RBH Sound SI-1010P In-floor or In-Ceiling Subwoofer Review

We’ve been reviewing a lot of “super subs” lately, but not everyone can fit a giant, 100lb+ subwoofer in their home. Most people, I think, would prefer great bass without a great big sub. That’s where something like the RBH Sound SI-1010 comes into play. As opposed to sitting in the room, it’s hidden in the floor or ceiling and sound passes through a discrete air vent cover. From an aesthetics perspective, you can’t get much better than completely out of sight. However, the question remaining for an Audioholic is, how does it perform? And for the DIYer or custom integrator, how does it install?

SI-1010 and SA-500DSP Overview

Two key characteristics set apart the SI-1010 from a typical subwoofer. First, and most obvious, it’s hidden in either the floor or ceiling of a home. It lays flat against either the ceiling/floor, between the joists/trusses, and is screwed into the joists/trusses. The sound then passes through a 6” x 12” cut-out in the floor/ceiling. The SI-1010 comes with either a white cold air return vent cover for in-ceiling installations or a tan heating vent cover or in-floor installations. When finished, your guests would have no idea that what looks like a standard heating or air vent is actually part of a high powered subwoofer system. Alternatively, you can use any vent cover that matches your decor, as long as it doesn't restrict airflow.

The second key difference between a typical sub and the SI-1010 is that the SI-1010 is passive, meaning that it does not have a built-in amplifier. Instead, RBH uses their separate SA-500DSP subwoofer amplifier. Speaker wire is used to the connect the SA-500DSP to the SI-1010. The sub and amplifier can be purchased together (RBH refers to the combo as the SI-1010P) or separately. While this setup differs from typical subwoofers, passive designs are the standard for in-floor/ceiling and in-wall subwoofers.

    

SI-1010 installed in the floor

The SA-500DSP is RBH’s typical choice for powering their high-performance passive subwoofers. It’s a class D amplifier rated at 500 Watts RMS @ 4 Ohms and packed with a host of features. It sports balanced and unbalanced inputs and pass-through outputs, meaning you can daisy chain multiple amps. The unit can automatically power on/off when it senses a signal or be controlled via a 12v trigger input. An IR input on the rear panel makes for easy integration with control systems, otherwise the IR receiver built in the front panel works great. A rear USB port is available for firmware upgrades and a rear mounted dial can be used to adjust the front display brightness.

A front panel LCD gives users access to a host of adjustment setup options. First off, a night mode limits the dynamic range of amp so loud scenes don’t wake up neighbors or family. There are five pre-set EQs (Defeat, Music, Movie, Impact, and Dynamic). Additionally, users can set and save their own custom EQ via a built-in 9-band graphic EQ (20, 25, 31, 40, 50, 63, 80,
100, 125 HZ +-6dB).

For maximum flexibility, the SA-500DSP offers an adjustable low-pass filter (40Hz to 160Hz), slope (12dB, 18dB, 24dB, 30dB, or 36dB), subsonic control (a high-pass filter than can be set to flat, or frequencies from 16Hz to 40Hz), and phase (0°, 45°, 90°, 135°, 180°, 225°, 270° and 315°). After the amp is dialed in, settings can be saved to one of three memory banks. All these adjustments mean that you should be able to seamlessly blend the SI-1010P - or any RBH sub powered with the SA-500DSP – with your speakers.

SI-1010 with the baffle removed

SI-1010 with vertical baffle installed

Making all of these adjustments via the two-line LCD and control dial isn’t particularly fun, so I recommend using the included IR remote. Custom installers will be happy to know that power on/off, mute, and EQ modes are all adjusted via discreet IR codes (Hex keys listed in product manual).

Other than being hidden away and utilizing an external amp, the SI-1010 is much like any other subwoofer. It’s a sealed design with dual 10” aluminum cone drivers. RBH rates the SI-1010 with a 28Hz-200Hz (±3dB) frequency response. When compared to larger, ported subs, 28Hz isn’t deep for a system with an MSRP of over $2k. However, considering the size limitations placed on the design (it needs to fit in a standard floor cavity), 28Hz is pretty low.

At 68lbs, the SI-1010 is no lightweight. Much of that weight comes from the MDF used to construct the 13-1/2" W x 42" H x 9" D cabinet. Although the sub is hidden, it’s not small, which makes installation a two-person job.

