The PSB Image B4 is a new addition to the recently re-engineered Image line. The B4 is the smallest model in the lineup, and as such seems to be an ideal candidate for small rooms or nearfield listening. The B4’s are priced at $299/pair, which makes them a reasonable step up from entry-level self-powered desktop speakers. We recently received a test pair of B4s from PSB, and this First Listen covers our preliminary thoughts. As always, we’ll be back later with a more complete set of observations.
Like all PSB speakers, the new Image designs benefit from the acoustical test facilities of Canada’s National Research Council (ever wonder why so many good and reasonably priced speakers come from Canada?). PSB founder Paul Barton uses NRC to conduct fundamental studies of loudspeakers and room acoustics in its anechoic chamber as well as doing observational evaluations in its listening-studio facilities. Barton’s research at the NRC included an extensive three-year development project for PSB’s flagship Synchrony speaker line, whose technology he is now “trickling down” in the design of the Image Series.
The core of this work has been on driver design. All the Image models share long-excursion, very high-output woofers resulting in compact designs with output capabilities claimed to be as high as much larger systems. A highly accurate, one-inch titanium dome tweeter with ferrofluid cooling/damping and a very efficient neodymium magnet structure, borrowed from the Synchrony series, is said to extend output at the frequency extremes.
The Image B4s are certainly small, measuring just 5.25 x 9.2 x 6.7 inches deep. This size makes them quite suitable for desktop use. In addition, they have mounted points for bracket which would ease a wall mounting arrangement. I placed them on my standard Auralex foam supports, which angle the drivers toward the listener’s ears and get the speakers well off the desk surface. I also tried them in a medium sized listening room (and will try a smaller room for the full review to come). I used the NAD 3020BEE and Wadia 151 PowerDAC Mini amplifiers. My primary source component was the Esoteric DV-60 universal player (though as used with the Wadia, the Esoteric functioned only as a transport).
There’s a lot to like about the Image B4s, at least as nearfield devices. You have to be careful with really small speakers not to say “they’re great” when you really mean “I was surprised how good they were for their size.” In this case I’m tending to think the former, with the natural caveat of bandwidth (a 4” woofer simply isn’t going to deliver 30hz in useful amounts; PSB says the B4s are flat to about 70hz).
The frequency balance of the B4s is well chosen. By that I mean first that they sound quite flat overall, and then that there aren’t obvious dips or peaks within their frequency range. In addition, I found the B4s to have a very pleasant warmth in the upper bass and lower midrange. Too many small speakers are a bit weak here and as a result they sound small. Not the B4s. As a result with the B4s you hear excellent detail in string bass or cello, as well as more natural balance in vocals. This sound is not precisely neutral, but as we’ve said so many times, truly neutral balance seems to suck the life out of a lot of music. I also thought the smoothness and level of the treble was close to accurate, but (fortunately) not on the bright side of neutral.
Despite the general sense of slight warmth, you should know that the bass of the B4s is not weighty or extended. If you want punch or slam in the bass, you’ll have to add a sub or use another speaker. In the desktop scenario, that’s probably the case with almost any speaker that is usable, and so I think PSB did the right thing by getting the 100hz-20khz range so right. But that’s me; bass mavens will want to consider other speakers (or one of PSB’s add-on subs).
While thinking about other speakers, everyone should consider an issue that desktop speakers present, and which the B4s address masterfully. When used in a far field (e.g., with the listener is 8-12 feet from the speakers) the sound you hear is a mix of direct and reflected sound. That’s because speakers, especially those with multiple drivers of varying sizes (e.g., essentially all dynamic driver speakers), radiate sound through a wide range of angles. Typically there is ample power beyond an arc of 90 degrees, with strong output up to 360 degrees at some frequencies. This is often referred to as “wide dispersion”. What most speaker companies don’t discuss is that in the vital midrange the designer has to transition from a relatively big driver (e.g., the woofer, in a typical two-way) to a relatively small driver (e.g., the tweeter). A tradeoff that must be managed in this situation is created by the fact that the larger driver will have narrower dispersion than the smaller driver (this is due to physics; every designer has to deal with it when using cone drivers). So the designer has to balance power response and on-axis frequency response. If the speaker is made flat on axis, the power response (total response at all angles) below the crossover point is likely be lower than the power response above the crossover. So a compromise has to be made.