In this review, we will be comparing HT 1003 MKII and R-121SW, two Powered Subwoofer speakers from REL and Klipsch. Being Powered subwoofers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them. Let's have a brief look at the main features of REL HT 1003 MKII and Klipsch R-121SW first before getting into our more detailed comparison.
The sections below take each area in turn: driver and amplifier, frequency response, physical size and connectivity.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both REL HT 1003 MKIIand Klipsch R-121SW have a single woofer setup however the REL HT 1003 MKII's woofer is 10-inch whereas the Klipsch R-121SW features a 12-inch woofer.
Frequency Response
HT 1003 MKII has a frequency range of 24-200 Hz whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 24Hz, the HT 1003 MKII can go slightly deeper then the R-121SW's min frequency of 28Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Subwoofer class in our database.
Low Frequency
Subwoofer Speakers
High Frequency
Subwoofer Speakers
Klipsch R-121SW Port
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare REL HT 1003 MKII's and Klipsch R-121SW's external dimensions. REL HT 1003 MKII has external dimensions of 341.3 x 365.1 x 435.0mm () whereas Klipsch R-121SW has external dimensions of 423.0 x 407.0 x 532.0mm (16-5/8inch x 16inch x 20-15/16inch).
Klipsch R-121SW is clearly the larger of the two speakers. Its body is 41.9mm wider, 81.7mm taller and 97mm deeper than REL HT 1003 MKII.
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the REL HT 1003 MKII is approximately 1588.2cm2 / 246.2inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The HT 1003 MKII requires 27% less surface area than the R-121SW which gives it a small advantage on placement in tight spaces.
Weight Comparison The weight of a subwoofer may become an important factor if you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. The REL HT 1003 MKII weighs 15.51kg / 34.1lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the R-121SW 3% heavier than the HT 1003 MKII.
Here is a comparison of how HT 1003 MKII and R-121SW's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
24 Hz
vs
28 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
120 Hz
|
Generates higher frequency |
 Height |
341mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1588cm2
vs
2165cm2
|
Takes less floor space |
| Woofer Size |
12 inches
vs
10 inches
|
Larger woofer |
 Price per pair* |
599USD
vs
649USD
|
costs less (*prices may change depending on the seller, location and time) |
Size, drawn to scale
Both subwoofers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same floor and pushed back to the same wall, so the bigger one visibly takes more of the room.
Klipsch R-121SW needs about 36% more floor area. Klipsch R-121SW stands 97mm further into the room. Klipsch R-121SW is 82mm taller.
| General |
REL HT 1003 MKII |
Klipsch Reference R-121SW |
| Brand |
REL |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
24-200 Hz |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
300-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
12" |
| Woofer Composition |
|
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
341.3mm (13.4") |
423.0mm (16.7") |
| Width |
365.1mm (14.4") |
407.0mm (16") |
| Depth |
435.0mm (17.1") |
532.0mm (20.9") |
| Weight |
15.51kg (34.1lbs) |
16.00kg (35.2lbs) |
| Enclosure |
|
Bass Reflex |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |
A sealed subwoofer against a ported one. That is the most consequential line on this page: it decides how the bass rolls off, how it behaves in a small room, and how much output you get for the size of the box.
| Area | Better | Why |
|---|
| Bass depth | A | REL HT 1003 MKII goes deeper - 24Hz against 28Hz. A real difference, though most music has little content below 28Hz. |
| Amplifier power | A | REL HT 1003 MKII has the bigger amplifier - 300W against 200W RMS, about 1.8dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | Klipsch R-121SW moves more air: 12" against 10" is 1.44x the cone area, not the 1.2x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | REL HT 1003 MKII is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; Klipsch R-121SW is ported - a ported box gives more output low down for its size, at the cost of a steeper roll-off below tuning. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Cabinet size | depends | REL HT 1003 MKII is about 41% smaller by volume. In a subwoofer that is a real trade rather than a preference: box volume is how you get output low down without a bigger amplifier. |
| Warranty | A | REL HT 1003 MKII carries 3 years on parts against 2 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | B | Klipsch R-121SW costs less - $599 against $649, about 8% less. |
A REL HT 1003 MKII B Klipsch R-121SW
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both subwoofers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: REL HT 1003 MKII measures better, Klipsch R-121SW costs about 8% less. In a normal room, placement will make a bigger difference than the gap between these two. Films or music? If this is mainly a home cinema, Klipsch R-121SW will hit harder for the money; if it is mainly for music in a normal-sized room, REL HT 1003 MKII is usually the easier one to make sound right. If placement is the constraint - a corner, behind a sofa, under a desk - REL HT 1003 MKII is the one that will actually go there, and a well-placed small subwoofer beats a badly-placed big one every time.
One thing outweighs everything above: where the subwoofer stands. Room modes can add or remove 10dB or more at a given seat, which is far larger than any difference on this page. Before spending more, try the sub in two or three positions - the crawl test, where you put it in the listening seat and crawl the room to find where the bass sounds best, costs nothing and usually beats an upgrade.