multiplication of bass drivers. However, I also have never heard a speaker with minimal drivers create that wall of sound with the fullness that multiple drivers afford. It is a design principle that one either enjoys and accepts or does not enjoy and rejects. I appreciate the virtues of both and so regularly hear both types of designs. I feel they are both legitimate expressions that capture different aspects of sound reproduction.

If you do not want any such duplication effect, then you are not a line source listener. It is not as though the extra woofers ruin the bass, not at all. But like a panel speaker splays the imaging, so the extra drivers contribute to the wavelaunch equation. It is a quite acceptable solution for someone who does not want to have subwoofers and wants a grander experience than the typical floorstanding speaker. Keep in mind that if one selects either model and adds subwoofers, they are once again working with additional woofers. If the Trio15 10” Coaxial is selected and paired with subwoofer(s), there would be some avoidance of the multiple woofer wavelaunch, however there would also be some lightening of the midbass and midrange as discussed above. If one selected the Quintet15, there is a good chance the low end would be satisfying enough to eschew a subwoofer, but the line source type woofer arrangement will be in play.


Filling in the bottom and softening the top

Whenever bass is emphasized, midrange and treble become relatively less overt. When a speaker system sees an increase in bottom end presence, it draws attention away from the midrange and treble. That can be a bad thing or a good thing depending upon the speaker’s performance and listener’s preferences. This is true for all speakers, not only the PAP products.

The additional woofers of the Quintet15 draw more attention to the midrange on down, and in doing so there is less activity noticed in the midrange on up through the treble. That is not a criticism but an observation. When a given speaker doesn’t have appreciable bass, which I would say means it has a specification of 35Hz +/- 3 dB (my criteria is more demanding than many reviewers), the midrange and treble are obviously more noticeable because not much is happening beneath to consider. The more output and frequency extension there is in the speaker’s performance, by necessity the attention of the listener will be spread further to take in the performance holistically. This is one reason I think it is nonsense to say the music lives in the midrange, as if those frequencies are more important than others. My view is that it is often an excuse for bass and LF being excised. I think it’s strange that any audiophile who does not have space or financial constraints would wish to truncate a significant part of the spectrum, especially that part being responsible for adding cues about the recording space.

How much weight a speaker should put on the bottom end, the bass and LF, is a personal question. Preferences range widely and while some say there is a correct solution, you are wise to set your own preference as opposed to attempt to abide by someone else’s and be unhappy. So, do what you want. Be aware, however, that the more properly LF is integrated into the primary speaker’s performance, the more you will get in terms of scale and impact. The trade-off is in attention paid to the upper end of the frequency spectrum. Considering the Quintet15 10” Coaxial, my ears much more appreciate the fullness and perceived gentleness of the treble that comes with a fuller bottom end. I don’t like searing treble even if it is supposed to be realistic. When hearing some systems, I cringe at the supposed lifelike horns and voices of some sopranos because it simply irritates me. Live music that has too much zing or high-end energy will drive me out of the room. Similarly, I will be reaching for a different cable or component when there is an obvious emphasis in the treble calling too much attention to itself. The Trio15 10” Coaxial is better at dovetailing the treble presence than the Horn1. Again, if you want the sharpness of a super-crisp treble, then the horn will probably be your thing, but most of the time my ear is drawn toward the coaxial driver. The Quintet15 10” Coaxial is even better at pulling the treble back a bit to line it up with the mid/bass performance.

To reach much lower than 28Hz either with the Trio15 or the Quintet15 one must add one or two larger subwoofers. That does reformulate the experience and moves it in the direction of state-of-the-art sound as regards frequency extension. To put that comment into perspective, my standard for SOTA sound in terms of bass extension is below 25Hz and the Quintet15 10” Coaxial is very close to that standard.

By these comments I do not mean to imply that the Quintet15 bass is not impressive or that it is in some way deficient as a prodigious stand-alone speaker! Audiophiles can be jittery whenever a reviewer makes a statement that a particular product can be improved with the addition of ancillary equipment. Often that is primarily a subjective comment, but in the case of speaker frequency extension and dynamics it is a fact. I have used big subs with big speaker systems since I started reviewing 14 years ago and my preference is to reach 15Hz +/-3dB, a nearly impossible task for floor standing speakers except for the most extreme and exquisitely priced. My comments regarding the benefit of adding larger subs are made in the light of that experience. There are at a minimum hundreds of tower speakers on up to larger floor standing speakers that do not reach below 28Hz +/- 3dB, and I would say the same thing about them.

