Cambridge Audio Azur 650R A/V Receiver (TPV 97)

Cambridge Audio Azur 650R
Cambridge Audio Azur 650R A/V Receiver (TPV 97)

Some AVR makers think advanced features and functions are what most home theater enthusiasts want, but Cambridge Audio’s Azur 650R 7.1-channel A/V receiver is built for audio purists believe that less is more, simpler is better, and that the shortest path to great sound involves amplifier circuits that inject as little technical gobbledygook as possible in the signal path. This does not mean, however, that the Cambridge is not modern or up to date, because it is both, but rather that its priorities are simply different from those of most mass-market receivers. Instead of focusing on technical gongs and whistles, the Cambridge instead concentrates on providing a rugged, purist-grade amplifier section that’s backed up by a simple but effective bank of audio and video switching facilities and a powerful but no-nonsense set of surround sound decoders.

In keeping with the purist aesthetic, the 650R takes a “first, do no harm” approach in handling both video and audio signals. Accordingly, the receiver provides composite video, S-Video, component video, and HDMI (version 1.3c) video inputs and supports transcoding between those formats, but otherwise makes no attempt to provide more elaborate video scaling or processing functions. Similarly, the Cambridge provides a useful mix of analog (stereo and 7.1-channel) and digital (coaxial, optical, and HDMI) audio inputs, but takes special pains to give users the option of listening to audio signals with little or no signal processing or tone shaping applied. The latest Dolby TrueHD and DTS-HD Master Audio surround sound decoding modes are supported, but otherwise DSP modes are held to a minimum (Cambridge supports five basic alternative modes called Movie, Music, Room, Theatre and Hall). Finally the 650R incorporates an automated speaker setup system called CAMCAS (Cambridge Audio Mic Controlled Auto Setup) that provides basic channel level and speaker distance settings, but that pointedly does not offer room/speaker EQ functions. The sense one gets in setting up and then using the Cambridge on a day-to-day basis is that it is meant to be clean, simple, and straightforward in every way—giving you all the essentials you need, and nothing you don’t need or aren’t likely to use.

Frankly, I can see how two very different reactions to the Cambridge receiver might be possible. Enthusiasts who appreciate and expect the densely layered features commonly found in competing higher-end AVRs might find the Azur 650R seems, well, a little spartan. But high-end audiophiles, who are often skeptical of whizz-bang circuit add-ons that promise great things but that ultimately do more harm than good, will feel right at home with the approach Cambridge has taken. Let’s take a closer look at the 650R to see how it performs under real world conditions.


Consider this AVR if: You are a purist at heart and know and love the sound of good, clean, powerful amplification when you hear it; this is really the 650R’s greatest strength. Also consider the Cambridge if you would like an AVR that offers specialized controls (for example, the ability to set individual subwoofer crossover frequencies for each channel in fine, 10Hz increments) that audiophiles will actually want to use.

Look further if: You want a receiver that offers large numbers of HDMI inputs (the 650R offers only three), that provides automated room/speaker EQ functions (the 650R has none), or that incorporates a high-powered onboard video processor (the 650R supports format-to-format transcoding, but stops there). The 650R is not cheap, which may lead some to ask whether it is overpriced, but what you are paying for is amplifier circuitry that sounds much better than the norm for this price class.

Ratings (relative to comparably priced AVRs):

User interface: 8
Sound quality, music: 9
Sound quality, movies: 9
Value: 8


•A key centerpiece of the 650R involves its 7 x 100-Watt amplifier section, which is rated with all seven channels driven. Cambridge has this to say about the amplifier section: “the seven 100W audiophile grade fully discrete amplifiers are kept as separate as possible from the processing and input stages and feature a large power supply with a low flux toroidal transformer.”
•Provides a massive X-TRACT forced-air cooling tunnel that occupies a large center within the 650R’s chassis, and that runs from the front of the unit to a large vent in the rear panel. This is precisely the sort of construction detail you might expect to see on a big multichannel power amplifier, but that is relatively rare in AVRs.
•Unused amplifier channels can be used to bi-amplify main loudspeakers.
•CAMCAS (Cambridge Audio Mic Controlled Auto Setup) system provides automated speaker level and distance setting via included calibration mic.
•Allows users to set individual subwoofer crossover frequencies for each channel in 10Hz increments from 40H to 120Hz.
•For listening to stereo sources, the 650R provides both a pure “Stereo” playback mode and a useful “Stereo + SW” mode that digitally applies whatever subwoofer crossover setting have been chosen and that digitally derives a subwoofer output signal from standard two-channel signals (analog or digital).
•Provides extensive Tone/Sub/LEF configuration setting with a broad range of subtle trim options.
•Audio Split mode allows viewing one input while listening to another.
•Tuners: The receiver provides standard AM/FM reception.
•Provides A-BUS/Cambridge Incognito support for two addition zones, if desired.
•Three HDMI inputs (version 1.3c).
•Supports Dolby TrueHD and DTS-HD Master Audio surround sound processing modes.
•Supports high resolution PCM bitstreams.
•Uses Cirrus Logic CS43122 24-bit/192 kHz DAC for front left and right channels.
•Uses Cirrus Logic CS52526 24-bit/192 kHz CODEC for surround channels + 24-bit A/D conversion.
•Uses Cirrus Logic CS497004 dual 32-bit DSP.

