December 2008

The Nearfield
PSB Monitors And Headroom Audiophile Package
Article By Steven Stone
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  This installment of "The Nearfield" features two products from two different manufacturers that could be used together to form a complete desktop system. No, you don't have to use them together, but if you do, I think you'll be happy with the results.

PSB Imagine B Speakers
PSB's new Imagine B speakers sit near the upper third of their product line. Three steps below PSB's top of the line Platinum and five steps up from the Alpha series, the Imagine B proves being in the middle isn't a bad thing. The Imagine B (for bookshelf) combines a curvaceous cabinet design with newly developed drivers to form a high-performance small bookshop speaker with an affordable price of $1000 a pair.

The first thing you'll notice about the Imagine speaker is the cabinet. Made in China where well-finished cabinets have become the norm rather than an exception, the Imagine Bs take advantage of the latest state-of-the-art computer-controlled machining and design. Beneath the curved top, sides, back, base, and front baffle, the Imagine B employs a seven-layer laminated construction technique for maximum rigidity and minimum diffraction. The manufacturing process involves assembling the whole cabinet before any holes for the drivers are drilled. Available in either black ash or dark cherry veneer, I recommend going for the cherry because it looks simply fabulous. Unlike many moderately priced speakers the Imagine B actually looks better without its grill on.

Paul Barton, PSB's chief designer, created a unique midrange/woofer for the Imagine B. It uses a proprietary ceramic-filled polypropylene cone material, an aerodynamically molded basket, and a special distortion-reducing magnet design. The Imagine B's titanium dome tweeter employs Ferro-fluid cooling and sports a special protective dispersion cap and rubberized surround to further reduce diffraction effects. On the back of the speaker you'll find a quartet of heavy-duty gold-plated terminals so you can bi-wire or bi-amp the speakers. PSB also supplies a special bridging hardware for those who prefer to use only a single pair of speaker cables.

The PSB Imagine B uses a bass-reflex design with a fairly large 2.50-inch diameter rear port. The crossover between the tweeter and midrange /woofer is at 1800 Hz. Barton chose this point because it delivered the most similar dispersion between the two drivers. Published specifications indicate the Imagine B's bass response is flat to 52 Hz and its treble extends up to 23 kHz. That's pretty impressive for a speaker whose outer dimensions are only 7.5 by 13 by 12 (inches) with an internal volume of just .27 cu ft.

Sounds Like?
On my desktop I immediately noticed the Imagine B speakers had more midbass energy than most comparably sized speakers. That king-sized rear port is probably responsible for this midbass bump. I inserted a soft foam port plug to reduce the midbass and I liked the results. In a subsequent conversation with Paul Barton he told me that PSB supplies similar port plugs for the Imagine C center channel. Although the Imagine B speaker doesn't come with port plugs, they can be used with this design as well.

If you prefer to use speakers sans subwoofer the Imagine B's will fill the bill nicely. But if you already have a subwoofer for your desktop system the Imagine B will blend better with a port plug installed. If you use the Imagine sans port plug I suggest you set the subwoofer's high-pass at least 10 Hz below the Imagine's published roll-off specification of 52 Hz for optimum low frequency integration.

The Imagine B speakers have an even linear harmonic balance once you get into the midrange and treble. I especially enjoyed their upper midrange which has just the right blend of immediacy and finesse. The well-designed crossover delivers a smooth transition between midrange/woofer and tweeter, which preserves sonic cohesion in the critical the lower treble region. The titanium dome tweeters sound sweet and extended, exhibiting none of the peakiness of earlier generations of titanium tweeters.

As you might expect from a small bookshelf speaker, the Imagine B images well. Lateral focus ranks up with the best, such as the Paradigm S1 and ATC SCM7. Depth is also quite good, so that even with pop recordings you get some sense of layering and dimensionality. All the effort PSB put into cabinet design to reduce diffraction effects actually makes a difference. While the Imagines don't vanish as completely as the diminutive Role Kayaks or Gallo i-Diva speakers, they do seem to disappear better than comparably sized speakers such as the Paradigm Mini Monitor.

Micro dynamics through the Imagine B are extremely good, but the Imagine Bs lack that last smidgen of macro contrast I hear from the Paradigm S1 and ATC SCM7 speakers. An Imagine B reminds me more of the Harbeth PS3-2SE because it's very good at delineating small dynamic changes, but tends to slightly compress the crescendos.

I would rate the Imagine as a medium-high resolution speaker. The Paradigm Si and ATC SCM7 speakers dredge up a soupçon more low-level detail, but unless you regularly listen to high-resolution sources I doubt you'll hear this subtle difference. I notice it more on minimalist mic'ed classical recordings as a function of depth recreation rather than of individual details. The Imagine B certainly delivers far more information than the Paradigm Mini Monitors or Aperion 4B speakers.

