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Cambridge Audio Azur 551R

7.1-channel home theater receiver

5 Reviews

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Item # 779551RB

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Our take on the Cambridge Audio Azur 551R

Audiophile sound quality and home theater — not mutually exclusive

Many mistakenly believe that you have to choose between the delights of high-fidelity music and the fun of home theater. With Cambridge Audio's Azur 551R you get both in one captivating package. The 551R serves up the latest audio and video features your high-def home theater needs, along with the warm involving sound that Cambridge Audio is known for. This precision-built receiver includes potent, audiophile-quality amplification for seven speakers plus decoding for the superior high-resolution surround sound formats available with today's HD video sources. The beefy 551R is not just built, but overbuilt. Don't be fooled by its 60 watts-per-channel rating, which is measured all channels going full-tilt simultaneously. Under strenuous conditions, the 551R comes through with spectacular, low-distortion sound that few can attain. In stereo mode, you get a clean, solid 90 watts per channel.

Cambridge Audio Azur 551R

Connections for your favorite sources

HDMI inputs let you hook up your four best high-def components for easy switching. Analog-to-HDMI conversion with Faroudja processing sends all of your video sources to an HDMI-capable TV via a single-cable digital connection. Cirrus Logic dual 32-bit DSPs ensure that every audio nuance gets it due. These processors are designed to meet the mammoth digital calculating demands of today's big music and soundtrack files. So whether it's from your favorite film or philharmonic orchestra you'll become immersed in the warm involving sound.

Audio setup flexibility

The Azur 551R boasts some cool setup options that fans of high-quality sound will appreciate. The back surround channels are re-assignable for use with bi-amp capable front speakers. By doubling the power to a pair of biampable speakers, you'll get every ounce of performance you paid for. And, if you have a Blu-ray player with multi-channel output, the 551R will give it a warm analog welcome with 7.1-channel preamp input. Or if you have separate amplifiers, you can work the other side of the street and feed them 7.1 channels of analog audio.

Built for great sound

Cambridge Audio's London-based engineering team designed the Azur 551R according to their usual high-end standards. This receiver boasts seven discrete amplifiers, powered by a low-flux toroidal transformer. This combination provides steady power throughout the fluctuating demands of the music itself, and delivers sound via separate amplifiers for every channel. These are isolated from the processing and input stages to minimize interference and ensure performance without compromise. The rock-solid, low-vibration chassis contains Cambridge's clever X-tract™ cooling systems to minimize distortion and loss of efficiency caused by overheating. A perfectly balanced combination of natural convection and forced cooling draws away heat virtually silently.


    Power and processing:
    • 7-channel amplifier
    • 90 watts per channel into 8 ohms (1k Hz) at 0.006% THD, with 2 channels driven
    • 60 watts per channel into 8 ohms (1k Hz) at 0.006% THD, with 7 channels driven
    • Dolby® TrueHD, DTS-HD™ Master Audio, Pro Logic® IIx, and DTS Neo:6 decoding
    • analog-to-HDMI video upconversion (up to 1080p) via Faroudja FLI3210 video scaler
    • Cambridge Audio Mic Controlled Auto Set (CAMCAS) uses supplied microphone for easy speaker setup
    Audio Performance Features:
    • high-current amplifier design
    • Pure Analogue Stereo Direct mode switches off all unused circuitry for the cleanest possible sound
    • back surround speaker channels re-assignable for bi-amping front left and right speakers
    • 192kHz/24-bit digital-to-analog converters for all channels
    • 1080p-compatible HDMI digital video switching (4 in, 1 out)
    • HDMI version 1.4a with support for 3D video, Audio Return Channel, Deep Color, x.v.Color, SACD, and auto lip-sync
    • digital audio inputs: 4 optical, 2 coaxial
    • digital audio outputs: 1 optical, 1 coaxial
    • 5 audio/video inputs, including:
      • 1 front-panel input with composite
      • 4 rear-panel inputs with 2 composite video, 2 S-video and 2 component video
    • preamp output for a powered subwoofer
    • 7.1-channel analog audio preamp input
    • 7.1-channel analog audio preamp output for connecting an amplifier
    • RS-232C port for automated control systems
    • detachable power cord
    • direct IR flasher input, and 12V DC trigger out
    • back surround speaker channels re-assignable for bi-amping front left and right speakers
    General Features:
    • on-screen display for easier system setup and operation (via HDMI only)
    • 30 AM/FM presets
    • receiver remote
    • 16-15/16"W x 4-1/4"H x 14-3/4"D
    • weight: 22 lbs.
    • warranty: 3 years
    • Our 60-day money-back guarantee

