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RBH Sound SX-1212P/R Subwoofer Review

by Joshua Ricci July 27, 2014
  • Product Name: SX-1212P/R Subwoofer
  • Manufacturer: RBH Sound
  • Performance Rating: StarStarStarStarStar
  • Value Rating: StarStarStarStar
  • Review Date: July 27, 2014 18:00
  • MSRP: $ 5,300 as tested (Passive Version: SX-1212N/R $2,300)

SX-1212P/R Specifications

  • Dual 12” drivers in a large cabinet with bottom vent
  • Large 6 inch diameter “Aero” port with flares at both ends
  • MDF cabinet with double baffle, internally braced and damped
  • Amplifier: High efficiency Class D, 2400 watts RMS (No distortion rating given)
  • Frequency Response: 17-180Hz +/-3dB
  • Finishes: Satin Black Oak
  • Dimensions (H/W/D): 38.5” x 17.75” x 21”
  • Weight:  130lbs
  • Warranty: 5 years (1 year warranty on the amplifier & electronics)

RBH SX-1212P/R Signature Reference Driver Features

  • Long excursion design
  • Cast aluminum frame
  • Aluminum cone with inverted dust-cap
  • Rubber half roll surround
  • Dual stacked magnets
  • Pole vent
  • Under spider vents
  • Leads sewn into spider

RBH SX-1212P/R  Amplifier Features

  • Speaker Power SP1-2400: Class D, high efficiency (>90%), switching design
  • 2400 watt rms
  • USA designed and manufactured
  • Protection: DC, overload, low impedances, shorts, under/over-voltage, overheating
  • UL rated
  • Power-con AC connector (Neutrik developed positively locking and quick detachable AC mains connection for high power professional sound equipment)
  • Main power switch
  • Gain control
  • Balanced XLR input
  • Balanced XLR send
  • Mute button
  • Program select button (Applies internal low pass filter or disables it)


  • Excellent dynamics
  • Extension down to 15Hz with room shaking output
  • Solidly constructed


  • Large
  • Expensive


RBH SX-1212P/R Introduction

RBH SX-1212P/R no GrilleLately it seems like I have reviewed a long parade of small sealed subwoofers geared at getting past the beady eyes of home decorators first and then providing what bass the physics and engineering team can coax from their tiny cabinets only after they make it into the house. This time I have something a bit different provided by RBH Sound, a privately held audio company based in Utah that has been in existence since 1976. RBH decided to send me their biggest, baddest subwoofer to review, the SX-1212P/R, a large vented system which houses dual 12” drivers, a 2400 watt rated amplifier, and weighs in at 130lbs. It also carries an MSRP of a cool $5,300 making this RBH the second most expensive unit I have ever reviewed behind the Paradigm Signature Sub 2. A passive version of this subwoofer called the SX-1212N/R is also available for much less, in case you wish to provide your own amplification and processing. It retails for $2300 and features the same cabinet and RBH Reference 12” drivers but lacks the internal amplifier. Anyway…As you can probably tell from the description, this is not a small apartment subwoofer. 

The SX-1212P/R arrived in a really big box, which has to be around 24x24x48” and weigh close to 150lbs. It is a big boy sub for sure. The packaging consists of a very heavy gauge outer box and another heavy gauge cardboard box inside of that. Removal of the SX-1212P/R was the standard of open top, flip over and lift off the outer boxes. The inner box has cut foam glued to the inside walls which conforms to the sides and back of the SX-1212P/R cabinet. There are also large foam inserts which cover the top and bottom of the subwoofer and another thick foam piece which covers the very large cone shaped feet on the SX-1212P/R. The subwoofer is also wrapped in a cloth bag which is itself inside of a plastic bag with some desiccant. Other than the subwoofer, the only other items in the box are: the power cord, a short manual, and RBH’s product catalog. Despite the bulk of this sub, unpacking it wasn’t hard at all and moving it around once unpacked isn’t too bad. It is heavy, but I could get my arms around it to bear hug it and it was quite easy to move by walking it on the large feet by tipping it on one foot and spinning it around.

while not the most attractive sub we've reviewed, The RBH SX1212P/R has the look and feel of quality.

