DESCRIPTION Two-way, reflex-loaded, stand-mounted loudspeaker. Drive-units: 1" soft-dome tweeter, 5.25" woofer. Crossover frequency: 2.5kHz. Frequency range: 55Hz–20kHz. Nominal impedance: 6 ohms. Sensitivity: 85dB/2.83V/m. Maximum input power: 130W.DIMENSIONS 7.9" (200mm) W by 13.75" (350mm) H by 8.7" (220mm) D. Weight: 10.25 lbs (4.7kg).FINISHES Black vinyl.SERIAL NUMBERS OF UNITS REVIEWED JFNV00015BUC (both).PRICE $149.99/pair. Approximate number of dealers: >20 (a limited set of overall Pioneer dealers).MANUFACTURER Pioneer Electronics (USA) Inc., PO Box 1540, Long Beach, CA 90801-1540. Tel: (800) 421-1404. Web: www.pioneerelectronics.com.

PioneerSP-BS41-LR loudspeakerrobert j. reina

E Q U I P M E N T R E P O R T

The buzz was all over the audiophile ’net. “Pioneer has a new bookshelf speaker that’s killer for the money!”

Hmm, I thought. Pioneer. Speakers?To be fair, I’ve had the Pioneer brand on my mind for well over 30 years. The company

was my brand of choice for car-stereo electronics in the 1970s, for Dolby S cassette decks in the ’80s, for DVD players in the ’90s, and for plasma TVs in the ’00s and ’10s. I felt a bit guilty that I hadn’t focused on the fact that Andrew Jones, the very same design guru who

came up with Pioneer’s TAD Reference One loudspeaker ($70,000/pair), had had a hand in designing a few two-channel speaker models starting at $99.99/pair. The audio gossip was all about the second model from the bottom of Pioneer’s speaker line, the SP-BS41-LR ($149.99/pair). I thought I’d better get a pair and review them.

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DescriptionThis two-way, rear-ported SP-BS41-LR, a black bookshelf model, has an attractively curved cabinet designed to increase stiff-ness and reduce internal standing waves. The drive-units are a 1" soft-dome tweeter and a 5.25" cone woofer. I discussed with Andrew Jones what he’d tried to accomplish with the SP-BS41-LR. He told me he’d surveyed most of the $150/pair speakers on the market and had concluded that most were designed with cosmetics as a design criterion, but with little attention paid to sound quality. The biggest shortcoming he found was in the competi-tion’s crossovers. Most had a crossover consist-ing of either a single capacitor, or a capacitor and an inductor. Jones believes that it’s impos-sible to create a seamless integration of mid/woofer and tweeter with a crossover compris-ing only one or two elements. He was able to design a six-element crossover using quality parts, without exceeding his considerable con-straints of low manufacturing cost.

Jones also designed the SP-BS41-LR’s drive-units, paying special attention to the cone pro-file, voice-coil winding, and magnet structure, and felt fortunate in finding a cabinet supplier who was able to execute his curved design within his cost parameters. The final step was the integration of Jones’s design into Pioneer’s

manufacturing process. Although he and his team designed the SP-BS41-LR in the US and produced its first prototype here, he sent his team to Pioneer’s factory in China to closely supervise the first production run, to ensure that the production units matched his final prototype.

I sat the SP-BS41-LRs on my usual Celes-tion Si stands, loaded with lead shot and sand. The speaker’s attractive grilles of metal mesh, which separately protect the tweeter and woofer, are not removable.

ListeningI was immediately taken with the subtle low-level articulation and lack of midrange coloration in all recordings of voices. George Harrison’s lead vocal in his “Something,” from the 2009 remastering of the Beatles’ Abbey Road (CD, Apple 3 82468 2), was rich and silky, with every subtle nuance of his phrasing intact. Higher up the audioband, the Pioneer rendered Jonatha Brooke’s voice in “Linger,” from her Steady Pull (CD, Bad Dog BDR 60801-2), with an airy and biting but elegant quality, and perfectly captured this singer’s tendency to develop a “howly” quality in loud-er passages, as I’ve heard her do in concert.

