In this review, we will be comparing No.35 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 No.35 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 No.35and Klipsch R-121SW have the same driver set up: Both subwoofers have 1 x 12" drivers.
Frequency Response
No.35 has a frequency range of 17 Hz (-6dB, in room) whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 17Hz, the No.35 can go significantly deeper on the low side and provide stronger bass compared to 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
Cabinet Type
The REL No.35 has a Sealed type cabinet. On the other hand the Klipsch R-121SW have Bass Reflex type enclosure. Bass Reflex type subwoofers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs.
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 No.35's and Klipsch R-121SW's external dimensions. REL No.35 has external dimensions of 435.0 x 638.0 x 724.0mm (17-1/8 x 25-1/8 x 28-1/2inch) 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 No.35 is clearly the larger of the two speakers. Its body is 231mm wider, 12mm taller and 192mm deeper than Klipsch R-121SW.
Size, drawn to scale
Both speakers 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 surface and pushed back to the same wall, so the deeper one visibly sticks out further.
REL No.35 needs about 113% more floor or shelf area. REL No.35 is 192mm deeper, so it stands that much further out from the wall. REL No.35 is 12mm 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 No.35 is approximately 4619.1cm2 / 716.0inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The No.35 requires 113% more surface area than the R-121SW which gives it a small disadvantage 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 No.35 weighs 59.00kg / 129.8lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the No.35 269% heavier than the R-121SW.
Here is a comparison of how No.35 and R-121SW's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of REL No.35?
Here are the items that are included inside the box of No.35:
- Subwoofer
- Grille
- 6 ft AC power cord
- 32 ft Neutrik Speakon cable
- User manual and warranty information
- Reference remote
- 2 AAA batteries
What's in the Box of Klipsch R-121SW?
Here are the items that come with the R-121SW:
- Powered subwoofer
- Grille
- 6.5-feet AC power cord
- User Manual
- Important Safety Instructions
- Warranty Information
 Low Frequency Response |
17 Hz
vs
28 Hz
|
Generates deeper bass |
 Handheld Remote |
Yes
vs
No
|
Control the speaker by the included RC |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
 High Frequency Response |
120 Hz
vs
Hz
|
Generates higher frequency |
 Height |
423mm
vs
435mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
2165cm2
vs
4619cm2
|
Takes less floor space |
 Price per pair* |
599USD
vs
10000USD
|
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.
REL No.35 needs about 113% more floor area. REL No.35 stands 192mm further into the room. REL No.35 is 12mm taller.
| General |
REL No.35 |
Klipsch Reference R-121SW |
| Brand |
REL |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
900 watts |
200 watts |
| Frequency Response |
17 Hz (-6dB, in room) |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
900-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
12" |
| Woofer Composition |
Carbon fibre |
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
435.0mm (17.1") |
423.0mm (16.7") |
| Width |
638.0mm (25.1") |
407.0mm (16") |
| Depth |
724.0mm (28.5") |
532.0mm (20.9") |
| Weight |
59.00kg (129.8lbs) |
16.00kg (35.2lbs) |
| Enclosure |
Sealed |
Bass Reflex |
| Finish |
Piano Black Lacquer, 12 coats |
n/a |
| Available Colors |
Black |
n/a |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
|
2 Years |
| Labor Warranty |
|
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 No.35 goes deeper - 17Hz against 28Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | A | REL No.35 has the bigger amplifier - 900W against 200W RMS, about 6.5dB 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 No.35 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. |
| Speaker-level inputs | A | REL No.35 takes a speaker-level connection as well as line level. That is what lets it work with an integrated amplifier or a vintage receiver that has no subwoofer output at all. |
| Wireless option | depends | Only REL No.35 offers a wireless link (as a paid option). It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Cabinet size | depends | Klipsch R-121SW is about 54% 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. |
| Price | B | Klipsch R-121SW costs less - $599 against $10,000, about 94% less. |
A REL No.35 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 No.35 measures better, Klipsch R-121SW costs about 94% 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 No.35 is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, REL No.35 is the only one of these two you can connect at all.
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.