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Cambridge Audio Azur 651R
7.2-channel home theater receiver
Item # 779651RB | MFR # CAMB651RBL
This item is no longer available.
Our take on the Cambridge Audio Azur 651R by Crutchfield's Marshall Chase
Audiophile sound quality from a home theater receiver
Why choose between outstanding sound quality and the excitement of home theater? Cambridge Audio's Azur 651R delivers both in one captivating package. The 651R 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. Uniquely, the 651R's 100 watts-per-channel rating is measured with all channels going full-tilt simultaneously. Under the most demanding conditions, the 651R comes through with spectacular, low-distortion sound that few can attain. In stereo mode, you get a beefy 140 watts per channel.
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 Anchor Bay® processing can route all of your video sources to not one but two HDMI-capable displays — like a TV and a projector. Cirrus Logic dual 32-bit DSPs ensure that every audio nuance comes through. These processors are designed to meet the mammoth digital calculating demands of today's high-res music and soundtracks.
A multitude of setup choices
The Azur 651R gives you many ways to enjoy quality sound. The back surround channels are re-assignable for use with bi-amp capable speakers. By doubling the power to this speaker type, you'll get every ounce of performance you paid for. If you would like to enjoy music in another room, simply use the two back surround channels for music while keeping the film uninterrupted in your theater room. If you've got an infrared repeater system, use the supplied second-room remote to control the receiver. And, if you have a Blu-ray player with multichannel analog output, the 651R will give it a warm welcome with 7.1-channel preamp input. Or if you already have one or more high-quality separate amplifiers, you can feed them signals via the 7.1-channel analog output.
No-nonsense British design
Cambridge Audio's London-based engineering team designed the Azur 651R according to their usual high-end standards. This receiver boasts seven discrete amplifiers powered by a toroidal transformer which maintains steady power throughout that easily copes with the fluctuating demands of movie soundtracks and music. 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.
What's in the Box:
- 7.1ch AV receiver
- 6' AC power cord
- Main remote control (RC-651R)
- Zone 2 remote control
- 3 "AAA" batteries
- CR2025 3V Lithium battery
- Auto-setup microphone (with attached 19.5' cable terminated by a 3.5mm connector)
- FM wire antenna
- AM loop antenna
- Mini-to-RCA adapter
- User's Manual (En/Fr/Sp/It)
Power and processing:
- 7-channel amplifier
- 140 watts per channel into 8 ohms (1k Hz) at 0.006% THD, with 2 channels driven
- 100 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 Anchor Bay ABT2010 video scaler
- Audyssey Laboratories' 2EQ® for easy speaker setup (microphone included)
- Audyssey Dynamic Volume mode to keep listening levels steady
- dual-room/dual-source output
- powered audio output for 2nd room (using powered 2nd-room output allows 5.1 home theater in main room)
- 2.1-channel line-level output for 2nd room (requires amplification for each channel)
Audio Performance Features:
- high-current amplifier design
- Pure Analogue Stereo Direct mode switches off all unused circuitry for the cleanest possible sound
- 40-bit Analog Devices DSP (Digital Signal Processor)
- dual Texas Instruments Aureus™ 32-bit DSPs
- dual Cirrus Logic 24-bit DACs (digital-to-analog converter)
- back surround speaker channels re-assignable for bi-amping compatible front left and right speakers
- 192kHz/24-bit digital-to-analog converters for all channels
- 1080p-compatible HDMI digital video switching (4 in, 2 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: 5 optical, 5 coaxial
- digital audio outputs: 2 optical, 2 coaxial
- 5 audio/video inputs, including:
- 1 front-panel input with composite
- 11 rear-panel inputs with 4 composite video, 4 S-video and 3 component video
- preamp outputs for 2 powered subwoofers
- 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
- 30 AM/FM presets
- receiver and Zone 2 remotes
- 16-15/16"W x 5-7/8"H x 17-3/16"D
- weight: 38.3 lbs.
- warranty: 3 years
- Our 60-day money-back guarantee
Cambridge Audio Azur 651R Reviews
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Features and Specs
Audiophile Components: The Cambridge Audio azur 651R 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.
- All-Metal Case: The all-metal case and brushed aluminum front-panel is very stable and introduces less resonance to the audio signal.
- Isolated Processing Boards: The 651R features isolated input and video processing boards to ensure minimum noise distortion.
- Toroidal Transformer: The Toroidal transformer delivers a high purity, low-distortion signal; plus better bass response.
- X-Tract Cooling: The Cambridge Audio azur 651R 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 651R can operate extremely quietly, at a low temperature and enables a more compact enclosure than would normally be possible.
