KSW-12 Subwoofer


You have chosen a discontinued Klipsch product. This model has been replaced by a new version: the KSW-12 (NA). For information on the latest Subwoofers, please click here.

  • 12" down-firing driver
  • Matte-finish, black vinyl
  • 2 Line level/LFE RCA phono jacks and 2 High level speaker terminals

The Synergy Series KSW-12 subwoofer packs a powerful punch. It uses high-quality materials and the most reliable components to deliver deep driving bass that intimidates competing designs. Available in 120 or 230 volt versions this high performance subwoofer perfectly anchors a home theater or two-channel music system.

The KSW-12 couples a 12-inch driver to the floor for optimal performance. Its high-output down-firing design "grips" the air and fills a room with low frequency energy that's heard and felt with undetectable distortion. The built-in discrete MOSFET amplifier and 12-inch fiber-composite woofer are as efficient as they are reliable.

This subwoofer accepts LFE line-level and speaker level inputs. The classic jet ash vinyl veneer finish creates a deceivingly subtle exterior for its room-rocking capabilities.

Want to know how to get the best bass in your space? Visit our subwoofer FAQ section.

While no longer in production the KSW-12 is still owned and listened to by Klipsch fans around the world. To connect with other people who are passionate about audio and interested in Klipsch products visit our open forum bulletin board.



  • What is the best way for me to hook up my subwoofer?

    The optimal connection is to use the RCA (Phono) "sub" or "woofer" line out found on home theater receivers and pre-amps. Some subwoofers offer High Level inputs (speaker wire connections), they are there for use with a receiver or pre-amp without a sub RCA connection. You don't need to use both and in most cases it's not recommended. 

    Just as receivers and preamplifiers are different across brands, subwoofer brands may be different as well. Every room may be unique in the way it supports or cancels low frequency information. The quantity of bass desired may differ for each listener. Additionally, hookups to the same amps or receivers and the same subwoofers can produce different results if "bass management" settings (speaker size selectors, etc.) or subwoofer settings are different. The best thing to do is to experiment until it sounds just right for your listening style. 

    In some rare cases, you may find an RCA connector marked LFE (Low Frequency Effects) on a receiver or pre-amp; hooking up the "LFE" jacks usually only sends bass special effects of a 5.1- encoded movie to the subwoofer. In that case, when music is played on a two-channel source (for example, a CD), the subwoofer may not receive any signal at all. That situation would call for a hookup of both the "LFE" jacks and the speaker terminal jacks to a subwoofer, in order for the sub to produce bass with all sources. You would need to set the main speakers to "large" in the receiver or pre-amp set-up menu. If you have both LFE and sub out connections on a receiver or preamp, your best choice would be to use the ‘sub out’ connector, because the LFE signal may still be mixed in with the sub channel. 

    Be sure to check the owner’s manual that came with the subwoofer about connecting to both LFE in and speaker wire inputs. With some older subwoofers, this was listed as "optional" and it's fine to connect to both; however with most subs today, this is not recommended, as it may damage the sub electronics. So double-check the manual or contact our tech support department to clarify any questions regarding Klipsch subs. 

    In the end, it comes down to what sounds best to you, given your equipment and your individual tastes. It takes some time and experimentation, but when you have listened to all your options, you’ll know which one is best for you.

  • Where is the best place to put a subwoofer in my room?

    It is generally believed that the bass you hear below approximately 80 Hz is non-directional. This means that you can point the loudspeaker in any direction and the sound will still reach the listener's ears. Since much of the bass that subwoofers produce is below that frequency, you can place the subwoofer almost anywhere in the room. This is the opposite of full-range speakers, which have just a few placement options in a room that allow them to sound good, since they must be positioned for the best combination of imaging and tonal balance. Putting a subwoofer in a corner of the room may cause the sub to sound louder. If your subwoofer is a ported design, keep it at least twice the diameter of the port exit (probably 6-12 inches) away from the nearest wall, so that air flowing out of the port is not obstructed. If the bass seems too boomy, you can fine-tune the sub by moving it farther from the wall until it sounds smooth to your ears. 

    The best way to find the ideal place for your subwoofer is to hook it up and put it right where you will be sitting in the room. Set the subwoofer to level, low pass and phase. Play something with consistent, deep bass and move around the room on your knees; this way your head is about where it would be when you are seated. The spot where the bass sounds best is a spot where you might put your subwoofer. You may find more than one location. 