Once unpacked the SX-1212P/R is obviously a large sub being almost 40” tall overall but it turned out to be a little smaller than I thought it would be after seeing the huge shipping box. The overall profile is tall and thin with a smaller foot print than I had imagined. This impression is also helped out by the fact that the side walls have an aggressive curve to them so that they bulge out a bit in the middle and narrow towards the back panel and towards the drivers. This helps keep the SX-1212P/R from appearing as a simple cubic shape. The grille is a simple press fit unit cut out of MDF with black cloth fabric and a small RBH logo at the bottom. The bottom of the grille is curved and does not extend all of the way to the bottom of the enclosure, which also helps to break up the appearance a bit. The front panel is also beveled on the edges. The driver cones are aluminum and can be seen through the grille in the right lighting, which along with bright chrome finish of the four very large and heavy duty cone shaped feet on the bottom of the SX-1212P/R, give it some visual “pop.” These large feet hold the cabinet approximately three inches off of the floor and allow the bottom firing port to breathe. Since the SX-1212P/R review unit was primarily black on black I would not say that the SX-1212P/R is the most beautiful or strikingly finished subwoofer I have seen but it is better looking than most and has the look and feel of quality.

Design Overview

The SX-1212P/R is the largest, most powerful subwoofer in RBH’s lineup and is part of their Signature Reference series. It is a large bass reflex system employing a pair of proprietary 12” drivers which are stacked vertically on the front face of the enclosure and a large 6” diameter Aero port, which is heavily flared at both ends, fires from the bottom of the enclosure. The port is held off of the floor by four very large and heavy feet.  The 2400 watt rated amplifier is located on the back of the enclosure.

The RBH 12" sub drivers are well designed and plenty capable.

I removed one of the SX-1212P/R drivers so I could have a look at its design and construction and also have a gander at the interior of the SX-1212P/R enclosure. The drivers are of very nice build quality and feature aluminum cones for light weight and stiffness with inverted dust-caps. The frames are an open cast aluminum design, which allow plenty of clearance and venting under the spider and around the top plate. The suspension components consist of a rubber half roll surround and what appears to be a single spider of roughly 6.5” diameter with the leads sewn into it. The motor consists of a pair of roughly 6” diameter ferrite slugs about 1” thick coupled to a steel top plate that is around 12mm thick and a back plate of the same thickness with a large pole vent. The voice coil appears to be a single 2.5” diameter 4 layer unit. Out of their enclosure the RBH drivers don’t look as impressive as some of the heavyweight juggernauts out there, but there are two of them sharing the load. They were pushed somewhere north of 2” peak to peak excursion on more than one occasion and judging from the performance the SX-1212P/R delivered both during the measurements outdoors and in my room at home, these drivers are well designed and plenty capable.

sx1212 driver

RBH SX-1212P/R Driver

The amplifier powering the RBH SX-1212P/R is actually one that I have had some experience with a few times before, so I knew what it was right away. It is manufactured and designed in the USA by SpeakerPower as the SP1-2400. The SP1-2400 is a mono plate amplifier with a high efficiency Class D switching design rated at 2400 watts continuous. The efficiency is said to be over 90% and the amplifier is claimed to be able to produce the rated power for at least 4 seconds with the indefinitely sustained power limited by thermal buildup to about 3dB less than the rating. Also this rating is specified down in the bass range. This may not sound like much but the fact is that most amplifiers these days are rated by a very short burst method and can only produce their rated power under ideal conditions for a fraction of a second at 1Khz.

One thing that the amplifier does not have is a ton of controls or special features. It offers only the most basic controls and connections. There is a single balanced XLR input and a single XLR output to send the signal on to another unit. There is a powercon connection for the AC cord which is a feature most often seen in professional audio equipment and one I wish would trickle into the consumer market a bit more. This type of connector has a positive locking mechanism that prevents any possibility of the AC cable coming loose or being yanked out on accident, but still allows quick removal in a few seconds and generally is made of higher quality materials, for heavier duty, high current applications compared to the typical, generic IEC type power cord used with most home audio products.  Other features on the amplifier include a fuse and a main power switch. A mute button is also included on the amplifier as well as a program select button (PGM), which is either in or out and engages or bypasses a low pass filter in this case. There is a gain control knob as well and...That’s it…There is no phase control, no low pass filter adjustment, no EQ presets, no speaker level inputs, no auto on/off…There isn’t even an unbalanced RCA connection to be found on this amplifier. All of this is perfectly fine with me since I don’t use any of that to begin with, but I could see the lack of connections and controls potentially bugging some people even if at the end of the day they may not need any of that extra stuff.

