RTJ 410 and RTJ18 Modular Sub/Sat Speaker System Review

Sub Levels

RTJ pic1RTJ Modular Speakers Introduction

I’ve known Jeff Permanian, owner of JTR Speakers and the new company, RTJ Audio, for several years now. I’ve always appreciated what he is doing, and found his speakers and subwoofers to be excellent values. Today’s review will cover the new RTJ 410 module and RTJ 18sub that I had the pleasure of hearing at a pop-up demo Jeff did at Gene’s place. Is this the ultimate home theater speaker? Read on to find out.  

I, like many of his installer friends, have bugged him for years to introduce a step up line that is exclusive to installers, because his products were so ideal for dedicated home theaters. I had consulted on theater after theater that were putting in speakers not nearly as good as his, but often at many times the price. Jeff finally let me know, amid the pesky pandemic, that he was, in fact, working on such a project. He gave me little snippets here or there. He let me know it would be a complete lineup, improve on JTR with exclusive products, but nothing all that concrete. Then he sent me a picture of the RTJ 410 module. No information. I recognized the 10″ midbass drivers. He had used those before. There were two of them side by side, above and below the waveguide. I thought to myself, “is this waveguide over 20” wide?”. What has Jeff done? This is a mistake! I messaged Jeff back, asking about its size. It was 20” wide, with a large roundover he custom tooled to have made. Wow! I thought Jeff was nuts to introduce such a large speaker. It’s too big, people won’t buy this.  

Then I remembered something Earl Geddes had taught me. While bigger waveguides often bring bigger problems, they also provide improved pattern control over a wider bandwidth. Maybe this isn’t such a bad idea after all? I asked Jeff some more questions. Sure enough, he had taken many of the things I had suggested to him over the years and included them into this speaker. As if he was trying to build my dream speaker. In fact, one of the first things he said to me when we talked at Gene’s was, “Hey, it’s almost your dream expanding array!” He wasn’t wrong,it was pretty close. It’s not how I would have built it, but then, in front of me sat a speaker that was 8’ tall. My idea likely would have been even taller, even less practical. 

RTJ Audio Super Speaker Unveiled: An Absolute Monster, Bass to Die For!

When I arrived at Gene’s, I had been on the road for 2 hours. I had been working with my wife and watching my kids until 5pm that day and immediately loaded my car with test gear and took off for Gene’s. I was exhausted. Maybe it was the massive size of Gene’s existing RBH Sound SVRTS towers? My exhaustion? Somehow these massive dual 18” and 4x 10” and….22” waveguide didn’t seem THAT imposing. Don’t get me wrong, these speakers are huge, but they didn’t look ridiculous in Gene’s room. Put a nicer finish on these and I could see someone putting these in their room. Behind a screen? Not a problem, the size is actually ideal for a high output home cinema. I walked around the enormous towers and quickly realized they weren’t that deep, just 15”! Impressive packaging. In fact, those 18” sealed subwoofers are much smaller than many subs I’ve reviewed using 12” and 15” drivers. Gene’s dual 12” RBH subwoofers are bigger. After this walk around, I was keen to dig into listening, and to hearing from Jeff more about going into this design. 


While everything in this speaker is impressive, I think for many, the subwoofer was the star of the show. Not that the 410 is bad, just that it was the sub that stuck out for all of us. Admittedly, stick four 18” high excursion drivers in any room, and fun will be had. For many, this might look familiar, a lot like a JTR Speakers RS1? You would be forgiven for thinking that, but…They aren’t identical. The biggest and most meaningful difference for the 2021 lineup is that the RTJ line is exclusive to dealers, so the subwoofer was optimized for custom installers. All subwoofers are passive and come with a rack-mount amp, as it should be. Controls for the Room gain adjustment and amp gain are on the back to keep nosey customers from mucking up their own system (For those of us who have installed these types of systems, it’s a reality we all deal with, customers making changes and then complaining about bad sound). We heard the 18s powered by an 8000 watt amp, which was feeding 4000 watts per side, or 2000 watts per driver. That is RMS, not some fairyland weaksauce peak number. Is it enough? Jeff can provide you with two amps, give you 4000 watts per driver, but keep in mind, we popped a breaker repeatedly with this setup. You will need one dedicated 20amp breaker per amplifier. 

