Short answer: the KEF LSX II LT for better sound quality, the JBL One Series 104 for the lower price. The KEF LSX II LT ranks #27 of 60 powered bookshelf speakers at $600. The JBL One Series 104 ranks #58 at $129, $471 cheaper.
What the KEF LSX II LT offers: Coaxial (Uni-Q-style) driver keeps the tweeter centered in the midrange, giving wide and consistent dispersion both horizontally and vertically (about ±60° each) - a wide sweet spot for multiple seats or positions. The KEF Connect app provides genuinely useful DSP control: desk/wall boundary compensation, adjustable bass contour (standard/less/extra), treble trim, and subwoofer integration, letting you tune the sound to wherever it’s placed. Distortion at a moderate 86dB looks good for the speaker’s compact size. Tonal profile stays consistent from 0° to 30° off-axis, so side-seat listeners hear essentially the same balance as someone centered. Extensive connectivity for its size: HDMI, USB, optical, sub output, plus Wi-Fi/Bluetooth. Clearly outperformed the reviewer’s soundbars, including ones bundled with their own subwoofers, as a TV audio replacement. Watch for: Small drivers mean it’s SPL-limited: bass compression kicks in around 88-92dB/1m per speaker, and multitone distortion crosses the reviewer’s 3% threshold around 96dB - not intended for loud or large-room duty. F3 of 55Hz and F10 of 46Hz mean it loses much of its bass by around 50Hz; a subwoofer (controllable through the same app) is needed for real low end. Diffraction dips appear around 4-5kHz and again near 8kHz, likely tied to the tweeter housing or surround, giving a mild reduction in treble attack and sibilance. A possible port or enclosure resonance shows up around 800Hz in the rear-radiation measurements, though the reviewer wasn’t certain of the exact cause or whether it’s audible. No analog input on this LT variant, so a turntable can’t be connected directly - only the pricier standard LSX II model includes one.
What the JBL One Series 104 offers: Heavy internal EQ from the amplifier meaningfully compensates for otherwise poor raw driver measurements, and casual listening on undemanding content sounded like a scaled-down JBL 305P Mark II - well above typical computer-speaker quality for the price. Solid build quality for a $90-130 powered pair with dual built-in amplifiers. Watch for: Measuring the passive drivers alone (bypassing the amplifier’s EQ) showed “no bass, no low mids, and highly irregular highs” - a disaster by the reviewer’s description. Even with the amplifier’s correction applied, there’s an on-axis cancellation around 7.4kHz from the coaxial driver design, and JBL’s own published frequency-response graph uses a compressed 95dB vertical scale that hides real deviations the reviewer’s 50dB-scale CEA-2034 measurement reveals. Female vocals and “lisping” content became bright and annoying; the reviewer’s verdict was “can’t recommend it though if you want a true hi-fi experience.”
Buy the KEF LSX II LT if sound quality matters more than the price. Buy the JBL One Series 104 if the price matters more than sound quality.
If sound quality matters at all to you, skip the JBL One Series 104. It ranks near the bottom of the 60 powered bookshelf speakers, so look higher up the list instead.
Specifications Side By Side
| KEF LSX II LT | JBL One Series 104 | |
|---|---|---|
| Price | $600.00 | $129 |
| Ranked | #27 of 60 in Medium Size Powered Bookshelf Speakers | #58 of 60 in Medium Size Powered Bookshelf Speakers |
| Dimensions | 9.5"H x 6.1"W x 7.1"D (241.3 x 154.9 x 180.3 mm) | 9.7H x 6W x 4.9D in (per manufacturer, 104-BT) |
| Inputs | Wifi, USB-C, HDMI, Optical, Bluetooth | - |
| Outputs | RCA Subwoofer | - |
| Drivers | 115mm (4.5in.) magnesium/aluminium alloy cone woofer, 19mm (0.75in.) aluminium dome tweeter | 4.5" coaxial low-frequency driver, 0.75" soft dome tweeter |
| Weight | 15 lbs / 6.8 kg | 4.5 lbs / 2.06 kg (master), 3.8 lbs / 1.73 kg (slave) |
| App | No | No |
| Bluetooth | No | - |
| EQ | No | Yes (fixed, amplifier-applied) |
| Output Power | 100w RMS Per Speaker | 60W total Class D (30W per speaker) |
| Bass Extension (-3dB) | 55Hz (measured, Erin’s Audio Corner) | 45Hz with the amplifier’s DSP bass boost active (measured, Audio Science Review) |
| Bass Extension (-10dB) | 46Hz (measured, Erin’s Audio Corner) | 35Hz with the amplifier’s DSP bass boost active (measured, Audio Science Review) |
| Sensitivity | 84dB (measured at 0.3V/1m, Erin’s Audio Corner) | - |
| Frequency Response | - | 60Hz - 20kHz (Manufacturer specified) |
| DSP | - | Yes |
Related Speaker Comparisons
More useful head-to-heads from the same speaker class:
- Vanatoo Transparent Zero Plus vs Dayton Audio M4
- Edifier S1000MKII vs Dayton Audio M4
- Neumann KH80 DSP vs Donner Dyna 3
- Edifier S1000W vs JBL One Series 104
- KEF LSX II LT vs Edifier MR4
Prices on this page were last checked August 24, 2026 at 6:53 AM 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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
KEF LSX II LT: $600.00 Amazon eBay
Pros: Coaxial (Uni-Q-style) driver keeps the tweeter centered in the midrange, giving wide and consistent dispersion both horizontally and vertically (about ±60° each) - a wide sweet spot for multiple seats or positions. The KEF Connect app provides genuinely useful DSP control: desk/wall boundary compensation, adjustable bass contour (standard/less/extra), treble trim, and subwoofer integration, letting you tune the sound to wherever it’s placed. Distortion at a moderate 86dB looks good for the speaker’s compact size. Tonal profile stays consistent from 0° to 30° off-axis, so side-seat listeners hear essentially the same balance as someone centered. Extensive connectivity for its size: HDMI, USB, optical, sub output, plus Wi-Fi/Bluetooth. Clearly outperformed the reviewer’s soundbars, including ones bundled with their own subwoofers, as a TV audio replacement.
