To review PSB’s most recent Imagine series of speakers—with the small but impressive PSB Imagine B-50 Bookshelf speakers being the centrepiece of this review—is to offer a mandatory glimpse into the extraordinary life of the originator and owner of PSB, Paul Barton. I know you are not reading this review for a hagiographical essay on the life and times of the owner of PSB. Still, one cannot help but place Barton at the forefront of speaker design and production in Canada and give due credit to his work with Dr. Floyd Toole.

For fifty years, Paul Barton has been constructing speakers here in Ontario, Canada, to create a neutral, unbiased “glass mirror” through which sound is transmitted faithfully through PSB speakers. He achieved that goal by working with the audio giant Floyd Toole and the National Research Council of Canada (NCR). We will have a little more to say of this shortly, but Paul’s work with Floyd, beginning in 1974 and continuing until Floyd left to work with HARMANN in 1991, really was a sea-change in the world of speaker design, all of it based on objective measurements done within the NCR’s anechoic chamber and those measurements finally correlated to double-blind tests with listeners from all over the world. Presently, PSB is now part of the Lenbrook Group of Companies, and Paul continues to create and design, with a very active relationship with NAD. Now, let’s come to “the little engine that could”—the PSB B-50 Bookshelf speakers (USD 699/pair).

These little guys measure 6.75” W x 11.8” H x 9.8” D and contain a 5.25” woven-carbon-fibre mid-range woofer and 1” titanium-dome tweeter. The striking design of the woofer on top of the tweeter takes one back for a moment, but its unique placement comes with a well-thought-out audio rationale. With the woofer on top and the tweeter on the bottom, the in-phase lobe of the two drivers tilts upward. Had they been reversed with the tweeter on top, the in-phase lobe would point downward. To be clear, an in-phase lobe in a sound wave refers to the region where sound waves from different sources or paths combine constructively. That is, when sound waves are in phase, their peaks and troughs align, resulting in a combined wave with greater amplitude. This constructive interference creates a lobe or a region of increased sound intensity. This, of course, refers to the direction in which the sound waves from both drivers combine most effectively and when the “sound waves” are “in phase,” they reinforce each other, leading to a stronger, clearer and more intense sound in that direction—basic audio engineering. All of this, that is, the positioning of the woofer on top of the tweeter, affects how the sound is projected into the room and influences the ideal listening height and speaker placement. All of this becomes ever more clear when we recognize that PSB recommends 24” stands for these speakers, creating an ideal ear height of 36” to 39” for the listener. I used a pair of old Focal 24” stands, permitting me to sit in the isosceles triangle position and to hear a full palette of sound; or, to stand, and still hear the same full palette of sound.

Although designed here in Ontario, Canada, the B-50s are manufactured in China, and lest the manufacturing nationalists get worked up here, as is my nature at this point in my life, we should be ruthlessly honest that this is a mandatory cost-saving measure that is tolerable if, and only if, the highest of quality control measures are guaranteed by the manufacturing centre abroad. Having spent a long number of very enjoyable months with the B-50s, listening to them and looking at them critically, I would say the quality of the “build” is excellent. The overall impression is what one might call an elegance of minimalism—a slim and compact cabinet design, offering neutral Satin Black and White finish options, a discreet aluminum trim with chamfered edges that can diffuse themselves discreetly into almost any physical space and will serve as music portals into all but the very largest of rooms. Lastly, being a 2-way bass reflex speaker, there is a bass slot at the rear of the speaker, but I know many individuals looking at the B-50s will instantly get their subwoofer out. I’m going to suggest—hold on; the B-50s have a reported bass extension down to 45Hz (-+3dB). We’ll discuss the bass presently, but let’s now discuss crossovers, for a moment.

The PSB B-50s use a 4th-order Linkwitz-Riley crossover at 2200 Hz. This is a pretty reasonable place to put the crossover because our hearing is particularly sensitive to frequencies in the midrange, around 2000 Hz. Anything in a speaker feedback system that guarantees an uninterrupted energy-sound signal from woofer to tweeter and back again around this sensitive 2000 Hz point, we will perceive as seamless sound. In a phrase—our brain will be happy. Not wishing to belabour the point, but the use of this excellent 4th order crossover, is one of the main reasons, I would speculate, that Paul can place the woofer on top, the tweeter on the bottom, and have that “in phase” tilt in the sound wave—I may be wrong, here. Generally, 4th-order crossovers are a type of audio filter used to separate the audio signal into different frequency bands and refer to the steepness of the filter’s slope, which in this case is 24dB per octave. This steep slope guarantees that frequencies outside the desired range are attenuated quickly, creating a clear separation between the woofer and the tweeter, further guaranteeing that when the signals from the woofer and tweeter combine, they do so without causing phase cancellation, ultimately leading to what all of us want, a smoother and more coherent sound.

