Sunday, July 11, 2021

RBH Sound SI-1212 Signature In-Floor/In-Ceiling Subwoofer with DA-1802DSP Amplifier Subwoofer System Review

If you have been like the majority of people during the pandemic, you have either been quarantined, done a lot of binge watching, or both. During this binge watching you may have come to a realization that it’s time to upgrade your surround sound system. You may have also learned that, while streaming services are getting more and more popular, they are also appear to be a new vehicle to get new release movies to us. We saw this with Wonder Woman 1984, and it won’t stop there.


Being able to watch first run movies at home may have motivated you to not only upgrade your home theater equipment, but to also build a home theater. While a majority of the sound frequencies we hear are highs and midrange, we don’t want to forget the bass or lower frequencies. After all, try watching any action movie with a lot of explosions without a subwoofer. The movie will just seem flat. Having a good quality subwoofer will help you get the most out of any movie. Up for review today is the RBH Sound SI-1212 in-ceiling/in-floor subwoofer, and DA-1802DSP amp.


Unlike most products you get in the store, RBH Sound sells their products only through authorized dealers. You go to an authorized dealer, and they help you design your system based on your needs and room size. But in speaking to RBH Sound about my theater room, I not only wanted in-wall speakers so they’re hidden, I also wanted the subwoofer to be hidden as well. I was told they just had a new in-ceiling/in-floor subwoofer come out. It’s a design which features two 12’s in a sealed enclosure.


I went to their corporate offices to pick up the subwoofer, and they also showed me the driver they use. The box was very well made, employing HDF, and looked great with an excellent black finish. On one end of the enclosure was the wiring terminal and on the other end was the port. The port is not a traditional port/vent as you would expect in a ported sub. This is a sealed sub.  But to allow it to be installed in-ceiling or in-floor, the face that the two drivers are mounted on is recessed and covered.  And it’s this small cavity that has an opening with a black cloth cover, and you would have a return vent cover mounted in front of it in your wall. Quality of materials used was excellent as was the fit and finish. The actual driver is mostly metal with a beefy magnet, thick rubber surround and stamped steel basket. It is a heavy gauge steel basket so it can handle a lot of power. The basket was of a very high quality, as was the spider which had sewn in tinsel leads. The aluminum cone was also of excellent quality, as was the large rubber surround designed for high excursion. All of the components used are of exceptional quality as was the fit and finish. 


One additional feature that is not only really cool, but also really unique, is a resettable fuse.  RBH Sound includes a physical resettable fuse mounted in the enclosure with the subs.  This is to further protect the drivers.  If the subs are being overpowered, the fuse will trip, protecting them, and then reset once the overpower has passed.  This ensures the drivers will never need to be replaced once the enclosure is installed in the floor/ceiling.  Extremely cool!!!


The subwoofer I received included the DA-1802DSP DSP/AMP. The subwoofer is passive, but RBH Sound has the DA-1802DSP DSP/AMP that can be sold with the subwoofer as a package. With 1800 watts RMS, the DA-1802DSP does a great job powering the subs.  The DA-1802DSP provides 1800 watts RMS into 2 channels (900 watts RMS to each sub) so you will get every ounce of performance.


Features and specs:


Series:  Signature In-wall

System Type:  In-floor/In-ceiling Subwoofer

Frequency Response:  20Hz-200Hz (+/- 3dB) when Powered with RBH Amplifier

Sensitivity:  90dB (2.83V @ 1 Meter)

Recommended Power:  100-1000 Watts

Subwoofers: (2) 12" (300mm) Aluminum Cone

Crossover Frequency:  N/A

Crossover Slope:  N/A

Impedance:  4 Ohms

Cabinet Material/Color:  High Density Fiberboard (HDF)/Black

Cabinet Finish:  Black Enclosure

Baffle and Grille:  Baffle Black; Grille Black or White Fabric

Grille Options:  Heat Vent (in-floor), Cold-air Return (in-ceiling)

Enclosure Dimensions:  13-1/2" W x 56" H x 9" D (335mm W x 1423mm H x 229mm D)

Grille Cutout Dimensions:  12" W x 6" H  (305mm W x 153mm H)

Weight:  85 lbs. (38.55 kg)


RBH DA-1802DSP Stereo Amplifier

DSP:                                     24 Bit/96Khz  (31 PEQ filters user programable)

                                             Optimized Filters for RBH Subwoofers (included)