Regardless of being a bit bare bones compared to some other plate amplifiers what this amplifier platform offers is huge power reserves in a lightweight and compact package. Due to my previous experiences with these amplifiers I was curious to see how the SX-1212P/R drivers handled things when the amplifier was really let loose, but they proved they were up to the task, though at times the amplifier appeared to have the 12” drivers on the ropes so to speak. Even with the 20+ second long sine wave sweeps during outdoor testing, at full volume, in direct sun, the amplifier heat-sink only got warm to the touch. While I was testing the SX-1212P/R’s burst capabilities in my basement home theater room the amplifier was connected to the same 120v 15A ac line that I plug all of the subwoofers without 240v capability into and it was noticeably dimming the lights in the room. I have never encountered that from any other subwoofer I have reviewed. This is a very powerful and expensive amplifier being used in the SX-1212P/R.

RBH SX-1212P/R (SP1-2400) Amplifier

The cabinet of the RBH SX-1212P/R is constructed of medium density fiberboard or MDF as are most speakers these days. The walls, top, bottom and back panels appear to be ¾” thick material while the driver baffle is a full 1.5” thick. The drivers are recessed and flush mounted into the baffle. On the bottom of the enclosure is the large 6” port which is heavily flared on both the inlet and outlet. The grille is a simple cloth over wood assembly but it locks into the baffle solidly and is well constructed. Internally the SX-1212P/R enclosure features vertical braces running up the middle of the side walls and back of the enclosure. There is also a large brace in the middle of the enclosure which the port travels through. The enclosure is also lined heavily top to bottom with damping material including thick pieces of foam at both the top and bottom panels. The port even had acoustic damping sheets applied to it. Sometimes with larger enclosures you can run into problems with panel flex, vibrations or resonances, but I never encountered any of that with the SX-1212P/R even during the measurements session outdoors. This is most likely due to the extensive bracing and huge amount of damping material in the cab.

The satin black oak finish of the review unit was smooth and understated. I would call the overall look of the SX-1212P/R review unit classy and business like, with the curved black of the enclosure side walls contrasting against the chrome feet and aluminum driver cones. The enclosure, build and overall parts quality of the SX-1212P/R is very high.

SX1212pr drivers removed sx1212pr port

RBH SX-1212P/R Cabinet View

RBH SX-1212P/R Subwoofer Sound Quality Tests

The RBH SX-1212P/R was placed in the front right corner of my basement HT room facing into the wall and plugged into the system with an XLR cable. I left the gain of the amplifier at its maximum and disengaged the PGM button to defeat the internal low pass filter. I allowed Audyssey to run its auto equalization on the system and afterward checked the balance of the SX-1212P/R against the main speakers as I often find it to be off a bit. The low pass to the SX-1212P/R was set at 100Hz inside of my Onkyo processor.

Music listening

strange-cousins-from-the-westAfter casually listening to music for a while with the SX-1212P/R in the mix I decided to take a few measurements of the SX-1212P/R’s bass response in my room and as expected it was a little heavy on the bottom end below 40Hz which made it seem a bit slow and plodding.

After this was corrected with a bit of manual EQ I decided to listen to a few select tracks from the Clutch album Strange Cousins From the West. This album has excellently recorded acoustic drums and a hefty bass guitar and drum mix. With the low end of the SX-1212P/R throttled back a bit so that top-to-bottom balance was restored, I could hear the resonance of each rack tom and floor tom clearly against the bass guitar which itself often has a growling sometimes biting tone to it. Much better…On some tracks the very bottom end of the snare drum will even just start to bleed into the crossover region between the subs and mains and I thought that the SX-1212P/R, once dialed in, did very well at resolving details in the crossover region without obviously making itself known.

 For something a little more aggressive, with a hyper punchy kick drum, I listened to a few tracks from God Forbid: Determination and cranked the volume way up. This album has the kick drum mixed probably a little too hot but it can be fun with a good bass system and I’d say the SX-1212P/R qualifies because it reproduced the triggered kick drum sounds with snap and power even during dense double kick patterns. In order to switch musical genres completely to something with more of a rap or hip hop feel, I switched over to Cypress Hill: Black Sunday. I wasn’t surprised when the SX-1212P/R was unfazed by either the loud, repeatedly booming bass tones or the mellow, old school sampled R&B beats and bass lines. All of it was reproduced easily with clarity and no sense of strain. Switching gears completely again I played some selected 16 Horsepower tracks which feature upright bass. The SX-1212P/R had no trouble remaining neutral and blending with the mains as the upright bass was suitably woody, droning and thumping in character.

