Arcam AVR350 Surround Sound Receiver

Holy Guacamole!

       Arcam's headline claims that their new AVR350 is the "Best ever sounding receiver from Arcam," thereby implying that it sounds even better than Arcam's own widely praised AVR300. But the AV350 looks exactly the same as the AVR300 (except for HDMI throughput jacks). And Arcam's own specs for the new AVR350 are exactly the same as for the AVR300. So one can be forgiven for casting a jaundiced eye upon manufacturer claims of superiority, in an industry where "new" and "improved, better, best" are so overused and abused. And you the consumer might well ask why you should spend an extra $500 for the AVR350 receiver that offers no more power and no more features (save HDMI throughput) than the AVR300. Besides, the AVR300 already offers excellent, indeed world-leading, surround receiver sonics, so it doesn't seem likely that Arcam (or anyone) could improve significantly upon the AVR300's sonics. Yet better sonics is precisely what Arcam is touting as the principal advantage of the AVR350, as the principal reason why you'd want to spend $500 more than for the AVR300.
       Thus, our reviewing task was clear. We had to directly compare the new AVR350 to the AVR300 (plus other surround processors), and see if we could hear any differences, then ruthlessly analyze whether these differences are truly sonic improvements, and finally assess whether the sonic improvements (if any) in the new AVR350 are worth the extra $500.
       We've just completed all our testing, comparisons, and analyses. Our scientific, coldly objective, ruthlessly analytical judgement of the AVR350's sonics, and its margin of sonic superiority over the AVR300 (and other brands of surround processors), can be summed up in two words.
       Holy guacamole!!!
       We have such high regard for the AVR300's sonics that we weren't expecting such a significant sonic improvement to be possible, but there it was, plain as day. The sonic superiority of the AVR350 over the AVR300 (and other brands of surround processors) is obvious in degree, and is important in its nature, and yields many felicitous benefits for both music and film. We'll discuss these aspects in detail below. For now, note that Arcam's headline claim, for the AVR350's sonic superiority, has proven to actually be fully justified, indeed to be a modest understatement (typically British), and it is not at all the typical advertising hype one sees elsewhere.
       This also means that the AVR350 is easily worth the extra $500 over the AVR300. Look at it this way. The AVR350 costs merely 25% more than the AVR300 ($2499 vs. $1999 in the USA). And the AVR350 offers holy guacamole sonics, which are twice as good as the already excellent AVR300, in many key aspects. When you get sound that's twice as good by paying merely 25% more, that's a bargain in anybody's book.
       Usually, as you near the pinnacle of equipment performance, the law of diminishing returns sets in, and you have to pay twice as much to get just a 10% performance improvement. But here Arcam has triumphed over even the law of diminishing returns, by giving you spectacularly better sonics for just 25% more. And Arcam is indeed working at or near the pinnacle, since the sonics of the AVR350 far outclass the sonics of all other brands of surround processors or receivers we have tested to date, regardless of price.
       Thus, if you're in the market for a surround receiver, the Arcam new AVR350 is your obvious first choice. If you already have a surround receiver, regardless of its price, you should consider sonically upgrading to the Arcam AVR350. Even if you already own the excellent AVR300, you'll be richly rewarded by upgrading to the AVR350's sonics.
       And Arcam is to be thanked and congratulated, for having pursued and brought to market a new product whose chief benefit is better sound. No added watts, significant new features, or gimmicks. Just better sound for us all. Much better sound.

