Test Report: Wharfedale DX-1 Speaker System

It seemed that audio companies had surrendered the home-theater-in-a-box concept to the TV manufacturers. But the introduction last year of three world-beating mini speaker systems — the Cambridge Audio Minx, the Polk Audio Blackstone TL3, and Sound+Vision’s 2011 Product of the Year, the Paradigm MilleniaOne — showed a renewed interest in this seemingly abandoned category.

The latest well-regarded audio company to get (back) into the HTiB business is Wharfedale, which announced its $799 DX-1 system at last September’s CEDIA Expo. The DX-1 is a classic HTiB: four 7.5-inchhigh two-way satellites, a matching horizontal center speaker, and an 8-inch subwoofer. True to form, the whole system ships in a single box.

Wharfedale didn’t go out of its way to make the DX-1 look stylish — but it did build the speaker enclosures from relatively non-resonant MDF rather than the usual flimsy plastic, and used curved sides to stiffen the cabinets. The system’s available in gloss black or gloss white, and it’s designed to look good with the grilles on or off.

The core of the system, the DX-1 Satellite, is a two-way minispeaker with a 3-inch midrange/woofer and a 0.75-inch tweeter. What most distinguishes it from a mass-market HTiB speaker is inside. Where mass-market HTiB speakers tend to use just a single capacitor (and maybe a resistor) in the crossover, the DX-1 Satellite uses three capacitors, two chokes, and two resistors.

Why should you care? Because a more complex crossover tailors the signal better for each driver. A single-capacitor crossover gives you a first-order (6 dB/octave) filter on the tweeter, while the woofer runs full-range. The DX-1’s crossover provides a third-order (18 dB/octave) filter on the tweeter and a second-order (12 dB/octave) filter on the woofer. The result is less low-frequency signal into the tweeter (thus lower distortion) and less high-frequency signal into the woofer (thus better dispersion).

Similar story for the DX-1 Centre, which sits horizontally and adds a second midrange/woofer. Besides the extra driver, the big difference is that the Centre’s cabinet is ported while the Satellite’s is sealed.

To fill out the low end, Wharfedale includes the DX-1 Subwoofer, a minisub with an 8-inch woofer powered by a 70-watt rms amp. Its back panel includes volume and crossover frequency controls, a phase switch, power and auto-on switches, and stereo RCA line inputs, as well as dual ports for the woofer.

Looking over the DX-1 system’s specs, like any audio aficionado would, I thought, “Probably decent sound but low output.” Let’s give a listen and see if that guess is correct.

Setup

The Satellite and Centre both have plastic keyhole mounts on the back so you can hang them on the wall. I figured most people would put them on stands, though, so that’s what I did: two Satellites and the Centre in front, and two more Satellites to the sides of my room just behind my listening chair. The curved bottom of the Centre made stand-mounting difficult, and my search of the box revealed no rubber wedge or similar device to prop it up, so I wadded up some Blu-Tak poster adhesive and shoved it under the back of the speaker. Toeing in all the speakers to point straight at me gave the best sound. The grilles sounded fi ne with movies but dulled the treble a bit with music, so I tossed them back in the box.

I connected all the speakers to my AudioControl Savoy amp, which was fed signals from a Denon A/V receiver. I then connected the Denon’s subwoofer output straight to the subwoofer’s line input.

Sadly, like almost every other manufacturer, Wharfedale fails to specify a subwoofer crossover point in the manual. A little experimentation showed 120 Hz to be a reasonable compromise.

The bright blue LED on the front of the sub proved annoying when I turned down the lights to watch movies, but a piece of electrical tape fixed that.

Performance

When I’m faced with a small speaker system, my first instinct is to find its limits. So I loaded the Captain America: The First Avenger Blu-ray and skipped to the scene near the end where Cap fights his nemesis, the Red Skull. In my roughly 3,000-cubic-foot listening room, the DX-1 system sounded pretty good at 98 dB peak level, measured from my listening chair. At 100 dB, though, I got too much distortion. So the DX-1 is adequate for a bedroom or small den, but not for full-bore listening in a large room. No surprise there. What did surprise me, though, was the fidelity of the sound. I’ll get my complaint out of the way right now: Male voices lacked that last bit of body when heard through the DX-1 Centre. Except for that small fl aw, though, the system rendered voices impeccably. All of the voices in Captain America, from the German-accented growling of the Red Skull (Hugo Weaving) to the soft tones of Cap’s love interest, Peggy Carter (Hayley Atwell), sounded incredibly natural.

The DX-1 system even handled one of the toughest voice tests on DVD — singer Arnold McCuller’s solo at the end of “Shower the People” from James Taylor’s Live at the Beacon Theatre — as perfectly as I can remember hearing it from an affordable speaker, with none of the distortion or strain that McCuller’s voice often causes in inexpensive systems. The excellent timbre matching between the Satellite and Centre produced a huge sound field with 5.1 material, making movies and music videos especially immersive.

The system’s performance with music was even more impressive. The second movement of the Concerto for Violin, Cello, and Orchestra from David Chesky’s String Theory (available on CD or high-rez download at hdtracks.com) blew me away. The violin and cello imaged impeccably among the speakers, while the orchestra stretched out all the way across the front of my listening room. This is the kind of performance I associate with good $3,000-per-pair bookshelf speakers, not with an HTiB system. Still, the DX-1 system’s limited power handling prevents it from delivering orchestral works and big-sounding pop/rock recordings with the sense of majesty you’d hear from larger and more expensive speakers.

