I began my critical evaluation of the A31 amplifier with some two-channel music by way of Moby's "Everloving" off the hit album Play (V2). Right away, the A31 proved exceedingly resolute in that it shone appropriate light upon every detail and nuance in a wholly convincing and natural way. The control it exhibited over my speakers' drivers was impressive, but not so much so as to call attention to itself. Instead, the amp and drivers seemed to work in harmony. I was taken aback by the level of low mid-bass articulation that was present, which I found equal to that of its high-frequency performance. The whole sonic spectrum was (largely) uncolored and sounded wholly natural to me, possessing zero grain, edge or other maladies that would've otherwise spoiled the performance.
The A31's high-frequency performance was one of openness, but also one that remained natural in its timbre. Cymbals sounded like real cymbals, versus artificial enhancements in order to show off traits such as air and decay. Not to say that these weren't present via the A31, it's just that neither drew attention to itself in a "look at me" fashion. Likewise, the bass was incredibly resolute and impactful, and though I have heard a bit more heft from my Pendragons, I preferred the A31's articulation and speed, for I have a subwoofer for brute force. Dynamics, much like the rest of the A31's performance, felt right, in that they were neither trumped up nor sluggish. As for the A31's soundstage, I found it to be fairly three-dimensional, provided the material called for it, meaning it was capable of extending beyond the front baffles of the speakers and further back as well, while the side to side extension was wall to wall and beyond. As with everything else I've just described about the A31's sound, its soundstage definition was equally detailed and neatly arranged, but in a wholly natural-sounding way.
Next I cued up another favorite, Mike Oldfield's Tubular Bells III, and the track "Far Above the Clouds"(Warner Bros. UK). This track is a little more chaotic in comparison to "Everloving," but even with its more bombastic dynamic swings and high-frequency energy, the A31 never faltered. In truth, I never felt as if I was even tapping its full potential, as the resulting sound was effortless. The explosion of bells was precisely that - an explosion - and while they may have rocked my room, they never overpowered my ears nor caused fatiguing. Instead, the bells were clearly delineated from one another and presented with such focus and control that their presence in my room was one of three-dimensionality, as they were not only arranged side to side but front to back very clearly. Again, the dynamic swings of this track were incredible and at times more than a little palpable, in that they quite literally stirred the soul. Bass and low mid-bass control was again exceptional, as was definition and presence amidst the high-frequency onslaught happening around it. Moreover, the A31 wasn't critical (at all) of my choice of speaker, as it managed to reproduce similar results with all the options I had on hand, whether they were lower-sensitivity bookshelf speakers (Wharfedale) or commercial cinema loudspeakers (JBL).
Moving on, I went with an old pop favorite, The Wallflowers' hit "One Headlight" off their album Bringing Down the Horse (Interscope Records). Front-man Jacob Dylan's vocals were presented in their full unaltered dry but sultry state. I noticed a bit more inflection in Dylan's voice than through previous amplifiers, as well as a bit more surrounding air, which lent a greater sense of dimension, not to mention scale, to the performance and to his physical being. Other features that jumped out at me were the track's many snare hits and rim shots, which were rendered with just a bit more detail and nuance throughout, compared to what had been provided by previous amplifiers employed in my system. Low-level detail was brilliantly fleshed out and, even when I dropped the volume to background levels, the experience didn't diminish, it merely scaled.
Moving on to movies, I cued up a guilty pleasure of mine, the disaster flick 2012 (Columbia), on Blu-ray disc. This time, with the A31 having to play nice with its two-channel sibling the A21, I couldn't detect any dissimilarities between the two when using one for mains and the other for center and/or rear channel duty. Dialogue was always intelligible, arguably more so as a result of the A31's power and resolution as described above. There were moments when previously garbled lines of dialogue came through just a touch clearer, resulting in my being able to clearly hear what was being said, even if that hadn't been the sound mixer's intention. Actors always came across as natural-sounding, with their scale appropriate to a) the action on screen and b) to my judicious use of my Integra's volume knob. When the world does literally begin to crumble beneath the characters' feet, the resulting sound was truly epic and, yet again, I felt as if I was able to discern more of it due to the A31's (and A21's) incredible clarity and definition throughout. As with my first tests, I have heard a bit more low-end oomph, but again, I tend to cross my speakers over at anywhere between 50 and 60Hz (80Hz for bookshelf speakers), so that uber-low bass is going to be dealt with by a sub and is only being pointed out here for evaluation purposes. Dynamics ran the gamut from wow to I think I may have messed myself, depending upon the scene and my choice of overall volume. Regardless, the A31 never wavered nor seemed to run out of juice. The entire performance was one of terrific balance and sheer effortlessness.