The RBH sub easily reproduced bass with ease and clarity with no sense of strain.

I also ran the NIN track Discipline at a very stout playback volume to see if the SX-1212P/R could reproduce the bottom of the low frequency sweep towards the end of the song with any power or clarity and I have to say it was probably one of the better reproductions of this I’ve heard lately, with clarity and ease all of the way from the bottom of the sweep, which starts to develop below 20Hz.

Movie listening session

TriangleThe movie Triangle is a strange and somewhat disturbing film but it has a ton of bass in it and a couple of demo worthy scenes, so I decided it would be a good candidate to see how the SX-1212P/R would perform with a bass heavy movie soundtrack. The first real bass event in Triangle is a doozy and one of the two demo worthy scenes contained in this films soundtrack. The small group is on a boat out at sea when a very ugly storm appears out of nowhere and unleashes on them, destroying their boat. This scene is very dynamic and loud and has significant bass which is very hot and extends down to below 20Hz with power in some places.  With the master volume at -10, which is the volume that I typically use for subwoofer reviews, the SX-1212P/R thundered out the bass during this scene in impressive fashion without any hint of strain. It also produced some shaking in my seat in parts that indicated to me that it was reproducing the content below 20Hz with vigor.

Later on when the cruise ship arrives it is accompanied by a powerful drone that is not very deep in frequency but is quite loud. The SX-1212P/R had no problem sustaining this loud bass. The rest of the movie is chock full of things like the sound of heavy footsteps on wooden decks, mechanical and engine noises and ominous horror movie drones that are used to build tension. The SX-1212P/R reproduced all of these various bass sounds, some of which are quite weighty and deep, without any issue. I have heard smaller lesser subs obviously compress or struggle a bit with some of this. Some of the “background” bass parts in this movie that are supposed to build tension are indeed mixed so loud that it can start to become fatiguing after a while. The fact that the SX-1212P/R reminded me of this tells me it was reproducing these signals whole-heartedly.

The other scene that I consider to be demo worthy in this movie involves an attack by a masked gunman with a 12ga shotgun. The gunshots are deep and loud with huge dynamics especially on the first couple of shots. The SX-1212P/R did very well here producing a visceral gut punch with apparent ease. Typically I can hear certain bass heavy moments starting to tax the subwoofer when I watch movies at this playback level. Most subwoofers, even expensive and powerful ones, will struggle a bit with these playback levels in my room, but I didn’t get any sense of that with the SX-1212P/R which tells me that it has generous amounts of headroom. 

As usual the SX-1212P/R was subjected to a battery of sub busting movie demo scenes in order to see just what it is capable of and how well it is protected. I used the same -10 master volume that I playback movies at for all of the subwoofer reviews. These are a few of the worst of the worst when it comes to identifying weaknesses or causing distress to subwoofers. You can talk about how taut and clean your sub sounds with light jazz at room conversation level all day long, pitch definition and clarity or what have you, but nothing is an utter sound quality fail quite like your sub making obnoxious noises, wheezing, shutting down, or clanking in distress in the middle of your Sunday night movie because it doesn’t have enough output to do the job your listening habits demand, or is not protected well enough to hide the fact at the very least.

First on the list was the plane crash scene from Flight of the Phoenix. This is one of the loudest bass events I have found in any movie to this date. The bass in this scene is just plain hot and contains a mix of frequencies culminating in a very loud 30Hz drone during the barrel roll of the plane. The SX-1212P/R rocked this one out and while I think I may have heard a bit of something from it, perhaps a hint of distortion, this was the most powerful and uncompressed that this scene has been reproduced by any sub that I have reviewed for Audioholics. Definitely an A+ on this one.

The RBH SX-1212P/R reproduced the plane crash in Flight of the Phoenix with greater authority than any other sub we've previously reviewed on Audioholics.

Next up was The Hurt Locker where the 50-caliber is being fired in the desert. With this scene the subwoofer is asked to produce huge amounts of bass under 20Hz accompanied by a reduced but still significant level of upper harmonics. Very few bass systems reproduce this content fully. The SX-1212P/R did pretty well here with plenty of volume but I could tell that the lowest parts of the signal were significantly below the bandwidth of the port tuning which made the individual gun blasts slightly less powerful feeling than they can be.

