Short answer: the Pioneer SP-BS22-LR (Philharmonic AAM Mod), though neither ranks well in its class. Both are rated 2.8/5 for sound quality (#62 and #63 of 89 bookshelf speakers), and the Pioneer SP-BS22-LR (Philharmonic AAM Mod) costs $168 against $495.94 for the MartinLogan Motion 4i, with sound quality a draw, the lower price decides it. Both are rated below 3.0/5 among the 89 bookshelf speakers; for better sound, the Ascend Acoustics HTM-200SE2 ranks #7 at $368.
What the MartinLogan Motion 4i does well: Best treated as a satellite: crossing it to a subwoofer lifts its predicted preference score from 2.73 to 6.36, so the shallow bass matters far less in a 2.1 or home-theater setup. Watch for: Bass-shy to the point of needing a subwoofer: the measured -3dB point is 159.7Hz, so on its own it produces almost nothing below roughly 160Hz.
What the Pioneer SP-BS22-LR (Philharmonic AAM Mod) does well: 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. The tradeoff: Some directivity error appears near the crossover frequency.
Buy the Pioneer SP-BS22-LR (Philharmonic AAM Mod). Both are rated the same for sound quality, and it costs $327.94 less than the MartinLogan Motion 4i.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| MartinLogan Motion 4i | Pioneer SP-BS22-LR (Philharmonic AAM Mod) | |
|---|---|---|
| Price | $495.94 per pair | $168 per pair |
| Ranked | #63 of 89 in Medium Size Bookshelf Speakers | #62 of 89 in Medium Size Bookshelf Speakers |
| Configuration | Passive 2-way bookshelf speaker | - |
| Enclosure | ported, rear | - |
| Drivers | 1” x 1.4” Folded Motion tweeter, 4” paper cone woofer | 1x 4” curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1” silk dome tweeter (replacement) |
| Crossover Frequency | 2,900 Hz | 3000Hz |
| Coverage | 80° x 80° | - |
| Frequency Response | 70Hz - 23kHz (±3dB, Manufacturer specified) | - |
| Bass Extension (-3dB) | 159.7Hz (measured, Audio Science Review via spinorama.org) | 78Hz (measured, Audio Science Review) |
| Sensitivity | 87.5dB (2.83V/1m, measured, Audio Science Review) | 83dB (2.83V/1m, measured by Audio Science Review) |
| Impedance | 4 ohms nominal | 8 ohms nominal (approx. 5 ohms minimum, measured by Audio Science Review) |
| Recommended Power | 20-150W | - |
| Dimensions | 12.6” x 5.6” x 5.7” (320 x 143 x 145 mm) (H x W x D) | 12.6”H x 7.1”W x 8.5”D (320.0 x 180.0 x 215.0 mm) |
| Weight | 6 lbs (2.72 kg) | 9 lbs (4.1 kg) |
| Country | United States (design) | - |
| Measurement Source | Audio Science Review | - |
| Spinorama Preference Score | 2.73 | 5.07 |
| Spinorama Preference Score with Perfect Sub | 6.36 | 7.82 |
| DIY Kit | No | Yes |
| Bass Extension (-10dB) | - | 60Hz (measured, Audio Science Review) |
| Woofer Cabinet | - | ported, rear |
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Prices on this page were last checked September 26, 2026 at 11:14 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
MartinLogan Motion 4i: $495.94 per pair Amazon Crutchfield eBay
Pros: Best treated as a satellite: crossing it to a subwoofer lifts its predicted preference score from 2.73 to 6.36, so the shallow bass matters far less in a 2.1 or home-theater setup. Directivity is the strong point, with sound-power deviation (NBD 0.426) lower than its on-axis figure (0.547), meaning the off-axis output tracks the front more evenly than most budget cabinets and the image stays stable around the room. The Folded Motion tweeter measures cleanly for the price, and 87.5dB measured sensitivity (2.83V/1m) means modest amplifiers drive it easily. Measured bass extension of 159.7Hz (-3dB), with a measured sensitivity of 87.5dB.
Cons: Bass-shy to the point of needing a subwoofer: the measured -3dB point is 159.7Hz, so on its own it produces almost nothing below roughly 160Hz. The balance is bright and uneven, deviating 2.7dB across 300Hz-5kHz with a clear upward tilt, and the review’s verdict is a “bass-shy, bright” speaker. A port resonance near 850Hz and high woofer distortion add audible roughness through the midrange, and impedance dips below 3 ohms, so it wants an amplifier comfortable with low-impedance loads.
Full MartinLogan Motion 4i review and specifications →
| Bass Extension (-3dB) | 159.7Hz (measured, Audio Science Review via spinorama.org) |
|---|---|
| Configuration | Passive 2-way bookshelf speaker |
| Country | United States (design) |
| Coverage | 80° x 80° |
| Crossover Frequency | 2,900 Hz |
| DIY Kit | No |
| Dimensions | 12.6” x 5.6” x 5.7” (320 x 143 x 145 mm) (H x W x D) |
| Drivers | 1” x 1.4” Folded Motion tweeter, 4” paper cone woofer |
| Enclosure | ported, rear |
| Frequency Response | 70Hz - 23kHz (±3dB, Manufacturer specified) |
| Impedance | 4 ohms nominal |
| Measurement Source | Audio Science Review |
| Recommended Power | 20-150W |
| Sensitivity | 87.5dB (2.83V/1m, measured, Audio Science Review) |
| Spinorama Preference Score | 2.73 |
| Spinorama Preference Score with Perfect Sub | 6.36 |
| Weight | 6 lbs (2.72 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Pioneer SP-BS22-LR (Philharmonic AAM Mod): $168 per pair eBay
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.
Full Pioneer SP-BS22-LR (Philharmonic AAM Mod) review and specifications →
| Bass Extension (-10dB) | 60Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 78Hz (measured, Audio Science Review) |
| Crossover Frequency | 3000Hz |
| DIY Kit | Yes |
| Dimensions | 12.6”H x 7.1”W x 8.5”D (320.0 x 180.0 x 215.0 mm) |
| Drivers | 1x 4” curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1” silk dome tweeter (replacement) |
| Impedance | 8 ohms nominal (approx. 5 ohms minimum, measured by Audio Science Review) |
| Sensitivity | 83dB (2.83V/1m, measured by Audio Science Review) |
| Spinorama Preference Score | 5.07 |
| Spinorama Preference Score with Perfect Sub | 7.82 |
| Weight | 9 lbs (4.1 kg) |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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