RTJ 110

The enclosure is unusual in consumer audio. It is built like a pro audio cabinet, in all the best ways. Baltic birch plywood nearly an inch thick, internal rib bracing, and glued together the same way Jeff has always built pro audio cabinets. This thing is designed to take a beating. It’s a much stronger enclosure than MDF and it allows it to forgo the kind of bracing typically required for MDF boxes. While some might argue that MDF is inherently more dense and better damped, below the 100hz that this box operates, that is of no consequence at all. The enclosure is a pure pressure vessel, and it is stiffness that matters. Plywood is MUCH stiffer than MDF. It is also much lighter, so while this speaker is not light, it isn’t anywhere near as heavy as it would have been had MDF been used. I am sure any installer will be happy about that.

18Sub driver motor  18Sub driver

 RTJ 18sub

What about the driver? Is it anything special? In fact, the first question that Don Dunn and Gene DellaSala asked was who else uses this driver. The answer to that I already knew. Nobody. This driver is unique to Jeff. He designed it himself along with his supplier and its proprietary to him. For those who know where he sources his drivers, just know you can’t source this one. It’s completely unique to his company, and it really is a special driver. Jeff decided to massively upgrade the driver he had been using in his JTR speakers by adding a lot more aluminum to the motor. This is done to reduce eddy currents caused by the higher inductance and, as a result, higher distortion. The motor has been dramatically improved and inductance now sits below 1mh. As a result, this driver has a massive 3.5” voicecoil, 36mm (that is one-way) x-max, and a ridiculous multi-kilowatt power handling. There are virtually no other companies selling subwoofers for any price using a driver this good. While the car audio scene has drivers with similar x-max and power handling, they don’t have that low inductance, they just aren’t this linear. As you will see in our limited measurements section, it seems to have all paid off. This subwoofer has the lowest distortion I have ever measured and a very good response. I look forward to seeing what James Larsen comes up with once he has time to put it through his testing.  

RTJ 410 Module

What about the 410? What makes it tick? Is it just a glorified, oversized JTR speaker? Again, the answer is no. This speaker is using unique pieces to provide better sound and better measured performance. Specifically, the waveguide is a brand new design. It’s much larger than any waveguide that is used by almost any other speaker. Most of JTR’s speakers used waveguides that were no larger than 15”, most were about the same size as the midbass drivers, and while this made sense aesthetically, Jeff likes to cross his waveguides over very low, often around 500hz. This means the waveguide was not providing significant directivity control down to the crossover point. The 22” waveguide used in the 410 allows for directivity control down to around 600hz, much closer to the crossover point.

RTJ 40

The 410 module also uses a Coaxial BMS compression driver from Germany that was designed specifically for high end studio monitors. Some have criticized these parts as low fidelity parts designed for stage use. That is incorrect. This driver was designed for very high-quality pro equipment and studio monitors, meant for the highest levels of fidelity. Additionally, the advantage of using a coaxial driver like this is that is that the 410 acts like a point source down to 650 hz. In fact, because of the wavelengths at 650 hz and below, this speaker is practically a point source at all frequencies. The BMS driver has two concentric annular rings which produce both the midrange and high frequencies. That allows the BMS driver to cover from 650 hz up to and beyond 20khz. These compression drivers have very good response, very low distortion, and very high output. This driver will not compress at any level used in studio or residential use, something that can’t be said about the vast majority of tweeters used in home audio speakers.

RTJ woofer

The ten-inch drivers are custom made for RTJ in the United States. These drivers are built to be top quality with low inductance, low distortion, a linear response, and good compression behavior. Again, through the use of such an excellent driver mixed with the sheer number of them assures this speaker will play at very high levels without losing linearity. Using two drivers next to each other will impact the directivity, however, the very low crossover point largely eliminates this benefit. While it is possible the drivers may still improve directivity control, I would not consider that the major benefit. Rather, this speaker’s advantage is a moderate size with good output and linearity.

