Sunday, December 20, 2020

RBH Sound SI-615 Signature Series In-Ceiling Speaker Review

If you’re a fan of home theater, in ceiling speakers are now more important than ever. For a long time, they have had an important role. In the past, depending on your room layout, in-ceiling may have been your only option for surround channels. But with Dolby Atmos and DTS:X and the introduction of height channels, in-ceiling speakers have become much more important. Up for review today is the RBH Sound SI-615 in-ceiling speakers.


Unfortunately, with COVID-19, and all of the quarantines, you may have been doing a lot of binge watching. And this may have made you re-experience your home theater gear. It may not be to the level that you would like it be. If you’re like most people, you could go several years between upgrades. Believe it or not, Dolby Atmos has been available for consumers for over 5 years now. It may be time for you. Time does fly, I know.


Both Dolby Atmos and DTS:X encompass height channels. This takes surround sound to a whole new level, fully enveloping you in sound. There are speakers available that have a speaker on top, facing the ceiling.  It fires up so the sound hits your ceiling, bouncing back down at you, giving the perception of the sound coming from the ceiling. But the best solution for the best experience is to install in-ceiling speakers. Once deciding that ceiling speakers are the way to go, go to RBH!


I like going with manufacturers that have a long history and a proven track record. I also like high quality products that not only sound amazing, but are also very well made to give years of service. RBH Sound has over four decades of experience making great sounding products. If you want to “Redefine the way you experience sound”TM which is their Trademark, go with RBH. And based on your budget, they have a couple of models to choose from for ceiling speakers. Up for review today is their top of the line SI-615.

Features and specs:

Model Name:
Signature In-wall
System Type:
In-ceiling 2-way Speaker
Frequency Response:
50Hz-20kHz (±3dB)
88dB (2.83V @ 1 Meter)
Recommended Power:
15-120 Watts
(1) 6-1/2" (165mm) Aluminum Cone
(1) 3/4” (19mm) Ring-Radiator
Tweeter Protection:
Swivel Tweeter(s):
Crossover Frequency:
3,000 Hz
Crossover Slope:
8 Ohms
Cabinet Material/Color:
Black Frame
Magnetic White Steel (Paintable)
Cutout Dimensions:
7-3/4" (197mm) Dia.
Finished Dimensions:
9" Dia. x 4-3/8" D
(229mm Dia. x 111mm D)
3.65 lbs. (1.66 kg)
25 Years


The RBH Sound SI-615 came in a nice-looking printed box with photos and specs of the speaker. Opening the box revealed a well protected speaker held in place with custom cut cardboard. The speaker was in a white cloth bag, a nice elegant touch. Pulling out the speaker revealed a very well made speaker. Materials used in the construction are both metal and plastic. Quality of materials used was excellent, as was the fit and finish. The crossover components appear to be custom made, as the capacitors had the RBH logo on them. Also included was the manual, and cutout template for installation.



Here’s the concern. There’s a lot of great sounding speakers. But they don’t sound the same, just like Celine Dion sounds different from Adele, for example. The difference is voicing. When you’re watching a movie, and a helicopter is flying, and you hear it fly from the front left to the rear right, you will hear the sound transfer from front left to center to ceiling to rear right speakers. So you want the front and rear and ceiling speakers to be the same, with the same drivers. That way they have the same voicing, so as objects like a helicopter moves across your sound field back and forth across the speakers, it sounds the same. This way it’s not distracting, and you stay caught up in your movie.


I had the chance to talk to Shane, the engineering guru at RBH Sound. I inquired into the design of the SI-615, and if they had a new model in the works with an AMT tweeter to go along with their Signature Reference series. He instantly understood my concern that it was about voicing. He advised that they currently don’t have an in-ceiling with an AMT tweeter. He further expounded that the ring radiator tweeter not only has a great sound and does not lose fidelity to the AMT. It also has a really wide dispersion, important in an in-ceiling design. The foot print of the ring radiator tweeter is small, working well with their design. And the sound signature is also similar. So, it incorporates well with the Signature Reference series. If you have an RBH Signature Reference series system, the SI-615 is the in-ceiling speaker to go with for height channels, to match the rest of your system.  I couldn’t wait to put it to the test.