There is another level of bottom end fortification achieved with the addition of my Perlisten D212s subwoofers. The deepening of the LF by necessity pulls attention from the rest of the spectrum because it is there, whereas it was not prior. The upper end of the Quintet15 10” Coaxial perceptually recedes slightly relative to the additional output and extension. I have to watch the output of the prodigious D212s because it can easily obscure the finesse of the Quintet15. However, I do love the additional expansion in to deep LF not only with the Trio15 but also the Quintet15. Remote management of the subs individually by .5dB increments allows for contouring the interplay between the Quintet15 and the subwoofers down to 15Hz. Lowering the output of the subwoofers brings out more of the 10” Coaxial driver’s upper range. Once again, it is like choosing to reverse a tinting process, to achieve a denser, more solid result. Does the Quintet15 demand a subwoofer? No, it does not unless you are either a bass freak or want to incorporate it into an HT application where you want to feel the massive impact of explosions, etc.

2 Responses to PureAudioProject Quintet15 10” Coaxial open-baffle speaker system Review

  1. Stephen Carlson says:

    Great review. I have owned the the Trio 15 coax speakers for a couple years now. I love the ability to fine tune their presentation by swapping out crossover components and cabling. Once I got my speakers located and settled in I felt the coax were lacking in a bit of high end sparkle. I played with cables and resistors swapping in silver cables to the tweeters and replacing the inline crossover resistors with Path Audio resistors in an effort to get a bit more energy. Then a day came along when I felt the mids were to forward and pronounced. This lead me to model the crossover to see how I could back off the midrange slightly. The crossover for the coaxial is no simple affair. I believe its fourth order for the mid. Once I got the crossover modeled in Xsim it was apparent that dropping the value of the R15 resistor would drop the output of the midrange. Swapping an 8 ohm resistor, supplied by PAP for purposes of tuning the speaker, was a revelation. With this small change to the crossover everything fell into place. The midrange forwardness I was perceiving fell back into plane with the rest of the spectrum and the treble I felt the speakers were lacking began to shine through as it was no longer crowded out by the mids. YMMV of course but the point is to underlie the versatility of PAPs open crossover design. I too run two SVS 4000 subs with my Trios. The added palpable weight they add is addicting and adds to the you are there feeling. More importantly when properly positioned the subs help to balance out the inevitable frequency nodes in the room. This allows the speed and accuracy of the PAP 15″ woofers to shine through. Once you here proper open baffle free moving mid bass its hard to go back to the congested midbass of a box speaker.

  2. Stephen,
    God’s Peace,

    You seem to be a well versed owner who has explored many of the enhancements of the Trio15 Coax! Kudos on your creativity and persistence in tuning to perfection. I know of few companies that combine the flexibility and precision with on site tuning of a crossover and the fit and finish of a mass produced speaker. It’s a winning combo imo and one reason I have done so many reviews of PAP speakers.

    I am happy that you added your thoughts about subwoofers. My article is not to suggest that there is anything inherently deficient with the PAP speakers, or even with the Quintet15 version. Vastly capable subs add to all but the most radical and extremely expensive large floor standing speakers, many upwards of $100K. After a review, I put the Perlisten subs with all floor standing speakers and would not use any of my speakers without them. It’s a case of more is better regardless of the speaker.

    You’re right about the “internal” wiring. An upgrade to it is also potentially efficacious. That is another bonus with the design, well, any open baffle design that allows such things.

    One thing I did not see in your comments is passive bi-amping of the speakers. That, too, brings a sea change in performance and is well worth the effort. I love the impact and resolution that the Legacy Audio i.V4 Ultra brings with its four channels at 600 wpc. I use a Y cable to split the signal to obtain 4 line level signals for the amp channels. At the very least, perhaps try bi-wiring as an affordable upgrade. Perhaps you have done all this already. Remember that if you are doing bi-wiring or bi-amping you want to remove the tiny jumpers on the crossover board. I believe there is an image on the PAP website with instructions. I’ll not debate whether a more prodigious amp in two channel or a four channel amp with passive bi-amping is superior. Most of the time I have to run the actual comparison real time to know definitively. Even the cabling can make a difference.

    I’ll add this tangentially; I’m quite pleased over the years with the combo of the Eastern Electric Minimax Tube DAC Supreme and the Kinki Studio EX-M1+, as both allow discrete opamp rolling! I can tune a rig to a very high degree with opamp rolling both of these components, a rarity. There is a compounding benefit in having a lot of flexibility with both of those components. While not state of the art, they are very pleasing when tuned well.

    Blessed Easter,
    Douglas Schroeder

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