The Crossovers

The crossover in all RTJ speakers are built to the highest standards using the best reasonable parts for the job. This includes high power inductors, some steel core are used because of the very low series resistance and price/performance. However, air core inductors are used where they make the most sense and the most improvement in sound. Large paralleled resistors are used to ensure sufficient power handling without degradation or reliability problems. Film capacitors are used for the improved sound and reliability over electrolytics. Far more important is the quality of the parts is the quality of the design. Most manufacturers seek to eliminate as many parts as possible in a crossover to keep costs down. Some make ridiculous claims, such as how this improves sound quality by removing veils. Crossover parts don’t impart a veil, the degradation is typically as added distortion or reliability issues. The amount of distortion added is very minimal. However, the problem with overly simple crossovers is that the amplitude response is compromised. Jeff makes no such compromises, the RTJ uses as many elements as is necessary to get the best possible on-axis response. Some may argue that the passive design is a compromise. While an active system allows for superior performance, it also adds complexity. This places a lot on the installer, who now needs to deal with at least twice as much amplification, twice as much wiring, and ensure they load the DSP properly. Passive systems are simple. You plug them in and they work. While DSP gives you lots of flexibility to add a lot more equalization of the response and steeper crossover slopes, in many cases, 4th order slopes offer optimal performance with the best on and off-axis response. The major argument for steeper slopes is greater driver protection, but if the drivers are fully in their linear operating range, the detriment isn’t there. Passive crossovers are lossy, which is not optimal, but the lossy problem is not audible. While many point to passive systems as having reliability problems, most well designed passive speakers last decades. That is not commonly true of DSP electronics, with the DSP platforms needing hard resets routinely, and the hardware eventually going.

As for the actual crossover design. The speaker uses Linkwitz Riley 4th order crossovers at 650hz and 6200khz. This design ensures optimal phase alignment between drivers. A lot of speaker companies save money in the crossover. RTJ does not, using both high quality and high power powers, along with enough parts to get a good response. The crossovers are well optimized to ensure a smooth response. 


Overall, the design and build quality of the RTJ speakers punches well above their price class. Even with the higher price point demanded by these higher end custom install speakers, they remain a series value in the market. Few subwoofers are nearly as good as the RTJ subwoofers. Few speakers combine the high fidelity, careful directivity control, and high output of the RTJ 410 modules. Those that come from companies like Pro Audio Technology and Procella, two companies whose products typically cost more for a similar level of product. Of course, none of this tells us how they sound. Read on to see what I thought.  

Sound Quality – RTJ vs RBH SVTRS Speaker Systems

Many people have argued that the current state of science has brought us to a point where all we need is measurements to know how a speaker sounds. That by simply looking at a speaker’s measurements, a person can tell how it sounds. There may be truth to that, but there are several variations in measurements that make up outstanding performance, but impart a unique sound character. Here, two issues led to a speaker comparison that couldn’t have been more different, yet in which both had positive qualities. It was hard to say one was right and one was wrong. The first is directivity. While the Audioholics reference system at Gene’s place uses high end RBH Sound SVTRS speakers, the directivity of this speaker is asymmetric and fairly wide in the horizontal direction. The RTJ speaker has a 100 degree waveguide, meaning that the sound is down 6dB’s by 50 degrees to either side. That is a far narrower directivity than the RBH speaker, reducing the strength of sidewall reflections. That fact became important in our listening tests. The second factor was the room curve chosen. I didn’t calibrate the RBH system, nor was it calibrated to a specific standard room curve (ie. Harman Target Curve). No attempt was made to match the sound signature of the RTJ to that of the RBH system. What I quickly realized was that the RBH system had a fairly flat in-room response, with the treble extended nearly flat out to 20khz. Normally the response would be 10dB different between 20khz and 20hz, imparting a downward tilt to the in-room response. In the bass, there was a significant upward tilt, but instead of being 4-5 dB relative to 1khz, as is normal, it was closer to 7-8dB. This lead to a bass forward sound that is certainly very popular, especially for movie viewing. The RTJ’s final sound signature, like the RBH, depends on the installers’ calibration. For my own listening tests, I chose a Harman like curve on the RTJ, but because of limitations in the EQ software I was using, I followed a curve that was fat through the midrange. To my ears, this was an excellent compromise.

  RTJ Modular Loudspeaker System Review: Audiophile or Just LOUD?

Jeff has always made a fairly neutral speaker, but I think this is his best effort yet.

