Paradigm Defiance X15 Ported Subwoofer Review

Paradigm Defiance X15 Introduction

In our review of the Paradigm Defiance V12 and X12 subwoofers, we were so impressed by the performance of the X12 that we inquired to Paradigm about getting our hands on the X15 to see what the Defiance platform could do in its most powerful form. Paradigm was enthusiastic to send us their flagship Defiance subwoofer, and, as was promised at the end of the X12/V12 review, here is our evaluation of the Defiance X15. The Paradigm Defiance X15 is the big dog of the Defiance subwoofers. It is a massive, ported 15” subwoofer with an MSRP of $1,499. Unlike the other Defiance subs, it is not something that can be tucked away in the corner or easily hidden. The X15 is a monster that was designed to produce prodigious amounts of bass and is accordingly huge. The superb performance of the Defiance X12 has raised expectations quite high for the X15, so now we will see if it fulfills the promise of its smaller yet mighty sibling.

Appearance

As with the Defiance V12 and X12, the Defiance X15 is a simple cube in shape, but its significantly larger size does leave one with a different aesthetic impression than its smaller siblings. Where the X12 was ‘medium’ sized, the X15 is inarguably large, and its much larger size gives it a certain presence that the 12” Defiance subs just don’t have. Unlike the V12 and X12, the X15 cannot be discreetly tucked away into a corner with hopes that it won’t be noticed, because it is just too big for that. It’s sleek and understated Satin Black finish prevent it from becoming an eyesore, and it is far too visually simple to be considered unattractive, but there is no way for it not to be a significant addition to a typical domestic room. It will join your furniture as a piece of the room, in both footprint and scenery.

The good news is that the X15 looks cool. Its clean and smooth cube shape, slick front baffle finish, and eye-catching cone add up to an artful but reserved aesthetic. With the grille on, it is just a soft-black geometric shape, but without the grille, it is a more interesting sight. The front baffle has an almost metallic sheen that reminds me of brushed aluminum and imparts a sense of weight and solidity. The ribbed surround and inverted dustcap of the cone make it one of the more distinctive and classier-looking woofers in the subwoofer world. It is very modernist: sharp and restrained without being dull. One aspect of its appearance that I would put on my wish list for it is for the grille to use magnetic attachment instead of grille guides so that the front baffle would have an even cleaner look. However, its visual appeal already possesses a lot of simplicity.

Design Analysis

The Defiance X15 is a ported subwoofer using a 15” cone with a beefy amp. But, there are a lot of ported 15”s in the subwoofer market, so what does the X15 do to separate itself from the rest? It turns out that in many ways this is a unique subwoofer. From a feature standpoint, it is the only ported 15” to use Paradigm’s subwoofer control app. That can make setting up and dialing in this behemoth a bit easier than regular subs that are only controlled by the amp panel. Another aspect that differentiates this sub from the other king-size subs is that it is not tuned quite as deep in frequency, which is both an advantage and a disadvantage, but we will get into that a bit deeper later on. For now, let’s describe its basic construction, and we will begin with the driver.

The Defiance X15 driver is much like the Defiance X12 driver, except that it uses a larger diameter cone. The X15 also uses a cast aluminum basket and polypropylene cone, and the motor structure is alike: it uses two 6” diameter, 1” thick magnets. One key difference about the size is that a 15” driver has a much easier time achieving a lower resonant frequency than a 12” driver since there is more room for a larger spider (the spider is the part of the suspension that attaches the voice coil former to the basket). The smaller the spider, the tighter the suspension, and that raises the resonant frequency, so it’s easier to get a loudspeaker driver to play lower frequencies when the spider does not have as much tension. The greater mass of the 15” cone is surely a significant factor here as well.

As with the X12, the X15 uses an inverted ART surround. To quote from the X12 review:

“ART is the name Paradigm has given to their patented surround design that uses a pleated ‘ribbing’ over the length of the surround; it is an acronym which stands for Active Ridge Technology. Supposedly, ART allows for more headroom than conventional half-roll designs. When typical surrounds are stretched at high excursions, particularly in the inward-stroke, deformations can occur from the high tension, and these deformations can cause distortion or even tears in the surround. This ridged surround design by Paradigm supposedly reduces these deformations by directing material stress to points that can better cope with it due to the shape of the surround. Paradigm claims that ART allows 1.5 times the excursion for the same surround roll that results in a 3 dB increase in headroom.”

