Short answer: the Wharfedale Diamond 12.1 for better sound quality, the Pioneer SP-BS22-LR (Philharmonic AAM Mod) for the lower price. The Wharfedale Diamond 12.1 ranks #9 of 22 bookshelf speakers at $599. The Pioneer SP-BS22-LR (Philharmonic AAM Mod) ranks #17 at $168, $431 cheaper.
The case for the Pioneer SP-BS22-LR (Philharmonic AAM Mod): A crossover/tweeter mod of the discontinued, budget Pioneer SP-BS22-LR designed by Dennis Murphy. The tradeoff: Some directivity error appears near the crossover frequency.
What the Wharfedale Diamond 12.1 gets right: CEA2034 spinorama shows an almost flat on-axis response for a budget bookshelf speaker. The catch: A directivity error appears between 2-3kHz, showing up as a dip in both the on-axis and predicted in-room curves.
One note: the Wharfedale Diamond 12.1 is discontinued, but it still ranks #9 of 22 bookshelf speakers by sound quality, ahead of most of what is still sold new, so it is worth considering used.
Buy the Pioneer SP-BS22-LR (Philharmonic AAM Mod) if the price matters more than sound quality. Buy the Wharfedale Diamond 12.1 if sound quality matters more than the price.
If sound quality matters at all to you, skip the Pioneer SP-BS22-LR (Philharmonic AAM Mod). It ranks near the bottom of the 22 bookshelf speakers, so look higher up the list instead.
Specifications Side By Side
| Pioneer SP-BS22-LR (Philharmonic AAM Mod) | Wharfedale Diamond 12.1 | |
|---|---|---|
| Price | $168 | $599 Discontinued |
| Ranked | #17 of 22 in Medium Size Bookshelf Speakers | #9 of 22 in Medium Size Bookshelf Speakers |
| Drivers | 1x 4" curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1" silk dome tweeter (replacement) | 5" advanced polypropylene cone woofer, 1" textile dome tweeter |
| Weight | 9 lbs / 4.1 kg | 15 lbs / 6.8 kg each |
| Sensitivity | 83dB (2.83V/1m, measured by Audio Science Review) | 87dB |
| Impedance | 8 ohms nominal | 8 ohms |
| Crossover Frequency | 3000Hz | 2.6kHz |
| Dimensions | - | 12.2"H x 7"W x 10.9"D (310 x 178 x 277 mm) |
| Discontinued | - | Yes |
| Woofer Cabinet | - | ported |
The Two Speakers In Full
Pioneer SP-BS22-LR (Philharmonic AAM Mod): $168
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.
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 →
| Crossover Frequency | 3000Hz |
|---|---|
| Drivers | 1x 4" curvilinear-cone woofer (stock Pioneer), 1x Peerless BC25TG15 1" silk dome tweeter (replacement) |
| Impedance | 8 ohms nominal |
| Sensitivity | 83dB (2.83V/1m, measured by Audio Science Review) |
| Weight | 9 lbs / 4.1 kg |
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Wharfedale Diamond 12.1: $599 Discontinued
Pros: CEA2034 spinorama shows an almost flat on-axis response for a budget bookshelf speaker. Predicted in-room response is very nice aside from a dip around 2kHz. Horizontal beamwidth of about ±70 degrees is wide, though a bit uneven.
Cons: A directivity error appears between 2-3kHz, showing up as a dip in both the on-axis and predicted in-room curves. Vertical directivity requires staying within about 30 degrees of the tweeter axis for accurate tonal balance. Distortion rises substantially at 96dB SPL/1m below 50Hz, where the woofer runs out of headroom without a high-pass filter - a real limitation for a compact 5” driver at higher output. Discontinued.
Full Wharfedale Diamond 12.1 review and specifications →
| Crossover Frequency | 2.6kHz |
|---|---|
| Dimensions | 12.2"H x 7"W x 10.9"D (310 x 178 x 277 mm) |
| Discontinued | Yes |
| Drivers | 5" advanced polypropylene cone woofer, 1" textile dome tweeter |
| Impedance | 8 ohms |
| Sensitivity | 87dB |
| Weight | 15 lbs / 6.8 kg each |
| Woofer Cabinet | ported |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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Product prices and availability were last checked August 12, 2026 at 5:33 PM UTC 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.