Short answer: the Klipsch Flexus Sub 100. It ranks #16 of 48 subwoofers by sound quality, rated 3.4/5, at $349.99; the Klipsch HD Theater 600 ranks #25, rated 3.3/5, and costs $399, which makes this an easy call rather than a real tradeoff.
What the Klipsch Flexus Sub 100 does well: Independent CEA-2010 testing records 90.2 dB at 20 Hz and 109.1 dB (avg of 3/4 bands) through 40-80 Hz. Watch for: Only works with Klipsch Flexus soundbars, not as a standalone LFE sub.
Why pick the Klipsch HD Theater 600: Independent CEA-2010 testing records 108.2 dB (avg of 3/4 bands) through 40-80 Hz. The catch: Without a published 20 Hz result, deep-bass capability is less certain than the midbass figure.
Worth knowing: the Klipsch HD Theater 600 has been discontinued and is hard to find new at this point.
Buy the Klipsch Flexus Sub 100. It is rated higher for sound quality than the Klipsch HD Theater 600 and costs less, which makes it the one to get unless you need something the other one does better.
Still deciding? The full Subwoofers rankings cover every ranked option.
Specifications Side By Side
| Klipsch Flexus Sub 100 | Klipsch HD Theater 600 | |
|---|---|---|
| Price | $349.99 | $399 Discontinued |
| Ranked | #16 of 48 in Small Home Subwoofers (Under 30 lbs) | #25 of 48 in Small Home Subwoofers (Under 30 lbs) |
| Enclosure | sealed | ported, rear |
| Output SPL at 20 Hz | 90.2 dB | - |
| Output SPL at 25 Hz | 96.7 dB | 87.1 dB |
| Output SPL at 31.5 Hz | 101.2 dB | 98.4 dB |
| Output SPL at 40 Hz | 105.9 dB | 104.9 dB |
| Output SPL at 50 Hz | 109.0 dB | 107.6 dB |
| Output SPL at 63 Hz | 112.4 dB | 112.1 dB |
| CEA-2010-A Average (40-80Hz) | 109.1 dB (avg of 3/4 bands) | 108.2 dB (avg of 3/4 bands) |
| Dimensions | 13.4”H x 13.2”W x 13.7”D (339.9 x 335.0 x 349.2 mm) | 13.9”H x 12.5”W x 12.5”D (353.1 x 317.5 x 317.5 mm) |
| Weight | 20.7 lbs (9.4 kg) | 17 lbs (7.7 kg) |
| Warranty | 2/5 | - |
| Measurement Source | Brent Butterworth | Brent Butterworth |
| Drivers | 10” (254mm) driver | 8” (203mm) driver |
| Country | - | United States |
| Discontinued | - | Yes |
Related Speaker Comparisons
More top alternatives to Klipsch Flexus Sub 100:
- SVS SB-1000 PRO vs Klipsch Flexus Sub 100
- SVS 3000 Micro vs Klipsch Flexus Sub 100
- Klipsch Flexus Sub 100 vs MartinLogan Dynamo 700w
- Klipsch Flexus Sub 100 vs ELAC SUB1010
- Klipsch Flexus Sub 100 vs Monitor Audio BRW10
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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
Klipsch Flexus Sub 100: $349.99 Amazon eBay
Pros: Independent CEA-2010 testing records 90.2 dB at 20 Hz and 109.1 dB (avg of 3/4 bands) through 40-80 Hz. The sealed enclosure with a 10” driver suits a small room.
Cons: Only works with Klipsch Flexus soundbars, not as a standalone LFE sub. The 339.9H x 335.0W x 349.2D mm cabinet and 9.4 kg mass still need deliberate placement.
Full Klipsch Flexus Sub 100 review and specifications →
| CEA-2010-A Average (40-80Hz) | 109.1 dB (avg of 3/4 bands) |
|---|---|
| Dimensions | 13.4”H x 13.2”W x 13.7”D (339.9 x 335.0 x 349.2 mm) |
| Drivers | 10” (254mm) driver |
| Enclosure | sealed |
| Measurement Source | Brent Butterworth |
| Output SPL at 20 Hz | 90.2 dB |
| Output SPL at 25 Hz | 96.7 dB |
| Output SPL at 31.5 Hz | 101.2 dB |
| Output SPL at 40 Hz | 105.9 dB |
| Output SPL at 50 Hz | 109.0 dB |
| Output SPL at 63 Hz | 112.4 dB |
| Warranty | 2/5 |
| Weight | 20.7 lbs (9.4 kg) |
- Reviews, Comparisons and Sound Samples
- Independently measured by Brent Butterworth; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Klipsch Flexus Sub 100 vs MartinLogan Dynamo 700w
- Klipsch Flexus Sub 100 vs ELAC SUB1010
- Klipsch Flexus Sub 100 vs SVS 3000 Micro
- Klipsch Flexus Sub 100 vs Monitor Audio BRW10
- Klipsch Flexus Sub 100 vs SVS SB-1000 PRO
- Klipsch Flexus Sub 100 vs Klipsch R-10SW
- Klipsch Flexus Sub 100 vs Monoprice Premium Select 8in 200-Watt
Klipsch HD Theater 600: $399 Discontinued eBay
Pros: Independent CEA-2010 testing records 108.2 dB (avg of 3/4 bands) through 40-80 Hz. The ported, rear enclosure with 8” (203mm) driver is a compact way to add useful midbass support to a modest system.
Cons: Without a published 20 Hz result, deep-bass capability is less certain than the midbass figure. The 353.1H x 317.5W x 317.5D mm cabinet and 7.7 kg mass still need careful placement and calibration. Discontinued.
Full Klipsch HD Theater 600 review and specifications →
| CEA-2010-A Average (40-80Hz) | 108.2 dB (avg of 3/4 bands) |
|---|---|
| Country | United States |
| Dimensions | 13.9”H x 12.5”W x 12.5”D (353.1 x 317.5 x 317.5 mm) |
| Discontinued | Yes |
| Drivers | 8” (203mm) driver |
| Enclosure | ported, rear |
| Measurement Source | Brent Butterworth |
| Output SPL at 25 Hz | 87.1 dB |
| Output SPL at 31.5 Hz | 98.4 dB |
| Output SPL at 40 Hz | 104.9 dB |
| Output SPL at 50 Hz | 107.6 dB |
| Output SPL at 63 Hz | 112.1 dB |
| Weight | 17 lbs (7.7 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Brent Butterworth; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Klipsch HD Theater 600 vs ELAC SUB1010
- Klipsch HD Theater 600 vs Monitor Audio BRW10
- Klipsch HD Theater 600 vs ELAC IW-S10EQ in-wall
- Klipsch HD Theater 600 vs MartinLogan Dynamo 700w
- Klipsch HD Theater 600 vs Klipsch R-10SW
- Klipsch HD Theater 600 vs Polk Audio PSW10
- Klipsch HD Theater 600 vs Monoprice Premium Select 8in 200-Watt
- Klipsch HD Theater 600 vs SVS 3000 Micro
- See all 12 comparisons