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Strata Mini loudspeakers
as reviewed by Sam Roberts
I consider myself not only an obsessed audiophile, but an obsessed technophile as well. Since my early teens, I have not only sought to have an excellent sounding system, but to know what makes it tick and how tweaks could make it sound better. I have built numerous speakers for friends and relatives and although on the surface they seemed fairly simple to construct, in reality there is a great deal of art, science, and luck involved. From driver selection and cabinet design, to crossover design and construction, speaker designers truly earn their money. Often the simple works best, but we are all looking for what more lies beyond the simple; if not then we would just buy a nice set of mid-priced two-way monitors and let upgrades be damned.
When I first saw the Strata Mini from AV123 at the Rocky Mountain Audio Fest I was quite surprised at not only the sound, but at the caliber and number of components used at such a low price point. In fact I really couldn’t make myself believe they could sound as good as they did for so little with so many components asked to work together as one, and when the opportunity arose to review a pair I jumped at the chance to validate my initial impressions away from the less than ideal show environment.
The Strata Mini is the newest speaker from online retailer AV123. Their head honcho Mark Schifter is well known for his previous work with Audio Alchemy, and their Onix and Perpetual Technologies products have been quite successful in their own right. AV123’s headquarters is located about an hour from my home in Colorado, and I was able to pick up the review pair in person and shoehorn them into my vehicle despite the large dimensions and substantial weight of their shipping materials. This is a comforting thought for someone who has gotten several pairs of speakers delivered in the past and had to deal with shipping damage, rest assured that the Stratas packaging is almost bombproof. AV123 also offers a 30-day in-home trial period, so although they have no dealer network you have the opportunity to listen to them in your room without risk and pay only the shipping fee to return them.
Once home I had a friend help me heave their 94 pound (each) heft down to my listening room and began setting them up. Again, this is a $1995 speaker we are talking about, yet they came wrapped in a cloth sack to prevent any marring of their finish, and come complete with white cotton gloves, hefty spikes, and jumper cables to use when connecting them with one set of speaker cables. The one omission that would have made for a world-beating package would be a small SPL meter as it is almost mandatory to allow them to perform at maximum potential, though they are readily available from local sources.
The Strata Mini uses a unique array of four drivers per speaker. Starting at the rear, each Strata has a custom-made 8” subwoofer in a rear-ported chamber with a dedicated 350-watt amplifier featuring high and low level inputs, phase adjustment, variable crossover frequency, and level controls. Moving to the front of the speaker you will find a 5.25” cone midbass coupler made by Atohm, an 8” planar magnetic midrange panel, and a 1” planar magnetic tweeter. The front of the cabinet is tilted back at an angle presumably to time align the drivers. The midrange and tweeter are in sealed chambers, though they are not dipole radiators like many other similar designs. One of my curiosities about this speaker was how they were able to implement a four-way design and keep the complexity of the crossover and the cost of its components low. In studying the literature, AV123 has performed a delicate balancing act by allowing the 5.25” midbass to roll off on a 2nd order slope, while bringing in much steeper 4th order crossovers on the midrange and tweeter. This arrangement serves to ensure the planar elements are left to do what they do best: bringing in the heavy hitting cone drivers to handle the bass and mid-bass chores. Cabinetry, fit, and finish are first rate, and though these are not small speakers by any means, their sleek shape allowed them to fit into my room with minimal grumbling from my spouse.
Listening and Comparison
My reference speakers are the Dali Helicon 800s, an extremely revealing speaker with excellent soundstaging that utilizes its own unique driver combination of dual 8” woofers, a 6.5” wood-pulp cone midrange, and a tweeter module based on a 1” soft-dome tweeter and ribbon super tweeter working in conjunction to cover the top octaves. The Dalis are manufactured in Denmark and are considered by many to be a good value at their $6800 price point. After I had determined agreeable positioning and dialed in the bass on the Stratas by SPL meter and by ear, I marked off their positioning with tape and began listening to both speakers over the course of several weeks by alternating each speaker pair out every day or two. The Stratas needed less break-in time than most other speakers I have had on hand and were very listenable straight from the box. That said you could make the Stratas sound sublime or quite dodgy depending on whether you take the time to properly tune the subwoofer controls, as well as optimizing their room position. I also found their vertical dispersion to require careful setup, and tilting them forward by unscrewing their rear spikes slightly, seemed to produce the best tonal balance and imaging.