Power Supply:                   Switch Mode Power Supply

Output Stage:                   Class D

Power Output:                 2x600W @ 8 Ohms, 2x900W @4 Ohms, (1200W/1800W Bridged)

Frequency Response:      10Hz-22kHz (+/- 0.5dB)

THD:                                    <1%

Slew Rate:                          >30V/micro second

Damping Factor:              >300

Input impedance:             20K Ohms

S/N Ratio:                          >95dB

Input Sensitivity:               1.4V

Input Connector:              XLR (RCA with Adapter)

Output Connector:          Binding Post/Speakon

Protection:                         Thermal, Overload, Under Voltage

Cooling:                              Quiet Mode Variable Speed Fans

Rack Size:                           2U

Dimensions (WxHxD)      19”x3.5”x10.5” (483mmx88mmx260mm)

Weight:                               13.5 lbs. (6.13Kg)

Options:                              RS485 Programming Cable


The RBH Sound DA-1802DSP came in a standard cardboard box. Opening the box revealed a well-protected amp held in place with some custom foam. Materials used in the construction are mostly metal. Quality of materials used as well as fit and finish were excellent. Buttons, knobs and connectors are tight, well put together and it felt very solid in hand.


To really check the quality, I took off the top to get a good peek inside. There’s a couple large aluminum heatsinks, several large capacity caps, the transformer and beefy internal wiring, along with multiple coils, and quality soldering.  The rear connectors are tight and solid on the inside. Circuit boards also appear well put together.  Hats off to RBH Sound on a well-designed, well built, quality amplifier! 


Now that I’ve seen its high build quality, lets get it connected!  Connecting the DA-1802DSP was very simple.  There’s the detachable power cord, along with 5-way binding post for the speaker wire.  The inputs are XLR, and included in the box were a pair of XLR to RCA adapters.  Your current equipment may not have XLR inputs, but if you plan on going that route in the future, this amp can grow with you. I also loved the fact that the DA-1802DSP came with front rack ears built-in. That way if you have an AV rack, its ready to be mounted.


The amp is pre-programmed in the RBH Sound Lab for the specific sub it’s purchased with. The front of the amp is very simple. The internal settings are locked for this particular amp, so there are no software adjustments to be changed by the consumer.  The LED showed the model SI-1212 for the sub followed by “BRG” and an image of a lock.  This is to tell you that it is in “bridged mode,” that it’s set-up for the SI-1212 sub, and the settings are locked.  Yet if you wanted to make any internal software adjustments, RBH can walk you through that.  From the dual connectors for inputs and outputs on the back of the amp, you can tell that it is actually a two-channel amp.  But as the SI-1212 only has a one channel input connector on the back of the enclosure for the two subs, so the amp is bridged to one channel.  And the speaker connectors on the back of the amp are easy to read with instructions for which wire is to be connected to which terminal when it is in bridge mode.  This makes it really easy to hook up.


You obviously need good midrange and tweeters for a high-quality surround sound system. After all, most of the audio in our movies and music comes from the frequency ranges produced by these drivers. But you need to watch an action movie with a lot of explosions without a subwoofer. Watch it again with a good subwoofer and you will see just how flat a movie feels without a subwoofer. To get the most enjoyment out of your music and movies, you need a high-quality subwoofer.  Subwoofers are not all created equal. After all, get a just “ok” subwoofer and while you may see and hear T-Rex coming, you may not actually “feel” him coming. With the RBH Sound SI-1212 subwoofer system, you’ll definitely feel him coming. Let’s see how it sounds.



Ready Player One- Race scene: all of the engines revving had really good depth and life-like dynamics. All of the various car explosions had not only excellent low-end extension and pitch definition, they were extremely life-like as well. As the wrecking balls created their havoc on the various cars, they did so with excellent authority and in your chest punch that was really tight and clean. T-Rex’s stomping and biting of cars had the same realistic dynamics. When Kong is racing to beat Percival to the finish line, not only was it extremely deep and clean, I was expecting to get complaints from my teenagers on the 2nd floor.  Impressive, since I was in the basement. Even though it’s a sealed sub, it played with serious authority!

The Great Wall: there are some great scenes with drums and black powder explosions. At the 17:59 mark, they beat against the huge drums with nun chucks to signal the army to use long range weapons. The striking of the drums with nun chucks had not only great definition of the pad, but also played deep with foundation shaking authority! At the scene of the general’s funeral, the playing of the drums was not only really deep with excellent authority, they were extremely musical, providing much better than expected resolution of the sticks beating against the leather drum pad! At the scene where they go to capture a creature, the black powder explosions were so life-like with such dynamics and room shaking bass.  I questioned who had the better system, my theater room or the last movie theater I went to. And all of this was done so cleanly with excellent dynamics and great control of the motor structure.