Although the subwoofer sounded tuneful and satisfying, its deep bass output was limited. For example, the bass notes that kick off Holly Cole’s rendition of Tom Waits’s “Train Song” elicited chuffing noises from the sub’s ports, and the driver bottomed out a couple of times when trying to reproduce the powerful synth-bass lines in electro-pop band Olive’s “Falling.” You can’t expect much from an 8-inch driver and a 70-watt amp, but this sub needs a limiter.

Wondering how the DX-1 compares with the HTiB systems listed earlier? I didn’t have them on hand for direct comparison, but I can make a few comments based on what I said in those reviews. I’d say the DX-1 sounds better and plays louder than the Cambridge Audio Minx; sounds slightly better than, but doesn’t play as loud as, the Polk Blackstone TL3; and sounds almost as good as, but doesn’t play as loud as, the Paradigm MilleniaOne.

Bottom Line

In the DX-1, Wharfedale seems to have put fidelity first and foremost, without making any of the compromises that could have gotten greater output from the system. If you’re looking for an inexpensive yet extraordinary system for a bedroom or small den, I can’t think of another I’d recommend more highly. Just don’t push it beyond its limits.

Test Bench

Frequency response
• satellite 100 Hz to 20 kHz ±2.8 dB
• center 100 Hz to 20 kHz ±5.1 dB
• subwoofer 37 to 122 Hz ±3 dB

Sensitivity (SPL at 1 meter with 2.83-volt signal)
• satellite 80.7 dB
• center 82.6 dB

Impedance (minimum/nominal)
• satellite 3.7/7 ohms
• center 82.6 dB

Bass limits
• satellite 80 Hz at 81 dB
• center 80 Hz at 84 dB

Bass output, subwoofer (CEA-2010 standard)
• Ultra-low bass (20-31.5 Hz) average: NA

20 Hz, NA
25 Hz, NA
31.5 Hz, 88.9 dB

• Low bass (40-63 Hz) average: 108.3 dB
40 Hz, 103.7 dB
50 Hz, 110.1 dB
63 Hz, 109.8 dB

I measured the Wharfedale DX-1 satellite and center speakers atop a 2-meter-high stand with the measurement microphone at a distance of 1 meter from the fronts of the speakers. The curves you see here represent an averaged quasi-anechoic frequency response from 0° to 30°, smoothed to 1/12th of an octave. To get the low-frequency measurement for the satellite, I close-miked the woofer. For the center, I close-miked the woofers and port and summed their responses. I then spliced the bass responses to the averaged responses at 240 Hz. I measured the response of the subwoofer by close-miking the woofer and ports, then summing their results. Frequency response curves for the satellite and center are normalized to 0 dB at 1 kHz, and the curve for the subwoofer is normalized to peak at +3 dB.

The satellite speaker measures great. In my opinion, anything that measures with less than ±3-dB variance on our averaged response curves is a well-engineered speaker, and the satellite measures ±2.8 dB. The only major response error is a 3-dB dip at 2 kHz. Off-axis response is also great. At 45° and 60° there are no major response anomalies, just a very gentle treble rolloff. Adding the grille caused only subtle response changes, except for a reduction in treble averaging 2.5 dB between 9.5 and 15.8 kHz. Bass output isn’t great, but it’s adequate to blend with the sub; turns out 120 Hz was a good choice of crossover point.

The center’s on-axis response is almost as good as the satellite’s (±3.2 dB), but its averaged curve doesn’t look as good because interference between the woofers causes a broad dip between 1.8 and 8 kHz. This dip shouldn’t cause overt colorations in the midrange, but it could make the treble and lower mids sound a bit emphasized (unless you have absorptive material on the side walls of your room). Off-axis response is typical for a woofer-tweeter-woofer center speaker — at 45° and 60°, a dip of 10 to 20 dB appears between 1 and 4 kHz, and at 60° the response dips by 13 dB at 10 kHz. The center’s grille caused a treble reduction averaging 2.5 dB between 11.3 and 17.8 kHz, but no other significant changes in response. Impedance (see chart) of the satellite and center drops a little low for inexpensive speakers (which will presumably be connected to an inexpensive receiver), but it should be manageable. For the satellite, it drops to 3.7 ohms at 285 Hz with a phase angle of +7°. For the center, it’s 3.7 ohms at 265 Hz and +4°. Sensitivity is low, though. Average of on-axis quasi-anechoic output from 300 Hz to 10 kHz runs 80.7 dB for the satellite and 82.6 dB for the center. It’s unlikely you’ll be playing this system real loud, so I imagine most inexpensive receivers can drive these speakers with no problem. I probably wouldn’t recommend using the DX-1 system with one of those all-in-one DVD player/receiver components that come with many mass-market HTiB systems, though.

The subwoofer’s frequency response goes up to 122 Hz, just enough to mate properly with the satellite and center. Combined low-pass function of the subwoofer’s crossover and driver is -19 dB/octave. I measured the DX-1 subwoofer’s output using the CEA-2010 technique, outdoors at 2 meters, and added 6 dB to each result to simulate measurements at 1 meter. For such a tiny sub, output is pretty good in the low bass (40-63 Hz) octave, but it drops quite a bit at 31.5 Hz and there’s no measureable response at 25 or 20 Hz. (The average low bass response is calculated in pascals, as per the updated CEA-2010A standard. Calculated by the original CEA-2010 standard, it would be 107.9 dB instead of 108.3 dB — an insignificant difference.) Note that none of the results was dictated by a limiter, so either the limiter threshold is set very high or a limiter isn’t present.