Comments: While there is much to like in the Azur 650R, I should point out three minor shortcomings that need to be addressed.

First, the Cambridge provides only three HDMI inputs (and none on the front panel). At this price point, I would expect more HDMI inputs—especially in light of the many HDMI-equipped source components one might want to connect to the receiver (e.g., Blu-ray players, network media players, cable boxes, DVRs, and so on).

Second, while the 650R does offer the CAMCAS automated speaker setup system, it does not provide a room/speaker EQ system—a feature that is welcome and expected on receivers in this price class. While purists may frown on using room EQ systems, the fact is that large number of serious enthusiasts enjoy and use them on a daily basis (and remember, EQ systems can easily be bypassed or turned off should purists wish to do so).

Third, the Cambridge support high resolution multichannel PCM, but does not support direct DSD bitstreams (the native format for SACD discs). This omission does not seem consonant with the 650R’s “audiophile’s first” mission profile—especially in light of the fact that Cambridge itself offers a Blu-ray universal player that can output DSD bitstreams.



The Azur 650R setup menu is refreshingly straightforward to use, and it is also well-documented in the receiver’s user manual. A simple one-touch button puts the menu list onscreen (or turns it off again), and menu options are easy to follow from that point forward.

The CAMCAS automated speaker setup system is easy to use and much less complicated than most elaborate room EQ systems tend to be. Again, note that CAMCAS sets speaker levels and distances, but provides no means for detecting or compensating for room/speaker response anomalies.


The 650R remote control is not backlit, but is otherwise a functional delight. One point that I appreciated, and that I think many enthusiasts will applaud, is that most control buttons offer single functions that are relatively unambiguous—this in contrast to multi-function, context sensitive buttons that invoke different (and often perplexing) functions at different times.

One potential drawback I noted is that the remote provides no mechanism for making on-the-fly channel level trim adjustments. Since this is a function many serious listeners might need/want to use from time to time, I hope Cambridge addresses the requirement in future models.


The 650R provides clean, simple, noise-free video switching functions and format-to-format transcoding that works as expected (but without providing additional scaling or other video processing functions).


The 650R sounds more like a good high-end integrated amplifier or preamp/power amp combo than it does like a traditional AVR. Here’s what I mean by that comment. If you know and love fine two-channel audio components then you might find, as I sometimes have, that most AVRs (good though they may be) sound a little bit veiled or just slightly compressed—almost as though they are “homogenizing” the sound of fine music recordings to some degree. But not so the Cambridge 650R; it is not only reasonably powerful but rich in sonic finesse, detail, and resolution so that you tend to hear much deeper into recordings than you typically would with most AVRs—even quite expensive ones.

In doing reviews of AVRs for The Perfect Vision, I typically make a point of comparing the analog sound of a good universal player vs. the sound of the same player feeding identical digital data to the receiver for the receiver to decode. Frankly, many receivers tend to blur or at least minimize distinctions in such player vs. receiver comparisons, but with the 650R exactly the opposite was the case. While its surround sound decoders performed well with no apparent glitches and its DAC’s sounded good-to-very-good, high quality audio-oriented disc players (e.g., the Oppo BDP-83 SE) sounded spectacularly good through the Cambridge Audio, bringing much of their full sonic potential to bear. When fed by high quality analog audio source components, then, the Cambridge will reward you with wide, deep, richly detailed soundstages and a big, wide-open sound overall. This is what truly sets the 650R apart.

While the Cambridge’s digital front end may sound slightly brighter and bit more sharp-edged that today’s nicer audio-oriented disc players, it certainly is no slouch, as it seems to specialize in information retrieval. In practice this means that when you play movie soundtracks through the 650R you may find the overall sound seems more nuanced and noticeably more “complete” than when listening through competing AVRs. If your speakers are up to the task, surround sound imaging through the Cambridge is especially good, so that you’ll hear a smoother, better integrated and more continuous wraparound circle of sound from your system than you may be used to.


While I was evaluating the Cambridge receiver in The Perfect Vision listening room one project I was working on involved compiling a list of ten favorite soundtracks for evaluating surround sound systems, and a I listened to candidate films through the 650R I was struck repeatedly by three things. First, this receiver seems to reproduce subtle low-level sonic information with a certain self-assured clarity that few other AVRs can match. Second, it offers top-shelf surround sound imaging—provided, of course, that your speaker system is up to the task. Third, it delivers dynamics that just don’t wilt under pressure—not even when driving large, near full-range main speakers rich in bass content. Put these qualities together and you’ve got an AVR that does an unusually effective job of putting listener in the center of the action seen onscreen. An example drawn from the film Apocalypto will help illustrate these points.