    What's in the Box:

    • 7.1ch AV receiver
    • 6' AC power cord
    • Remote control (RC-551R)
    • 3 "AAA" batteries
    • Auto-setup microphone (with attached 19.5' cable terminated by a mono-RCA connector)
    • FM wire antenna
    • AM loop antenna
    • F-type coax connector
    • User's Manual (En/Fr/Sp/It)
    • Quick Start Guide

    Featured Video:

    If you are looking quality sound and reasonable price, this is it. Clean and low distortion. Unlike the Japanese brands, solid and well built.

    Anonymous, Alexandria LA


    Cambridge Audio Azur 551R Reviews

    Average Customer Review(s):

    (5 Reviews)

    Wait for 551R V2 due in June 2014

    upbull340 from Omaha, NE on 5/16/2014

    Crutchfield Customer Review (What's this?)

    Know what you are getting before buying this receiver. Read the manual. There are some limitations that you may not be able to live with especially if you are looking for all the bells and whistles that are found on most receivers. For me size, cooling and sound were most important. I don't need room correction software, I just want good sound from a simple design. I have one problem and that is with my COX DVR. Every time I change channels or raise or lower the vol I can hear a thumping sound through my speakers via my HDMI connection. No problem with my Roku or Oppo HDMI connections. I'm currently using the unit with my Salk speakers in 2-channel stereo mode and think the sound is as good as my former NAD receiver for half the price. If you are serious about this unit go to the Cambridge Audio website and read about the 551R-V2. More HDMI in and out connections, 3D and 4K support. I may return this because of the thumping sound with my DVR and wait for the V2 release as I think it will be that good.

    Pros: Sound quality, cooling, no fan noise that I can hear, lightweight and small footprint. Appears to be well built.

    Cons: Older video chip, no display screen dimming, rather large and heavy remote (have to admit its nice to have some room between the buttons though).

    Cambridge Audio Azur 551R

    Anonymous from Alexandria LA on 9/10/2013

    Crutchfield Customer Review (What's this?)

    If you are looking quality sound and reasonable price, this is it. Clean and low distortion. Unlike the Japanese brands, solid and well built.

    Pros: Clean and low distortion

    Cons: None

    36 Days of trial

    cuznsteve from Oakland gardens NY on 4/23/2013

    Crutchfield Customer Review (What's this?)

    The box it said , 36 hours of continuous use before judging, so I am , and quarks are coming out , but heal , so i will continue on the path , useing 5-10 hours a day until my 60 days trial period is up then I will come with questions or please exchange, and i know Crutchfield with support me as they always do . Shop with confidence , you are in great hands, and wise minds, and big hearts. Shop Crutchfield , absolutly.Thanks for listening, the 551R is a beauty!



    OSD Menu Issue

    SteveD from Boston, MA on 10/30/2012

    Crutchfield Customer Review (What's this?)

    This receiver sounded pretty good, however, I was unable to program the inputs/outputs properly as the OSD (the only way to program the receiver) woudl not display on my TV. Apparently the OSD menu is in such a low resolution that some TV's will not recognize the menu and not be able to display it. There are no other methods to output to the TV (i.e. s-Video or Component, etc) other than the HDMI output. Another issue is with fast forwarding on my DVR (Directv) once I restarted the program there was a loud squeak or squelch that went through the speakers and it was a terrible noise. I am not sure if that would have went away if I was able to program it correctly but that is something I wanted to bring up. So without being able to properly program the unit I cannot attest to the sound quality, however, if you have a TV that will not recognize a low resolution OSD you may have issues with this unit. The silver lining is the folks at Crutchfield were very helpful, while they did not know much about the unit itself they were very accommodating in sending me a new unit (thought it might have been the one I was sent was defective) as well as taking both units back and sending me shipping labels to do so. Great service here, wish the receiver worked out better for me. In the end I purchased a $600 Denon unit that set up in minutes and sounds pretty good so saved myself a few $$ but lost a lot of time finding this all out.