At first, I was somewhat conservative with the volume level, my subconscious perhaps reminding me of how fragile those planar drivers looked, but upon further review of their stated 86dB efficiency and the lack of ANY printed power handling specification in the manual, I let fly with 500-watts per channel from my Bel Canto monos. I was astounded by the level of clean, musical output these speakers can provide. On tracks such as Everything to Everyone by Everclear, the limit will be determined by your sense of self-preservation, not the Stratas. That said they also excel at microdynamics, and switching to the self-titled album by Rodrigo y Gabriela I could pick out all the subtle intricacies in their playing - even at “shh the baby is sleeping” levels.
The sound overall was quite organic and avoided sounding bright, sterile, or mechanical in any way. If anything, the Stratas are voiced somewhat on the forgiving side, offering up just enough detail and attack to satisfy those with high-end source components. During my time with the Stratas I was fortunate enough to have in my system for review, the Empirical Audio Off-Ramp Turbo I2S converter, as well as an I2S modified Benchmark DAC-1. With this combination, listening fatigue was a non-issue in that I was able to listen to bright recordings such as David & David’s Boomtown at high levels without distress. The Stratas presented a rich and full-bodied sound with a strong center image and excellent image depth. Image width extended outside the boundaries of the speakers and placement of instruments and vocals was generally very good.
Despite my reference speakers retailing for over three times the price of the Strata Minis, the differences were subtle and often a matter of taste or musical inclinations rather than outright performance. The Dali’s have one of the most extended and detailed top ends I have heard in anything under $10,000, and this was the only obvious difference in balance between the two speakers. The Strata has a smooth and natural character in the top octaves, and though the sound is adequately detailed, it is not quite as present or forward as the Dali and misses a bit of the crystalline impact of chimes, bells, and cymbals. This is something that in my opinion very few speakers achieve at even triple the price of the Stratas and as such is not a serious demerit in my book, and they did not sound closed in or lacking air on any recordings I played, again more preference than anything.
The Stratas midrange was exceptionally layered and provided greater image depth than the Helicons and conveyed a seductive richness while avoiding any chesty coloration with vocals. Audiophile standards such as Patricia Barber’s Modern Cool were produced with vivid dynamics and an engaging pace with the planar driver showing its trademark speed. On ambient and electronic discs such as The Magnificent Tree by Hooverphonic and Melody A.M. by Royksopp, the Stratas produced an immersive and liquid soundstage that really drew me into the music and had me listening at higher than normal levels. This had the unfortunate side effect of my wife being able to scare the bejesus out of me while in a meditative state on several occasions, unable to hear her approach from behind me with a mile wide grin on her face. The soundstage was perhaps slightly narrower than what I am used to with my reference speakers, and at times there was a bit less separation of instruments and voices, but overall the presentation was quite engaging and natural.
Midbass retained the impact and presence needed to make rock and pop recordings sound convincing, and the usage of a traditional cone driver for this range seems critical in the overall success of the Strata design. The midbass never seemed bloated, and setting the subwoofer crossover point will be critical to achieve this, as every room will have different problem frequencies; however, most speakers allow far less flexibility in this regard making it far more likely that the Strata will behave in most domiciles.
Over the time I had the Stratas in my system I steadily wound the subwoofer level further and further down. This was not because the bass was muddy or lacked musicality; it was simply a case of becoming more in touch with the speakers’ other strengths and finding a level that allowed for perfect integration. For those who don’t believe in moderation, the bass output from the 8” woofers is quite powerful and will sufficiently load all but the largest rooms without strain. The subwoofers integrated quite well with my room and given sufficient distance from the rear wall, the rear-ported design will reward you with excellent impact and extension. The bass never lacked the speed to keep up with the planar drivers, nor did it call undue attention to itself outside the fabric of the music. Although the extension is not flat to 20 Hz, it would seem quite redundant to pair a subwoofer with the Stratas unless you feed them a steady diet of organ music.
I greatly enjoyed my time with the Strata Minis and I would highly recommend them to anyone shopping for speakers in the $1500-$4000 range. They offer a long list of strengths and in my experience offer the best value I have heard at anywhere near their price. I didn’t like to see them leave, but my wife brought me back to my senses when she noted that much of our basement is already filled with audio equipment, and these wonderful speakers deserve a home where they will be enjoyed daily. AV123 has a hit on their hands but they don’t seem to be resting on their laurels. At RMAF they demoed the Stratas with a prototype-switching amp that is said to offer up incredible performance at even more incredible prices. Be sure to check out this up-and-coming web retailer.