Demo scene number 3 was the rail-gun test scene from Batman: The Dark Knight. This one isn’t particularly deep or taxing on most subwoofers but it has very loud and abrupt bursts of bass good for judging how dynamic the bass system is in the middle and top of its bandwidth. The SX-1212P/R had no problems with this one and filled the room with concussive force. Just for fun I turned this up even louder and ran it again which resulted in an even more forceful reproduction. Excellent!

Final Note on Listening Tests

Pulse Blu-rayAs a final torture test I usually use the server room scene from the horror movie Pulse. This particular scene is one of the more demanding that has been released with loud, sustained, warbling bass centered at about 17Hz. To top it off there really isn’t a lot of accompanying noise in the soundtrack either. This scene makes a lot of ported subs, even good ones, audibly wheeze, some subs skip this sub 20Hz content almost completely and don’t even try to reproduce it. A lot of other subs cut out and go into protect mode or get driven into distress very easily while trying to reproduce this content. This scene is particularly tough for ported subs since the port tuning is usually near the center frequency of this signal and it can cause the ports to chuff or compress. The SX-1212P/R easily produced the most powerful and relaxed reproduction of this track of any of the units I have reviewed in this room. I may have heard what was a bit of port wind noise but I am not entirely sure since the SX-1212P/R was shaking my seat and the entire room at the time. Having a large flared port does help quite a bit at keeping the port air flow laminar. The port tuning being near the meat of the signal in this scene helps the subwoofer produce lots of output efficiently as well. Regardless of whether there may have been a hint of port noise or not the SX-1212P/R produced a huge amount of bass with an ease that was exceptional with this very demanding track.

RBH SX-1212P/R Subwoofer Measurements & Analysis

The RBH SX-1212P/R subwoofer was measured while placed outdoors on the ground in a large field with the nearest large objects a minimum of 60ft away from it, laying on its side with the drivers facing towards the microphone. An Earthworks M30 measurement microphone was placed on the ground at a distance of 2 meters from the nearest enclosure face of the subwoofer, pointing towards the drivers. The grille was left off of the SX-1212P/R. The amplifier was set to maximum gain and the PGM select button was out for all measurements unless otherwise noted. For more info on the testing equipment and procedures please visit our Powered Subwoofer Testing Outline and Procedures Overview.

sx1212r normalized distance

RBH Sound SX-1212P/R: Normalized Response Comparison of Measurements at Different Distances

The RBH SX-1212P/R was measured in various orientations in order to find the one which offered the best response shape, output and blending of the driver and port output. An orientation with the RBH lying on its side with both drivers firing directly at the microphone was found to offer the best overall response.

Since the RBH SX-1212P/R has a port that fires from the bottom which places it on a separate plane from the drivers and makes it impossible to have all radiation points directly firing at the microphone or even an equal distance from it, it was necessary to develop a calibration file for it in order to more accurately represent its total acoustic power. This is done by taking measurements at various distances and comparing them. A much longer 10 meter distance is used as the control since it reduces the path length differences of the radiators on the speaker from the microphone to a very small percentage and allows the full output of the DUT from all radiators to be better represented. This is shown in the graph above.

As can be seen the 1 meter measurement indicates the least amount of deep bass because the port contribution is diminished due to the port being further away from the microphone.  Let us call that extra distance that the port contribution has to travel to reach the microphone 50cm just for the sake of keeping it simple. So while the output from the drivers is only traveling 100cm to the microphone at a 1 meter distance, the port contribution is traveling 150cm. 50% further which causes a comparative loss of signal strength at the microphone. Moving the microphone back to a 2 meter distance shows an increase in deep bass due to the port contribution being better represented. Now the path length difference is only 25% with the drivers at 200cm and the port at 250cm from the microphone. By the time the microphone is moved back to a full 10 meters from the subwoofer the port contribution and thus deep bass output is increased greatly over the 1 meter measurement. At this point the drivers are at 1000cm distance from the microphone and the port is at 1050cm distance, which is only a 5% difference in path length. The 10 meter measurement is a more accurate representation of the total output of a subwoofer with multiple radiation points. In room the multiple boundaries confine the total output of the subwoofer system at the long wavelengths in the bass range so the much longer 10 meter measuring distance is a more accurate representation of the systems total power that will be delivered in a typical room.

