Short answer: the Rythmik E15. It ranks #24 of 212 subwoofers by sound quality, rated 4.1/5, at $1,599. The REL Acoustics T/9x ranks #47, rated 3.9/5, at $1,549, $50 cheaper, which does not close the gap in sound quality.
The case for the Rythmik E15: A compact sealed 15” Direct Servo subwoofer, narrower and shallower than Rythmik’s F15, driven by the 600W H600 amplifier. The catch: No independent measurements yet, so its output can’t be compared directly with ranked subwoofers; the rating is estimated from the measured sealed Rythmik F12 and ported Rythmik FV15HP (119.3 and 122.0dB in the 40 to 80Hz CEA-2010 bands).
Why pick the REL Acoustics T/9x: Flagship of the Serie T/x line pairing a front-firing 10-inch FibreAlloy driver with a down-firing 10-inch passive radiator powered by a 300W Class A/B amplifier. Watch for: Passive radiator configuration requires careful boundary positioning away from corners to avoid room mode excitation.
Buy the Rythmik E15. It is rated higher for sound quality, and the $50 saving on the REL Acoustics T/9x is not enough to make up the difference.
About the ratings: neither speaker has been measured yet, so both ratings are estimated from measured siblings and predecessors (likely ranges: Rythmik E15 3.7 to 4.2; REL Acoustics T/9x 3.7 to 4.1). Treat this verdict as provisional.
Looking for alternatives? See the complete Subwoofers rankings.
Specifications Side By Side
| Rythmik E15 | REL Acoustics T/9x | |
|---|---|---|
| Price | $1,599.00 | $1,549.00 |
| Ranked | #24 of 212 in Medium Home Subwoofers (30-75 lbs) Estimated | #47 of 212 in Medium Home Subwoofers (30-75 lbs) Estimated |
| Weight | 104.1 lbs (47.2 kg) | 45.4 lbs (20.6 kg) |
| Dimensions | 19”H x 17”W x 20”D (483 x 432 x 508 mm) | 13.4”H x 15.2”W x 15.5”D (340 x 387 x 393 mm) |
| Country | United States | United Kingdom |
| Warranty | 5/3 | 3 |
| Enclosure | sealed | passive radiator |
| Drivers | 15” servo-controlled woofer | 10” (254mm) active FibreAlloy driver, 10” (254mm) down-firing passive radiator |
| Amplifier Power | 600W | 300W RMS (Class A/B) |
| Frequency Response | - | 27Hz at -6dB (manufacturer specified) |
Related Speaker Comparisons
More top alternatives to Rythmik E15:
- Rythmik E15 vs Rythmik F12
- Rythmik E15 vs SVS SB-3000 R|Evolution
- Rythmik E15 vs Arendal 1723 Subwoofer 1S
- REL Acoustics T/9x vs ELAC Varro RS700
- Arendal 1723 Subwoofer 1S vs REL Acoustics T/9x
Prices on this page were last checked October 11, 2026 at 4:59 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
Rythmik E15: $1,599.00 Estimated Rythmik Audio eBay
Pros: A compact sealed 15” Direct Servo subwoofer, narrower and shallower than Rythmik’s F15, driven by the 600W H600 amplifier. Sold direct.
Cons: No independent measurements yet, so its output can’t be compared directly with ranked subwoofers; the rating is estimated from the measured sealed Rythmik F12 and ported Rythmik FV15HP (119.3 and 122.0dB in the 40 to 80Hz CEA-2010 bands).
Full Rythmik E15 review and specifications →
| Amplifier Power | 600W |
|---|---|
| Country | United States |
| Dimensions | 19”H x 17”W x 20”D (483 x 432 x 508 mm) |
| Drivers | 15” servo-controlled woofer |
| Enclosure | sealed |
| Warranty | 5/3 |
| Weight | 104.1 lbs (47.2 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- No independent measurement review is linked for this model; it is ranked from hands-on listening and comparison against similarly priced speakers.
- Head-to-Head Comparisons
REL Acoustics T/9x: $1,549.00 Estimated Amazon eBay
Same family: the REL Acoustics T/5x (smaller subwoofer, ranked lower, estimated 3.5/5) and the REL Acoustics T/7x (smaller subwoofer, ranked lower, estimated 3.6/5). See every REL T Series generation.
Pros: Flagship of the Serie T/x line pairing a front-firing 10-inch FibreAlloy driver with a down-firing 10-inch passive radiator powered by a 300W Class A/B amplifier. Extends reach down to 27Hz at -6dB with fast musical transient speed.
Cons: Passive radiator configuration requires careful boundary positioning away from corners to avoid room mode excitation. Commands a premium price without onboard DSP or smartphone app calibration.
Full REL Acoustics T/9x review and specifications →
| Released | Apr 2021 (5 years ago) |
|---|---|
| Amplifier Power | 300W RMS (Class A/B) |
| Country | United Kingdom |
| Dimensions | 13.4”H x 15.2”W x 15.5”D (340 x 387 x 393 mm) |
| Drivers | 10” (254mm) active FibreAlloy driver, 10” (254mm) down-firing passive radiator |
| Enclosure | passive radiator |
| Frequency Response | 27Hz at -6dB (manufacturer specified) |
| Warranty | 3 |
| Weight | 45.4 lbs (20.6 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- No independent measurement review is linked for this model; it is ranked from hands-on listening and comparison against similarly priced speakers.
- Head-to-Head Comparisons