The X15 uses a 900-watt class-D amplifier with a whole slew of inputs that can accommodate a wide range of setups. It has left, right, and LFE RCA inputs, an XLR input, left and right speaker-level inputs, and it also has a slot for an onboard wireless receiver (the receiver/transmitter is sold separately). The only physical control it has is a volume knob, and all other adjustments are done through the Paradigm Subwoofer Control app.

To describe the Paradigm Subwoofer Control app as well as the X15’s room equalization correction app, I will quote the V12/X12 review, since all of the same things apply:

“Paradigm has allocated all other controls of the Defiance subwoofers to a smartphone app that is compatible with iOS and Android devices. The ‘Paradigm Subwoofer Control App’ has all of the conventional control functionality of regular panel controls and a few neat features that are well outside the ability of typical subwoofers. The Paradigm Subwoofer Control App can control the volume, low-pass filters, phase, low-frequency boost (that can adjust the 20-30 Hz region by ±10 dB) and can access preset listening modes. One unique and useful feature of the Paradigm Subwoofer Control App is the ability to run a tone sweep from 20 Hz to 120 Hz that allows the user to pause and hold the tone at any frequency in this range. This feature allows the user to identify points of audible in-room rattling and vibrations. The Paradigm Subwoofer Control App can control a multitude of subs independently. The App also has helpful explanations for every control, so the user isn’t forced to refer back to the manual to understand every aspect that can be changed.

As was mentioned above, the Defiance subs also use Anthem’s ARC Mobile App. Audioholics previewed the Anthem ARC Mobile App with good results. ARC is the highly-regarded room correction equalization software developed by the audio electronics manufacturer Anthem, and the ARC Mobile App brings that equalization functionality to Android and iOS devices. For ARC-enabled speakers such as Paradigm’s new Defiance subwoofers, ARC Mobile uses the microphone of the iOS or Android device to record the in-room frequency response of the subwoofer. ARC’s algorithm then forms a correction curve which is sent to the subwoofer for a more linear and smoother sound at the listening position. Since low-frequencies are the band that is most dramatically affected by room acoustics, this can be particularly helpful in achieving an even, neutral response. The ARC Mobile App makes it simple to EQ troublesome room modes that are the plague of subwoofer frequency bands, and no wired components are needed to use it.”

The Defiance X series subs are also compatible with Anthem’s new ARC Genesis room correction software that we recently covered in our article on Anthem's updates to ARC Genesis room correction. In addition to having the ability to use the smartphone’s microphone, the Defiance X subwoofers also come with their own microphone that is very likely better suited for the task of capturing a room frequency response.

The Defiance X15 uses a pretty hefty enclosure that constitutes the bulk of its 92 lbs. Side panels and front baffle are made from 1” thick MDF, and there is also a heavy-duty window brace in the cabinet mid-point. There is a generous amount of poly-fiber stuffing lining the sidewalls. The port is 16” long and 4” diameter and is flared on both ends. That may give the X15 a slightly deeper tuning frequency than the X12, which also a 4” diameter port but was only 14” long. One interesting thing we see is that, like the X12, the interior sidewalls of the X15 has a coating of some kind, and this can help the MDF from absorbing moisture from the atmosphere which can alter MDF’s shape and density. The feet are made from a tall plastic base that has a rubber contact with the floor, but Paradigm also provides some optional metal spikes for those who don’t want the rubber to cause streaks or impressions on carpeted surfaces. One thing to note is that the cabinet has pretty hard edges, and this makes for sharp corners. This is a sub that you do not want to fall down against one of its corners. It could leave a nasty gash, and that is something to think about for those looking at an X15 for a household with rambunctious children or someone particularly clumsy.