    Pros: Small size fits in tight cabinets

    Cons: OSD will not display on some TVs No alternate output out than HDMI No way to program without OSD

    Nice but no OSD operation display..........

    Larry from So California on 6/20/2012

    Crutchfield Customer Review (What's this?)

    Very nice unit but it was missing on screen display so if you have it located where you can't see it you will not no what your selections are. You will not be able to rename your devices, stuck with the generic names of inputs. A very nice unit with just about all you need except for missing the software needed for the above mentioned items.

    Pros: Built like a European Car, very solid and heavy, nice sounding, just about all you need without the average big box units out there.

    Cons: For the price there should be a on screen display not just for the setup and the availability to rename your inputs.


    Hands-on research

    Features and Specs

    Number Of Channels 7
    Stereo RMS Power (watts) 90
    THD in Stereo 0.006%
    Frequency Bandwidth (stereo) 1k Hz
    Minimum Impedance L/R 4 ohms
    Minimum Impedance Center 4 ohms
    Minimum Impedance Surround 4 ohms
    General Features
    Internet-ready No
    Bluetooth No
    Apple AirPlay No
    App Remote Control No
    USB port for iPod/iPhone No
    FM Sensitivity Not Given
    HD Radio Tuner No
    On-Screen Display Thru HDMI
    Auto Speaker Calibration CAMCAS
    HDCP 2.2 for 4K Video No
    HDR-compatible No
    HDMI Standby Pass-through No
    4K Video Upscaling No
    HDMI to HDMI Upconversion Yes
    DLNA Certified
    MHL-compatible No
    Multibrand Remote Control No
    Learning Remote No
    LCD Remote
    Width (inches) 16-15/16
    Height (inches) 4-1/4
    Depth (inches) 14-3/4
    Weight (pounds) 22
    Parts Warranty 3 Years
    Labor Warranty 3 Years
    Multi-room Audio--Video
    Powered Multi-room Audio Output No
    Preamp Multi-room Audio Output No
    Multi-room Video No
    Multi-room HDMI Output No
    Surround Processing
    Dolby Digital DD, EX, TrueHD, DD+
    Dolby Atmos No
    DTS DTS, ES, HD, HDMA, Neo6
    DTS:X No
    Inputs & Outputs
    Phono Input No
    Audio-Video Inputs 5
    Audio-only Inputs 2
    Component Video Inputs 2
    Component Video Monitor Outputs None
    Optical Digital Inputs 4
    Coaxial Digital Inputs 4
    Optical Digital Outputs 1
    Coaxial Digital Outputs 1
    HDMI Inputs 4
    HDMI Monitor Outputs 1
    Subwoofer Outputs 1
    Multi-Channel Analog Input Yes
    Multi-channel Preamp Output Yes
    Main Speaker Output Pairs 1
    Main Speaker Terminals Posts
    Ethernet Port None
    USB Connections None
    Removable Power Cord IEC 2-prong

    Product Research

    Audio Features
    Video Features
    Convenience Features
    Remote Control

    Audio Features

    Audiophile Components: The Cambridge Audio azur 551R employs a Toroidal transformer and isolated processing boards for a high purity, low-distortion signal. The AV receiver's X-Tract near-silent cooling system combined with a rigid low-resonance chassis maximizes the system's audio signal quality.

    7 Discrete Amplifiers: Seven discrete amplifiers driven by a low-flux toroidal transformer are separated from the processing and input stages delivering ultra-low noise and distortion, thereby guaranteeing performance without compromise. This careful design of the amplifier stages ensure that the 551R can reproduce the dynamics required for movie and music soundtracks. The 7 channel amplifier is rated at 90 watts with 2 channels driven (1kHz, 8-ohms, 0.006% THD) or 60 watts with all 7 channels driven (1kHz, 8-ohms, 0.006% THD).