The Imagine B's overall musicality also reminds me of the Harbeth PS3-2SE. The Imagine is a low-fatigue monitor that sounds as welcome at the end of the day as it does first thing in the morning. For desktop users who turn on their systems when they first sit down to work this attribute should not be underestimated. If you are the kind of person who listens to music 24/7 the Imagine makes a fine constant companion.

Hitting The Sweet Spot for a G-Spot
The PSB Imagine B speakers have a lot going for them. They look great, sound fine and are attractively priced. My only reservation about them for desktop use is that their midbass may be a bit over-ripe without a foam port plug. But the upside is that some prospective owners will instantly find their desktop's low end satisfying without adding a subwoofer. If I had a budget of $1000 to spend on desktop speakers I would certainly put the Imagine B speakers on my must-audition list.

Headroom's Bi-Amped Audiophile Desktop Package
Headroom has a well-deserved reputation for delivering high-value portable audio solutions. They have recently expanded into the world of high-end desktop audio with a line of desktop preamps, DACs, amplifiers, and speaker stands. Since they make nearly everything needed to put together a complete system, it made sense for them to offer one complete with cabling and speakers. The Headroom Bi-Amped Audiophile Desktop Package is Headroom's best and most expensive system. It includes their $1599 ultra desktop headphone amp, $399 desktop power supply, $1599 desktop mono-amp pair, $499 Headroom speaker stands, two pairs of 5' DiMarzio speaker cables priced at $179, one pair of $160 DiMarzio M-Path 4.5' interconnects, and a pair of $1995 Harbeth HL-P3ES-2 speakers. The whole shebang costs $5860.80 because of Headroom's 10 percent system discount, which saves you $650 over the combined individual prices.

The heart of this system is Headroom's Ultra Desktop Headphone Preamp. It can handle two analog, one USB, and both Toslink and coaxial S/PIF digital inputs. It acts as a preamp, D/A converter, and headphone amp all in one very compact package. Its front panel controls include a master volume, rear output on/off switch, headphone cross-feed on/off switch, three-position gain switch, and a three-position "brightness" switch. The rear panel has all the input connectors plus one stereo analog output. You'll also find a two-way analog input selector and an analog/digital input selector tucked in among all the input and output connections. From an ergonomic point of view having these two selector switches on the back panel is not terribly convenient. If you frequently switch inputs you will either have to memorize their positions and functions (since you can't see them) or risk accidentally disconnecting something when you move the preamp to access them. I would have preferred to have the preamp gain switch on the back since once you set that for your system you will rarely, if ever, have to readjust it.

The Ultra Desktop Preamp feeds a pair of mono-block power amps. The 170-watt Headroom Desktop Mono-Block Power Amp uses the most recent generation of Class-D amplifier electronics from Bang & Olufsen. Each amplifier contains an ICE Power 50ASX-2 module which performs signal amplification, AC/DC conversion, and fault protection. The amps also employ additional circuitry for power supply regulation, input buffering and mode selection. Each power amp also contains its own AC-to-DC and DC-to-DC conversion circuitry so no additional outboard power supply is required. The amplifier's front panel has a mute switch and a pair of LED indicators for over-current and thermal overheats protection. On the back of the amplifier you'll find beefy high-quality connectors made by Cardas Audio and WBT Electronics.

Headroom's desktop speaker stands are much heavier than you'd expect. Their two-piece design allows you to alter not only a speaker's height but also its angle. The stands ample size allows you to place a Desktop Mono-Block amplifier and either the Desktop Ultra Preamp or a Desktop power supply within the bottom section of the stand. The stand also sports a headphone rest so your entire desktop system can be within easy reach.

The supplied cables from DiMarzio, who are better known for their guitar pick-ups and electronics than for audiophile wire, are well made and appear to be of good quality. Since this isn't a cable review I didn't spend much time comparing them with the other cables in my arsenal, but obviously Headroom thinks enough of them to include them in this premium system.

The last parts of this package are the Harbeth PS3-SE2 speakers, which I reviewed in a recent installment of this column. They are fine speakers that work beautifully in a desktop environment.

Sounds Of The System
Naturally I reviewed this system as a whole before I began to substitute other components. I was immediately impressed by how smooth and musical it sounded. While much of this musicality can be laid at the feet of the superb Harbeth speakers, Headroom's electronics made their presence felt by not getting in the Harbeth's way. I also used Earthquake's Supernova Mk IV 10 subwoofer to augment the Harbeth's low end. Fitting the extra set of interconnects via a splitter into the back of the Ultra Desktop Amplifier was a bit of a challenge but no worse than on some full-sized preamps.