The ability of the SP-BS41-LR to reproduce layers of midrange detail with lifelike low-level

dynamic articulation made me want to listen to piano recordings. Pianist Marilyn Crispell uses quite a bit of silence, space, and decay in her music, which fits in nicely with the am-bient sound Manfred Eicher likes to create in all recordings for his label, ECM. In the title track of Crispell’s Amaryllis (CD, ECM 1742), I could hear every little detail of her phrasing, presented cleanly and with plenty of air—the rich sonority of her instrument shone through. Recordings of more challenging piano works, such as the Allegro moderato of Rachmaninoff’s Sonata 1, in Robert Silverman’s recording (CD, Stereophile STPH019-2), were reproduced with perfect clarity—Silverman’s crisp phrasing on his Steinway was very easy to follow.

John Medeski’s frantic upper-register im-provising on Lee Morgan’s “Afrique,” from Medeski, Martin & Wood’s Tonic (CD, Blue Note 5 25272), was reproduced without a trace of smearing or harshness, and the sense of air in Tonic, the large club where this album was recorded, was quite evident. Before the SP-BS41-LRs appeared in my house, I’d never heard so inexpensive a loudspeaker reproduce complex high-frequency transients with such realism. I therefore began to mine my jazz collection for percussion recordings, specifi-cally those featuring drummer Paul Motian. In addition to Crispell’s Amaryllis, I cued up

I measured the Pioneer SP-bS41-Lr’s frequency response in the farfield with Dra Labs’ MLSSa system and a calibrated DPa 4006 microphone. For the nearfield measurements i used an earthworks QtC-40

microphone, whose 1⁄4" capsule provides only a minimal obstacle to the flow of air through the port. the Pioneer speaker’s b-weighted sensitivity on the tweeter axis was 85.8db/2.83V/m, which is within experimental error of the specified 85db. the electrical impedance remained above 6 ohms at all frequencies (fig.1, solid trace). the average was closer to 9 ohms, which both means that the SP-bS41-Lr—who thought of that name?—will be an easy load for the partnering amplifier to drive, and suggests

that the specified 6 ohms figure is too pessimistic.the impedance traces have glitches evident at 180,

470, and 700Hz, which implies the existence of some kind of enclosure resonances at these frequencies. investigating the vibrational behavior of the enclosure panels with a simple plastic-tape accelerometer revealed a rather lively cabinet. the side panels (fig.2) have ridges of resonant energy evident at 570Hz, as antici-pated, but also at 470Hz; and while a lower-frequency ridge is visible, this is just above 200Hz, rather than at the 180Hz i had expected from the impedance plot. i would expect some lower-midrange congestion to stem from this behavior.

M E a s U R E M E N Ts

Fig.1 Pioneer SP-bS41-Lr, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

Fig.2 Pioneer SP-bS41-Lr, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of side panel (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

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Motian, Joe Lovano, and Bill Frisell’s Time and Time Again (CD, ECM 1992). In “Cambodia,” Motian’s role is to provide largely arrhythmic textural colors, and through the Pioneer his phrasing on ride cymbal was as natural as I’d heard from any budget-priced speaker.

Part of the reason for the SP-BS41-LR’s transient realism was its ability to reproduce extended and uncolored high frequencies, and the way the highs seamlessly integrated with the midrange. I found myself searching for jazz recordings that spotlight the dynamic and tonal range of the trumpet. On the title track of Miles Davis’s ’Round About Midnight (CD, Columbia CK 40610), his horn was silky and holographic, with just the right amount of metallic bite and long decay. On a mellower note, in the ballad “Tristan’s Way,” from Liam Sillery’s Priorité (CD, OA2 Records 22082), Sillery stretches out the long, slow, soulful trumpet melody before moving on to an im-provisational passage. Through the Pioneers, the lower register of Sillery’s horn bathed the rhythm section in a mellifluous glow.