The overall design suggests a subwoofer that should be very powerful but does give up infrasonic output to achieve loud levels in more audible ranges. That isn’t a bad trade to make providing it can catch most of the deep bass in movie and music content, and we will see if that is the case in our listening and test measurements. The X15’s main competitors are manufacturer-direct brands, which tend to have tuning frequencies below 20 Hz. However, the sensations of sub-20 Hz frequencies tend to be subtle unless it is very high in SPL, and I have seen many people overstate the impact of this frequency range. Paradigm has decided it is more sensible to provide impact where it can be more easily felt rather than lose punch for some ill-defined rumble that is hardly audible. Now, let’s see how well this strategy works in practice by listening to some music and movies…

Listening Sessions

The best placement for a single sub in my room gives me a relatively flat response for an un-EQ’d single subwoofer, with a window of +/- 4 dB from 25 Hz to 100 Hz with no broad dips in important ranges. This location trades low-end room gain for a relatively flat response, a worthwhile trade for my tastes. The receiver used was a Pioneer Elite SC-55 and the crossover was used mostly at 80 Hz. As always, I will note here that since room acoustics have a huge effect on low frequencies, the way these subwoofers sound in my room at my listening position is not necessarily going to be the way they sound anywhere else for anyone else, so readers would do well to keep that in mind, and not just for this subwoofer in this review, but for any subwoofer in any review.

Music Listening

Hans Zimmer is a composer who has never been shy with bass, and many of his scores are good for letting the subs stretch their legs. One such score is the music for the film ‘Man of Steel,’ the most recent cinema incarnation of Superman. ‘Man of Steel’ is a relatively heavy-handed take on the story of this iconic character, and that really comes through in Zimmer’s music. It’s a serious, propulsive score, and low-frequency instrumentation is frequently used to underline the gravity of the on-screen drama. Double bass, bass drum, tubas, and the lower octaves of the piano all keep the sub busy for the reproduction of the ‘Man of Steel’ music soundtrack. The Defiance X15 had no trouble keeping all of these instruments distinct. Percussion sounds were punchy and nimble, and strings had weight and texture. As with many of Zimmer’s scores, the ‘Man of Steel’ music score had a larger-than-life sound and demanded to be played loud- a demand that I gladly acquiesced to when I was armed with the Defiance X15. While I did play this music loud, I didn’t come close to pushing the limits of what this sub could do, in an effort to preserve my hearing. It has a seemingly endless amount of headroom. Orchestral music will not tax this subwoofer, in sound quality or in dynamic range. Overkill is the keyword in this instance. The Defiance X15 could have handled a room twice as large as mine without a problem. I would say the bottom line here is that if you have a large room and enjoy orchestral music at loud levels, the Defiance X15 is a superb choice.  

The most famous organ composition is undoubtedly Bach’s ‘Toccata & Fugue in D Minor, BWV 565’, and so famous is it that many people simply refer to it as ‘Toccata & Fugue’ even though there are many Toccatas and Fugues. But it is ‘the one.’ From the first bar, it is instantly recognizable, and it is well-known as a piece that brings out the thunderous grandeur in a capable pipe organ. One of the classic recordings of this and other Toccatas and Fugues from Bach is E. Power Biggs’ 1974 performance at the monumental Cathedral of Freiburg, Germany, entitled ‘Bach: The Four Great Toccatas & Fugues.’ Sadly, I do not have the highly sought-after SACD version of this performance, but the regular CD contained the same low-frequency information I was interested in for evaluating the Defiance X15. As with the ‘Man of Steel’ music score, the Defiance X15 was not challenged by this disc. Pipe organ music doesn’t dig into deep bass very frequently but when it does it can be quite powerful. The Defiance X15 was certainly able to bring that power when requested, and it did it seamlessly with the rest of the sound. It is mostly only playing the fundamental component of lower notes that are harmonically rich, but it did not announce itself in doing so or ever seem like a separate component of the overall sound.