I also really liked the rest of the design of the RBH SI-615. They use a nice aluminum driver with a fairly big rubber surround for good excursion, bumped back plate for extra excursion of the voice coil for better bass performance, and vented pole piece for cooling. On the front is the ring radiator tweeter that also pivots so you can angle it to the listening position. There’s even woofer attenuation to help, depending on your installation location. The internal wiring to the woofer is nice and beefy, and the gold-plated push terminals are of high quality, accepting up to 14 ga wire.  With the large magnet, I could tell they are designed to handle some power.  The magnet is at least twice the size of our previously reviewed Revel in-ceiling speaker.


I’m typically not a fan of the free-air design, but I understand why they do it. Speakers sound best in an enclosure. In-ceiling or in-wall speakers don’t always have a cabinet, hence the free-air design. You get the best sound when they sit in an enclosure, where two speakers can be designed for a specific amount of airspace. But you don’t always have room for an enclosure. If you do have room, RBH does offer a back can. In fact, they offer two, one is standard (7.84”)and one is short (3.58”). You’ll get better bass performance from the standard back-can, but if space is limited you can at least use the short back-can. And I’m even impressed with the back cans. They are well made of thick gauge steel, have a built-in foam gasket for a tight seal and the wire is soldered to the connection on the inside. The included poly fill helps performance with the small can size.  Having the can also greatly reduces sound leakage into rooms above.


RBH Sound takes great pride in their products. They are a premium manufacturer offering a range of speakers. The SI-615 is currently their top of the line in-ceiling speaker, using top of the line components and build quality. Use one of their back cans, and it’s even better. With SI-663R’s for the front and SI-760Rs for the surrounds and rears, these four SI-615’s seem to be a perfect fit as Shane had suggested. They look great and are built great, now let’s get them installed!


Installation proved very simple, and the manual was well written and easy to follow.  Although I hardly needed it, you may find it useful.  There are four feet on the speaker with a front facing screw.  Once you have the speaker wire connected at the back and the SI-615 held in place, you screw them in place.  Once you start with each screw, the foot will twist into place.  And with each turn of the screw, the foot is lowered into place until it is up firmly against the inside of your drywall holding the speaker firmly in place.  Now with them installed, lets see how they sound!


Listening tests- music


Rhapsody in Blue: Clarinet had very good resolution, sufficient to hear the woodiness of the reed, and tonguing technique. Piano sounded very dynamic and natural with nice low-level harmonics. The bassoon had nice texture and low-end extension. Brass was extremely dynamic and silky smooth and not too brassy. Tympani had nice dynamics, played with authority as well as good definition of the mallet on the pad.

Mayo Natono Piano Trio “Scabions”: as was stated in the review of the SI-663R and SI-760R, they performed extremely well with piano. I grew up around piano, and have been around it all my life, so I’m a bit of a snob with critical expectations with piano reproduction. And for a third time, I was floored with the piano performance. It was just a tad behind the performance of the SI-663R and SI-760R. But it was much better than I was expecting to hear from in-ceiling speakers. The ability of the SI-615’s to resolve the layers of harmonics have never been experienced by me with in-ceiling speakers to this level. The dynamics were also phenomenal, with excellent texture of the strings. The amount of resolution surprised me as well, being able to hear the slide across the bass. The pitch definition was very good and the low-end extension of the bass was about as expected with a short can, yet was still solid. I definitely did not miss anything from the AMT’s. The ring radiator tweeter performed in spades.

Junior Wells- Why Are People Like That: Vocals sounded extremely natural with excellent texture of the timber. The bass played with authority and good low-end extension. Drums were also very dynamic and played with very good impact and authority. Harmonica was silky smooth with excellent dynamics, harmonics and extremely natural sounding. Cymbals were also really crisp and clean.