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 651R can reproduce the dynamics required for movie and music soundtracks. The 7 channel amplifier is rated at 140 watts with 2 channels driven (1kHz, 8-ohms, 0.006% THD) or 100 watts with all 7 channels driven (1kHz, 8-ohms, 0.006% THD).
Amplifier Assignment: The seven amplifier channels built into the receiver are typically used for 7.2 channel surround (Front L/R, Center, Surround L/R, Surround Back L/R, and Dual SW) in the main room. These seven amplifier channels can be configured to accommodate various home theater setups.
- 7.1ch: Seven speakers are powered in the main room - Front L/R, Center, Surround L/R, and Surround Back L/R. Zone 2 will need to be powered by a separate amplifier. Bi-amplification is not an option.
- 5.1ch + Height: Seven speakers are powered in the main room - Front L/R, Center, Surround L/R, and Front Height L/R (no Surround Back channels). Zone 2 will need to be powered by a separate amplifier. Bi-amplification is not an option.
- 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 5.2ch surround in the main room, and Zone 2 must be powered by a separate amplifier.
- Zone 2: You can also reassign the surround back amplifier channels to power speakers in Zone 2. The receiver will be limited to 5.2ch surround in the main room and you will not be able to bi-amp the front speakers.
24-bit/192kHz DACs: The Cambridge Audio azur 651R utilizes a Cirrus Logic 192kHz/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 TI 32-Bit DSPs: The Cambridge Audio azur 651R employs dual Texas Instruments 32-bit DSPs (Aureus DA788) for compatibility with the latest Dolby Digital/DTS formats, Dolby Pro Logic/DTS Neo:6 surround processing, and Dolby Pro Logic surround processing.
- Dolby Digital: Dolby Digital, Dolby, Digital EX, Dolby Digital Plus, Dolby TrueHD
- DTS: DTS, DTS-ES, DTS-HD Master Audio, DTS-HD High Resolution, DTS 96/24, DTS Neo: 6
- Dolby Pro Logic: Dolby Pro Logic II, Dolby Pro Logic IIx, Dolby Pro Logic IIz
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 651R 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 651R is acting just like a normal Hi-Fi integrated amplifier.
- Multi-Channel Stereo: Create a multi-channel stereo presentation whereby the incoming Left and Right channels are output to the Front Left, Surround Left, Surround Back Left, and Front Right, Surround Right, Surround Back Right channels respectively. A mono-Subwoofer channel is also created.
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 651R 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.
Audyssey Technologies: The 651R features a collection of Audyssey audio technologies for optimal sound quality. Audyssey 2EQ/Room EQ, Audyssey Dynamic EQ, and Audyssey Dynamic Volume help achieve the best performance in your particular room and with your speaker setup.
- Audyssey 2EQ/Room EQ: Audyssey 2EQ/Room EQ Auto Speaker Setup tailors the 651R's performance to any room and comes complete with a microphone to complete this simple procedure. Audyssey 2Q uses the measurement from up to 3 positions to correct room response in addition to the speaker settings. Using the supplied microphone, Audyssey 2EQ automatically determines the number of speakers you have connected, their "size" and crossover frequencies (for the purpose of bass management), plus their distances from the listening position. Audyssey 2EQ/Room EQ can also remove deficiencies in playback caused by sub-optimal room acoustics. It does this by capturing any acoustical problems at the listening area in both the frequency and time domain and applying sophisticated corrective equalization. The result is an improved sound quality, clarity of dialogue, and a well balanced sound for more than one listening position. You can also choose to manually setup the receiver's speakers settings.
- Audyssey Dynamic EQ: Audio engineers mix music and movie soundtracks at reference levels much louder than typical home listening levels. At lower volumes the human ear perceives sound differently; voices change, bass dissipates, and the surround effect becomes less enveloping. Dynamic EQ adjusts the frequency response curve based on volume to maintain consistent bass output, octave-to-octave balance, and surround impact, resulting in rich sound at any volume. You can set the Dynamic EQ to 0, 5, 10, or 15 dB.
- Audyssey Dynamic Volume: Audyssey Dynamic Volume solves the problem of large variations in volume level between television programs, commercials, and between the soft and loud passages of movies. Dynamic Volume addresses the issue of commercials that are too loud and movie soundtracks with vast differences between soft and loud passages; the results are more intelligible dialogue, loud passages maintain impact, and soft whispers are heard clearly. When the volume level changes, Dynamic EQ also adjusts the frequency response to maintain sound quality. You can set the Dynamic Volume to Heavy (late night listening), Medium (daily listening), Light (consistent dialog), or off (full dynamics).