Cons: Small drivers mean it’s SPL-limited: bass compression kicks in around 88-92dB/1m per speaker, and multitone distortion crosses the reviewer’s 3% threshold around 96dB - not intended for loud or large-room duty. F3 of 55Hz and F10 of 46Hz mean it loses much of its bass by around 50Hz; a subwoofer (controllable through the same app) is needed for real low end. Diffraction dips appear around 4-5kHz and again near 8kHz, likely tied to the tweeter housing or surround, giving a mild reduction in treble attack and sibilance. A possible port or enclosure resonance shows up around 800Hz in the rear-radiation measurements, though the reviewer wasn’t certain of the exact cause or whether it’s audible. No analog input on this LT variant, so a turntable can’t be connected directly - only the pricier standard LSX II model includes one.
Full KEF LSX II LT review and specifications →
| App | No |
|---|---|
| Bass Extension (-10dB) | 46Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 55Hz (measured, Erin's Audio Corner) |
| Bluetooth | No |
| Dimensions | 9.5"H x 6.1"W x 7.1"D (241.3 x 154.9 x 180.3 mm) |
| Drivers | 115mm (4.5in.) magnesium/aluminium alloy cone woofer, 19mm (0.75in.) aluminium dome tweeter |
| EQ | No |
| Inputs | Wifi, USB-C, HDMI, Optical, Bluetooth |
| Output Power | 100w RMS Per Speaker |
| Outputs | RCA Subwoofer |
| Sensitivity | 84dB (measured at 0.3V/1m, Erin's Audio Corner) |
| Weight | 15 lbs / 6.8 kg |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- KEF LSX II LT vs Dayton Audio M4
- KEF LSX II LT vs Edifier S2000MKIII
- KEF LSX II LT vs KRK Classic 5
- KEF LSX II LT vs Edifier MR4
- KEF LSX II LT vs JBL 705P
- KEF LSX II LT vs Vanatoo Transparent One Encore Plus
- KEF LSX II LT vs IK Multimedia iLoud MTM
- KEF LSX II LT vs Topping MA4
- See all 47 comparisons
JBL One Series 104: $129 Amazon eBay
Pros: Heavy internal EQ from the amplifier meaningfully compensates for otherwise poor raw driver measurements, and casual listening on undemanding content sounded like a scaled-down JBL 305P Mark II - well above typical computer-speaker quality for the price. Solid build quality for a $90-130 powered pair with dual built-in amplifiers.
Cons: Measuring the passive drivers alone (bypassing the amplifier’s EQ) showed “no bass, no low mids, and highly irregular highs” - a disaster by the reviewer’s description. Even with the amplifier’s correction applied, there’s an on-axis cancellation around 7.4kHz from the coaxial driver design, and JBL’s own published frequency-response graph uses a compressed 95dB vertical scale that hides real deviations the reviewer’s 50dB-scale CEA-2034 measurement reveals. Female vocals and “lisping” content became bright and annoying; the reviewer’s verdict was “can’t recommend it though if you want a true hi-fi experience.”
Full JBL One Series 104 review and specifications →
| App | No |
|---|---|
| Bass Extension (-10dB) | 35Hz with the amplifier's DSP bass boost active (measured, Audio Science Review) |
| Bass Extension (-3dB) | 45Hz with the amplifier's DSP bass boost active (measured, Audio Science Review) |
| DSP | Yes |
| Dimensions | 9.7H x 6W x 4.9D in (per manufacturer, 104-BT) |
| Drivers | 4.5" coaxial low-frequency driver, 0.75" soft dome tweeter |
| EQ | Yes (fixed, amplifier-applied) |
| Frequency Response | 60Hz - 20kHz (Manufacturer specified) |
| Output Power | 60W total Class D (30W per speaker) |
| Weight | 4.5 lbs / 2.06 kg (master), 3.8 lbs / 1.73 kg (slave) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- JBL One Series 104 vs NHT Pro M-00
- JBL One Series 104 vs Kali Audio IN-UNF
- JBL One Series 104 vs Edifier S1000MKII
- JBL One Series 104 vs Edifier S1000W
- JBL One Series 104 vs Dynaudio LYD 5
- JBL One Series 104 vs Pioneer DJ VM-50
- JBL One Series 104 vs Klipsch The Fives
- JBL One Series 104 vs Audioengine A5+ Classic
- See all 26 comparisons