Short answer: the Klipsch RP-600M II for better sound quality, the Fosi Audio SP601 for the lower price. The Klipsch RP-600M II ranks #74 of 130 bookshelf speakers at $449.99. The Fosi Audio SP601 ranks #112 at $399.99, $50 cheaper.
What the Klipsch RP-600M II offers: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. Roughly 10-20° wider horizontal radiation than the original, giving more soundstage envelopment while retaining precise imaging. A major step up in overall tonal neutrality compared to the original RP-600M, largely eliminating that model’s midrange resonance issues. Unusually, sounds better with the grille on - the grille smooths out the elevated treble rather than degrading the sound, a rare trait among speakers the reviewer has tested. More refined back-panel hardware, including anodized binding posts and jumper cables for optional bi-amping. Responds well to EQ correction (verified using measurement software and a miniDSP), letting the on-axis response be made genuinely linear. Watch for: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced. Horizontal dispersion is very slightly less linear across angles than the original RP-600M, a minor trade-off for the wider overall radiation pattern. Klipsch’s marketed sensitivity (about 94.5dB) is, like the original, a half-space rating roughly 9dB above the anechoic reality (closer to 85-86dB). In-room bass rolls off around 60Hz in practice, and a 120Hz boost paired with a midrange scoop gives kick drums their “tambour” without real low-end weight - a subwoofer is still recommended. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Toeing the speaker out for better on-axis tonality (rather than using the grille) introduces slightly more diffuse imaging from added sidewall reflections.
What the Fosi Audio SP601 offers: Two-way bookshelf design with a 6.5” paper/aluminum-alloy composite cone woofer and 1.5” silk dome tweeter. Bass reaches a respectable 60-70Hz in most rooms (F3 59Hz, F10 40Hz) for a budget bookshelf speaker. Distortion at 86dB and 96dB measures reasonably well at face value, and compression issues at extreme output are generally in line with what’s expected for a speaker at this price point. The overall tonal character can be substantially improved with basic EQ - the reviewer found a boost around 400Hz plus a cut around 4kHz brought it to an acceptable baseline. Watch for: An unusually erratic, up-and-down frequency response (a scooped midrange followed by an upper-mid bump, a dip, another small bump, then a strong 3-4dB peak around 4-7kHz) makes the speaker’s overall character genuinely hard to characterize - the reviewer compared the experience to a similarly disliked model, the Triangle Borea BR03, which has a comparably inconsistent response. The 4-7kHz peak gives a sharp, sibilant edge to S and T sounds in vocals. A strong diffraction dip around 4kHz followed by a peak can’t be fully corrected with EQ; the reviewer recommends sidewall absorption panels instead, since off-axis energy in the 2-7kHz range actually exceeds the direct sound reaching the listener. Multitone distortion becomes more noticeable and grainy at higher volumes, concentrated in the upper-midrange where hearing is most sensitive. A peaking distortion issue right at the crossover region suggests a possible combination of tweeter distortion and midwoofer/crossover-component strain. The enclosure sounds notably hollow when tapped, and a flashlight inspection suggested a lack of internal damping material, along with likely insufficient bracing. Vertical listening position is fairly tightly constrained around the tweeter axis. Still requires a subwoofer for real kick-drum impact and bass authority.
Buy the Klipsch RP-600M II when sound quality outweighs the price for you, and the Fosi Audio SP601 when the price outweighs sound quality instead.
Skip the Fosi Audio SP601 if sound quality matters to you. It ranks near the bottom of the 130 bookshelf speakers.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Klipsch RP-600M II | Fosi Audio SP601 | |
|---|---|---|
| Price | $449.99 per pair | $399.99 per pair |
| Ranked | #74 of 130 in Large Size Bookshelf Speakers | #112 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) | 40Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) | 59Hz (measured, Erin's Audio Corner) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) | 14.5"H x 9.1"W x 14"D (368.3 x 231.1 x 355.6 mm) |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) | 4 ohms nominal, 4.1 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | 86dB (measured, Erin's Audio Corner) | 85.4dB (measured, Erin's Audio Corner) |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn | 6.5" woofer, 1.5" Silk Dome Tweeters |
| Weight | 13 lbs (5.9 kg) each | 11.5 lbs (5.2 kg) |
| Woofer Cabinet | ported | ported, rear |
| Spinorama Preference Score | 4.75 | - |
| Spinorama Preference Score with Perfect Sub | 6.88 | - |
| App | - | No |
| Bluetooth | - | No |
| EQ | - | No |
| DSP | - | No |
| Power Handling | - | 80w RMS Per Speaker |
Related Speaker Comparisons
More worthwhile head-to-heads for Klipsch RP-600M II:
- Klipsch RP-600M II vs KEF Reference 1 Meta
- Klipsch RP-600M II vs GR-Research NX-Studio
- Klipsch RP-600M II vs March Audio Sointuva AWG
- Klipsch RP-600M II vs AsciLab C6B
- Klipsch RP-600M II vs Audio First Cadentia 3
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The Two Speakers In Full
Klipsch RP-600M II: $449.99 per pair Amazon eBay
Pros: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. Roughly 10-20° wider horizontal radiation than the original, giving more soundstage envelopment while retaining precise imaging. A major step up in overall tonal neutrality compared to the original RP-600M, largely eliminating that model’s midrange resonance issues. Unusually, sounds better with the grille on - the grille smooths out the elevated treble rather than degrading the sound, a rare trait among speakers the reviewer has tested. More refined back-panel hardware, including anodized binding posts and jumper cables for optional bi-amping. Responds well to EQ correction (verified using measurement software and a miniDSP), letting the on-axis response be made genuinely linear. Measured bass extension of 70Hz (-3dB), with a measured sensitivity of 86dB.