As you will see in the in-room measurements, the response wasn’t perfect. There weren’t any immense problems in the in-room response, it just had some roughness. A lot of this came from the room. There was a pesky 200hz dip in the response related to their position. Ultimately, we couldn’t get rid of it, so I decided to largely leave it alone. It didn’t seem audible. Surprisingly, the overall timbre is probably best called warm. I am sure most would not have believed, by looking at these speakers, that they could sound warm, but the response curve I imparted on the system did just that. We found that if we attempted to flatten the in-room treble response to better match that of the RBH, it could become brittle and harsh sounding on certain recordings (we found this true on the song “Mad About the Boy” by Cecile McLorin Salvant). The RBH didn’t share that problem. I’ve long wondered if the different directivity of a speaker like the RTJ would make the correct target curve for an in-room response different. Since flattening the response is artificial, it makes sense that a speaker with a greater falling response off to the sides would naturally have a greater tilt. It makes little sense to tune for a flat response, as this would lead to a much brighter sounding speaker, as we heard. My suggestion to integrators calibrating this or any speaker like it, don’t attempt to flatten the treble response out, the response should fall naturally toward 20khz.  It ultimately sounded much more natural to Jeff, Don, Gene, and myself.

First let’s discuss the sound signature before getting into some specific tracks. The RTJ system sounded clean, effortless, and relatively neutral. The first time I ever heard a speaker with this kind of dynamics, I found the experience transformative. My experience had been that more typical speakers sounded fantastic when it came to their ability to recreate instruments’ natural timbre. However, they always made the performance sound small. It never sounded real to me because it just didn’t match the dynamics and levels I was used to hearing in real life. Remember, a piano, guitar, and trumpet are very loud in real life. However, I also found that most speakers capable of natural dynamic range also sounded lousy.  Bright, ear piercing, harsh, often with a cupped hand effect. Just not neutral. The RTJ speakers had that realistic level of dynamic range, but also sounded very neutral. Jeff has always made a fairly neutral speaker, but I think this is his best effort yet.


Imaging has always been a strong suit for Jeff’s speakers, but I should really talk about this in more appropriate terms. This requires a bit of nuance, and that became especially apparent hearing them back to back against the RBH speakers in Gene’s room. The RBH speakers had a larger and more spacious sounding image, but it was also less defined and precise. It’s the classic sound signature of a wide dispersion speaker. The RTJ speakers sounded more intimate, better defined, with a kind of image specificity only a constant directivity speaker can produce. This is my preference. Gene prefers the more spacious presentation of the wider dispersion speaker. Neither is right nor wrong, it’s just a preference. However, what that means is that a room utilizing the RTJ speakers needs to be treated carefully.  Whereas you may want to absorb or diffuse some of the lateral reflections with a wide dispersion speaker in order to add back in some intimacy and specificity, the opposite is true of the RTJ. Significant lateral absorption will likely make the speaker sound too much like a point source with no apparent source width. The image will largely sit between the speakers. If I were tuning a room with these speakers, I wouldn’t absorb the first reflection point and I’d likely use more diffusion at ear level. Absorption would be used above and below ear level or toward the front of the room to simply keep the RT time to a reasonable level. In fact, the magnetic mounts that Gene used for his Sonitus panels made it easy to switch out some of the absorption for diffusion. 


The RTJ systems bass was the best quality, best sounding bass I have ever heard.

Talking about the bass response of these speakers is just silly. With four 18” high excursion subwoofers and 8000 watts of power, bass was everything you would expect. You want silly bass, it can produce silly bass.  Our first night with the system, it wasn’t setup right, but that didn’t stop the group from turning it up to ridiculous levels and turning the bass level up with it.  It was outright ridiculous.  What impressed me was just how tight and distortion free the bass sounded.  There were no signs of distortion or compression, no inappropriate noises, everything remained clean, even if excessively loud.  The next morning, the first thing we did was take some baseline measurements, turn the bass down to reasonable levels, and tune the system for neutrality.  It was at this point that I realized just how good these subwoofers are.  The systems bass was the best quality, best sounding bass I have ever heard.  I know the word “tight” is a bad word in the psychoacoustic community. It’s ill-defined, but I know of know better word to describe what I heard.  The bass had a kind of cleanliness I am just not used to hearing from even high end subwoofers.  It was so good, I would honestly put this up against the most expensive subwoofers I’ve ever seen or experienced, and I would bet this quad sub setup would still come out on top.  It’s that good.  Don’t take my word for it, our own measurements of the system further showed that it was an extremely flat/linear subwoofer with among the lowest distortion we have ever measured, totally consistent with what we heard.  Further, because it was a sealed system with such good low end extension and so much excursion, the system was capable of low single digit extension in Gene’s theater room.

One track we listened to over and over as reference test material was “Mad About the Boy” by Cecile McLorin Salvant.  It’s a spotless and dynamic recording.  The relatively simple nature of the song made Cecile’s voice stand prominently, making it easier for us to really sus out the sound of the system.  Voices are something most people recognize and colorations in voices will often give rise to the perception that a system sounds natural, nasally, bright, etc.  Listening to Cecile sing made clear this was a neutral sounding system.  Going back and forth between the RTJ and RBH systems was an interesting exercise.  Neither sounded wrong, but they didn’t sound the same either.  Mostly this came down to the room curve applied to each system.  The RBH had been balanced for a fairly flat response from 100hz to 20khz in the room.  This was Gene’s preference at the time of this comparison, but does not match the Harman curve or my preference.  By comparison, the RTJ system was given a curve that mostly matched the natural response shape, but also fell closely in line with the Harman curve.  A bit more bass, a slightly quicker treble roll-off above 3khz, but otherwise a similar shape.  As a result, the RTJ system sounded warmer in its presentation of Cecile’s voice.  To make the RTJ system sound more similar to the RBH system, I adjusted the high shelf, but this largely caused Cecile to sound strident during some of the dynamic swings.  It wasn’t overloading or distorting, it’s a common problem with compression driver based speakers.  The narrower directivity of the speaker means a steady-state response will show greater roll-off than a wide dispersion speaker, but our perception of Timbre is really set by the listening window response, not the in-room steady state.  These won’t precisely match, so flattening the in-room response of a waveguide speaker can lead to a far greater boost in treble than the similar shaped in-room response of the wider dispersion speaker.  In other words, the responses might have seemed similar, but what we heard had far more high frequency energy.  Ultimately, I reverted to the original curve, which, while warmer, sounded better with the RTJ speakers.  Again, this is not a coloration, the RBH system was too flat.

dreams and daggers      echos of spain

Another song I use as reference material is the John Williams rendition of Suite Espanola No. 1, Op. 47: No. 5, Asturias Leyenda.  I originally got into this song because of Robby Krieger’s rendition of it on “Spanish Caravan.”  I had been curious about the origins of that song, and found it was a Spanish classical piano piece that had been transposed to guitar in a flamenco style.  This is the version that John Williams played, as well as Robbie Krieger.  Flamenco guitar has a very dynamic style of playing.  The music plays around not only with changes in notes, relying heavily on runs but also rhythm and changes in loudness (dynamics).  I enjoy the musical style, but I also find it very revealing of a speaker’s capabilities.  Played at realistic volumes (Flamenco style Spanish guitars can achieve levels between 80dB and 100dB peaks), many speakers seem to struggle to cleanly reproduce the strumming.  In Asturias, a melody is played through the strumming and must be distinguished from the rhythm.  This is what I look for when listening.  The RTJ super towers cleanly reproduced all the notes and dynamics, fully intact, at realistic levels, and with a wonderful ease about it.  In addition, I could clearly hear the melody through the strumming.  The speakers were impressive, and I played the sound more than once, lost in the music.

Playing this song for everyone gave me a chance to point out the connection to Spanish Caravan by the Doors(Image of Spanish Caravan), so I played that next.  There was a newly remastered version, which often means noise reduction and loudness.  Here, I think it has been made louder than the original, but the recording was also cleaned up.  None of the digital versions of the Doors music has ever matched the original Albums in terms of dynamic range, not so much a function of any advantage to records (quite the opposite in fact), rather it’s a reflection of the push toward ever louder recordings, requiring less and less dynamic range, more and more compression.  Many people complain about this, not realizing they actually prefer it this way.  I am not one of those people, and it’s too bad so much great music has been ruined.  However, I still enjoyed the song. I hadn’t listened to it in quite a while, so it was nice to hear Krieger’s version as played on that song, along with this cleaned up compressed rendition.  

That led me to play Rider on the Storm, also by the Doors.  Why?  Well, besides being one of my favorite songs, it opens with a binaural and natural recording of rain.  This is played in the background throughout the song.  Played back on a system with good spatial reproduction will create a very enveloping presentation of the rain, potentially surrounding the listener.  This would be true with speakers utilizing cross-talk cancellation or a surround system.  None of the speakers we played met that criteria, but the directivity of the speaker can impact how they reproduce the spaciousness of these types of recordings. As expected, the weaker lateral reflections led to a less enveloping reproduction of the rain, but it lead to a more natural and intimate reproduction of Jim Morrison’s voice and the music.  Jim sounded like he was right in front of us, solidly locked to the center between the speakers.  The song sounded great on the RTJ’s and it brought me back to fond memories of listening to the Doors as a kid.  This is a band that had its heyday long before I was born, but was part of my musical education growing up.  My father being a child of the times and wanting me to understand the importance of such music in today’s world. 

thedoors_singles-480x480     ab67616d0000b27371f0e7bceb73987025a05b79

At some point along our listening journey, someone decided we needed to listen to Techmaster P.E.B. “Bassgasm”(Insert music image for Bassgasm).  As the name implies, apparently, this song is meant to be nothing more than loud extreme bass.  I can imagine some teenagers playing this in their cars, overloaded with subwoofers, as they drive by, hoping the extreme low frequency pressure wave they are producing will impress the girls.  Why we played it, I have no idea.  I can’t rightly call this music.  It’s some sort of rhythmic noise with excessive amounts of deep bass.  Wow!  I’ve heard a lot of this type of music before.  I was that teenager back in the day.  Often the systems being pushed to play this just sound like they are farting.  An endless stream of distortion and garbage.  This felt like the bass punched me in the gut, grabbed me around the neck, and shook me until I passed out.  The bass I heard was unholy.  Lesser systems not only couldn’t reproduce the bass, but everything else would be completely lost in the noise.  Nearly no other speaker on the market has the output that the 410 module does.  I hate to even discuss this song, it gives the wrong impression of this speaker, given how well it can reproduce real music.  However, I would be remiss if I didn’t share this experience.  What it tells me is that this is an excellent speaker choice for someone who wants to largely listen to bass heavy pop, rock, and Hip Hop.  A lot of listeners don’t like a neutral tonal balance, they like the bass excessively high (I’ve tuned dozens of systems with the bass a good 10-20 dB too loud), and many systems can’t handle that.  It means if the dynamic peaks in the bass might each over 100dB, with mass turned up this loud, suddenly it needs to exceed 120dB.  Something many systems can’t do.  It’s not a problem for the RTJ, it will handle anything you throw at it.  I know this speaker is not unflappable. I know it has limits, but we never even came close to reaching them.  This and other songs like it literally drove me out of the room.  While I can’t say I enjoyed the music, I can say I was really impressed with how cleanly it reproduced the music. This speaker can party!      

bad to the boneIn a moment of fun, reflective of what makes this hobby so valuable to so many, we put on George Thorogoods “Bad to the Bone.”  A song that nobody can stop themselves from tapping their foot to while mimicking the famous chorus “B-B-B-B-Bad…Bad to the bone.”  Don Dunn entertained us all with his own near perfect lip sync performance.  I wouldn’t call this song reference material, it’s just a fun, enjoyable song we all knew and loved.  I bring it up to point out that in our time together with these speakers, we had a lot of fun.  All of us listen to a lot of speakers all the time. We all listen to and love music.  That we could come together around this speaker and have so much fun is telling of how good they are.  They got out of their own way and let us enjoy ourselves.  

Some of you will wonder where the movie reviews are?  Why aren’t we talking about how they sounded at Tom Cruises F14 flew by the tower?  Well, we didn’t listen to any movies.  It wasn’t really an option, given the setup we had.  However, it should also be obvious that this speaker would rock a movie just as well as it did music.  While some falsely believe that speakers are optimized for one purpose or another, reality is, a speaker that is optimized to do its job as a speaker can reproduce movies and music just as well.  Between the neutral presentation and wide dynamic range, I have no doubts that this speaker would accurately reproduce any movie you played through them and hit reference levels in even the largest home cinemas.  While we didn’t watch any movies, readers should have no concerns.  These speakers are excellent for both. 

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