Sometimes it's almost a race to review the next cheap, probably terrible but possible hidden gem of a speaker. I had never heard of Pure Acoustics before starting this hobby, but over the last year or so I noticed them on Parts Express (http://www.parts-express.com/pure-acoustics-supernova-s-surround-speaker-pair-black--303-504) and Amazon (http://www.amazon.com/Pure-Acoustics-Supernova-5-25-Inch-Speaker/dp/B0041SWYQA) sporting pretty reasonable prices and generally positive user reviews. The Parts Express reviews where especially interesting to me since it's a retailer all about DIY speaker building.
In trying to do some research on the brand I couldn't find much. Some people likened them to an "American Fluance" (http://www.hometheaterforum.com/topic/328760-pure-acoustics-supernova/). Other's thought they would be terrible. I've even read posts stating the Roy Allison, founder of Acoustic Research, had a hand in the design of the Supernova line. (http://www.audiokarma.org/forums/archive/index.php/t-595723.html)
So when I decided to pull the trigger on a pair, I was crossing my fingers that I found another reasonably priced gem. Unfortunately, I don't think I’ve found that. Let's go into more detail below.
Full Disassembly Album
Complete Measurement Graphs and Comparison Album
The speakers themselves are good looking enough. Not much to see, a black, wood grained printed vinyl box. There is some slight curvature to the side walls, but it is cosmetic only, the internal dimensions are rectangular with flat sides. Taking the rather massive MDF grills off reveals something a little nicer looking. A gloss black front, contrasted by a good sized tweeter with large wave guide. Woofers are an orange-ish copper in color. While its more dressed up than a Pioneer BS22, I thought it looks like a cheap speaker trying too hard to look like something it's not.
To the rear is a pretty standard 5 way biding posts, rear port and wall hanging mount.
I found the screw tops to the binding posts need to be unscrewed nearly all the way to reveal the holes if you are using bare wire. That's a bit annoying. Since they are rear ported, wall hanging mount probably isn't the best idea of getting the best SQ possible is your goal.
There seems to be some confusion of what the actual ohm rating on these speakers are. There is conflicting information if they are 8ohm or 4ohm. I went to buy DMM from Harbor Freight, and like most Harbor Freight stuff it didn't work. But from my measurements and direct comparisons with the Pioneer BS22 and Infinity Primus p153, the Supernova S didn't measure as though it was drawing more power from the amp. So I'm going to guess, that these are 8ohm nominal.
There are many similarities in general frequency response below 1khz. I imagine due to floor reflections. However you can see that the Pure Acoustics has both the lowest volume output in the in the lower octaves AND the nearly reaches the output of the Infinity Primus p153 in the upper octaves. It makes for a very lopsided response graph.
In my time listening to them, I immediately noticed midrange output that was giving every voice a tunnel like quality to it. There is also some major elevated tweeter output (+10db from ~7khz to ~15khz at close mic measurements, ~+6db at 1m measurements) causing some pretty extreme sibilance with just about any hard S sound. This has been the first time it was some obvious to me. Snares/high hats are all just in your face and distracting. I don't think the midrange in playing full range, but it had obvious audible output till about 9khz. Maybe as an attempt to help combat the huge peak in tweeter output. Regardless, it’s doesn’t seem to be helping. And if it actually is, then there are some other design choices that should have been rectified before extending the output that far was the chosen solution.
The combination of the way too loud tweeter and the extreme lack of bass make for a combo that is pretty hard to listen to.
In some of the less measurable areas, I found the sound stage to be pretty narrow smeary mess. The audio is very contained to the edges of the speaker cabinet. There isn't anything going on that helps envelope you in sound or make the audio feel bigger than the speaker locations.
In a possible random coincidence, /u/strategicdeceiver posted his review of the Fluance sx6. I immediately noticed some strong similarities between his measurements of the Fluance and my measurements of the Pure Acoustics. While I have not heard the Fluance, if the similarities in these measurements carried over into other the rest of the audio experience, then the Fluance would also be severely lacking speakers.
I don't think that it will take Force powers to tell you to "Move along, move along". I can understand the positive praise from Amazon, as most reviewers are not very technical or have experience with many other speakers. Even known crap tends to have high marks there. But I am very surprised that the Parts-Express reviews would also be so high.
If you are looking to speakers in the $120 range there is no reason to put these on your short list. Skip right past these and look to the Pioneer BS22 or the Infinity Primus p153 depending on your audio preferences.