The Pioneer SP-BS21-LR bookshelf speakers. They look pretty snazzy at first glance, don’t they? That prominent Pioneer logo gives off a bit of a car audio vibe, more akin to something you’d spot on a car’s rear deck than a home speaker.
I’ve been sitting on these Pioneer SP-BS21 speakers for a while now, putting off this review for a variety of reasons. Way back in September, I even did some DSP correction for them and prematurely labeled them as “craptastic.” Despite my initial impressions, I keep seeing these speakers recommended in budget audio circles, so it’s time for a full, in-depth review to share my complete thoughts.
Visual Examination: Grills On and Off
Removing the speaker grills from the Pioneer Sp Bs21-LR proved to be more challenging than expected, requiring some DIY paper clip wizardry. It makes you wonder what sonic secrets, or perhaps visual horrors, are lurking underneath.
A closer look at the removed grills of the Pioneer SP-BS21. While they contribute to a cleaner aesthetic when attached, these grills appear to be acoustically detrimental. If I were Andrew Jones, the renowned speaker engineer behind these, I might have had some strong words for the marketing team who decided to include these sonically-compromising grills.
Without the grills, the Pioneer SP BS21 speakers take on a whole new level of… well, let’s just say “unique” aesthetics. I typically prioritize sound quality over looks, but the exposed drivers are undeniably unconventional. The square frame woofer awkwardly placed in a circular cutout and the plastic waveguide tweeter give off a distinctly budget vibe. It becomes clear why the grills were deemed necessary for marketing purposes. Honestly, without the grills, you almost want to face them backwards to avoid looking at them. The unfortunate reality is that the grills significantly degrade the sound, forcing a choice between sonic compromise and visual… distinctiveness.
Driver and Component Overview
The Pioneer SP-BS21-LR tweeter is a 1-inch textile dome nestled within a plastic waveguide. This waveguide is purportedly designed to match the sound dispersion characteristics of the woofer. While directivity matching isn’t my primary concern, Andrew Jones is known for aiming to create a cohesive soundstage where the tweeter seems integrated within the woofer’s output, and that design philosophy is present here.
The woofer on the Pioneer SP BS21 appears, to my eye, to be slightly undersized relative to the large waveguide on the tweeter. This might be a consequence of utilizing readily available, off-the-shelf components to meet a budget price point. The woofer design is reminiscent of drivers found in Aura speakers or even those used in larger soundbars.
A profile view of the Pioneer SP-BS21 woofer highlights a substantial plastic ring housing. This detail makes it seem more like an afterthought in design than a deliberate aesthetic choice. However, upon closer inspection, the driver features a reasonably sized magnet and a decent quality spider, suggesting that it’s a respectable component considering the speaker’s budget-friendly price.
The rear panel of the Pioneer SP-BS21-LR reveals a rear-firing port and gold-colored binding posts, a nice touch for speakers in this price range. Notably, Andrew Jones’ signature is prominently displayed, adding a touch of audiophile credibility to these budget speakers.
Setup and Initial Listening Impressions
Setting up the Pioneer SP-BS21 speakers on a desktop environment demonstrates their size. Even for bookshelf speakers, they require stands or risers to elevate the tweeters to ear level for optimal listening. In a pinch, some improvised, non-vibrating supports can suffice to achieve the necessary height.
My first, uncorrected listening impressions of the Pioneer SP BS21 speakers were immediately characterized by “boomy” bass and a sense of inefficiency.
However, they do possess some redeeming qualities, particularly if your listening material is light on bass or if you prefer moderate listening volumes. If you can manage to hear past the overemphasized bass, the waveguide design contributes to surprisingly good imaging, creating a sharp and focused, albeit somewhat detached, soundstage.
The rear port design is a point of concern, but experimenting with port stuffing or placement adjustments didn’t effectively mitigate the prominent bass issues. Even when pulled away from walls and positioned in a more open space, the boominess persisted, sounding more akin to a cheap 4-inch subwoofer from an entry-level 2.1 system than a refined bookshelf speaker.
Frequency Response Measurements and DSP Correction
Here’s a close, unsmoothed frequency response measurement of the Pioneer SP-BS21, windowed to minimize room reflections. This reveals the true sonic issue: it’s not just boomy, it’s actually exhibiting muted treble. The frequency response graph shows a significant ±5dB variance above 1kHz.
This measurement also clarifies the perceived inefficiency. The substantial dip in output, nearly 10dB down from the woofer around 5kHz, is audibly significant and explains why they seem to lack volume and clarity without substantial power.
The DSP correction applied to the Pioneer SP-BS21 is a cut-based approach. This means reducing the output of frequencies that are too prominent to achieve a flatter, more balanced response. In this case, significant cuts were necessary across the frequency spectrum to bring up the recessed treble. Additionally, a bass boost was applied below the port tuning frequency to attempt to extend the low-end response. This bass adjustment was largely done by ear, as accurate low-frequency measurements were challenging with my setup. While the corrected sound is more balanced, the speakers still benefit from being positioned at least a foot away from walls in a desktop setup.
Listening Impressions After DSP Correction
My trusty JVC 1024vbk amplifier recently met its end in a blaze of glory, quite literally experiencing a “Viking funeral” as it was retired. Currently, I’m using a Muse M50 desktop amplifier, which provides around 30 watts per channel on a good day. A review of the Muse M50 is forthcoming. While not as powerful as the JVC, it’s neutral enough for critical listening impressions.
Amplifier choice is crucial here because, after DSP correction, the Pioneer SP-BS21 speakers become remarkably inefficient. You’d need a substantial amplifier to drive them to loud volumes. The small Muse M50 struggles to push them to even 85dB on the desktop, and pushing further introduces audible distortion, likely from the amplifier and possibly the tweeter straining to compensate for the correction. This distortion manifests as a smearing of high frequencies, potentially causing listening fatigue or headaches. A more powerful amplifier might yield better results, but there’s a risk of damaging the speakers or crossover trying to achieve spirited listening levels, given their 80W power rating.
Final Verdict
In their uncorrected state, the Pioneer SP-BS21 speakers sound flawed. It’s not the typical harshness of cheap speakers lacking crossovers, but rather a tonally unbalanced and boomy sound profile. It’s as if a passive crossover was used to aggressively suppress certain frequencies, resulting in noticeable gaps in the treble range. If you intend to listen at volumes below 85dB and apply DSP correction, you might find these speakers tolerable. However, in my honest opinion, I cannot recommend the Pioneer SP-BS21, even with correction. They sound frustratingly underwhelming, and the necessary corrections significantly compromise their already limited performance.
If you happen to own these speakers, removing the grills and applying DSP correction is worth trying to experience their potential. However, if you’re dissatisfied, I strongly suggest selling the Pioneer SP-BS21 and investing in alternatives like the Micca MB42x or the Pioneer BS-22s, which generally offer better out-of-the-box performance.
Click here to get the DSP correction file for the Pioneer SP-BS21-LR speakers.
Explore the system finder for more speaker recommendations.
More Content You Might Enjoy:
[
