The Pioneer SP-BS21-LR bookshelf speakers make a striking first impression with their prominent Pioneer branding, reminiscent of car audio systems rather than home speakers. Despite initial recommendations and a visually appealing design, these speakers warranted a closer look, and after extensive testing, including DSP correction applied back in September, the results are in. This review delves into the specifics, revealing why, despite their popularity, the Pioneer SP-BS21-LR might not be the audiophile’s ideal choice.
Aesthetic Appeal vs. Acoustic Reality
Removing the speaker grills of the Pioneer SP-BS21-LR proved to be an unexpectedly challenging task, requiring tools more suited to clandestine operations than speaker reviews. This struggle to access the drivers hinted at potential compromises in design, prioritizing aesthetics over functionality.
The speaker grills themselves are a significant letdown from an acoustic perspective. If design legend Andrew Jones had conceived of these speakers, he might be dismayed by the acoustical impact of these grills, potentially hindering sound quality for the sake of visual appeal.
With the grills removed, the Pioneer SP-BS21-LR speakers reveal a less flattering truth. While personal preference varies, the exposed drivers present a somewhat disjointed aesthetic. A square driver set within a circular frame, coupled with a plastic waveguide tweeter, evokes a sense of budget-conscious construction. It becomes clear why the grills were deemed necessary for marketing purposes – to conceal a less refined design. However, the acoustic compromise of using the grills is significant, forcing a choice between visually concealed speakers with muffled sound or sonically clearer audio from less visually appealing speakers.
Driver Examination
The Pioneer SP-BS21-LR incorporates a 1-inch textile dome tweeter nestled within a plastic waveguide. This waveguide is intended to harmonize the tweeter’s dispersion characteristics with the woofer, a design philosophy championed by Andrew Jones, aiming for a cohesive soundstage where the tweeter’s output appears integrated with the woofer.
Visually, the woofer cone appears somewhat undersized relative to the tweeter’s prominent waveguide. This might suggest constraints in sourcing off-the-shelf components for budget-friendly designs. The woofer design bears a resemblance to drivers found in soundbars or entry-level audio systems.
The woofer assembly includes a substantial plastic ring housing, giving the impression of an add-on rather than an integrated design element. Despite this, the driver features a reasonably sized magnet and a respectable spider, indicating a level of component quality that belies the speaker’s budget price point.
The rear panel of the Pioneer SP-BS21-LR features a rear-firing port and gold-plated binding posts, alongside Andrew Jones’ signature, adding a touch of perceived prestige to these entry-level speakers.
Setup and Initial Sound Impressions
In a desktop setup, the Pioneer SP-BS21-LR speakers, despite their size, necessitate stands to elevate the tweeters to ear level for optimal listening. Improvised stands can effectively achieve the desired height adjustment.
Initial uncorrected listening impressions reveal a sound profile characterized by boominess and inefficiency. The speakers exhibit limitations when handling bass-heavy content or when played at higher volumes. However, in less demanding scenarios, they demonstrate decent imaging capabilities, attributed to the waveguide design, producing a sharp, focused, yet somewhat detached soundstage.
The rear port contributes to the perceived boominess, and neither port stuffing nor repositioning significantly mitigates this issue. Even when moved away from walls, the low-frequency response resembles that of a budget 2.1 system’s subwoofer rather than refined bookshelf speakers.
Measurement Analysis and DSP Correction
Frequency response measurements, taken with minimal windowing to reduce reflections and without smoothing, expose a significant issue: a highly uneven response, varying by ±5dB above 1kHz.
Contrary to initial subjective impressions of boominess, the measurements reveal a more nuanced problem: attenuated treble frequencies. This explains the perceived inefficiency, as the output around 5kHz is nearly 10dB lower than the woofer’s output, a substantial and audible deviation.
DSP correction was applied, employing a cut-based approach, reducing frequencies above the lowest points to achieve a flatter response. In this instance, substantial cuts were necessary to restore a perceptible treble response. Additionally, the bass response below the port tuning frequency was boosted by ear to enhance low-end extension, compensating for perceived deficiencies in the measured response.
Post-Correction Listening Experience
Following DSP correction, the Pioneer SP-BS21-LR speakers were evaluated using a Muse M50 amplifier, delivering approximately 30 watts per channel. This amplifier replaced a higher-powered JVC model. The amplifier change is crucial because, after correction, the Pioneer BS21-LR’s efficiency is significantly reduced, requiring substantial power for adequate volume.
The Muse M50 could drive the corrected speakers to around 85dB at a desktop listening distance, beyond which distortion became noticeable, potentially originating from the amplifier or the tweeter struggling to reproduce corrected high frequencies. This distortion manifested as a smearing of high-frequency detail, potentially causing listening fatigue. While a more powerful amplifier might yield better results, the speakers’ 80W power rating raises concerns about potential damage at higher volumes.
Final Verdict and Recommendations
Uncorrected, the Pioneer SP-BS21-LR speakers present a flawed sound profile, not typical of cheap, crossover-less designs, but exhibiting tonal imbalances and boominess. This suggests a passive crossover design that aggressively attenuates certain frequencies, creating significant gaps in the treble range. Even with DSP correction, while listenable at lower volumes (below 85dB), the speakers remain underwhelming. Ultimately, the Pioneer SP-BS21-LR are not recommended, either with or without correction, due to their fundamentally flawed sound and the extensive compromises required to achieve even moderate performance.
For those who own these speakers, removing the grills and applying DSP correction is advisable to realize their full, albeit limited, potential. However, for potential buyers, it is recommended to consider alternatives such as the Micca MB42x or the Pioneer BS-22s, which offer superior performance without the need for extensive correction.
Click here to get the DSP correction file for the Pioneer SP-BS21-LR speakers.
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