So, what do they sound like?

Well, first, a statement of thanks, particularly to Mr. Don Corby of Corbys Audio and Shelby Coppola, Public Relations Lenbrook/Audioscenic. Due to circumstances that were out of my control, I found myself burdened, again, with a health issue that is both time and energy-consuming. It was only through the kindness of Don and Shelby that I was given more than a generous amount of time to work with the PSB B-50 speakers and to use Don’s Canadian-built Saturn Integrated Amplifier to power all my selections. I am very grateful to both of these wonderful people for their patience.

Sound

Now, back to the sound. I am playing two of my three music examples on an old but acceptable Yamaha CD player through the Canadian-built Saturn Integrated Amplifier connected by Rob Fritz’s fantastically impressive cables from Audio Art Cable and out through the PSB B-50s.

It is my habit to start with liturgical Russian or Eastern Orthodox music from the greatest of Russian/Slavic composers to get a true feel for the vertical breadth of four-part choral music sung and recorded in some of the greatest architecture in Christendom. This serves as a litmus test for any two speakers I review, in the never-ending hope of hearing something so authentic that I believe I am in that energetic sound space, that religious space. This is a tall order for any speaker, especially for one so small.

The liturgical music of Alexander Grechaninov, written for Passion Week (1912) and performed by the Phoenix Bach Choir and the Kansas City Chorale (professional choirs) under the leadership of Charles Bruffy, fits my requirements brilliantly. These two very fine American choirs—perhaps the finest in America, presently—are recorded in the magnificent Church of the Blessed Sacrament in Kansas City by Chandos in the Direct Stream Digital Super Audio CD, a recording that catches the phrasing and breath of the chorister in the back row and the thoroughly audible below-the-bass-clef low Ds in the basses with stunning clarity. What is so striking about this music is Grechaninov’s ability to use traditional Orthodox chants in each selection as a foundation upon which to offer stunning harmonic modulations and gorgeous harmonies with an expanding chromatic palette, all tied beautifully to the Russian text. There are moments of true transcendent beauty in Grechaninov’s music, all the more heightened and brought out through Bruffy’s brilliant sculpting of the choir’s phrasing, the rhythm of his climaxes, and leading to a sense that this music has a symphonic-like nature as it follows the narrative of the Passion of Christ. This is music that is magnificent, difficult to perform and only reachable by top-notch choirs and a top-notch conductor. You have it all on this disc!

Well, on goes the CD, and I sit back and listen and imagine. The vertical sonority of the B-50s is surprisingly good, offering a spatial height that is no less the result of Chandos’s brilliant engineers but also the “air,” the “space,” and “energy” within the acoustic space of the Church of the Blessed Sacrament, reproduced faithfully through the B-50s. As I increase the volume of the Saturn Integrated Amplifier, my very limited and defined listening space gets bigger and bigger. I am immersed in a beautiful, liquid, neutral midrange that can float into the higher soprano range unimpeded, gracefully, and at the same time, give prominence to the basses on the selection, “In Thy Kingdom.”

The B-50s reproduce the perfectly balanced 4 part voices with a “naturalness” and an evenness in tonality that is quite impressive. As I listen and listen, I begin to hear a consistent character from these little guys: stable and neutral mid-range, very fine imaging, the glorious illusion of space above and below occupied with authentic sound, an impressive soundstage and an accurate reproducibility of the recorded source.

My second example is the famous opening movement, “Sonnenaufgang,” of Richard Strauss’s Also Sprach Zarathustra, performed by Herbert von Karajan and the Berlin Philharmonic in their 1974 recording on Deutsche Grammophon. Let’s be completely honest: was there ever a greater match made in heaven—the Berlin Philharmonic’s strings, Strauss’s use and orchestration of the string section and Karajan’s almost fanatical occupation with the string section of his orchestra? This is a piece where all parties shine with transcendent luminosity!