While calibration has a lot to do with that quality, a good, well-behaved sub is needed for that as well, and the Defiance X15 certainly fits that definition. If you want your living room to sound like a cathedral, you will need the right recording paired with the right audio equipment, and a serious subwoofer is a must in that list of equipment. The Paradigm Defiance X15 is very much a serious sub that can create the aural foundation of a pipe organ in transforming any domestic room into one of the world’s great cathedrals.

Taking a sharp turn away from Bach’s celestial compositions, I headed toward a more hellish soundscape with the album ‘The Poisoner’ from the group Controlled Bleeding. ‘The Poisoner’ is on the experimental side of electronic ambient music; it is a sonic journey through a foreboding, ominous place. This is ambient music in that it paints a picture of a setting, but it is not mellow or calm as is most ambient music; it conjures up a menacing environment. Low-frequency sound is used heavily and in many forms, such as the shuddering of industrial machinery, cavernous reverberations of some distant enormous drum, subsonic earthquake rumbles, and the low-pitched ringing of monastery bells, among other plunderphonics. It’s scary stuff that would be a bit much even as background music to a haunted house. It also has enough layers of low-frequency sounds to be a real curveball for middling subwoofers. Playing ‘The Poisoner,’ the Defiance X15 proved to be no middling subwoofer. The many low-frequency elements were kept separate and unconfused the way it might have been with a low-end sub. The bass was so thick and guttural that it could be felt in my lower digestive tract at higher loudness levels. Even at loud levels, the bass was textured and lost none of its definition. The Defiance X15’s deft reproduction of ‘The Poisoner’ is not a surprise given how adept it had shown itself to be with all preceding content; it had proven itself to be a high-fidelity device. It will recreate whatever signal is fed to it, and if that signal is as complex as the low frequencies of ‘The Poisoner,’ that will not be an impediment. This music is like the soundtrack to a nightmare, and the X15 brought that nightmare to life (which is good for the X15, but bad for my anxiety level).   

Pipe organ music, orchestral music, and ambient music can use bass extensively, but few other music genres indulge in heavy bass as much as Drum’n’Bass music. This is an electronic genre that mixes high-tempo breakbeats with continuous bass rhythms to create a wickedly rough-and-tumble sound that will give any subwoofer a real workout at high loudness levels. Toward this end, I picked the album ‘3rd State Consciousness,’ which is a mix of unreleased tracks from various artists spun by Technical Itch who is a well-known veteran producer of the harder end of Drum’n’Bass music. ‘3rd State Consciousness’ is track after track of ferocious beats and unrelenting heavy bass that is a battering aural experience when listened to in its entirety. I usually throw in at least one album like this for each sub review to see how much punch the sub can throw in more strenuous music content. I cranked the system volume and fired up ‘3rd State Consciousness’ knowing full well the beating I was bringing on to myself. On that point, the Defiance X15 did not disappoint. I ran the bass hot, and the X15 pummeled me with chest-thumpin’ beats. My sofa felt as though it had a bass shaker attached to it, but with the X15, there is no need for such an accessory; it can hit just as hard with pressure waves of air. I could feel the bass lines as a buzzing in my spine, which, after some time, seem to cause me to experience some dizziness which led to some possible health concerns about this voluntary aural battery. Whatever deleterious effects that blasting an entire 80-minute hard Drum’n’Bass album might cause, the long story short is that the Defiance X15 is a terrific choice for those who like the bass in their music to be impactful and unrelenting.  

Movie Watching

One movie that I watched using the Defiance X15 was ‘Aquaman.’ Anyone who has seen this popular 2018 superhero movie can attest that its use of bass is very prodigious. The low-frequency content here digs deep and hits hard. Of the many scenes that place a large workload on the subwoofer, the standout scene has to be where Aquaman confronts the Karathen, a Kraken-like creature that guards a sacred trident. Few subwoofers could run that scene at a high loudness level without strain, so how did the Defiance X15 do? The X15 belted out the ground-shaking collisions and titanic monster stomping with verve. I could hear objects from around the room shake that I thought I had previously secured from low-frequency sound vibration. I didn’t get a sense of compression or distortion no matter how loud I ran the scene. Whatever output ceiling this sub has, I was afraid to find it for fear of the damage that it might do pipes and conduit around my house. I also have a cockatiel on another floor of my house that I didn’t want to frighten, so I restrained myself from pushing the sub to full blast. The point of mentioning all of this is that I don’t think most people would reach the performance limit of this sub unless they were intentionally trying to just for the heck of it. It’s a very powerful subwoofer and a great choice for those who want the peace of mind that their equipment will always be operating under their maximum limits, which is always a good idea for high-fidelity playback.  