The SP-BS41-LR’s reproduction of the highs let me focus on things in rock recordings that I’d never noticed before. In the instru-mental introduction to “Little Wing,” from Jimi Hendrix’s Axis: Bold As Love (CD, MCA MCAD-1601), a track I’ve heard many dozens

of times, I found myself ignoring Hendrix’s trademark rhythm guitar and being transfixed by that glockenspiel melody, whose upper harmonics shimmered and decayed without getting lost in the mix.

I was very impressed with both the quantity and the quality of the Pioneer’s bass reproduc-tion even in my large listening room, which has proved a challenge for the smallest book-shelf speakers at the low end. In “Aurora,” from Jon Hassell’s Last Night the Moon Came Dropping Its Clothes in the Street (CD, ECM 2077), there is an interlude between Peter Freeman’s thundering electric bass guitar and the electronic bass of Jamie Muhoberac that at times drops below the bass guitar’s bottom note. Although Pioneer claims a lower limit of 55Hz for the SP-BS41-LR (we’ll see what John Atkinson’s measurements tell us), I never noticed a lack of bass clarity with this track, or any lower-register notes on which the speaker seemed to peter out. Similarly, in John Rutter’s

Requiem, with Timothy Seelig conducting the Turtle Creek Chorale and the Women’s Cho-rus of Dallas (CD, Reference RR-57CD), the pipe organ’s pedal notes never lost definition, the ensemble remained clear and crisp with

no loss of definition even at fairly high volume levels, and the “air” of the recording venue (a church) was quite audible.

With rock music, the SP-BS41-LR was able to produce a good sense of high-level dynamic drive and heft, especially for so small a speak-er. However, if I pushed the Pioneers too hard, the limitations of the laws of physics did come into play. I cranked up “Vrooom,” from King Crimson’s Thrak (CD, Discipline 8 40324 2), and although the distinction between the bass lines of Tony Levin on Chapman Stick and Trey Gunn on bass guitar was quite clear, when I tried to push the SP-BS41-LR past 95dB in my large room I began to lose a bit of detail, the speakers sounded a bit squashed and compressed, and some smearing emerged.

turning to the Pioneer’s acoustic behavior, the low- frequency saddle in the impedance-magnitude trace suggests that the rear-panel port is tuned to 60Hz. the red trace in fig.3 shows the output of the port, measured in the nearfield. it peaks between 40 and 90Hz, but its smooth upper-frequency rolloff is marred by two high-Q resonances, at 570 and 900Hz. the blue trace in this graph is the nearfield output of the woofer. as expected, it has a sharp notch at the port tuning frequency of 60Hz. the black trace below 300Hz in fig.3 is the sum of the nearfield woofer and port responses. the peak apparent in the upper bass is actually an artifact of the nearfield measurement technique; the SP-bS41-Lr’s low frequencies will actually be close to flat before rolling off

to reach –6db at the port tuning frequency.Higher in frequency, the Pioneer’s farfield output (fig.3)

is respectably even before featuring a small peak between 10 and 15kHz. the plot of the speaker’s horizontal disper-sion (fig.4) shows that the small suckout below the top-octave peak fills in to the speaker’s sides, but also that the tweeter’s output above 10kHz falls off rapidly, which will ameliorate the audibility of that peak. Lower in frequency, the Pioneer’s dispersion is broad and even, with no sign of the usual off-axis flare at the bottom of the tweeter’s pass-band. in the vertical plane (fig.5), suckouts in the crossover region develop more than 5° above and below the tweeter axis, which suggests that the stands used be tall enough to place the listener’s ears close to the tweeter axis.

Fig.3 Pioneer SP-bS41-Lr, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with nearfield woofer (blue trace) and port (red) responses and their complex sum respectively plotted below 300Hz, 1kHz, 300Hz.

Fig.4 Pioneer SP-bS41-Lr, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

I was very Impressed wIth both the quantIty and the qualIty of the Bass REPRODUcTION.

