Pioneer SP-BS22-LR (Philharmonic AAM Mod) vs Micca RB42

Last updated: October 1, 2026

Short answer: the Pioneer SP-BS22-LR in Philharmonic AAM form, though neither ranks well in its class. The Micca RB42’s curved cabinet fit and finish look far more expensive than the speaker is, but its spinorama shows significant peaks and valleys in the on-axis and listening-window response starting a few kHz up. The AAM mod by Dennis Murphy of the discontinued budget Pioneer shows only some directivity error near the crossover. Both are rated below 3.0/5 among the 90 bookshelf speakers; for better sound, the Neumi BS5 ranks #22 at $139.99.

Pioneer SP-BS22-LR (Philharmonic AAM Mod) vs Micca RB42

Buy the Micca RB42 new; the Pioneer SP-BS22-LR (Philharmonic AAM Mod) is no longer sold new, so it only makes sense as a used find.

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Specifications Side By Side

Pioneer SP-BS22-LR (Philharmonic AAM Mod) Micca RB42
Price$168 per pair Discontinued$159.99 per pair
Ranked#63 of 90 in Medium Size Bookshelf Speakers#75 of 90 in Medium Size Bookshelf Speakers
Bass Extension (-3dB)78Hz (measured, Audio Science Review)85Hz (measured, Audio Science Review) - the reviewer noted an artificial boost around 100-300Hz, so true extension may be worse than this on-axis reading suggests
Bass Extension (-10dB)60Hz (measured, Audio Science Review)62Hz (measured, Audio Science Review) - the reviewer noted an artificial boost around 100-300Hz, so true extension may be worse than this on-axis reading suggests
Drivers1x 4” curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1” silk dome tweeter (replacement)4” coated paper woofer, 0.75” silk dome tweeter
Weight9 lbs (4.1 kg)6 lbs (2.7 kg) each (per retailer listing)
Sensitivity83dB (2.83V/1m, measured by Audio Science Review)80dB (2.83V/1m, measured, Audio Science Review)
Impedance8 ohms nominal (approx. 5 ohms minimum, measured by Audio Science Review)4-8 ohms
Crossover Frequency3000Hz-
Dimensions12.6”H x 7.1”W x 8.5”D (320.0 x 180.0 x 215.0 mm)8.7H x 4.9W x 7.9D in
Woofer Cabinetported, rearported, front
Spinorama Preference Score5.074.59
Spinorama Preference Score with Perfect Sub7.826.87
DIY KitYesNo
Frequency Response-50Hz - 20kHz (Manufacturer specified, typical in-room)
Power Handling-15-100W each

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The Two Speakers In Full

Pioneer SP-BS22-LR (Philharmonic AAM Mod): $168 per pair Discontinued eBay

Pioneer SP-BS22-LR (Philharmonic AAM Mod) ranking card

Pros: This is Dennis Murphy’s “Affordable Accuracy Monitor” (AAM) mod of the discontinued, budget Pioneer SP-BS22-LR: the stock tweeter is swapped for a Peerless BC25TG15 dome and a redesigned 3rd-order crossover is built to match it to the stock 4” woofer. CEA2034 spinorama shows only small variations from a flat on-axis response with some directivity error near the crossover, a marked improvement over the unmodified Pioneer, which the reviewer notes shows much more variation from flat. Distortion at 86dB SPL/1m is reasonably controlled above 200Hz, and tweeter distortion barely rises even at 96dB SPL/1m. Measured bass extension of 78Hz (-3dB), with a measured sensitivity of 83dB.

Cons: Some directivity error appears near the crossover frequency. Distortion climbs in the woofer’s range (below 200Hz) at both 86dB and 96dB SPL/1m. Minimum impedance dips to about 5 ohms with a couple of resonance peaks. This is a DIY project, not a finished retail product: Murphy sold ~$168 pre-built pairs for a while but no longer does, so it now requires sourcing a used/discontinued Pioneer SP-BS22-LR pair plus building the crossover and swapping the tweeter yourself. The mod itself is public domain, but there is no current turnkey way to buy this speaker.

Bass Extension (-10dB)60Hz (measured, Audio Science Review)
Bass Extension (-3dB)78Hz (measured, Audio Science Review)
Crossover Frequency3000Hz
DIY KitYes
Dimensions12.6”H x 7.1”W x 8.5”D (320.0 x 180.0 x 215.0 mm)
Drivers1x 4” curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1” silk dome tweeter (replacement)
Impedance8 ohms nominal (approx. 5 ohms minimum, measured by Audio Science Review)
Sensitivity83dB (2.83V/1m, measured by Audio Science Review)
Spinorama Preference Score5.07
Spinorama Preference Score with Perfect Sub7.82
Weight9 lbs (4.1 kg)
Woofer Cabinetported, rear

Micca RB42: $159.99 per pair Amazon eBay

Micca RB42 ranking card

Pros: Curved cabinet fit and finish look closer to a speaker costing three times as much. Rated for a wide 15-100W amplifier range with 4-8 ohm compatibility, giving flexibility with modest amplification. Measured bass extension of 85Hz (-3dB), with a measured sensitivity of 80dB.

Cons: CEA2034 spinorama shows significant peaks and valleys in the on-axis and listening-window response starting a few kHz up, with excess high-frequency energy the reviewer found fatiguing over time despite an initial impression of “detail.” Off-axis response diverges heavily from on-axis, meaning tonality shifts with room and listening position in ways EQ can’t correct. Distorts and the woofer visibly flaps under moderate volume; low 83dB sensitivity makes it a harder amplifier load than its size suggests.

Bass Extension (-10dB)62Hz (measured, Audio Science Review) - the reviewer noted an artificial boost around 100-300Hz, so true extension may be worse than this on-axis reading suggests
Bass Extension (-3dB)85Hz (measured, Audio Science Review) - the reviewer noted an artificial boost around 100-300Hz, so true extension may be worse than this on-axis reading suggests
DIY KitNo
Dimensions8.7H x 4.9W x 7.9D in
Drivers4” coated paper woofer, 0.75” silk dome tweeter
Frequency Response50Hz - 20kHz (Manufacturer specified, typical in-room)
Impedance4-8 ohms
Power Handling15-100W each
Sensitivity80dB (2.83V/1m, measured, Audio Science Review)
Spinorama Preference Score4.59
Spinorama Preference Score with Perfect Sub6.87
Weight6 lbs (2.7 kg) each (per retailer listing)
Woofer Cabinetported, front