Installation

We made a 23-minute YouTube video and wrote a full article covering every aspect of installing the SI-1010, so I’ll keep this section short and encourage you to watch the video below. Installing the sub is an easy task if the home is still under construction. Installing it in a finished home is trickier, but definitely still possible. The tools and skills required are basic, as long as the speaker wire is in place. Running wire in a finished home is beyond the scope of this article, but suffice it to say that there’s almost always a way to run wire as long as you have the right tools and know-how.

YouTube Instructional Video: How to Install an In-Floor or In-Ceiling Subwoofer

The SI-1010 is either hoisted up between floor joists or gently laid down on the ceiling, between ceiling trusses. Once it’s in position, it’s secured by driving screws through the joists/trusses and into the sides of the SI-1010. This is where each installation will vary. Depending on the construction of your home, you may have to use extra lumber to secure the sub in place. Really, unless you’re installing it in a floor with 2x10” joists spaced 16” on-center, you will have to use a little extra lumber and ingenuity to secure the sub. This isn’t an issue with the design, as comparable subs installs the same way. It’s just the nature of custom installation products.

The SI-1010 temporarily in place. For final installation another set of 2x4s was used to raise the unit until it fit snugly against the floor above.

Note that RBH sells both a vertical and horizontal baffle for the SI-1010. Changing the baffle rotates the vent 90 degrees. And don’t worry, if you order the sub with the wrong baffle you can purchase the correct one and swap them yourself. I speak from experience.

Listening Tests

Listening tests were conducted in a large, open area that includes the living room, dining area, and kitchen. To account for the natural roll off of the SI-1010, the SA-500DSP EQ was set to +6dB@20Hz, +6dB@25Hz, +6dB@31Hz, and +3dB@40Hz.

The XX - Coexist

Coexist, The xx's second and latest album, is one of my favorite indie albums (Wikipedia say's the band falls under the "dream pop" category. Maybe that's why I find it easy to take a nap when listening to it). Many of the tracks have a powerful bass line, which makes it a great album for testing a subwoofer. I listened to nearly the entire album, and the SI-1010 sounded great. The bass lines were clearly defined and I could follow each ascending and descending note. On track #6, "Sunset," which caused very audible distortion with the MartinLogan Vision soundbar I reviewed, I noticed some rattling when I put my ear close to the sub. It didn't seem to be mechanical noise from the drivers, rather it was from the metal mud ring rattling against the MDF subfloor. A little foam weatherstripping would solve that issue, but even that isn't particularly necessary as I only heard the rattle on one track and only when putting my ear close to the sub. The bass guitar, synth, and steel drums employed throughout the album sounded clear and punchy with the SI-1010. What more could you ask for?

Mad Max Fury Road

Mad Max: Fury Road, one of the great films released in 2015, was an easy choice for demoing the SI-1010. I had heard it used in a number of Atmos demos at CEDIA 2015 and have watched it at home myself.

No need to skip to the right chapter to find demo worthy content. The opening scene is complete with large dynamic swings, sounds swirling, and hard hitting bass. Even as the WB and Village Roadshow Pictures logos flash on the scene, the roar of a vehicle and deep, rough sound of Max’s voice were cleanly produced by the SI-1010. The sub had to play up to 120Hz to blend with the soundbar I’m using at the moment, and such a high crossover means the sub has to reproduce male vocals. The SI-1010 performed solidly. I was impressed with how well the SI-1010 handled Max’s voice while at the same time digging low enough to produce bass that resonated through the house. Throughout the movie – which is non-stop action – the SI-1010 never failed to impress. There were one or two occasions where I knew that a bigger, ported sub like the RBH SV-1212P would have more low end output, but that's to be expected. What was more important to me was that even when I pushed the SI-1010 and SA-500DSP to their limits in my 6,000+ cubic foot area, they kept their composure.

 

Lego Movie

Next up was the Lego Movie. I bought this movie for my son, but as is often the case with modern animation, I ended up enjoying it as much or more than he did. This is a great movie to own not just because it's a joy to watch, but because it's a great excuse to show off your home theater.