I was interested to hear how the B-50s dealt with C1 in the double basses, the C1 in the pipe organ and the C1 in the contrabassoon in the very opening of Strauss’s piece. The frequency of this note is approximately 32.7 Hz which is slightly above the hearing level of most homo sapiens. To get this, C1, which is one octave below the C two ledger lines below the bass clef, requires the C extension on the double bass. Now, our little B-50s have a bass extension of 45Hz, which simply tells us that the speaker can reproduce frequencies as low as 45 Hz with a certain level of accuracy and volume. This is often measured at a specific decibel level, such as -3dB, which indicates a slight drop in volume at that frequency compared to the speaker's average output. However, a speaker can reproduce lower frequencies but dependent on its design and the acoustics of the listening space, it may not sound with the same accuracy or volume. I have my Apple MacBook Pro USB from my Apple Music account through to the Mytec HiFi Manhattan II DAC to the Saturn Integrated Amplifier and out through the B-50s. Let’s listen.

The opening low C1 sound is clear and forthright; now, I have to turn the volume up on the Saturn to 70% of the total volume, but the entire opening is handled with remarkable clarity for such a small speaker. The Berlin Philharmonic is ravishing in its sound, with the strings beautiful in the upper part of their range and the Berlin brass well-behaved but forceful. Karajan, as Karl Bohm conducted also, played the sixteenth note in measures 6-7 and 9-10 completely in time, which is what Strauss wanted. This major-to-minor and minor-to-major rhythm has been elongated to the point it turns into an eight note or the length of a dotted eighth note. Karajan gets it right! For contrast, I put on Andris Nelson’s recording of the same piece with the City of Birmingham Symphony Orchestra to compare openings. Nelson accentuates the bass drum roll at the beginning of the piece. When Strauss moves to the subdominant F chord in bar 15, the bass drum roll reaches epic thunder level, I mean almost over the top. And here’s the huge surprise—the B50s, however, don’t bat an eye. Even the indefinite pitch of the bass drum at an epic high volume level is handled without a trace of distortion. Remarkable. One more time, only this time with Maestro Blomstedt and the Staatskapelle Dresden, and the opening C1 is the most discernable pitch of all the performances I’ve listened to. You can hear the pitch as a low C. Now, this may sound ludicrous and obvious to some, but how the conductor balances the low C1 in the strings—the double basses—against the Contrabassoon and the pedal in the organ and the grosse trommel is a never-ending canvas of varied hues of sound. Sometimes, because of the balance required by the conductor, because of the actual recording itself, because of your amp and your speakers and finally, your room, this opening note may come out sounding more like a gravelly low indefinite pitch. Whatever I offer the B-50s, these little guys punch way above their weight and size and are faithful to the recorded sound. Remarkable, again.

Now, how did we get here where a speaker this size could command such a frequency range and presence of this significance? Without a doubt, it has to be Paul Barton and Ian Colquhoun of Axiom Audio, another Canadian, and others, and their work with Floyd Toole at the NCR in Ottawa in the 1970s. What Floyd discovered in his anechoic chamber—a chamber which is a laboratory instrument consisting of an isolated environment structured in such a way as to reduce reflection of signals on the walls, including all types of waves, from electromagnetic to acoustic ones—and his work with different listening participants, was that people identify good sound as accurate sound. Wow! Looking back almost fifty years, this sounds obvious. But considering the different sounds of different speakers at the time, Floyd centred on something very significant. The more an audio system—the most important part being the loudspeaker—produces the sound of a musical source accurately, the more the participants categorized the speaker as producing a “good sound.” So, accurate sound is good sound. What do we know to be good and accurate sound? The sound of the modern symphony orchestra is our aural model of true and accurate sound. Why? We have almost 400 years of Western high culture manifested in ensembles that performed in magnificent halls, cathedrals, large venues, etc., and this is ingrained in our collective consciousness. The diversity of instruments, their unique individual colour and their collective colour throughout the full spectrum of range of human hearing is our standard of acoustical excellence. The whole history of recording is, in my opinion, the best and brightest minds working on capturing this moniker of musical excellence and setting it onto vinyl, CDs and streaming to capture, authentically and accurately, what we hear in the concert halls. Once the orchestra could be recorded at a high level of accuracy, then everything else was a piece of cake. And what is the most important element for a sound system to do to replicate the model of true and accurate acoustic sound? The frequency response of the system must reproduce all the frequencies in the audible spectrum, from the lowest of bass to the notes of the highest treble that we can discern. Before Floyd Toole, this was considered a good idea. But, after Floyd’s work, this became a necessary template for speaker construction. What do I hear even in these small bookshelf speakers? I hear a full-frequency response across the audible spectrum.