Souped-Up Hotrod

       If the AVR350 is a kissing sibling of the AVR300, with identical specs, how could its sound have been improved so spectacularly?
       As you know, many automobiles can be turned into souped-up hotrods by the judicious substitution of higher performance trick parts here and there. If the modifier knows what he's doing, he can achieve dramatic performance gains at a merely modest increase in cost. That's just what Arcam's engineers did here, bestowing a holy guacamole sonic improvement upon the already excellent AVR300 by the addition and substitution of a few key trick parts that raise the cost only modestly, and thereby morphing it into the souped-up hotrod performance version called the AVR350. Think of the AVR350 as being to the AVR300 what the M series is to the standard BMW, and the AMG version is to the standard Mercedes.
       Why did the AVR300 deserve the attention of Arcam's engineers for hotrodding? Probably karma. As they say, what goes around, comes around. Arcam first developed their Mask of Silence technology at a time which happened to coincide with the design gestation of their AVR300. Arcam then took the bold step of introducing this new Mask of Silence technology in their new entry level receiver (the AVR300), rather than in their flagship products (such as the AV8 Surround Processor). This enormously benefited the AVR300's sonic performance, triumphing over the competition, as we recognized in our review. But it temporarily allowed the sonics of the entry level AVR300 to outshine the sonics of even Arcam's own flagship, the AV8.
       Of course, after the AVR300's introduction, Arcam engineers quickly set to work adding this new Mask of Silence technology to their higher end products, first the new AVP700 and then the new AV9 flagship. Trickle up instead of trickle down benefits, generously donated by the first kid on the block with this new technology, the AVR300, and sent round the circle of other Arcam surround products.
       As the Arcam engineers successively applied the new Mask of Silence technology to their higher end products, they inevitably learned some new tricks about optimizing this new technology, for best sonics. And in Arcam's higher end products these engineers also had a larger parts budget, for implementing these new, better sounding tricks. These new tricks included new Mask of Silence parts, including the Stealth Mat (used heretofore only in Arcam's FMJ top line products). And this new Mask of Silence technology also made more aurally obvious the sonic benefits of using a more expensive op amp, the OP2134 (used heretofore only in Arcam's more expensive products such as the AVP700).
       Since the AVR300 had generously sent its new technology round the circle, it was only fair that what the AVR300 sent to go around the circle should come back around the circle, to benefit the AVR300. So the Arcam engineers tried these new, more expensive tricks, learned from the higher priced AVP700 and AV9, on the AVR300, to find out what sonic improvements these new tricks might bring to the AVR300. When they heard the same dramatic, holy guacamole improvements that we now hear, they decided to make them available to you the public. Since these higher performance trick parts make the whole unit cost modestly more, Arcam decided to bring it out as a new product, the AVR350, while keeping the AVR300 in the lineup for those customers who simply could not go above its $1999 (USA) price point.
       By borrowing from their high end products just those trick parts which gave the best sonic bang for the buck, Arcam's engineers have given you in the AVR350 a souped up hotrod which sonically performs like those high end Arcam products, and sounds significantly better than the stock basic product (the AVR300), but at a modest price increase over the base AVR300. They have achieved and fulfilled the ideal fantasy of everyone who's ever lusted after a souped-up hotrod: start with an inexpensive base chassis, and add just enough of the right trick parts, at modest cost, to turn it into a high performance overachiever that can wipe out competitors that cost far more money.
       In our judgement, the original AVR300 already achieved world-leading sonics, so with the AVR350 Arcam has stepped even farther ahead, even before the competition had a chance to catch up to the AVR300. Arcam clearly has a highly self-motivated esprit de corps, which does not rest on its laurels, and does not wait for the competition to catch up, before they go back to work, to develop yet better sound for your sake.
       Incidentally, the AVR350 does offer one au courant new feature lacking in the AVR300, HDMI input and output jacks, with switching between two HDMI inputs for the one output. But this new feature is of limited advantage. It offers merely passive throughput switching, without any active buffering and without any HDMI input receivers in the AVR350. This lack of active buffering means that the HDMI cable run from your source to the AVR350, plus the cable run from the AVR350 to the display, both add up together, toward the maximum length allowable for HDMI (whilst a cable run directly from your source to the display might well be much shorter). And this lack of an onboard HDMI receiver means that the AVR350 ironically cannot tap into the audio portion of the very HDMI signal it is switching, in order to play it back through your system. Of course, Arcam is probably (like many manufacturers) wisely waiting for next year's arrival of HDMI 1.3 receivers, which will allow the input of more advanced audio (and video) signal formats.
       Note that bringing HDMI signals into any chassis also brings in far greater (worse) electromagnetic noise, which in other brands of processors typically makes their sound worse, when this added noise corrupts all their on-board digital processing (see discussion below). Thus, it's a testament to the efficaciousness of Arcam's Stealth Mat that the AVR350, with its HDMI signal throughput, is quieter than the AVR300 without this HDMI feature. This also suggests that you would be wise to eschew utilizing the AVR350's HDMI throughput feature, in order to prevent this added HDMI noise from even entering the AVR350 chassis in the first place, so the Stealth Mat does not even have to fight it.