I jumped straight to the scene where Emmet Brickowski falls into an intricate maze of underground tunnels and is bounced around like a Plinko ball. Every smack into a wall was accompanied by a tight, powerful thump from the SI-1010. I didn't notice any distortion, compression, or other audible artifacts to indicate that this sub had met its match. It sailed through the scene and was ready for the following chase that ensues after Emmet escapes Bad Cop with the help of Wyldstyle. Again, this was no problem for the SI-1010  subwoofer. I could feel the bass resonate through the floor a bit more than with a typical subwoofer; however, I wouldn't factor that into a purchase decision as the difference is minimal.

To round out this listening test, I skipped forward to the destruction of Cloud Cuckoo Land. The SI-1010 kept pace with the gun shots, explosions, falls, and general chaos. I replayed this scene twice, the second time I went over to my equipment rack to see how the SA-500DSP was fairing.  According to the font panel LCD, the amp went above about 90% power, so I was pushing the unit hard. I checked the temperature with my hand and it was quite cool. I don't have an objective measurement, but it was far cooler than my Denon AVR-X4000, which tends to run pretty warm. The SA-500DSP seemed to be a good match with the SI-1010, but more on that in the measurements.

RBH SI-1010 & SA-500DSP Measurements and Analysis

We were curious to see how the SI-1010 subwoofer measured so we took it outside and performed a groundplane frequency vs output test. We also put the SA-500 amplifier on the bench with our Audio Precision APx585 Audio Analyzer.

SI-1010P Subwoofer Measurements

We positioned the SI-1010 sideways on the floor with the microphone 1 meter away equadistant from both drivers. The front panel cover was removed so we could test for the highest output possible. RBH informed us with the panel removed, the SI-1010p will play about 1.5-2dB louder than with it installed.  If you don't need to hide the woofers for aesthetic reasons, then we'd recommend removing it.

 

RBH SI-1010 SPL vs Frequency Response @ 1 meter Groundplane

The SI-1010 sealed narrow enclosure somewhat prevents it from digging as deep and loud to comparably priced large box subwoofers.  The measurements above did however demonstrate that this sub has quite a lot of output for something you can conveniently hide in a ceiling or a floor, something you can't do with a big bulky box subwoofer.  The -3dB pt of the system was 40Hz with NO EQ applied but virtually ever sub on the market employs low frequency boost to yield better extension.  As is, the SI-1010 played loud and clean with no hint of distress.  It stopped getting any louder as a result  of the limiter circuit build into the SA-500DSP.  If I had a more powerful amp, I am confident this sub would have a good deal more output to reveal.  The SI-1010 is flat all the way to almost 400Hz making it an ideal sub to blend with small satellite speakers that require a higher than 80Hz high pass filter.

RBH SI-1010P SPL vs Frequency @ 1 meter Groundplane with EQ

With EQ applied, I was able to lower the bass extension to a -3dB pt of around 25Hz which held up even at high SPL output.  However, due to the long sweep tones, it tripped the self-resettable fuse in the subwoofer that protects the driver from excess current when sweeps exceeded 110dB.  Although this is a bummer on the test bench, it's not something that ever happened in real world listening tests with real program material.  It is actually a good design compromise to increase reliability.  The one thing you don't want is to blow a driver once you have this box installed in your ceiling or floor.  I checked with RBH and since this products inception over 10 years ago, they've had only a few unit requiring service in the field due to a blown driver and that was before the SA-500 amp was being used to power it.

If you want your SI-1010 to exhibit the frequency response measured above, than you'll need to set the EQ boosts in the SA-500DSP amp to the following settings:

20 Hz: +6dB
25 Hz: +6dB
31 Hz: +6dB
40 Hz: +3dB

Using the SA-500 amplifier with EQ boost, the SI-1010P was able to earn our large Bassaholic Subwoofer Rating which is quite astounding for an in-wall type subwoofer product. 

SA-500DSP Amplifier Measurements

The SA-500DSP amplifier sports a Class D output stage with a linear power supply.  We were big fans of the original SA-400 amp that RBH has been using for their other in-wall or externally powered subwoofers so we were curious as to how the more compact but up to date SA-500DSP would perform.  On paper, the SA-500DSP is rated at 100 watts (500 watts RMS @ 4 ohms) more output compared to the SA-400 and it also has a host of DSP options like adjustable PEQ and subsonic filters, as well as adjustable crossover and programmable EQ settings.  More features for sure, but what about performance?