Cons: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced. Horizontal dispersion is very slightly less linear across angles than the original RP-600M, a minor trade-off for the wider overall radiation pattern. Klipsch’s marketed sensitivity (about 94.5dB) is, like the original, a half-space rating roughly 9dB above the anechoic reality (closer to 85-86dB). In-room bass rolls off around 60Hz in practice, and a 120Hz boost paired with a midrange scoop gives kick drums their “tambour” without real low-end weight - a subwoofer is still recommended. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Toeing the speaker out for better on-axis tonality (rather than using the grille) introduces slightly more diffuse imaging from added sidewall reflections.
Full Klipsch RP-600M II review and specifications →
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) |
| Sensitivity | 86dB (measured, Erin's Audio Corner) |
| Spinorama Preference Score | 4.75 |
| Spinorama Preference Score with Perfect Sub | 6.88 |
| Weight | 13 lbs (5.9 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: The Truth about Klipsch’s “NEW” Sound. RP-600M Update. More from Erin’s Audio Corner →
- Erin’s Audio Corner Website Klipsch RP-600M II
- GR-Research: We Bought The "NEW" RP-600M II Is KLIPSCH Listening?! More from GR-Research →
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner Measurements (spinorama.org)
- Head-to-Head Comparisons
- Klipsch RP-600M II vs Dynaudio Emit 20
- Klipsch RP-600M II vs Philharmonic BMR Monitor
- Klipsch RP-600M II vs JBL Studio 630
- Klipsch RP-600M II vs Behringer B2030P
- Klipsch RP-600M II vs Ascend CBM-170 SE2
- Klipsch RP-600M II vs Infinity Reference R162
- Klipsch RP-600M II vs GR-Research X-LS Encore
- Klipsch RP-600M II vs Infinity IL10
- See all 72 comparisons
Fosi Audio SP601: $399.99 per pair Amazon Fosiaudio eBay
Pros: Two-way bookshelf design with a 6.5” paper/aluminum-alloy composite cone woofer and 1.5” silk dome tweeter. Bass reaches a respectable 60-70Hz in most rooms (F3 59Hz, F10 40Hz) for a budget bookshelf speaker. Distortion at 86dB and 96dB measures reasonably well at face value, and compression issues at extreme output are generally in line with what’s expected for a speaker at this price point. The overall tonal character can be substantially improved with basic EQ - the reviewer found a boost around 400Hz plus a cut around 4kHz brought it to an acceptable baseline. Measured bass extension of 59Hz (-3dB), with a measured sensitivity of 85.4dB.
Cons: An unusually erratic, up-and-down frequency response (a scooped midrange followed by an upper-mid bump, a dip, another small bump, then a strong 3-4dB peak around 4-7kHz) makes the speaker’s overall character genuinely hard to characterize - the reviewer compared the experience to a similarly disliked model, the Triangle Borea BR03, which has a comparably inconsistent response. The 4-7kHz peak gives a sharp, sibilant edge to S and T sounds in vocals. A strong diffraction dip around 4kHz followed by a peak can’t be fully corrected with EQ; the reviewer recommends sidewall absorption panels instead, since off-axis energy in the 2-7kHz range actually exceeds the direct sound reaching the listener. Multitone distortion becomes more noticeable and grainy at higher volumes, concentrated in the upper-midrange where hearing is most sensitive. A peaking distortion issue right at the crossover region suggests a possible combination of tweeter distortion and midwoofer/crossover-component strain. The enclosure sounds notably hollow when tapped, and a flashlight inspection suggested a lack of internal damping material, along with likely insufficient bracing. Vertical listening position is fairly tightly constrained around the tweeter axis. Still requires a subwoofer for real kick-drum impact and bass authority.
Full Fosi Audio SP601 review and specifications →
| App | No |
|---|---|
| Bass Extension (-10dB) | 40Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 59Hz (measured, Erin's Audio Corner) |
| Bluetooth | No |
| DSP | No |
| Dimensions | 14.5"H x 9.1"W x 14"D (368.3 x 231.1 x 355.6 mm) |
| Drivers | 6.5" woofer, 1.5" Silk Dome Tweeters |
| EQ | No |
| Impedance | 4 ohms nominal, 4.1 ohms minimum (measured, Erin's Audio Corner) |
| Power Handling | 80w RMS Per Speaker |
| Sensitivity | 85.4dB (measured, Erin's Audio Corner) |
| Weight | 11.5 lbs (5.2 kg) |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons