This week we’re reviewing the Onkyo RZ-900 7.2 Dolby Atmos home cinema amplifier and Klipsch RP-280FA speakers. This is currently one of the most popular A/V receivers and the first Dolby Atmos floor-standing speakers, a variation of the excellent Klipsch RP-280F.
Onkyo RZ-900 – overview
The RZ-900 is a home cinema amp, capable of amplifying 7 speakers simultaneously. It is compatible with all multi-channel and HD stereo formats and it offers audio streaming functions from a local network or Internet (Internet radio, Deezer, Spotify, etc.). Its HDMI 2.0 controller is UHD 4K and 60 fps certified, making it compatible with the future HD Blu-ray format. There are two notable features ? this amplifier is both THX Select2 and Dolby Atmos (5.1.2) certified.
Onkyo RZ-900 – power output
As is often the case with home cinema amps, it is quite difficult to determine the power spread over 7 channels simultaneously using a wideband signal (bass to treble). Onkyo states that there is 200 W for each operating channel. Listeners should rely on this value, which although it is standardised, is not representative as it is a continual beep. In practice, the Onkyo RZ-900 delivers 2×100 W from 20 Hz to 20 kHz with hi-fi distortion. The THX Select2 Plus certification ensures a very high sound level in a 30 m² room with low distortion. This amp is designed to power floor-standing speakers such as the Klipsch RP-280FA, as well as a large centre speaker, surround and Atmos speakers, i.e. a 5.1.2 configuration (.1 for one or two active subwoofers). A glimpse through the top lid reveals a very large toroidal transformer. This is a good sign.
What is Dolby Atmos?
This is a multi-channel object-directed audio format in which an increasing number of Blu-ray films are now available. Unlike standard multi-channel formats (Dolby Digital, DTS-HD, etc.), containing 6 or 8 sound tracks, Dolby Atmos contains additional sounds (representing 15 % of the overall audio data) assigned to the room’s speakers. Contained within this 15 % of additional data, is highly accurate sound placement details, which an amp such as the Onkyo RZ-900 analyses to place sound effects with extreme precision. If this was already possible with Dolby Digital or standard TrueHD coding, accuracy with Atmos is even greater with 3D placement (width,length, height) whereas the standard 5.1 or 7.1 formats are only in 2D (width, length).
Are Atmos speakers essential’
Yes, but it isn’t these additional speakers but the dynamic sound placement on the other 5 or 7 speakers, which makes all the difference with Dolby and standard DTS formats. When we discovered the new Atmos standard and the latest range of ceiling-directed speakers, we were somewhat wary. Indirectly directing sound above the listening point and using the ceiling as a reflector is very unreliable.
Are there Dolby Atmos Blu-ray discs?
Yes, most films mixed in Dolby Atmos sound exist in Atmos Blu-ray versions. The Dolby TrueHD 7.1 track is enhanced with Atmos data, supported by the amp’s Atmos decoder. If the amp isn’t Atmos compatible, the TrueHD 7.1 core is only decoded. The format is therefore backwards compatible.
Onkyo RZ-900 – connecting your Atmos speakers
The Onkyo RZ-900 features 7 amplified channels and 11 outputs for speakers. If only 7 speakers can be amplified simultaneously, 11 can be connected. Three pairs of terminals for back surround and ceiling speakers and any speakers located in another listening area can be used. In order to connect Dolby Atmos speakers, such as Klipsch RP-280FA, the HEIGHT terminals of the Onkyo RZ-900 must be used. In the device’s menu, you can then define if these are front ceiling, central ceiling or back ceiling Atmos speakers. As for the Klipsch RP-280FA speakers which direct sound towards the ceiling, above the listening point, we chose the ?centre? setting.
Important: the zone 2 amplified output only works when the Dolby Atmos mode is active. This is understandable when the 7 channels are required in Dolby Atmos and zone 2 is not amplified.
As for operating your Atmos speakers, simply follow the instructions on the screen of your TV, connected to the HDMI output to perform your speaker settings and acoustic settings using the microphone output. Menus are clear.
Klipsch RP-280FA – overview
Klipsch RP-280FA tower speakers are based largely on the Klipsch RP-280F speakers, which we reviewed last year when the new Reference Premiere range was launched. Their specific feature is that they have an integrated Atmos speaker (identical to the Klipsch RP-140SA) at the top, whose drivers are directed upwards at a 30° angle to distribute the sound towards the ceiling above the listening point. The RP-280FA is deeper than its predecessor, due to the 2-way Atmos section and to maintain the same size of enclosure. The speaker’s overall finish is different as it is a wood veneer and not a vinyl finish like Klipsch. The RP-280FA is more appealing in visual terms and more pleasant to the touch also.
