Jamo D 7PEX Speaker System
Having lived in Denmark for a couple of years as a kid, I guess I've learned a little about the Danish mindset. Many Danes display a self-effacing modesty, to the extent that Carlsberg will only say that theirs is "probably the best beer in the world." Yet, in their typically understated way, this little country (with a population about equal to that of Missouri) has made deeper inroads into the lives of Americans than most people think. Just don't blame them the next time you step on one of your kid's Lego blocks.
Although most Americans have probably never heard of Jamo, they are Europe's largest speaker company, producing a huge range of models. The D 7PEX is their version of an all-out THX Ultra 2 design (PEX stands for Package for Surround EX), incorporating five D 7LCR satellites for the three front channels and the rear surrounds, a pair of D 7SURs for the side surrounds, and a D 7SUB subwoofer to handle bass. I decided to go all out and try the system with two subwoofers. Knowing that a nine-speaker setup was coming, I prepared my room for an onslaught of speakers that I envisioned might make my room resemble the Grateful Dead's famous Wall of Sound. Imagine my joy when the UPS guy strolled up with a stack of seven smallish boxes on his hand truck. Naturally, I'd forgotten that, with a THX speaker system like this one, the subwoofers handle everything below 80 hertz. It generally takes big speakers to make big bass. In this case, because the dual subwoofers (which the UPS guy delivered on a second hand truck) handle the deep bass, the other speakers could be much smaller.
When Jamo designed this setup, they realized that home theater buffs are fundamentally different from traditional audiophiles: If you're going to try to stuff as many as nine speaker boxes into someone's room, they'd better not get in the way. To this end, Jamo developed speakers that will deliver the best results when you hang them on the wall like pictures. The D 7LCR is a three-way, five-driver design with two small midrange drivers flanked vertically around an unusual dual-concentric-dome tweeter. By centering the crossover at 2.5 kilohertz, Jamo satisfies the THX vertical-directivity requirement while allowing for an impressive 200-watt continuous-power-handling rating. To get the bass to extend deep enough to cover the 80-Hz THX cutoff, this midrange/tweeter array is flanked laterally by a pair of 5.5-inch metal cone woofers, which also adds to the mix the impressive dynamic abilities that metal cones are best known for. All of this is housed in a package that's less than 7 inches deep, and it even comes complete with hangers so that you can attach it directly to the wall. On the back, there are two pairs of binding posts. At first, I thought that the designers must have been in an audiophile mood, giving us the ability to biwire the speaker. It turns out that, by connecting the second pair of binding posts using a set of jumpers, you can boost the lower frequencies to achieve a flatter response, should you decide to use the speakers on stands rather than on the wall.
Another requirement of the THX Ultra 2 specification is that the surround speakers should generate a diffuse soundfield so that the sound wraps around to the back of the seating area without drawing the listener's attention specifically to the speaker's location. To achieve this, each D 7SUR uses no less than seven drivers, with two midranges and a tweeter firing to each side, along with a woofer firing straight into the room. On each side, the two midranges are set close together, with a tweeter placed just above them. This arrangement widens the vertical dispersion and provides a smoother response from the listening position when you place the speakers at the recommended height of about 6 feet. To ensure accurate timbre matching among the channels, the D 7SUR uses the same drivers that are in the D 7LCR.
To extend the sound around to the back of the room, the full-blown D 7PEX setup employs another pair of D 7LCRs mounted high up on the back wall. Even though there still aren't a lot of DVDs with an encoded rear surround signal, if your room layout allows for it, there's no denying the extra dimensionality that rear surround channels can add when used correctly.
As Jamo designed all of these speakers to be used with a pre/pro that sends any bass below 80 Hz to the subwoofer outputs along with the LFE channel, it was clear that I was going to need some serious low-frequency air-moving ability. Luckily, the D 7SUB proved well up to the task. To push the envelope just a little further, I went ahead and used two of them. Now, this might seem like overkill, but there are benefits beyond ultimate output ability when you spread the bass-handling duties around a little. Due to the standing waves that room boundaries create, subwoofers often produce a fairly lumpy response. If you spread the bass to more than one subwoofer, you can often even out the response to get better overall results.