    Bi-Amp Mode: This receiver allows you to reassign the surround back amplifier channels to make bi-amp connections (compatible speakers required). A bi-amplification connection uses two amplifiers for one speaker. One amplifier is connected to the woofer section of a loudspeaker while the other is connected to the combined midrange and tweeter section. With this arrangement each amplifier operates over a limited frequency range, making its job easier. The receiver will be limited to 5.1ch surround.

    24-bit/192-kHz DACs: The Cambridge Audio azur 551R utilizes a 192 kHz/24 bit D/A converter on each of the unit's seven channels for exceptional sound quality. The 192kHz sampling and 24-bit word length capabilities of the DACs allows you to play high-resolution recordings and hear the increased clarity, detail and dynamic range of those recordings.

    Dual 32-Bit DSPs: The Cambridge Audio azur 551R employs Cirrus Logic dual 32-bit DSPs for compatibility with the latest Dolby Digital/DTS formats, Dolby Pro Logic/DTS Neo:6 surround processing, and Dolby Pro Logic surround processing.

    Note: Dolby Digital and DTS listening modes can only be selected if your audio source is connected to the A/V receiver via a digital audio connection (HDMI, optical, or coaxial). To enjoy true 7.1ch Dolby Digital TrueHD and DTS-HD surround sound, the receiver must be connected to your Blu-ray player via HDMI.

    Matrixed Surround Modes: These modes allow a surround-sound experience from source material that has no encoding at all. The surround sound effect is achieved by digital signal processing of the analog or digital stereo source used. Five modes are possible; Movie, Music, Room, Theatre, and Hall.

    Stereo Modes: The surround receiver also provides two-channel stereo playback, as well as an analog stereo direct mode.

    • Stereo/Stereo + Sub: Only the front left & front right speakers (and subwoofer if selected) have output in this mode. If an analog source is selected, it will be converted to digital via 24 bit A/D converters to allow digital domain sub creation and bass/treble controls. If a digital source is selected, the 551R will be processing either LPCM stereo (from the digital outputs of a CD player for instance) or a Stereo downmix of DD or DTS material (from the digital output of a DVD player for instance).
    • Analog Stereo Direct: Selects the analog inputs for the current source directly with no A/D conversion, DSP processing, Bass/Treble, or subwoofer channel active. Provides the very best fidelity for analog Hi-Fi source equipment. In this mode the 551R is acting just like a normal Hi-Fi integrated amplifier.

    Dolby Pro Logic II/IIx Music Settings: While listening in the Dolby Pro Logic II/IIx Music format, there are three further enhancements you can adjust.

    • Panorama: A Prologic II/IIx mode that extends the front stereo image to the surround sound speakers for a more enveloping experience. This mode can be either On/Off.
    • Dimension: Allows gradual adjustment of the center image from being produced only by the Center speaker (Setting 0) through levels of being spread between the center channel and left and right speakers to finally being produced by the front left and right speakers only (Phantom Center, Setting 7). Useful in optimizing the front/center/right soundfield for best integration of the three speakers.
    • Center Width: Adjusts the soundfield to be gradually shifted from the front of the room to the back to suit taste, speaker positioning, and size of room. Setting 0 has the image furthest forward, 6 furthest back.

    DTS-HD Speaker Remap: As there is no official speaker layout for discrete 7.1 channel audio, it could be possible that the original master track of a 7.1 soundtrack was mastered with a different speaker layout than the one being used in your home. DTS has addressed this issue for DTS-HD Master Audio and High Resolution Audio by including in the bitstream flags to tell the receiving AV Receiver which of a seven nominal 7.1 speaker layouts was actually used. By using special DTS Speaker Remap algorithms the 551R is able to electronically "reposition" the speakers (i.e. direct the audio propagation), so that the playback matches the original encoded layout for the best possible sound quality.

    CAMCAS (Cambridge Audio Microphone Controlled Auto Setup): Cambridge Audio's Microphone Controlled Auto Set-up (CAMCAS) tailors the 551R's performance to any room and comes complete with a microphone to complete this simple procedure. The CAMCAS system performs two sets of tests; first checking which speakers are connected and whether they are wired correctly and in phase, then second automatically measuring and adjusting the speaker delay timings and levels. You can also choose to manually setup the receiver's speakers settings.