    Corner placement of the subwoofer typically yields the loudest output (highest efficiency). This does not mean that it will always sound best in this position; experimenting with placement is always suggested. It's also important to have the sound from the sub reach the listener in sync with the sound from the main speakers; otherwise the sound may not blend properly. You should not be able to hear your subwoofer as a separate entity—it should seem that your main speakers go deeper with greater impact and authority.

  • Can I put more than one subwoofer in my room?

    Sometimes, adding a second subwoofer can smooth bass response throughout the room. This is due to h3 acoustic standing waves in the room which are dependent on the basic room dimensions (height, length, and width) and the placement of the sub and primary listening area. With a single sub, it is possible to obtain h3 bass at one spot, with very weak bass elsewhere in the room. You can hear this by carefully listening to bass as you move a few feet in any direction. If you have h3 bass/weak bass problems, using a second sub in a different location may reduce the severity of the problem. The important thing to remember is to find what sounds best to you! Each room is different; experiment until you find the placement that produces the most pleasing bass to your ears. 

    Some people feel they can never have enough bass. So long as they are placed properly, multiple subwoofers typically produce more bass. It is important to note that unless the second subwoofer goes deeper than the first one, adding additional subwoofers will only raise the bass volume—it will not produce deeper base. You’ll need to experiment with different positions (as previously described) to find the best places for two or more subwoofers. Some people use one subwoofer for a certain frequency range and the second for another (such as the LFE channel in 5.1 recordings). Other options are to connect one subwoofer to the front channels and one to the rear channels, or one to the center channel and the other to the remaining channels.

  • The back of the subwoofer is warm. Is this normal?

    A subwoofer will run warm when in use, by design. However, it should not be uncomfortable to leave your hand on the back panel for 5 seconds.

  • I'm not getting any sound out of the subwoofer. What should I check?

    Unplug the system to allow the subwoofer to “reset.” Also, test the speaker using another device. You can plug one end of an audio cable (you may need a RCA female to Mini-plug male adaptor) into the headphone output jack of devices such as a portable CD player or MP3 player; plug the other into either ‘line in’ RCA jacks on the sub to determine if the problem is with the subwoofer or the soundcard drivers. If problems persist, please fill out an online ticketwith our technical support team. 

    Subwoofer Direct CD Test: 

    If you get little or no sound from your subwoofer, perform a "direct in" test to determine if the problem is more than a simple cable or level-setting issue. Start by using a different set of RCA connector cables, then connect the analog audio out from a CD player or DVD player directly into the subwoofer's LINE IN connections. Then, turn the volume level on the subwoofer all the way down. While playing a CD, raise the volume level on the subwoofer; you should hear the bass portion from the source material. If the subwoofer still duplicates the problem, then the issue may be a blown woofer or involve the sub amplifier. However, if the subwoofer functions correctly, then the issue may be with a cable, the receiver and/or a level setting.

  • How do I set subwoofer phase?

    Depending on the absolute phase of your main speakers and amplifier and the distances of the subwoofer and the main speakers from the listening position, the bass in the crossover region may be smoother if you reverse the subwoofer’s phase. Typically, though, phase is left at 0° for most applications.

    While seated in your listening sweet spot, play music with bass content that is familiar to you and then have someone switch the 0/180 phase switch on the sub to 180-degrees. This will let you determine if the bass sounds louder in your seating position. The more bass-heavy setting is where the output of the subwoofer and the main speakers are most in phase. Use whatever position (0/180) is louder at your seating location. (Note: some subwoofers may contain a “variable” phase control, which provides variable control between 0 and 180 for even more precise phase control of your subwoofer.) However, if you do not notice any difference when changing the 0-180 setting, it only means there are no issues in your room and all is fine.

  • I’m experiencing a humming or buzzing noise with my subwoofer. What should I check?

    This could be a ground loop hum/buzz or possibly a transformer hum through the speakers. In fact, large subwoofer transformers are more susceptible to a slight hum noise.

    A speaker hum at your listening location is never normal. To determine if the sub amp is functioning correctly, the best thing to do is disconnect all of the connection inputs going into the subwoofer. Keeping the subwoofer plugged into the AC outlet, turn it on; if the hum still exists, there may be a ground loop issue or a problem in the sub amplifier. In that case, the amp should be serviced or replaced. If there is no hum at that point, the issue might involve the preamp or another ‘upstream’ source component. Some common causes of a ground loop hum are cable TV connections, digital recorders or satellite dish receivers.

    If the hum issue is found to be with a cable TV coax wire, then a device called a MAGIC box possibly may help eliminate the ground loop from cable TV, or an OTA antenna. Some, if not all surge protectors have a cable or satellite in and out cable connection; try that as well.