As important was Floyd’s work on measuring the response of speakers over 360 degrees, called “total radiated sound power.” For the rest of us who hear our music in weird-shaped, surfaced walled rooms, this measurement is very important. Sound power is a measurement that captures the total amount of sound radiating from every direction out of a loudspeaker. Measurements are taken from the speaker’s on-axis, and then the speaker is turned in 15-degree increments and measurements are taken until one has returned to the original on-axis. Then, the speaker is laid on its side, and the speaker is measured once again in 15-degree increments. This measures the acoustic output of the speaker horizontally and vertically over 360 degrees. The computer ingests these measurements and produces the ‘total radiated sound power’ chart, which then produces the “directivity index.” With the “directivity index” in dB, you begin to see if the speaker offers a wide dispersion of sound power at all frequencies in an omnidirectional sense. And this is what I am hearing in the B-50s.

My final listening example is one of the finest recordings of 2024, Edward Elgar’s The Dream of Gerontius, with conductor Paul McCreesh leading his Gabrieli Consort and Players and the Polish National Youth Choir on Signum Classics CD. The soloists on this recording are Andrew Foster-Williams (Bass-Baritone) as The Priest, Anna Stephany (Mezzo-Soprano) as The Angel and Nicky Spence (Tenor) as Gerontius. This new recording may not supplant my Barbirolli and Janet Baker recording that I’ve had for 50 years, but it has placed before us a sound of “The Dream…” that will challenge some and utterly impress others. The Gabrieli Consort uses instruments on this recording from Elgar’s time, from around 1880 to 1923, that includes, obviously, the use of gut strings for the string players. Some of the textures are more transparent and cleaner in the strings than in the modern orchestra sound, and the softer passages are not just softer but carry with them an ethereal tone. The weight of the orchestra is slightly lighter, but there were very few moments when I was disappointed by the quality and weight of the overall sound. Please don’t misunderstand me. There is power and weight to this group, which is manifest during the prelude of the piece and many of the large choral selections. However, I have to state, without reservation, that one of the greatest joys of this recording is to find Nicky Spence as Gerontius—a singer only to be equalled by Heddle Nash on Sir Malcolm Sargent’s 1945 recording. Nicky Spence has the Heldentenorstamina, range and emotive power to make Gerontius, a man who is not only near to death but whose strength and stamina in these last moments must be herculean to render Elgar’s role believable and musically convincing—certainly, a significant paradox. But what a voice and intelligence to Spence’s performance. Except for a slight recessing of sound for some of the choral work, the recording is very good.

And what do I hear from the B-50s: all the positives that I have observed in my earlier selections are all brought together in Elgar’s “Dream.” The outstanding choral work, the vast range of the Elgarian orchestra and the three voice soloists are recreated in an authentic reproduction of the tonal and frequency character of the participants performing. For their size, the B-50s give us the weight of Elgar’s huge choral sections without any distortion, without any smearing of detail, even at the highest of volumes. The unique character of the gut string orchestra is faithfully produced, and the voices display a true and natural tone colour without any electronic colouring. Finally, as I put on the vast chorus “Hail to the Holiest…” at a substantial volume, I roam around my room, hearing a cloud of glorious sound that fills the height, width, and depth of my space. I need not be centred in one spot to share in the fullness of Elgar’s piece. An impressive omnidirectional character to the sound.

Summary

Let me conclude by saying these USD 699/pair PSB B-50 speakers are impressive, to say the least. With living spaces receding in size through purposeful planning, these little guys can offer you a larger-than-life portal through which to play your music. They will feed a space in a 360-degree fullness that will surprise beyond belief—whether you are sitting in the sweet spot or moving around the room. They are a tribute to Paul Barton’s work with Floyd Toole, and they stand as a testament to Paul’s outstanding work at PSB. Our ex-Primeminister, Joe Clark, informed of Dr. Floyd Toole’s work in audio just a couple of years ago, remarked that a documentary should be made about this man and his work because Canadians need to know. I would suggest a documentary about both men be made. Hell, we Canadians need something to crow about. It gives me great joy to assign the Audiophilia Star Component Award to the PSB B-50 Imagine series Bookshelf speakers.

Further information: PSB Speakers