In this review, we will be comparing Classic 99 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 Classic 99 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.REL Classic 99and Klipsch R-121SW have the same driver set up: Both subwoofers have 1 x 12" drivers.
Frequency Response
Classic 99 has a frequency range of 24-120 Hz whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 24Hz, the Classic 99 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 Classic 99's and Klipsch R-121SW's external dimensions. REL Classic 99 has external dimensions of 536.6 x 400.1 x 396.9mm () 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).
REL Classic 99 is 6.9mm narrower and 135.1mm less deeper than Klipsch R-121SW but it is also 113.6mm taller.
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 Classic 99 is approximately 1588.0cm2 / 246.1inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The Classic 99 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 Classic 99 weighs 22.36kg / 49.2lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the Classic 99 40% heavier than the R-121SW.
Here is a comparison of how Classic 99 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 |
 Base Surface Area |
1588cm2
vs
2165cm2
|
Takes less floor space |
 Height |
423mm
vs
536mm
|
Easier to fit in smaller spaces |
 Price per pair* |
599USD
vs
2099USD
|
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 135mm further into the room. REL Classic 99 is 114mm taller.
| General |
REL Classic 99 |
Klipsch Reference R-121SW |
| Brand |
REL |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
24-120 Hz |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
450-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
12" |
| Woofer Composition |
|
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
536.6mm (21.1") |
423.0mm (16.7") |
| Width |
400.1mm (15.8") |
407.0mm (16") |
| Depth |
396.9mm (15.6") |
532.0mm (20.9") |
| Weight |
22.36kg (49.2lbs) |
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 Classic 99 goes deeper - 24Hz against 28Hz. A real difference, though most music has little content below 28Hz. |
| Amplifier power | A | REL Classic 99 has the bigger amplifier - 450W against 200W RMS, about 3.5dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (12" against 12"). |
| Enclosure | depends | REL Classic 99 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. |
| Warranty | A | REL Classic 99 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 $2,099, about 71% less. |
A REL Classic 99 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 Classic 99 measures better, Klipsch R-121SW costs about 71% 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 Classic 99 is usually the easier one to make sound right. Two small subwoofers beat one big one in most rooms - a pair evens out the room modes in a way no single box can, whatever its specs. At $599 each, two Klipsch R-121SW cost about $1,198 against $2,099 for one of the other, which is worth a thought.
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.