Analysis of Sonic Improvements

       We directly compared the new AVR350 to the AVR300, and to other brands of competing surround processors and receivers. We employed our high resolution lab reference system, which is mercilessly revealing of the strengths and weaknesses of all products under test. This system includes the McCormack UDP-1 universal player, the Cary CD 303/300 CD player, the Arcam DV29 as a reference video source, Nordost Valhalla loudspeaker cables, Nordost Optix video cables, VonGaylord interconnect cables, power cordsets by VonGaylord and Wan Lung, and a surround array of Von Schweikert VR4 Jr loudspeakers.
       The Arcam AVR350 proved to be very consistent in all its various operating modes. Its sonic superiorities over the competition (and over the AVR300) were already triumphantly evident in the simplest operating mode with the shortest signal path, the direct analog throughput multichannel mode. An these same sonic superiorities were then also equally evident in most other operating modes, even as the signal path became more complex.
       The most immediately striking sonic superiority we heard was the AVR350's utterly black, silent background. All other units seemed to have a kind of modulation noise accompanying the music (or other sounds). This modulation noise in the background makes music (and other sounds) seem slightly veiled and confused, and it actually obscures subtle details of the recording that make a musical instrument, voice, etc. sound more convincingly real. We all have taken this background modulation noise for granted, and accepted it as a given of artificially reproduced sound. Indeed, many of us don't even hear it or notice it. But you will instantly notice it when it's suddenly gone in a new product like the AVR350, and, when you hear how much blacker the AVR350 sounds, the noise and veiling confusion will be obvious when you switch back to other units.
       It's easy to hear that the AVR350 has a quieter, blacker background, and does not have this modulation noise. Then, this absence of noise in turn produces several ancillary sonic benefits that you'll also notice in the AVR350. First, the blacker, quieter background directly produces the result that transients emerge more dynamically and with better articulation, from this lower noise floor. Second, the absence of modulation noise, with its veiling and confusing sonic effects, indirectly produces a further whole slew of sonic benefits. The AVR350 sounds more revealingly transparent and clearer without this noise, since the veiling and confusion caused by noise is gone. The AVR350's superior intertransient silence lets you hear more clearly the subtle timbral and textural noises that every musical instrument naturally makes immediately after each transient, so all music (as well as voices and sound effects) sounds more natural and more like the real live event. The AVR350 also sounds cleaner and more pristine without this noise, because even subtle levels of modulation noise actually distort music and sounds (adding distortion byproducts and sidebands). Additionally, the AVR350 sounds more articulate and faster without this noise, since noise smears transients over time, effectively defocusing them and slowing them down. And the AVR350 has better spatial imaging without this noise, since the subtle sonic cues defining space and location are no longer obscured by noise.
       Already, as you can see, the AVR350 is proving to be strikingly superior across the board, in virtually every sonic parameter by which we judge sonic performance. And remember that this sonic superiority, across the board, is already clearly evident in the most basic mode, direct analog throughput, and is then maintained in all other modes.
       Which trick parts in this AVR350 hotrod should take credit for these many sonic improvements? Since these sonic improvements are already evident in the direct analog mode (listening through the AVR350 power amplifier section as well), we should look to the AVR350's trick parts already in play here. The analog output buffer, through which all signals flow on their way to the power amplifier section, has been upgraded with the more expensive (and clearly better sounding) OP2134 op amp (borrowed from the more expensive Arcam AVP700 processor). Furthermore, this op amp has been re-configured for 6 dB extra gain in the AVR350, which means 6 dB less loop feedback in this buffer application, and less loop feedback can produce sonic benefits such as less modulation noise and distortion, and cleaner, more open sound. Additionally, the Stealth Mat (borrowed from Arcam's high end FMJ series), which absorbs noise radiated by the many digital circuits within the AVR350, might conceivably also be helping the analog buffer stage and power amplifier section to have the quieter black background that we hear.

Digital Operating Modes

       In all surround processors, most operating modes involve digital circuitry handling the signal (the exception being straight channel throughput of analog signals, without any alteration other than volume level), The AVR350's sonic superiority, already so clearly evident in straight analog throughput, becomes even more dramatic as soon as any digital circuitry becomes involved. Here the AVR350 proves to be sonically superior, to the AVR300 and to other competing brands, in all the many aspects described above, but its margin of sonic superiority is even greater in degree.
       Most of the credit for this extra margin of sonic superiority, in all digital modes, should go to the Stealth Mat, borrowed from Arcam's high end FMJ series. Why does the Stealth Mat improve sonics so dramatically, in all digital modes? The Stealth Mat is made from chopped carbon and nickel fibers, and was originally developed to reduce the radar image of aircraft, by absorbing that electromagnetic radiation we call radar. This Stealth Mat, positioned underneath the top lid of the AVR350, absorbs and acts as a dead end sink for all the electromagnetic noise that is generated within and radiated by the copious digital circuitry within the AVR350. Without the absorbent Stealth Mat, this electromagnetic noise would bounce off the large lid area, reflect back down into the digital circuitry, and continue to echo throughout the inside of the unit. This electromagnetic noise, generated and radiated by the digital circuitry, can easily degrade the sound if it gets back into this same digital circuitry, as it does with all other surround processors that do not use this Stealth Mat.
       How and why does this radiated digital noise degrade the sound when it re-enters the digital circuitry? Any kind of noise added to a digital signal produces an ever-changing amplitude indeterminacy, when that digital signal is later converted to analog for listening. This amplitude indeterminacy causes temporal indeterminacy for the exact instant that the digital signal crosses the zero axis (or any threshold) when converted to analog, so it produces the same sonic degradations as temporal indeterminacy does. Temporal indeterminacy is a well recognized evil under its other name, jitter. Jitter, and temporal indeterminacy, and amplitude indeterminacy, all cause the same sonic degradations when a digital signal is finally converted to analog. Distortion sidebands are produced, which smear the sound, distort the sound, create modulation noise, degrade intertransient silence, veil and obscure the sound (both via this noise and via the temporal smearing), defocus transients and degrade articulation, add phony artifacts which can sound like hashy brightness or hard glare, degrade spatial imaging (thanks to the veiling and smearing of subtle imaging cue information), etc, etc. That's a huge pile of sonic degradation.
       All these sonic degradations can be caused by amplitude indeterminacy, and therefore can be caused by any electromagnetic noise impinging upon digital circuitry and thus being added to the digital signal. The Stealth Mat in the AVR350 does not stop the digital circuitry from radiating electromagnetic noise outward. But it does largely prevent that outwardly radiating noise from bouncing back and impinging upon that same digital circuitry. And, by so doing, the Stealth Mat

(Continued on page 140)