sx1212r pgm

RBH Sound SX-1212P/R: Effect of PGM Button on Frequency Response

Above are the frequency response measurements of the RBH SX-1212P/R showing the effect that the PGM button had on the response of the system. Engaging the PGM button engaged a low pass filter which appears to be a 200Hz filter with a 12dB/octave roll off.

sx1212r base fr

RBH Sound SX-1212P/R: Frequency Response as Tested

Above is the frequency response measurement of the RBH SX-1212P/R subwoofer in an orientation that had the system lying on its side on the ground with the forward firing drivers facing the microphone. This is the basic configuration used for the majority of the measurements unless otherwise noted. The frequency response of the SX-1212P/R is stated as 17-180Hz (+/-3dB). The measured and port distance-compensated response fits within a 6dB total window over a bandwidth of 17-175Hz which confirms the manufacturer specifications almost exactly. The SX-1212P/R exhibits a shallow roll off above 150Hz and has enough upper range to match up with small satellite speakers between 100-150Hz.

However, the measurements do show a port resonance at about 190Hz, so the SX-1212P/R would likely be best crossed over below 100Hz. Overall the response is tilted slightly towards the low end and exhibits a bit of peaking near the vent tuning which indicates that the drivers could actually use a bit less enclosure volume with the tuning chosen in order to cut down the strength of the port contribution a bit. In room one would expect this response shape to become tilted even more heavily towards the low bass and perhaps may end up sounding a bit heavy handed as room gain typically kicks in below 30Hz. Indeed this was what was seen in my room at first, but an auto EQ system such as Audyssey or a manual EQ device can easily correct for this and reduce the low bass energy to bring it back in line.

sx1212r group delay

RBH Sound SX-1212P/R: Group Delay

The group delay of the RBH SX-1212P/R is characteristic of a vented system and exhibits some increased energy delay near the vent tune and rumble filter. The group delay does reach right at 1.5 cycles between 17-22Hz but above 25Hz it is well under 1 cycle which is a good result. Generally I am much more concerned with elevated group delay above 25Hz than below. Research and my own listening has shown that the ears of the average person are far more sensitive to high levels of group delay at higher frequencies rather than the extremely long wavelengths below 30Hz. Additionally room acoustics can play absolute havoc with the time response of a subwoofer once placed in room. That being the case unless something truly excessive or odd shows up in the group delay measurements it is generally of lesser importance to me than some of the other performance measurements.

sx1212r long term output

RBH Sound SX-1212P/R: Long-Term Output Compression

The long-term output compression measurements for the RBH SX-1212P/R indicate a very powerful system. As the output demands from the subwoofer are increased in 5dB increments past the 90dB at 50Hz base line measurement the SX-1212P/R remains resolute all of the way up through the 110dB sweep.

From 12.5-40Hz the SX-1212P/R produced the highest output that we've recorded from any subwoofer reviewed on Audioholics to date.

When asked for a further 5dB increase in output during the 115dB sweep the SX-1212P/R starts showing signs of being near its limits. By this point the drivers were starting to make suspension noise below the vent tuning and producing rather large cone excursions. That being the case the final sweep was only pushed another 3dB higher rather than a full 5dB as I was worried that driver damage may result. During this loudest measurement the SX-1212P/R’s drivers were clearly giving all that they could and had to have been producing excursions somewhere in excess of 2” peak to peak below the vent tuning and did make some obvious overload noises. However, at this point the SX-1212P/R was producing about 115dB over the 25-120Hz bandwidth and in excess of 110dB at 20Hz which is impressive indeed. It was still over 106dB at 16Hz!

Also despite my initial fears of the amplifier being a bit too much for the 12” drivers to handle the SX-1212P/R did indeed turn out to be more than adequately protected. As I got more comfortable with the SX-1212P/R I got a bit more brazen and during the CEA-2010 burst tests I really pushed it for everything it was capable of. While it may produce some suspension noise from the drivers and some distortion noise if you really beat on it below tuning, it will not hard bottom the drivers or otherwise damage itself. Keep in mind that this is a potent subwoofer with a rumble filter to help protect it and you will not encounter this unless you are asking it for immense amounts of output. Also note that during the repeat 90dB measurement, taken immediately after the loudest measurement, some heating of the voice coils in the drivers and a slight loss in sensitivity is indicated. One sign of a maximized and competent subwoofer design is when the amplifier and the driver or drivers reach their collective limits at around the same time. That was the case with the SX-1212P/R.