Disturbed- Sound of Silence: Vocals were pleasantly raw with excellent texture and timber. The piano came through really well and was very natural sounding. Strings were really smooth with great harmonics. The acoustic guitar was so crisp and clean, being able to actually hear the pick against the strings. The tympani also played with good impact, depth and authority.

For you gamers- Sugaan Essena- Jedi Fallen Order: Drums had really good dynamics, impact and played with a lot of authority. Vocals were nice and raw with a ton of resolution of the texture and timbre. The lute was also crisp and clean, with sufficient resolution to hear the bow slide across the strings.



And I must say, I was also very surprised with their performance. Although I’m not sure why, since I have experienced first-hand the stellar performance of the SI-663R and SI-760R. These are RBH speakers after all. I just wasn’t expecting this level of performance from in-ceiling speakers. During multiple of these music tracks, I was surprised with the soundstage. I was hearing not only a wide soundstage, but a very deep one as well. If you think you can find a better sounding in-ceiling speaker for the money, I wish you luck. The level of dynamic, resolution and size of soundstage make them perfect for height channels in a home theater. I must also say that I’m really picky about my music and sound. Unfortunately, some guys have to go in-walls or in-ceiling to make their wife happy (The wife Acceptance Factor).  Whereas I would always require either bookshelf or tower speakers. That was until now. Put a pair of these in each of your rooms for a whole house system, that would sound awesome!



Movie Listening


Ready Player One- Race Scene: The revving of all the different engines had excellent pitch definition of the midbass and bass, thanks in part to the stiff aluminum cones and excellent control of the motor structure thanks to the large magnet. And the firework going off to start the race showed nice dynamics. And all of the tires screeching, cars crashing showed even more impressive dynamics that were so life-like. Especially the King Kong part, it was so easy to get caught up in the movie, it was so enjoyable!

Spiderman: Far From Home- Ferris Wheel Scene: The roars of the fire monster had nice low end extension and real depth to them. Combined with all of the other explosions they provided the kind of dynamics and resolution I was used to paying a movie theater to get. Vocals were smooth, natural, with excellent texture. And the crackling of the flames was really crisp and clean, like a real camp fire.

Greatest Showman- Never Enough: Her vocals were so extremely silky smooth the resolution revealed the layers of texture of her timbre and dynamics she was able to portray. All of the emotion of her performance was portrayed so passionately it was almost magical. You feel like you were right in the audience. And as the song builds and builds the S1-615 handles it without a hint of strain.

I am turning into a believer of RBH Sound speakers. After reviewing the SI-663R and SI-760R, I expected good things form the SI-615’s. Yet I was still surprised, as they performed better than I expected. They are being used in a full 7.1.4 system as the height channels, and the voicing did prove to be similar to the SI-663R and SI-760R, with a fluid seamless soundstage among all the speakers. They are a perfect fit for height channels to be used with any of the Signature Reference series being used for fronts/surround/rear speakers.


Having said that, they sounded so well and performed so well, I could also see them being used in all channels of a surround system where only in-ceiling speakers can be used. They would sound great in a whole house system, or as a pair in a den, living room, or any room where you want quality sound hidden from view. I also highly recommend the use of one of their back cans as well. I recommend standard back-can if you have the depth for it, otherwise the will do great. You lose a little of the low-end extension with the short can, but I feel it’s worth it.


Whether you are looking for height speakers in a surround system or ceiling speakers for music in another room, the RBH SI-615 should be on your short list. Not only is it an excellent sounding speaker, it is also very well made for years of use and includes a 25 year warranty. And with a lengthy history of over 40 years, you can rely on the warranty. While not cheap, you do get what you pay for, and for their sound and performance they still provide a great bang for the buck and are worth every penny. Based on it’s design, features, quality and performance the RBH Sound SI-615 has earned our Editor’s Choice Award. For more info and complete specs, check out their website and www.rbhsound.comReference 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 front projector, Elite Screens EZ-Frame screen.