Another movie that I watched using the Defiance X15 was the big-budget Chinese film ‘The Wandering Earth’ on Netflix. I hadn’t originally intended to watch this movie, but it seemed like a good bass demo content for the Defiance X15, and Netflix’s announcement of bringing their audio bitrate up to 640 kbps up from 192 kbps had me curious. ‘The Wandering Earth’ is a science fiction film with a hilariously implausible central concept: the sun is suddenly increasing in size so humanity must move the Earth to another star system. Trouble comes when, in an effort to use Jupiter’s gravitational field as a slingshot, the Earth starts to spiral inward toward Jupiter instead. This movie has lots of planet-wide cataclysms and all manner of global disaster scenes as the tidal forces of Jupiter plays havoc on Earth’s structure. Needless to say, it is a feast for a capable sub. Although the sub had been calibrated for a flat response with the main speakers, I felt this bass was somewhat anemic, and that was due to the sound mix of the movie, not the sub. After increasing the subwoofer channel by 6 dB, I felt the bass was appropriately forceful given the scale of the catastrophe presented by the filmmakers.

After the gain adjustment, the X15 realized the epic pandemonium of ‘The Wandering Earth’ with clarity and potency. My sofa shook as the many earthquakes were rendered with bruising force. It is perhaps a comment on the weakness of the drama itself that the addition of a great bass sound does so much to improve the experience, but one of the advantageous things about a great subwoofer is that it can make mediocre action movies better when the sound mix takes advantage of low-frequencies. ‘The Wandering Earth’ isn’t a great movie, but it is a great demonstration of the contribution a good sub can make when other aspects of the movie fall flat.

Paradigm Defiance X15 Subwoofer Conclusion

The Paradigm Defiance X15 was tested using ground plane measurements with the microphone at a 2-meter distance in an open setting with well over 100 feet from the nearest large structure. The subs were tested with woofer facing the microphone. The subwoofer’s gain was set to maximum, phase was set to 0, and the low pass filter was left off. The weather was recorded at 75°F and 50% humidity.

The above graph depicts the frequency responses for the Defiance X15 subwoofer for its available modes. Nothing here is new to readers who remember the response shapes on our review of the Defiance V12 and X12. Music Mode has the most neutral response, where Movie Mode has more of a lift centered around 40 Hz. The rise around 40 Hz might help to bring out a bit more oomph in action movies since so much effects content uses that range. Night Mode filters out a lot of the deep bass, which is a good idea for those who want to be considerate to others nearby when using the sub. Deeper frequencies travel further and are less inhibited by obstructions like walls and flooring, so it’s better to just turn that range down rather than turning the sub volume down altogether. Night Mode also does not permit the sub to get louder past a certain point, so it keeps the volume at a tame level no matter what signal is passed on to it. In Music Mode, the X15 is impressively neutral from 25 Hz to 100 Hz with barely a decibel of variation. Paradigm’s specified window of +/-3dB from 18 Hz to 230 Hz is accurate! They could have used +/-1.5dB from 22 Hz to 180 Hz if they wanted a tighter window. I do like to see that upper-frequency extension above 100 Hz for those who want to use a higher crossover frequency than the traditional 80 Hz. A solid response in this upper bass range also means that the sub will play more predictably with the bass management’s filters.