Note on Output Compression Testing: This is by far the most demanding measurement type conducted on the subwoofers during our testing and will reveal any issues with overload, port compression, port noise, driver distress, creaks, rattles, buzzes, etc. Additionally, the test is conducted outdoors with just the subwoofer operating so there will be no nearby walls or objects to vibrate and no upper frequency content from other speakers in operation. These would normally help to cover up or mask any objectionable noises from the subwoofer in a typical room. Any sort of audible distress or issues with the subwoofer are readily apparent in this environment.

 sx1212r output compression

RBH Sound SX-1212P/R: Output Compression Magnitude

The chart above is the measurement information from the previous graph titled: Long Term Output Compression, presented in a different manner which shows only the amount of compression occurring in the signal. In other words how well is the speaker tracking the increases in output demanded by the signal input? As we can see the SX-1212P/R does very well through the nominally 110dB sweep with less than 1dB of signal compression above 23Hz and around 2dB near the vent tuning in the deep bass. Considering that the SX-1212P/R is producing about 110dB at 20Hz in a 2m ground plane setting during this measurement, it is an excellent result. We can see that during the next 5dB increase in the signal that the SX-1212P/R starts running out of steam a bit as the compression of the signal grows to around 2dB in the upper bass range and increases to near 6dB at the vent tuning (where cone movement is minimal, the impedance is low and current demand is highest). Increasing the output demands a further 3dB for the final measurements indicates that the SX-1212P/R is effectively out of headroom by this point as little extra output is produced and compression increases even further to around 3dB in the upper bass and around 9dB near the vent tuning.

G2 SX1212PR CEA2010

RBH Sound SX-1212P/R: CEA2010 2 Meter Ground-plane RMS Results

CEA2010 Results

The CEA2010 maximum-distortion-limited-short-term output results for the RBH SX-1212P/R are impressive reaching 120dB over the 40-125Hz bandwidth. An octave below 40Hz (at the 20Hz band), the SX-1212P/R flexed its low distortion drivers, big 6” flared port and powerful amplifier to record a mighty SPL of just under 113dB! The headroom available at 16Hz was equally impressive at 107.7dB. The SX-1212P/R did even better in room and recorded short term bursts of over 115dB at 20Hz and in excess of 110dB at 16Hz at the listening position. From 12.5-40Hz the SX-1212P/R produced the highest output that Audioholics has recorded from any subwoofer reviewed to date. That helps to explain why it was so much fun on those movie nights…

RBH SX-1212P/R Subwoofer Review Conclusion

sx1212 no grillIf you have a thirst for big bass output or an abnormally large room and have a healthy budget to work with, the RBH SX-1212P/R is worthy of consideration against other popular contenders such as the Velodyne DD18+, JL Audio Fathom series and Paradigm Signature series, but it offers something a bit different.

The SX-1212P/R is a big subwoofer at about 40 inches tall and it is expensive with an MSRP of $5,300, but it really doesn’t take up much floor space at all so it actually does better than expected at blending into the room despite its physical size. The SX-1212P/R doesn’t carry much in the way of “extras” or special “features” either, with only the most basic of controls and connections included, but in my experience, most of these “extra” things are seldom as useful as advertised and often do little to increase the acoustic performance of the speaker.

Most of the cost in the big RBH is in the drivers, the cabinet and the amplifier and that is exactly where they should be. One feature that the SX-1212P/R does have is the capability to shake even a large room with the critical 15-30Hz octave while displaying a sense of effortlessness and headroom like few subwoofers I have encountered. If you are looking for a system that will bring authoritative yet clean bass into even a large space the RBH SX-1212P/R may be just the ticket.

The RBH SX-1212P/R is a large powerful vented subwoofer and easily met the required output goals needed to earn the Audioholics Bassaholic Extreme Room rating. The Extreme Room rating indicates that this sub is recommended for maintaining adequate headroom in rooms or spaces of 5,000 cubic feet or more and/or for users who tend towards higher volume playback of material. For further information in how we make these recommendations, check out the Audioholics Subwoofer Room Size Rating Protocol.


RBH Sound SX-1212P/R Review
MSRP: $5,300

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

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
Bass ExtensionStarStarStarStarStar
Bass AccuracyStarStarStarStarStar
Build QualityStarStarStarStarStar
Fit and FinishStarStarStarStarStar
Ergonomics & UsabilityStarStarStarStar
Dynamic RangeStarStarStarStarStar
Attached Files