    Individual Crossovers & Advanced Bass Management: The azur 551R provides individual crossover adjustments and advanced bass management settings.

    • Tone Controls: The azur 551R offers independent Bass (100Hz) & Treble (10khz) adjustment from -10 to +10dB.
    • Speaker Crossover: Each speaker (front/center/surround/surround back) and subwoofer crossover point can be adjusted from 40-150Hz (in 10Hz steps) and also to 200Hz.
    • LFE Trim: The LFE channel (for DD/DTS material) can also be trimmed by up to 10dB (in 1dB steps); useful for late night listening or other situations where it might be desired to reduce the low frequency effect level temporarily.
    • Bass Augment: You can select whether to play front channel low-frequencies through either the front speakers or the subwoofer, or through both the subwoofer and front speakers.

    Dynamic Range Control: This setting controls the dynamic range of Dolby Digital movie soundtracks by compressing the audio to limit the difference in level between loud and quiet passages in the movie. The receiver's Dynamic Range Control can be set to Auto, On, or Off.

    Audio Inputs/Outputs: The AV receiver offers a variety of analog and digital audio inputs/outputs.

    • Digital Inputs/Outputs: The azur 551R features optical (4 in/1out) and coaxial (4 in/1 out) digital connections.
    • Binding Post Speaker Terminals: The receiver has binding-post terminals for all speaker connections. The binding-post terminals can accept bare wire, pin connectors, and banana plugs (single only). Speakers with an impedance of between 4-8 ohms are recommended.
    • 7.1ch Analog Inputs: The azur 551R features a 7.1 Channel input (Front left, Front right, Center, Surround left, Surround right, Surround Back left, Surround Back right, and Subwoofer) for connecting a DVD Audio player, Super Audio CD multi-channel player, or other component that has a multi-channel port so you can playback the audio with 5.1 channel or 7.1 channel surround sound.
    • 7.1ch Preamp Outputs: The A/V receiver features 7.1ch pre-amp outputs (Front L/R, Center, Surround L/R, Surround Back L/R, and Sub) for connection to external power amplifiers.
    • MP3 Input: The A/V receiver is fitted with a front-panel 3.5mm input for temporary connection of your portable digital audio player.
    • Headphone Output: The receiver features a 1/4" stereo headphone jack on its front-panel for connecting a pair of optional headphones. Plugging in a set of headphones will automatically mute the main speakers and pre-amp outputs, while selecting a 2-channel stereo down-mix soundfield. Headphones with an impedance of between 32-600 ohms are recommended.

    AM/FM Tuner w/ RDS: The Cambridge Audio A/V receiver features a built-in AM/FM tuner with RDS. RDS is a method for the transmission of additional information from local radio stations. It is only available in FM mode. RDS will only work if the local broadcasting stations have RDS transmission and the signal is strong enough.

    Video Features

    Video Inputs: In terms of connectivity, the 551R boasts four HDMI inputs and a single HDMI monitor output which fully support 3D, Deep color, and Audio Return from newer flat-panel TVs. It also features a wide selection of analog video inputs (Component, Composite, S-video).

    • HDMI (ver.1.4): HDMI (High-Definition Multi-Media Interface) is an all digital connection that can carry both audio/video in one cable. Direct digital transfer of audio/video and support for various types of High Definition video content and high resolution audio make this the best connection type to use. The four HDMI inputs can be assigned to the BD/DVD, Video 1, Video 2, CD/Aux/TV, Tape/MD/CDR or 7.1 Direct sources.
    • Component: Two component vides input capable of supporting 480i, 480p, 720p, and 1080i video signals.
    • Composite: Two composite video inputs which support 480i only.
    • S-Video: Two S-video inputs that support 480i only.

    Note: This receiver only features an HDMI monitor output (there are no analog monitor outputs). All analog video inputs will be upconverted to HDMI to send to your TV.