The above CEA-2010 measurements are short-term bursts that show the subwoofer’s clean peak SPL before heavy distortion sets in. Our measurements have been referenced to 2-meter RMS, which is 9 dB down from the standard requirement for the measurements to be shown at 1-meter peak. However most publicly available CEA-2010 measurements are shown at 2-meter RMS, so we followed that convention. The Defiance X15 has very respectable deep bass performance, but its mid-bass burst output is just beastly and has the highest numbers among subs that I have reviewed personally. The X15 punches at 120 dB from 50 Hz to 80 Hz and manages 118 dB at 40 Hz and 100 Hz. That is a tremendous amount of output, and it is no wonder that it could hit so hard in drums and percussion. This is a sub with good deep bass performance for movies but outstanding mid-bass performance for music. If you like your music loud and are looking for something that can keep up with a powerful speaker set, take a long look at the Defiance X15. 120 dB is the kind of output you can feel like a punch in the chest.

Frequency Breakdown of CEA-2010 Burst Measurements for the Paradigm Defiance X15 

The above graphs show the measured frequency spectrum of the increasing CEA-2010 burst tests. Essentially, they depict the behavior of the subwoofer reproducing short burst tones at successively louder levels, with each test tone raised by boosting the input gain by 1 dB until no more output was to be had from the subwoofer. The frequency marked above the graphs note the fundamental tone being tested, and this can also usually (but not always) be discerned in the graph by the horizontal axis frequency point of the “main ridge,” the highest levels on the vertical axis. The noise below the fundamental (that random spikiness to the left of the main ridge) should be ignored. What should be looked at are the smaller ridges to the right of the fundamental; these are the distortion products of the fundamental, and it is here where we see how cleanly the subwoofer handles a given output level. These are mostly harmonics: whole number multiples of the fundamental. More information about the meaning of the data in these graphs can be read in our article on Understanding Subwoofer Review Distortion Measurements.

From these graphs, it can be seen that while the third harmonic was the tripping point for the lower frequency CEA-2010 measurements, it is still outweighed by the second harmonic in nearly every instance. However, even though the second harmonic exists in higher quantities, it may still be much less audible than the third harmonic for two reasons. One reason is that the second harmonic lies precisely at an octave above the fundamental, and many sounds, especially musical instruments, have a similar harmonic structure, so this distortion, if it could be heard at all, may well sound like a natural part of the timbre of an instrument or sonic event. Another reason is that higher frequencies are much more easily masked by lower and frequencies, especially when the upper frequency is close in range to the lower frequency sound, and the second harmonic is much closer to the fundamental test tone than the third harmonic. More information about the audibility of distortion in bass frequencies can be read in our article on The Audibility of Distortion At Bass Frequencies. The most important takeaway from the above graphs is the large difference between the fundamental and distortion products at nominal levels. Distortion does creep up with the sub is approaching its maximum output limits, but at somewhat lower drive levels, distortion products are totally insignificant. And keep in mind that “somewhat lower drive levels” for the Defiance X15 is still very high output compared to many other subs. Halving a 120 dB amplitude level is still 114 dB, which is very loud, and at that level, distortion products are completely inconsequential.

Testing for long-term output compression was done by first conducting a 20-second sweep tone where 50 Hz hit 90 dB with the subwoofer 2 meters from the microphone. We then conduct further 20-second sweeps by raising the gain by 5 dB until no more output could be wrung out of the subwoofer. These tests show us the long-term continuous headroom that the subwoofer is capable of. In the graph for the Defiance X15, we can see the excursion limits of the sub at lower frequencies are not able to keep up with mid-bass frequencies as the drive level is raised. The shape of the compression suggests a limiter to keep the sub from being overdriven. Indeed, I pushed the sub as hard as it could be run, but I was never able to compel it to bottom out or make any other signs of distress. It is bulletproof, and such strong protection means that it knows when to stop pushing the cone. Mid-bass frequencies are not governed as much by excursion, and the X15’s light cone and powerful 900-watt amp give it an enormous quantity of mid-bass headroom. The output at 40 Hz and above is about what one would expect from an 18” woofer rather than a 15” woofer. 