Frequency Response

RBH SA-500 Frequency Response

The SA-500DSP is clearly NOT a fullrange amplifier. In fact, I measured a -3dB of about 2kHz so this amp is for bass duties only.  I checked the Low Pass filter response and found the unit measured a -3dB pt of the crossover you selected (ie. 80Hz) with the desired slope (in this case I had it set to 24dB/oct).  I would have liked to see the crossover point selected actually be the -6dB pt with the slope set to 24dB/oct as it is with THX certified products when matching subwoofer and satellite systems with a HPF slope of 24dB/oct in the AVR bass management circuit but it shouldn't be too hard to dial in a proper response since both the frequency and slope are adjustable on the SA-500 amplifier ( 9 bands and slope from 12 to 36 dB/oct).

RBH SA-500 Pre-Programmed EQ Settings

Shown above is what the pre-programmed EQ settings does to frequency response of the amplifier and corresponding subwoofer attached (in this case the SI-1010).  If one of these modes don't suite your needs, RBH does offer adjustability of +- 6dB for its fixed 9 band EQ of frequencies of 20, 25, 31, 40, 50, 63, 80, 100 and 125Hz.  I tested these and they worked as expected but would have preferred adjustable frequency and Q for finer tuning.

Power & Distortion Tests

I was able to hit the 500 watts continuous power rating into a 4 ohm load for the bandwidth of operation of concern.

RBH SA-500 Continuous Power vs Frequency

RBH SA-500 Power Sweep Test

Sweeping the SA-500DSP at 200Hz for power vs distortion revealed the actual 500 watt rating was hit at a rather high distortion of 0.4% THD + N.  This is acceptable at bass frequencies but far from state of the art as far as full range amplifiers are concerned. Using a CEA-2006 burst test, I was able to get 540 watts into 4 ohms at 1% THD +N for our dynamic power testing. 

RBH SA-500 FFT Distortion Analysis

There is no kind way of saying that this measurement is mediocre.  While the residuals at 1 watt are clean, the noisefloor of this amp just isn't all that stellar.  It should be a good 20dB lower than this.  However, I only found this to be slightly detectable as background noise if I stuck my head within a few feet of the connected subwoofer when it was turned on with no program material running through it in a quiet room.  In this day and age there should be no reason for this so we hope RBH can improve upon this in future iterations of the amplifier.  However, for long cable runs, we recommend using twister pair to minimize noise pickup since this amp seems a bit more sensitive to it than comparable linear AB amps we've previously tested.

RBH SI-1010 Subwoofer & SA-500DSP Amp Conclusion

The SI-1010 is one of only a few subwoofers that fill a niche in the market, consumers who want powerful bass but won't accept even the smallest subwoofer box visible in their room.  However, placing such a strong emphasis on aesthetics isn't without compromise. Unlike a freestanding box subwoofer, which has virtually no size limitations, the SI-1010 must fit in a standard floor cavity and pass sound through 6"x12" cut-out. Those design limitations ultimately hurt the value of the SI-1010. At a little over $2,000 for the subwoofer and matching amp, it performs similarly to traditional large boxed subwoofers for about $1000 less. This doesn't mean the SI-1010 is a poor performer, in fact it I think it's a great performer, just that you are paying a premium for this product category. In fact, when compared to similar products from the likes of Triad, it's quite the value. Ultimately, it comes down to how much you value being able to completely hide the subwoofer in your room.

Installation of the SI-1010 was on par with with what what I would expect from a subwoofer in this category. It's not particularly difficult, but will require a few hours of your time, depending on the installation scenario. It's nice to see two different baffles offered, which is something to check for when looking at similar products from other companies.

Price aside, the SI-1010 is a solid performer. It produced powerful bass without issue. While it doesn't dig down to the ultra low frequencies with as much authority as its big boxed counterparts, it does provides a solid punch in the critical 40Hz - 60Hz area with usable output down to 25Hz. The matching SA-500 DSP amp packs good power and is full of useful features, but we recommend using twisted pair speaker cables for long runs to reduce susceptibility of noise pick up.  The fact that you can install two of these subs for greater output and smoother response across all of your seats while being able to easily achieve our Large Bassaholic rating and not see any bulky boxes is quite an incredible feat of engineering that can't be understated.

Overall, I feel confident recommending the SI-1010 for consumers that place a high value on aesthetics, but still want serious bass performance for their home theater room.

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
EQ System
Features
Performance
Value