I ended my evaluation of the A31 with another Blu-ray disc, Iron Man 2 (Paramount). I chaptered ahead to the Monaco race scenes, set my volume to a level appropriate for a movie of this magnitude and was simply transported. The cracks of Ivan Vanko's whips were positively violent in their dynamic snaps and the resulting electrical crack was so vividly rendered that it made me shudder. More importantly, even with each crack spiking at around 100dB, the resulting sound was never fatiguing, sharp or brittle. I suppose I've heard a touch more top-end sizzle, but I'm not certain I'd say the A31 is wrong in its portrayal, as everything simply felt right in its delivery. Vocals again were intelligible and natural in their timbre, not to mention true to their respective actors, but also carried with them a wonderful sense of weight and physical presence. Explosions and crashing cars rocked my room, yet were pushed through effortlessly and with terrific focus and control - no warbled drivers here. What I actually found most impressive was how balanced the background score seemed to be in the face of all that was unfolding in front of it. I'm not suggesting that other amps simply ignore the score but, as with the rest of the performance, there just seemed to be a little more presence to it, lending a grander, more epic touch to the whole sequence. Not that it needed help.
Earlier in the review, I spoke about the A31's gain controls and how that was more a pro feature aimed at pairing different amplifiers together. Well, I used it (sparingly) when employing professional cinema equipment elsewhere in my signal chain, as it allowed me to better integrate the pro gear with the rest of my consumer-sourced equipment. While this isn't going to be of much use to 99 percent of those who buy an amp such as the A31, I found it very useful and, as a result, a huge selling point.
The A31 is a phenomenal overachiever as far as amplifiers go. However, there are a few items worth noting before making your final purchasing decision. First, the A31 is large and in charge, meaning its physical requirements may be a deal-breaker for some and/or in certain installations. Also, because it is but a three-channel amp, it will require you to have additional amplifiers present in order to power a full five- or seven-channel setup, which also requires more space. It's possible to get a Halo-branded amp with five channels. However, this may not allow for the same level of flexibility should you wish to power your stereo mains differently than the rest of your speakers. To each his own, I guess.
Along with being on the large side, the A31 does run warm and, under spirited listening, it can even get hot so proper ventilation is an absolute must, with open air installations being the best option, though by no means mandatory.
Lastly, I found the A31's binding posts to be a bit pedestrian and, well, not up to the same standard as the rest of the amplifier's build and sonic quality. While they were completely functional, they just felt cheap in comparison to everything else the Halo affords you.
Competition and Comparisons
Among its three-channel peers, I found the A31 to compete very favorably against both the Mark Levinson No 533H and the Krell Evolution 3250e. The Levinson No 533H has a slightly more sultry sound in comparison to the A31, but one that is still pleasing, though it costs decidedly more at $10,000 retail. On the other hand, the Krell Evolution 3250e has a slightly more spirited sound versus that of the A31, in that the Krell is a bit more dynamic and taut throughout. Like the Levinson, the 3250e also retails for far more than the A31, coming in at $10,000 as well. In all fairness the 3250e, even at $10,000, is a far cry from what Krell charges for another three-channel amp of theirs, the Evolution 403e, which retails for $25,000. I'm not suggesting the A31 bests the Evolution 403e, I'm just using it to help qualify (or perhaps quantify) its high-end value. All three amplifiers are unique and special in their own rights and deciding which is right for you is going to boil down to personal preference, as well as budget.
For more on these amplifiers and others like them, please visit Home Theater Review's Multi-Channel Amplifier page.
I'm not going to lie and say that $3,000 for a three-channel amp is wholly affordable, but I'd hardly put the A31 in the category of aspirational either, as that category is well populated. I hate the term mid-fi, as that carries with it a sort of negative connotation that the customer is somehow settling for middle of the road, which the A31 is clearly not. For me, the A31 from Parasound's Halo line of products is aspirational but obtainable, in that it competes very favorably with far costlier competition, yet can be had by many with just a little foresight and financial planning. The best part of a product like the A31, or any found within Parasound's lineup, is that the reliability is on par with a wood-burning stove. I've gotten word of users with ten-plus-year-old Parasound amps still performing as well as the day they were taken out of the box and, while this reliability may cost Parasound some sales down the road, it does go a long way toward justifying the A31's slightly higher price point.
In all fairness, I didn't request the A31 for review so much as I sought it out in order to utilize it in my reference system and mixing studio. It just so happened to not suck and live up to every expectation I had prior to its arrival. Is there a market for it? I think so, though undoubtedly traditional stereo and five- or seven-channel amplifiers will always be more popular than three-channel ones. That said, the Parasound Halo A31 three-channel amp is among the best I've encountered thus far in my travels and one that I'm not going to be parting with any time soon. If you're an existing Halo customer or simply want to take your two-channel rig to new multi-channel heights, you'll be hard pressed to do better than the A31 sonically, though you can definitely spend more.
Read more multi-channel amp reviews from HomeTheaterReview.com's writers.
Explore more reviews in our AV Preamp and Stereo Preamp review sections..
Find a pair of Bookshelf Speakers or Floorstanding Speakers to drive with the A31.