Klipsch RP-280FA – technology used
For those of you who aren’t familiar with Klipsch, just a reminder that this American company has been manufacturing speakers since the first half of the 20th century. Its particular trait is its horn loading technology, relating to high sensitivity. Klipsch has maintained prestige speakers designed decades ago as part of its Heritage range. In the Reference Premiere range, only the tweeter is horn-loaded. Known as Tractrix, this silicone-covered square amplifies medium frequencies which it accurately distributes further than a standard tweeter. This mechanical amplification only requires a low amount of energy from the amplifier which operates in the best conditions. As the tweeter’s dome moves ever so slightly, distortion is therefore low. Sound is consequently clearer and fuller (thanks to the horn-loaded tweeter’s emissive surface).
The woofers use ceramic-covered aluminium cones, again to reduce the signal’s distortion. These are supported by powerful magnets and their sensitivity (in Klipsch RP-280FA) reaches 98 dB at 1 m distance for 1 W injected. The power delivered by the amplifier is approximately 4 or 5 times lower than what is required by any other floor-standing speaker. The frequency response stretches from 32 Hz (very large back-firing bass reflex port) to 25 kHz.
With roughly ten Watts delivered by the Onkyo RZ-900, it’s a real home cinema experience without overworking the amplifier.
Klipsch RP-280FA – Dolby Atmos section
The top part of the speaker holds a 6.5″ Cerametallic medium-bass driver and the 1″ horn-loaded titanium dome tweeter. Far from being linear in its frequency response, this speaker has been designed in accordance with Dolby’s specifications. Medium frequencies are more present, in order to compensate for the attenuation caused by the path of the sound wave reflecting on the ceiling.
Onkyo RZ-900 and Klipsch RP-280FA ? listening configurations
For the purposes of this test, we listened using the Klipsch Reference Premiere RP-450CA (Klipsch Atmos range centre speaker, also with a wood finish) and Klipsch Reference Premiere RP-250S surround, as well as two Klipsch R-112SW for a Dolby Atmos 5.2.2 configuration. This was similar to the configuration awarded to the winner of our anniversary competition. Add to that a 65? OLED 4K TV (LG 65EG960V) and some ISO images from Dolby Atmos Blu-ray discs (Mad Max Fury Road and The Expandables). In addition, we listened in stereo on the Klipsch RP-280FA (with the Onkyo RZ-900 amp) and some FLAC files (16/44 to 24/192) as the amp is Hi-Res Audio certified.
For multi-channel listening, we used NorStone Silver 250 speaker cable and for stereo listening, Viard Audio Silver HD 12. As the Onkyo’s acoustic settings were not carried out, the Klipsch RP-280FA sounds really good in our dedicated listening room.
Onkyo RZ-900 – listening impressions
The Onkyo amp proved to be very balanced with a highly credible structuring of sound patterns and a pleasant smoothness. Listeners obviously don’t get the warmth of the best hi-fi amps, but whether it is FLAC files or listening to Deezer, the sound presentation is convincing. The Klipsch RP-280FA sound the same as the RP-280F with a striking airiness in the the mid and treble ranges, as well as the power to go down to the depths of the audio spectrum.
The RZ-900 can deliver just the right amount to support the four 8″ drivers and the significant volume of air enclosing them. The bass is well delivered. 
When used for home cinema purposes, the Klipsch RP-280FA prove themselves to be excellent. Listeners who have never experienced horn-loaded drivers in home cinema are likely to be amazed.
The most delicate sounds are delivered with surgical precision, giving the impression that all details are extracted from the sound track. This also applies to the centre and surround speakers.
Listening to Mad Max Fury Road is as we imagined, unrestrained and exceptionally rich. We literally bathe in a well articulated sound stage without the slightest sharpness at high volumes (Klipsch’s new LTS tweeters were developed for this). Sound literally rises and it?s the 360° sound stage which grabs the listener. The experience is superior to that of most major movie theatres. If you turn on the two Klipsch SW-112 subwoofers, you hear a festival of deafening and over-powering groans. These two monsters are really only necessary to maintain balanced listening at very high volumes (>105 dB) and the neighbours will have to be warned before any pyrotechnics.
Onkyo RZ-900 – what we liked
- The solid but elegant design
- The pleasant sound in hi-fi and frankly enjoyable sound in a home cinema setting (Atmos and non Atmos)
- The feeling of power each time you listen
- Deezer and Spotify
- The possibility of activating the bi-amp and listening in stereo to all the drivers of the Klipsch RP-280FA
Klipsch RP-280FA – what we liked
- The Klipsch sound
- The high quality finish compared to the RP-280F
- The LTS tweeter’s analytical capacities (never rough)
- The ability to go down really low
- The Atmos section
- The versatility in hi-fi/home cinema
Conclusion
The Onkyo RZ-900 amp succeeds convincingly in both hi-fi and home cinema. It pairs up excellently with Klipsch RP-280FA speakers. The speakers also shine if not more than the Klipsch RP-280F. Their Atmos section can be used in hi-fi with a hi-fi amp fitted with A & B Terminals. This stereo or 5.x.2 configuration provides a lot of enjoyment.