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comparisonsI compared the Pioneer SP-BS41-LR ($149.99/pair) with my trusty entry-level benchmark, the Paradigm Atom v.5 ($250/pair), as well as with the Wharfedale Diamond 10.1 ($350/pair), which I reviewed in the July 2011 issue.

The Paradigm Atom v.5 had a midrange richness similar to that of the Pioneer, with quite good inner detail. However, the Atom’s sound had a darker quality—its highs weren’t as extended or as clean as the SP-BS41-LR’s—and its transients seemed a bit more blurred. Finally, the Paradigm’s midbass was a touch warmer, the Pioneer’s cleaner.

The Wharfedale Diamond 10.1’s midrange was as clean as the Pioneer’s and seemed to re-solve even more detail. The 10.1’s highs were more extended, however, as well as more silky, airy, and delicate. The Wharfedale’s bass was as tight and clean as the Pioneer’s, but seemed more extended. Finally, the Diamond 10.1’s overall dynamic range seemed wider than ei-ther the Pioneer’s or the Paradigm’s.

summing UpOver the last few years, I’ve continued to be impressed by what speaker designers are ac-complishing at lower and lower price points. It seems that every time I get a new affordable

bookshelf speaker in-house, it raises the bar. One would expect the sound of a $149.99/pair bookshelf model to include some seri-ous compromises and tradeoffs, but within its size limitations, the Pioneer SP-BS41-LR has none. It is a dynamic, coherent, and color-less reproducer of music, with quite convinc-ing bass for its size. It should give lovers of all genres of music hours of convincing realism in the listening room, so long as those listen-ers keep their volume levels within reason and don’t attempt to rewrite the laws of physics.

Sure, spending two or three times as much can buy you a number of speakers that will do one or more things better than the Pioneer. But Andrew Jones set himself a very high design goal with the SP-BS41-LR, and he has fully attained that goal—and with-out compromise. An impressive achieve-ment indeed! nn

assOcIaTED EQUIPMENTaNaLOG sOURcEs VPi tnt iV, rega Planar 3 turntables; immedia, Syrinx PU-3 tonearms; Koetsu Urushi, Clearaudio Virtuoso Wood cartridges.DIGITaL sOURcEs Lector CDP-7t, Creek Destiny CD players.PREaMPLIFIcaTION Vendetta research SCP-2D phono stage, audio Valve eclipse line stage.POWER aMPLIFIER audio research reference 110.INTEGRaTED aMPLIFIER Creek Destiny.LOUDsPEaKERs Paradigm atom v.5, Wharfedale Diamond 10.1.caBLEs interconnect (all Mit): Magnum M3, Mi-350 CVtwin terminator, Mi-330SG terminator. Speaker: acarian Systems black orpheus.accEssORIEs Various by aSC, bright Star, Celestion, echo busters, Salamander Designs, Simply Physics, Sound anchor, VPi. —Robert J. Reina

in the time domain, the SP-bS41-Lr’s step response on the tweeter axis (fig.6) suggests that both drive-units are connected in positive acoustic polarity. the decay of the tweeter’s step smoothly blends into the start of the woofer’s step, which implies optimal crossover design. the cumulative spectral-decay plot (fig.7) is impressively clean, with only a very slight amount of delayed energy apparent at 1.7kHz.

the measured performance of Pioneer’s SP-bS41-Lr would not be out of place in a $1000/pair speaker, let alone one costing just $150/pair. Color me impressed. —John Atkinson

Fig.6 Pioneer SP-bS41-Lr, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).

Fig.7 Pioneer SP-bS41-Lr, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

Fig.5 Pioneer SP-bS41-Lr, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 45–5° above axis, reference response, differences in response 5–45° below axis.

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m e a s u r e m e n t s , c o n t i n u e d

Posted with permission from the September 2011 issue of Stereophile ® www.stereophile.com. Copyright 2011, Source Interlink Media, Inc. All rights reserved.For more information on use of this content, contact Wright’s Media at 877-652-5295.

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