    Analog-to-HDMI Conversion w/ 1080p Scaling: The A/V receiver's Faroudja 1080p video scaler (FLI2310) vastly improves performance from lower resolution TV broadcasts and DVDs as well as transcoding analog video inputs to the digital domain for simpler and neater connection to the TV using the receiver's HDMI monitor output. Composite, Component, and S-video inputs can be upconverted to HDMI and scaled to 1080p. Lower resolution incoming HDMI signals can also be scaled to 1080p. You can choose to bypass the scaler for a native resolution.

    Note: 3D TV content, 24fps content, or other video standards that 551R cannot process or recognize are always bypassed and sent natively, without scaling.

    3D Pass-Through: With the advent of 3D media, it is important to own a receiver that recognizes 3D video signals. The 551R is able to pass through 3D signals from your Blu-ray player, ensuring that the 3D effect doesn't get lost in translation. It also recognizes signals from 3D television broadcasts. By connecting a 3D-compliant Blu-ray disc player and 3D-compliant TV to the 551R, you will have a 3D home theater where you can enjoy high-definition sound and video on a level you've never experienced before.

    Deep Color Support: The 551R also supports Deep Color content, which can display a larger color range than standard-definition schemes. The result is a more lifelike, vibrant picture.

    Audio Return Channel: This feature allows audio to be sent from your compatible HDTV to your receiver through the same HDMI cable already being used to send audio and video to your HDTV. This eliminates the need for extra cables connected to your television.

    Lipsync Adjustment: This feature compensates for the timing shift between the audio and video of the receiver. If needed, the audio signal can be manually delayed to match the video signal; adjust from 0-500ms (in 10ms steps).

    Audio Split: The 551R allows you to view one source while listening to another. You can be watching any video input (HDMI, Component, Composite, or S-video) on your connected TV and listen to a different analog (RCA) or digital (Optical/Coax) audio source through the receiver.

    Picture Adjustments: You can adjust the Resolution (480p/576p/720p/1080i/1080p), Frame Rate (Auto/50Hz/60Hz), Color Space (Auto/RGB/YCbCr422/YCbCr444), Aspect Ratio (Auto/4:3/16:9), and Color (Auto/ITU.601/ITU/.709) for the A/V receiver's HDMI monitor output.

    Front-Panel A/V Input: The unit's front-panel composite video/stereo RCA input allows occasional connection of your digital camera, camcorder, or game console.

    Convenience Features

    Slim, Aesthetic Design: The Cambridge Audio azur 551R features a slim designed chassis which measures only 16.9375" (w) x 4.25" (h) x 14.75" (d); so it easily fits on a shelf or inside a cabinet.

    On-Screen Display (via HDMI): The AV receiver's on-screen menu provides quick information about your system's settings. You can easily make settings for your home theater system while viewing menus on the TV screen. Simple settings are enabled with the setting menus displayed on the TV screen. These menu displays can only be output to your TV via HDMI. The unit's front-panel LCD also displays the receiver's menu adjustments, as well as input source.

    X-Tract Cooling System: The Cambridge Audio azur 551R employs a unique cooling system called X-Tract. A perfectly balanced combination of forced cooling and natural convection effectively draws heat away from the substantial transformer and output stages and means the 551R can operate extremely quietly, at a low temperature and enables a more compact enclosure than would normally be possible.

    Backup Memory: The 551R has a function that preserves the preset memory and other settings. In the event of a power failure, or if the power cord of the unit is disconnected from the mains outlet, the back-up memory will preserve the preset memory for approximately one week. If the power supply is interrupted for 7 days or longer, the memory settings will be erased.

    Firmware: The tested unit contain firmware version 2.7/2.4/1.0 (as of 7/4/2012).

    Remote Control

    IR Remote Control: The azur 551R comes with an IR wireless remote control that can operate this receiver only.

    Remote Connections: The Cambridge Audio azur 551R is fitted with the following custom remote connections.

    • IR Input: This 3.5mm input is used to control the 551R from an external key-pad (sold separately).
    • RS232C Port: The RS-232C port is to be used in conjunction with an external controller to control the operation of the unit by using an external device. The RS-232C port may also be used in the future to update the operating software of the unit so that it will be able to support new digital audio formats.

    Our Product Research Team

    At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.