Good Sound From a Small Speaker

December 29, 2011

Review: PSB Speakers Imagine mini Speaker System

By Brent Butterworth (Sound and Vision)

Imagine mini Beauty Group Shot

It’s been a dream of audio engineers and enthusiasts for decades: Create a compact speaker system that performs like a big one. Paul Barton didn’t seem to me like the guy to do it — at least not until recently. The founder and chief engineer of PSB Speakers has had success with a few small models, but I associate him more with large, clunky tower speakers. However, Barton recently shifted his focus to lifestyle-oriented products. He has incorporated graceful, modern styling into his speaker lines, and also lent his efforts to headphones and iPod/iPhone docks.

Recommended speaker 2012 AwardThe Imagine Mini is Barton’s latest attempt to bring his uncompromising ideas about sound quality to a broader market. The $749-per-pair Mini is just 9.25 inches high, more the size of a home-theater-in-a-box speaker than something you’d expect from an esteemed brand like PSB. Yet the Mini employs the same technologies found in the larger, more expensive Imagine tower speakers. Same titanium-dome tweeter. Same clay-and-ceramic-filled polypropylene woofer cone material. Same ultra-rigid curved cabinet. Same sleek, no visible-fasteners design. The sole downgrade from the pricier Imagine models is that the Mini’s woofer has a dust cap shaped like a phase plug, rather than the real metal phase plug found on other speakers. (A phase plug fills the space in the center of the cone to eliminate resonance, and the metal provides thermal mass to help cool the driver’s motor structure).

It seems the Imagine Mini might sound much like the other Imagine speakers, at least in the midrange and treble. What about the bass, though? Can a little woofer in a tiny enclosure pump out enough low end to satisfy without a subwoofer? That’s the big question. PSB Speakers played it safe by sending along the SubSonic 1, an 8-inch subwoofer that at just $399 seems to be a different class of product. It’s a straightforward, front-ported design with no frills and none of the Imagine Mini’s visual charm. Along with two pair of Minis and the SubSonic 1, I borrowed an Imagine C center so that I could do a full 5.1 system. The Imagine C is the same center designed for use with the larger and more expensive Imagine models, and as I suggested above, its woofers are a little more upscale.

If you want true high-end sound quality in a truly tiny speaker, the PSB Imagine Mini is clearly one of the best options going.

Setup

For the left and right front channels, I placed two Minis on 28-inch-high stands about 16 inches from the wall behind them. For the surrounds, I placed two more of them on stands along the side walls, about 3 feet behind my listening chair. I liked the rubbery bottom on the Minis; it kept them from sliding around on the tops of the stands. But I didn’t like the concealed speaker-cable binding posts. The posts are under the speaker, and you feed the two legs of the cable through a couple of little holes and then into the binding posts. It looks nice, but who looks behind your speakers? And few males have hands small enough to get an easy grip on the concealed posts.

The Imagine C center has a curved bottom, and PSB supplies an angled rubber foot to keep it from rocking. This does allow you to point the speaker up if it’s on a low stand. But the wedge was too big to allow the Imagine C to sit flat on my center speaker stands, so I ended up propping it up with big blobs of Blu-Tak adhesive. No such problems with the SubSonic 1. I just put it in my room’s “subwoofer sweet spot,” the place where a single sub sounds best from my listening chair, and plugged it in. What was more challenging was getting a good blend between the subwoofer and the other speakers. Unfortunately, PSB doesn’t list a recommended crossover point in the Imagine Mini manual, so you’re left to your best guess. I started at 100 Hz, a setting that I figured wouldn’t stress the speaker’s little woofers. This made voices sound a little too thin, though, so I settled on 80 Hz.

The PSB Imagine C comes with a port plug that can be inserted to change the bass response. I originally thought the Imagine C sounded a little better with the plug in, but this system ended up benefiting from the extra upper-bass energy produced by leaving the plug out.

Performance

From the first moments after loading up the RioBlu-ray, I loved this little system. Rio, the animated tale of a pet exotic bird returning to his homeland, is packed with rich arrangements of Brazilian music, a wide variety of voice talents, and occasional flashes of near-bombast. One of the best set pieces involves two chained-together birds trying to fly off a cliff. It’s a great scene (especially in 3D), set to the bossa nova classic “Mas Que Nada” in 5.1 surround and punctuated by occasional collisions with hang gliders and beach umbrellas.

The enveloping sound and natural tonal balance of the Imagine Minis made this scene completely captivating. Having tested thousands of speakers, I tend to fixate on their flaws the way you’d be drawn to the first tiny scratch on a new car, but with this system I was able to relax and forget I was reviewing speakers. The dance scene a few minutes later, in which the main characters confront partying birds banging on improvised drums, had all the power and impact I’d hoped for. The tonal balance of the system, and of the Minis in particular, was ever so slightly on the soft side, with just a small reduction in treble yielding a subtly mellow sound that I thoroughly enjoyed.

The enveloping sound and natural tonal balance of the Imagine Minis made this scene completely captivating.