Paradigm Defiance X15 Total Harmonic Distortion per output level

The above graphs show the corresponding total harmonic distortion to the long-term output graphs. Essentially, they depict how linear the subwoofer remains for the corresponding drive level seen in the long-term sweeps. The quantity being measured is how much of the subwoofer’s output is distortion and is shown here as a percentage. We can see that at the highest drive level the Defiance X15 can be pushed into significant distortion quantities centered around 25 Hz in deep bass. It doesn’t have the highest excursion woofer, so that is not surprising. However, a higher excursion woofer would likely not be as capable in mid-bass output. Below that high-level 25 Hz distortion hump, we can see that a high-pass filter is keeping the driver under control and is not permitting much excursion, so distortion is quite low. At nominal levels, distortion is very low, in fact, the jaggedness that can be seen in the lowest sweep level here is from background noise, not the sub itself. At 100 dB and below, the X15 does not reach 10% THD until well under 20 Hz. Mid-bass frequencies are the X15’s strength; above 40 Hz it is barely able to pierce 10% THD even at 115 dB.

Component Harmonics of the Defiance X15

The above graphs depict measurements of the constituent harmonics from the long-term output sweeps and are what the total harmonic distortion measurements are composed of for the 2nd through 5th harmonics. These individual harmonics can give us a clue as to what might be the cause of some quirk or non-linearity. One thing we can see from the above graphs is that harmonic distortion is comprised almost entirely from 2nd and 3rd harmonics. This is good because the higher harmonics are more audible, and these are the two lowest harmonics. The second harmonic is the largest contributor to distortion, so most of the harmonic distortion of the X15 is comprised of the least audible type. For those interested in music applications, there is very little distortion in music ranges, i.e., 40 Hz and above, and it’s almost entirely 2nd order, so it would be totally inaudible. Distortion does pick up in the 20 Hz range though, and it may not make as much of a difference there to most users since that range is mostly used for effects noises for movie and television sound mixes. If a very loud explosion or an avalanche sound does have some 2nd order distortion, it’s unlikely that the listener would be able to make the distinction.

Paradigm Defiance X15 group delay

Group delay is the measurement of how much time it takes for individual frequency bands of an input signal to be produced by the speaker. It can indicate that some frequency components are developing slower than others or are taking longer to decay. It is generally thought that 1.5 sound cycles are needed for group delay to be audible at bass frequencies, although there is an argument that group delay should remain under 20 ms to be completely unnoticeable, but that is likely meant for mid and upper bass frequencies. By even the most conservative standards of audibility, the Defiance X15 doesn’t approach anything even remotely audible in the time domain. By the point that group delay does rise above 20 ms, it is below 30 Hz where it is beyond human ability to discern. Much like the Defiance V12 and X12 that we reviewed, this is excellent performance, some of the best I have seen for a ported subwoofer. There is no overhang or sloppy bass from the X15, and this lack of lagging energy helps explain why percussion sounds were as punchy as I had experienced. The X15 does not allow bass to linger.

Effects of the ‘Deep Bass Level’ Control settings on the Defiance X15 

One of the controls on the Defiance’s subwoofer control app is called the ‘Deep Bass Level,’ and the above graph shows the effects of the extremes of that setting so the range and shape change on the response can be seen. As its name implies, it adjusts the level of deep bass output on the Defiance subwoofers by 1 dB increments out to a +10 dB or -10 dB range. This can be handy for toning down bass in rooms that get a lot of room gain and can consequently end up with a bloated sound from too much deep bass gain. It can also be handy for those who want to spruce up the low-frequency effects sounds on movie night or just like the sound and feel of heavier deep bass. The frequency band most affected by this change lay between 20 Hz and 40 Hz.

Conclusion

Going into the Paradigm Defiance X15 review, I had certain high expectations that were set by the Defiance X12, and I have to say that those expectations have been met. The Defiance X15 is a larger and more expensive sub, but it plays louder and deeper than the X12 which was exactly what was promised. It delivers the goods. Before bringing this review to a close, I want to go over the pluses and minuses of the X15 as I do with every product, and, as always, I like to start with the minuses. One disadvantage of the X15 that will make it a non-starter for a number of people is the enclosure size; it’s a big sub. It will be hard to tuck this one out of the way in a corner to go unnoticed. The size is an unavoidable byproduct of the kind of performance that Paradigm is after, so you can’t really achieve this level of performance without the size. This isn’t really a criticism of the sub itself so much as it is a reality check that many people cannot accommodate a subwoofer this large. For those who are unsure if this sub will fit in their rooms, I suggest they do a mock-up of the size. It’s not difficult to do since the sub is basically just a 25” cube.