After awhile I substituted several other speakers for the Harbeth PS3-SE2s. Among the cavalcade were the ATC SCM7s, Paradigm S1s, and PSB Imagine Bs. In every case the Desktop Mono-Blocks had more than enough power to drive them to major head-banging levels. I never found it necessary to change the Headroom Ultra Desktop Preamp's gain setting from low to medium or high. I experimented with the preamp's "brightness" setting and quickly settled for "off" as my preferred choice. Although the Ultra Desktop Preamp's volume control doesn't look impressive or permit any balance adjustments between the channels, its stable tracking even at low levels when volume controls are most likely to exhibit channel balance errors impressed me.

As I mixed and matched between Headroom's components and my other reference gear my respect for the Headroom preamp and amplifiers increased. The Desktop Mono-Blocks sounded remarkably similar to my reference amplifier, the Bel Canto S-300 amplifier. This shouldn't be a big surprise since both amplifiers use similar Bang and Olufsen ICE amplifier modules. The stereo Bel Canto costs a mere $200 less than the Desktop Mono-Blocks and frankly I was hard-pressed to identify any major sonic differences between it and the Desktop Mono-Blocks. Given that the Headroom amps have two power supplies rather than one, they may be capable of more sustained dynamic peaks at high volume levels. However, in a desktop application I never got close to the loudness where I'd be able to compare these ultimate dynamic capabilities.

When I compared the Ultra Desktop Headphone amp with the Bel Canto DAC-3 the differences were more obvious. The Bel Canto has a more direct sound. By this I mean it sounds like it's doing less to the signal. On good sources the Bel Canto delivers a more involving musical experience due to its greater resolution and lack of coloration, but on MP3 music files many listeners may prefer the Ultra Desktop's slightly sweeter and more forgiving character. Especially on upper frequencies the Ultra Desktop's subtle upper frequency roll-off (when compared to the Bel Canto) rendered Internet radio stations more listenable. Sure, you can use the Ultra's "brilliance" switch to boost upper frequencies, but I found the boosted sound to be less refined than the Bel Canto.

If you are a headphone aficionado you will love the Ultra's headphone capabilities, and nothing on the Bel Canto short of hooking it up to a Stax headphone amp will come close to the Ultra. Regardless of what headphone I used, the Ultra delivered a splendid result. With headphones the gain control came in very handy, especially with less efficient headphones such as the Grado Rs-1's.

Trying to make a universal speaker stand is guaranteed to be less than 100 percent successful. Depending on how big your desktop speakers are and where their tweeter is located the stand's efficacy will vary widely. These stands do offer an immediate solution to the problem of "desk bounce" which is the desktop equivalent of floor bounce. This is the effect of the primary reflection from your desktop interfering with the direct sound from your speakers. By moving the speakers farther away from the desktop the Headroom speaker stands reduce this pernicious sonic situation. If you have your desktop covered in 0.75-inch thick felt, as I do, the stand's salubrious effects are less noticeable, but on a regular desktop surface they certainly make a world of difference. As to whether your speaker will fit on the stands, the main issue is going to be tweeter height rather than whether they can support your speaker. Even my heaviest speakers, the Aerial Acoustics Model 5Bs, were no problem for the stands. But with some larger bookshelf speakers, such as the Aerials, you may need to turn them upside down so the tweeter is below the woofer to get it on a closer plane to your ears.

The Parts Or The Whole?
While I can certainly recommend the entire Headroom Bi-Amped Audiophile Desktop package, I suspect that most readers will be more interested in purchasing individual components. Most audiophiles probably already own some gear that they would prefer to keep in their desktop system. I think the "stars" of the Headroom system are the Mono-Block amplifiers. Their compactness, energy efficiency, and excellent sound put them in the forefront of "desktop-friendly" amplifiers. Runner up is the Ultra Desktop amplifier. It's a versatile and flexible preamp that offers users good sonics coupled with useful features, especially for a desktop system where you use headphones. The speaker stands will either make an immediate improvement to your desktop listening experience or not. It all depends on your speakers. I love the Harbeth P3-SE2 speakers, but since they are widely distributed I see no compelling reason why you must purchase them from Headroom.
If you wish to purchase some components, but not the entire Headroom system, you will find the Headroom folks are quite flexible. It's possible they may offer a system discount even if you eliminate one or two components from your purchase.

Manufacturer Links

PSB Speakers

Headroom