All of Rio’s many and varied voice talents — including Jesse Eisenberg, Anne Hathaway, George Lopez, Tracy Morgan, and Jemaine Clement — sounded close to perfect through the Imagine C. I noted what seemed like a very slight emphasis somewhere in the midrange, which made the voices a little easier to understand without making them sound unnatural or bright. I played many DVDs and Blu-rays in the following days, and couldn’t find a single actor or actress whose voice the Imagine C didn’t get right.

The SubSonic 1 proved a perfect match — sonically, not visually — with the Imagine Minis. It has loads of punch in the upper-bass octave, so most of the impacts and explosions in action movies have the power and drama I crave. There’s nothing going on in the deep-bass region, though, so don’t expect any floor-shaking with this little sub.

How does the Imagine Mini fare when used without a subwoofer? Not well, in my opinion. When I played my vinyl copy of The Bears (1987), from the power-pop band co-led by King Crimson frontman Adrian Belew, the opening track, “None of the Above,” displayed a huge, wraparound ambience and the vocals sounded absolutely natural — yet what little bass there was felt a bit bloated and slightly distorted. Even Gary Burton & Keith Jarrett (1970), a jazz record so light it makes Diana Krall sound like the Mahavishnu Orchestra, felt groove-less when played full-range through the Imagine Mini. But add a subwoofer and everything falls right into place. Maybe you could use the Mini without a subwoofer for a desktop system, but anything more demands a sub.

Bottom Line

If you want true high-end sound quality in a truly tiny speaker, the PSB Imagine Mini I clearly one of the best options going. Match it up with a good subwoofer like the SubSonic 1 (and add more Minis and an Imagine C if you want surround sound) and you’ll have a system that sounds like something much bigger and much more expensive.

Recommended speaker 2012 Award

  • Features: 8
  • Performance: 9
  • Value: 7
  • Overall: 8

Test Results

I measured the Imagine Mini and Imagine C center speaker without grilles at a distance of 2 meters. Both sat atop a 2-meter-high stand to give quasi-anechoic results down to 250 Hz. The curves in the graph show an averaged response from 0° to 30°, smoothed to 1/12th of an octave. I close-miked the woofers and ports of both speakers, and then scaled and summed the results to get each speaker’s bass response. I then spliced the bass responses to the averaged quasi-anechoic responses to produce the curves you see here. To measure the SubSonic 1 subwoofer’s frequency response, I used a ground-plane measurement at 2 meters. The Imagine Mini and Imagine C responses are normalized to 0 dB at 1 kHz, and the subwoofer is normalized so that its peak response shows as +3 dB. The Imagine Mini exhibits the classic measured response for a great minispeaker: a slight hump in the bass to give it a little extra oomph, a flat midrange, and a slight downward tilt to the tonal balance to keep it from sounding thin. There’s what seems to be a slight tweeter resonance at 17.5 kHz, but the peak it creates is so narrow and so high in frequency that I’m positive I can’t hear it and I doubt you can, either. Off-axis response is outstanding. Other than the usual treble rolloff, there are no off-axis anomalies until you get out to 60° off-axis, where a 7-dB dip appears at 1.2 kHz. When measured on-axis, the sole significant effect of the grille is a 5.6-dB dip at 11 kHz.

Imagine Mini Home theatre Fequency Chart

Pretty much ditto for the Imagine C, except the tonal balance is flatter and there’s a bigger bump in the bass; except for that bump, the C would measure flatter than the Mini, which is quite a feat for a two-way center speaker. (This measurement is with the port plug removed.) Off-axis response is very clean out to 30°, but past that, at 45° and 60° off-axis, you see major interference between the two woofers, resulting in 28- to 30-dB dips in the 1-kHz region. These are big and probably audible dips. I wonder if they’re the cause of my perception of a slight midrange emphasis, i.e., the dip made the region from 1 to 2 kHz seem subjectively emphasized. The grille produces a 3.9-dB dip at 11 kHz, but no other significant measurable effects. Practically any amp or receiver can drive these speakers to reasonably loud levels. Average sensitivity from 300 Hz to 10 kHz at 1 watt (2.83 volts), measured quasi-anechoically at 1 meter, is a little low for the Imagine Mini at 84.6 dB, but about average for the Imagine C at 86.7 dB. Impedance runs 8 ohms nominal for both speakers. While the Imagine Mini drops to a somewhat low 3.1 ohms at 400 Hz, the impedance phase is just +4°, so it shouldn’t present a problem. Minimum impedance for the Imagine C is 4.8 ohms at 200 Hz, with phase of –3°. Maximum phase shift for the Mini is –71° at 132 Hz/9.3 ohms; for the C, it’s –69° at 94 Hz/17 ohms. I measured the output of the SubSeries 1 using CEA-2010 methodology. Measurements were made on the ground at 2 meters; 6 dB was added to the results to approximate measurements at 1 meter. The SubSeries 1 has amazing output in the low bass (40-63 Hz) region, comparable to that of many much larger subs, but the output in the ultra-low bass (20-31.5 Hz) is weak, with decent output at 31.5 Hz but practically nothing below that. (To get the 20-Hz figure to calculate the ultra-low bass average, I subtracted 18 dB from the 25-Hz figure per CEA-2010 practice.) Combined low-pass function of the crossover, driver, and enclosure is about –16 dB/octave.

 

For the full online Imagine mini review and more from Sound and Vision, click here.

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