Interstellar: the dust storm at the 18:30 mark shook my whole room. And when they got out of the truck to run inside the farm house, it was even more so. The base was deep, with tons of output. And when they got in the house and closed the door it wasn’t as loud, but was even deeper.  At takeoff at the 43:30 mark, not only did it shake the theater room, it shook the whole house, and even got my daughter’s room on the second floor shacking a little! In fact, this whole movie was a bass feast, providing clean, tight, deep bass with tons of output!



New Order- Blue Monday: bass was nice and tight, quick, with in your chest punch that you could really feel! And without a hint of muddiness.

Katy Perry- Dark Horse: bass hit really hard, clean with lots of output and authority.

Richard Strauss- Also Sprach Zarathustra- bass was extremely deep and really clean. The pounding of the mallets on the tympani had excellent resolution of the pad as well as excellent dynamics.

Timmy Trumpet and Savage- Freaks: beats were so punchy and hit so hard, my whole house shook. Bass was tight, very dynamic, yet really clean.


Using dual 12’s and giving them 900 watts RMS each from the accompanying DA-1802-DSP, I had high expectations  and was anticipating some very good to excellent clean tight bass. With the size of the  sealed enclosure, I was expecting good low-end and high output. I wasn’t wrong!


You would think I would have learned by now, but RBH Sound has done it to me again. Not only have they exceeded my expectations, they also surprised me. I measured the SI-1212 to be -3db at 20hz, which was right what it is spec’d at. I also wasn’t expecting the house shaking output that I got, which I’m used to getting from my reference 4-foot tall SVS ported cylinder sub. What I got was even more so!  I was enjoying it so much, I couldn’t resist and put on a track from my old school car audio days, Techmaster PB: Activate, and Time To Jam.  Holy cow!!!  It hit so hard!  I thought I was going to knock things off the shelves in the room next door.  I could only image if this sub was ported, the havoc it would bring!!


The RBH Sound SI-1212 and DA-1802DSP did everything extremely well. If the bass from the source material was a tight bass, you get the tight clean punch in the chest bass. And I’m talking about a real punch where you can feel the sound pressure wave hit you! If it was the more rumble bass type of bass like a rocket taking off, not only did my theater room in the basement rumble, it shook the whole house, being able to feel it on the second floor! The subs performed extremely well with this amount of power.  At one torture test I turned the gain/trim down on the front of the amp as I thought the subs may have reached their max, just to realize they were handling the power great and turn it back up a little more.


There were a couple of times when the sub did seem not to know its own limits and was pushed a little too far for where it should go, so I ended up turning the gain/trim down just a bit.  One thing is for sure, this amp has all the power that these two subs can take, so it’s a perfect match.  And with that amount of power, I could actually hear and feel those drivers were very well controlled!  The dynamics, control, and tightness of the punch when the scene or music called for it was amazing.  I had only heard that level of performance from just a handful of subs before.  The level of resolution they revealed surprised me especially since a sub designed mostly for home theater could be so musical!  The low-end extension was not as deep as some subs out there, but -3db at 20Hz, you will definitely FEEL it when T-Rex is coming. And the sub is completely hidden! Just imagine the look on your buddies faces when you’re giving them a demo, and they realize and ask… wait…where’s your massive sub for this much bass?!?! And they can’t find it!!


RBH Sound has a game changer on their hands, with this type of performance in a hidden in-ceiling/in-floor subwoofer. The RBH SI-1212 and DA-1802-DSP is true to the sound of the source material, and handled everything I threw at it extremely well. Not only did it perform in spades for movie material, it proved to also be very musical and performed exceptionally well with music material as well. Based on its design, features, quality and performance, the RBH Sound SI-1212 and DA-1802DSP has earned our Editor’s Choice Award. For more info and complete specs, check out their website at  But don’t just see them online, find an authorized dealer near you, because this level of sound needs to be heard to be believed. Reference gear used: Onkyo TX-RZ920 Receiver, Outlaw Audio 7000X amp, Emotiva BasX A-500 amp, RBH Sound SI-663R fronts, RBH Sound SI-760R surrounds and back surrounds, SI-615 in-ceiling height channels, Panasonic DP-UB9000 UltraHD transport, Sony Bravia projector, Elite Screens EZ-Frame screen.