Another consequence of the design is that the inevitable trade-off for such massive output at 40 Hz and above is that this sub doesn’t dig quite as deep as other large subs. It does dig deep, with usable output down to 16 Hz, but its output at 25 Hz and below isn’t quite on the level of some of the other large subs on the market. But, of course, hardly any of those large subs can hit as hard at 50 Hz and above. I’m not saying that the deep bass performance is at all bad here because the deep bass performance of the X15 is very good, but those interested in deep bass extremes will find greater deep bass dynamic range in subwoofers with lower tuning points. One thing to keep in mind is that deep bass is a more perceptually subtle, so the X15 will likely be perceived as a louder and more powerful sub against one that gives up mid-bass headroom for more deep bass extension. 

Now let’s talk about the Defiance X15’s highlights. First and foremost is its performance; the X15 has a superbly accurate frequency response in music mode, with good deep bass extension and outstanding mid-bass headroom. As we mentioned before, for those who like their music loud, the X15 is stellar, boasting 120 dB in burst testing and 115 dB in long-term testing in music ranges with very low distortion and virtually zero group delay in that same range. If you are looking for a sub that can rock your music hard, the X15 is a terrific value. It easily earns an Extreme Bassaholic Room Rating in Audioholics room rating scale which means that it should be able to handle rooms over 5,000 cubic feet in size (to learn more about our room rating system, read our article: Bassaholic Subwoofer Room Size Rating Protocol). It is indestructible too, thanks to robust limiters. Play it as loud as you want in the short term, because you can’t hurt it. You wouldn’t want to push it to its limits all the time, but a few moments of full-throttle will not damage it.

Aside from the Defiance X15’s performance, there is its relatively nice appearance. It is a sharp-looking sub that shouldn’t clash with most interior decors but would look most at home in more modern interior design. It has a simple, clean appearance that can stay out of the way of the room’s aesthetic especially if the grille is attached. Another aspect that is very modern is the Paradigm Sub Control App and Anthem’s ARC Mobile App, so you can configure the sub and dial it in almost entirely from your Android or iOS phone. The drawback of that is if the user doesn’t have an Android or iOS device, then all they can do is control a gain dial, but most users will very likely have a compatible device. App controls also make it easy to change settings on the fly, so if you wanted a bit more deep bass oomph, you can add a few more decibels in the ‘Deep Bass Level’ control, or if you wanted to take the sub down a notch without lowering the entire volume level, you could lower the ‘Deep Bass Level’ control by a few decibels or switch the sub to night mode. 

Who should be looking at Paradigm’s Defiance X15? On account of its good deep bass performance and superlative mid-bass performance, audiophiles who want a sub that is great for music but can handle movies well too. Those who like their music loud and have a large room ought to consider the X15. People who want a sub that can drive a house party without having to worry about it self-destructing are also good candidates for the X15. It’s a well-rounded subwoofer that happens to perform spectacularly well in the frequency range of the vast majority of recorded music. What comes to mind is something I stated in the Defiance V12/X12 review: most major loudspeaker manufacturers give short shrift to their subwoofer products, often considering them a necessary evil to cater to home theater checklists. But, Paradigm has long understood the importance of subwoofers to modern sound systems and the impact that a good sub can have on the overall sound. The Defiance X15 continues Paradigm’s trend as one of the few major loudspeaker manufacturers who take subwoofers seriously. Indeed, in the X15 they have a product that can stand with similarly-priced subwoofer offerings from dedicated subwoofer manufacturers. It will probably be a while before Paradigm launches another sub, but I am eagerly looking forward to whatever direction they go in this arena. Hey Paradigm, here is an idea: how about a Defiance X18?

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Bass Extension
Bass Accuracy
Build Quality
Fit and Finish
Ergonomics & Usability
Features
Dynamic Range
Performance
Value