Individual Crossovers & Advanced Bass Management: The azur 651R provides individual crossover adjustments and advanced bass management settings.
- Tone Controls: The azur 651R 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 651R features optical (5 in/2out) and coaxial (5 in/2 out) digital connections. One optical digital input is located on the front-panel.
- 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 651R 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.
- 7.2ch Preamp Outputs: The A/V receiver features 7.1ch pre-amp outputs (Front L/R, Center, Surround L/R, Surround Back L/R, and Dual 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 Inputs: In terms of connectivity, the 651R boasts four HDMI inputs and dual 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, Recorder 1, Aux, CD Recorder 2, or 7.1 Direct sources. The two HDMI outputs are parallel so the same video signal is output through both and can be used simultaneously.
- Component: Three component vides input capable of supporting 480i, 480p, 720p, and 1080i video signals.
- Composite: Five composite video inputs (4 rear/1 front) which support 480i only. There is also one composite video record output.
- S-Video: Five S-video inputs (4 rear/1 front) support 480i only. There is also one S-video record output.
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.
Anchor Bay ABT2010 Scaler (up to 1080p): The A/V receiver's Anchor Bay ABT2010 video scaler upscales any source, including analog standard definition, to 1080p. 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. The receiver also uniquely features a "bypass" mode to improve picture quality by avoiding the common problem of "double scaling", where your Blu-ray player, PS3 or video streamer has already upscaled content once, and your receiver then scales it again
Note: 3D TV content, 24fps content, or other video standards that 651R 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 651R 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 651R, 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 651R 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 651R 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 A/V input consists of a composite video input, S-video input, stereo RCA input, optical digital input, and 3.5mm aux input.
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.
Dual Room/Dual Source: The AV receiver's Zone 2 outputs allow you to play two different audio/video sources in up to two rooms. The receiver has dedicated stereo preamp outputs (2.1ch) for Zone 2, or the built-in amplifier can be configured to power speakers in the second zone. If Zone 2 speakers are powered by the receiver, the receiver is limited to 5.2ch in the main room. The volume of Zone 2 can be controlled by the Cambridge Audio receiver using either configuration or from your add-on amplifier when using the line-output. Zone 2 also offers a component-, composite-, and S-video output so you can watch an analog video source in another room.
- Compatible Zone Sources: You can
select the following input sources for Zone 2.
- Analog Audio/Video Inputs (to watch video in Zone 2, you need to connect the Zone 2 video monitor out in the same way as the video input device; there is no video conversion)
- AM/FM Tuner (you cannot select different AM/FM radio stations for each zone)
- Incompatible Zone Sources: Optical/coaxial digital and HDMI audio sources are not output to Zone 2.
Follow Main: The Follow Main function allows you to enjoy the AV receiver's Main Zone audio source in Zone 2, simultaneously (regardless of input audio signal types - analog or digital). Stereo playback is automatically selected for both zones when Follow Main is selected. Both the Main Zone & Zone 2 play at the same volume level during this mode. Utilize this function when you want to play back an audio source as background music in two rooms of your home.
Source Naming: You can rename each input so the display reflects the actual source.
Backup Memory: The 651R 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.
Auto Power Down: The 651R feature an automatic power down function and will by default shut down if no audio playback has been detected for 30 minutes.
Firmware: The tested unit contain firmware version 1.44/1.45/1.09 (as of 1/30/2013).
IR Remote Control: The azur 651R comes with an IR wireless remote control that can operate this receiver's main zone and zone 2 functions.
Zone 2 Remote Control: The dedicated Zone 2 remote lets you adjust volume up/down and the source input of Zone 2 (an IR repeater system will be required). Volume up/down is only available when you are using the 651R to power speakers in Zone 2.
Remote Connections: The Cambridge Audio azur 651R is fitted with the following custom remote connections.
- IR Input/Outputs: The receiver has remote input (3) and remote output (3) minijack terminals (3.5mm) for use with external IR receivers
- 12V Trigger Outputs: The 651R feature two trigger outputs (3.5mm) that can be used to signal to external devices for simple automation functions. The outputs are 0V for Off and 12V for On at up to 100mA.
- Control Bus Input/Output: The Control Bus Input/Output (RCA) connections Allow un-modulated commands from multi-room systems or other components to be received by the unit.
- 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.
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1 question already asked
Don't know - use 6 ohm loads myself. For those I will say it is a very stout and powerful amp and massive power supply. Still not sure how the 4ohm load will change it. [ CHRIS Feb 18, 2014 ]
Sorry, I can't tell you. I use 8 ohm speakers. [ William Feb 16, 2014 ]