The film Apocalypto uses frequent shifts between literal and figurative images and sounds to deliberately blurs lines of distinction between conventional narrative story telling and the invocation of prophetic (or apocalyptic) visions. The chapter “Ravage” shows this process in action, opening with a scene of a forest village near dawn that is supported by delightfully realistic and (highly three-dimensional) jungle sounds of birds chirping, wind sweeping through the trees overhead, and a dog barking in the distance. But soon the scene and the soundtrack shift to an off-kilter sequence where the story’s protagonist Jaguar Paw’s experiences a prescient dream of warning where a frantic fellow villager (who has plainly had his heart cut from his chest) warns him, in a slightly distorted and phase-shifted voice, to “Run!!” The reason for the warning soon becomes apparent as Mayan warriors attack Jaguar Paw’s village, and the sound designer deliberately “spotlights” selective sounds of violence for greater, while interweaving the film’s dark, otherworldly score as the action reaches a violent crescendo.

Through the 650R, those natural sounds at the start of the chapter sound strikingly vibrant, lush, and detailed. But then, as the chapter progress, the 650R seems to track perfectly with the sound designer’s intentions, first nailing the subtle distortions of the warning dream, and then exploding with the full force of the graphic violence that follows. The Cambridge distinguishes itself by maintaining clarity and unflappable dynamic composure through it all.


The Azur 650R really comes into its own when driven by high-quality source components playing high resolution music files. A good example would be “Bye Bye Blackbird” from Patricia Barber’s Nightclub [Mobile Fidelity SACD], which—as you might expect from the title—faithfully recreates the intimate sound and “vibe” of a small jazz club. On the track referenced, for example, the Cambridge caught the dark, smoky, almost sultry sound of Barber’s voice, the sublimely restrained and delicate brushwork of percussionist Adam Nussbaum, and the deep, earth, full-bodied growl of Marc Johnson’s bass. If your disc player is good enough, the Cambridge will also convey the clean, percussive attack of Barber’s piano, and will even let you hear the sounds of high harmonics from the various instruments energizing and then reverberating within the walls of the recording space. What’s significant here is that I found myself instinctively comparing the 650R not to other AVRs, but rather to high performance audio components. As one colleague put it, “it’s as if the Cambridge is primarily a big, multichannel, high-end integrated amplifier that just happens to offer the functions of an A/V receiver as well.” I second that assessment.

Part of what makes the 650R so enjoyable is that it not only gets the core sound of instruments and vocalists right, but also—on well-recorded material—conveys a sense of the context or setting in which the original recording was made. To hear what I mean, try listening to the track “Grandmother” from Rebecca Pigeon’s Raven [Chesky SACD]. At its best, this track should offer an unusually deep, wide soundstage so that you are in essence transported from your listening room to the recording space where Pigeon and her backing musicians are arrayed before you. Relatively long reverb times and sounds that are slow to decay give you an idea of the size and acoustical qualities of the room and make the performance seem much more believable. Where some AVR’s render the track from a somewhat flattened, two-dimensional perspective, the Cambridge lets it unfold—as it should—into three dimensions, with performers taking their places onstage with almost sculptural solidity. These may seem like fine distinctions to make, but they spell the difference between good performance and something more.


Cambridge Audio’s Azur 650R A/V receiver has been built, I think, with old-school audio purist in mind. Obviously, the 650R was designed with the thought that it would be used in conjunction with very high-quality video/audio source components. Unlike some AVRs, then, the Cambridge does not seek to modify or otherwise embellish upon the signals it is fed. Rather, it strives to reproduce those input signals with as much accuracy and purity as possible—a job it does very, very well.

While the 650R does not offer features that have become commonplace in competing AVRs, such as room/speaker EQ systems or extensive onboard video processing functions, it offers easy to use, noise free video switching and transcoding functions, plus superb core sound quality, which is something that never goes out of fashion.


Cambridge Audio Azur 650R 7.1 channel A/V receiver
Power output: 7 x 100 Wpc @ 8 ohms, with all channels driven
Decoding formats: Dolby TrueHD, Dolby Digital Plus, Dolby Digital and Digtal EX, and Dolby Pro Logic II and IIx; DTS-HD Master Audio, DTS-HD High Resolution Audio, DTS, DTS-ES Matrix and –ES Discrete; multichannel PCM (up to 7.1 channels at up to 24-bit/192kHz resolution); five DSP modes (Movie, Music, Room, Theater, and Hall).
Video inputs/outputs: Composite video (5 in, 4 out—2 for remote zones, 1 for recording); S-Video (5 in, 2 out—1 for recording), Component video (3 in, 1 out, HDMI version 1.3c (3 in—1 out).
Audio inputs/outputs: Stereo analog (8 in, 2 out—1 for recording), 7.1-channel analog (1 in, 1 out), optical digital audio (6 in, 2 out for recording), coaxial digital audio (5 in, 2 out for recording), HDMI version 1.3c (3 in, 1 out), AM/FM tuner, headphone output
Other: Control bus (1 in, 1 out), A-BUS keypad (2 out), A-BUS 24VDC external PSU (1 in), IR Emitter (1 in, 3 out), RS-232C (1)
Dimensions (HxWxD): 5.9" x 16.93" x 16.54"
Weight: 33 pounds
Warranty: Three years, parts and labor.
Price: $1799

Cambridge Audio

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