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High Performance Ported 12" With Multi-Tune

FVX12 multi-tuned ported servo subwoofer is the little brother of our FV15HP/FVX15 subwoofers. It is our answer to the need for a smaller home theater and music subwoofer that retains the dynamic and accurate bass that FV15HP/FVX15 become known for.

Correctly integrated, our vented subwoofers can achieve the tight bass normally associated with a sealed enclosure, yet with greater low frequency output. We recommend this subwoofer for systems in which home theater has a high priority. FVX12 also features multi-tune capability. Customers can select either one-port or two-port operation.


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Looking for an affordable musical subwoofer that can be also used for dynamic home theater use? The FVX12 uses our proprietary servo design to gain low frequency clarity and articulation. Ported design enhances low frequency output and combined with multi tuning options, proper integration with speakers, the listening room and the source electronics is simple to achieve.

While many of our competitors limit their best technology (such as servo) to their top level models, we wanted to make Direct Servo affordable, so we've held nothing back. As a result, you get the tight and music bass you wouldn't normally expect from a subwoofer at this price range.

Integration guide



Features & Options

Product features include:

  • Patented Direct Servo technology
  • Hypex Ucd module-based amplifier with toroidal power transformer and two large 12000uF/80V capacitors
  • 12" stiff metal cone high excursion driver
  • Solid and very inert enclosure with multi-tune feature
  • Bass extension control allowing adjustment of bass extension and excursion control
  • Selectable 12/24 db/octave crossover filter slope

Direct Servo technology

All our subwoofers feature our Direct Servo technology, which is our secret to achieving tight and accurate bass. The benefits are far more than simply achieving low distortion.

Direct Servo closed loop technology

Learn more in our technology articles >

Hypex Ucd module-based amplifier

Hypex Ucd modules are known among audiophiles to be one of the best sound class-D modules. While class-D can reduce the footprint of amplifiers, other companies have further incorporated switching power supplier to save cost and space. However, the disadvantages of switching power supplier are complexity of circuit leads to higher failure rate, higher compression at high transient current demand, and inflexibility of 120/240V switchable operation. The amplifier in FVX12 uses conventional toroidal transformer to address these issues. In addition, two large US-made (CDE) 12000uF/80V power filter capacitors are used to ensure stability of power supply even during the most demanding HT special effect.

12" high excursion driver

Driver features include:

  • Low moving mass to ensure an exceptional transient response
  • High flux density in the gap to ensure low distortion
  • Flux de-modulation shorting rings to lower inductance and improve linearity
  • Extended upper bandwidth response allowing a higher crossover point than most

Read more >

Quality enclosure

Our enclosures are very solid and well braced to minimize any cabinet resonances or coloration. The baffle into which the driver is mounted is double thickness.

We also provide a range of finishes. Our range of attractive and excellent value vinyl finishes including:

  • black matte
  • black oak

Bass extension controls

A370 controls The bass extension control in FVX12 enables the user to customize the frequency response of the low end. It combines multi-tune specific frequency contouring and damping control in one switch. The damping control determines the slope of roll-off and the amount of time domain ringing. High damping provides the least amount of time domain ringing and the most gradual roll-off curve. Low damping provides the steepest roll-off at the low end at the expense of added time domain ringing. There are two positions for 1 port operation which extends to 14hz. 1P-music uses high damping while 1P-HT uses low damping. High SPL playback should use 2 port setting. The damping in this position is low.

Crossover options

To suit different setups, we provide a 12 db and 24 db/octave crossover. If you are still using stereo receiver or conventional pre/power amp setup, then we recommend the 24 db switch setting. To understand more about how to correctly integrate your subwoofer, read our phase alignment article.

120V-240 Switchable Voltage Selection

Correct voltage must be selected before use. Voltage switch is shown below.

voltage selection



Driver 12" high excursion driver with custom sensing coil
Driver materials Metal cone with rubber surround
  Aluminum flux de-modulation shorting rings
Amplifier 400RMS Hypex Ucd module based patented servo controlled
Dimensions 17"(W) x 20-1/2" (H )x 22"(D) - (24" D with grille and control knobs)
Shipping Weight 97lbs (82 lbs net)
Frequency Response 14 - 200 Hz (-2 dB @ 18 Hz, -6db@14hz) with LFE input
  14 - 90 Hz (-2 dB @ 18 Hz, -6db@14hz) with LINE IN input
Multi-tune 20hz (2 ports) and 14hz (1 port)
Crossover slope Selectable 12 or 24 dB / octave
Crossover range (Low pass) 30 - 120 Hz (Line level frequency response tops out at 100hz)
Rumble Filter (High pass ) 20 Hz 18 dB / octave for two port tuning
Phase adjustment 0 - 180 degrees continuously variable
Bass damping factor settings Q=0.5 (1P-music) and Q=1.1 (1P-HT and 2P)and low (Q=1.1)
Finishes Available in black matte vinyl and black oak vinyl
Warranty 5 years warranty on driver and 3 years on electronics
  45 day satisfaction guarantee



FVX12 has two port openings. With one port open, the max extension is 14hz and the bass extension toggle switch should be set to either 1P-music or 1P-HT. The latter is recommended for HT playback. The bass extension toggle switch needs to match the number of ports used.

In the following is the frequency response when bass extension is set to 1P-HT with one port open and LFE input.

sealed response

Fig 1.0 - FVX12 Frequency response chart with LFE input 1P-HT and one port open

To achieve lower group delay in one port operation (such as for music playback), users can set the bass extension switch to 1P-Music. It has a more gradual roll-off and yet lower extension (-6db at 14hz) compared to that of 1P-HT. In the following is the requency response comparison between these two modes with LINE-IN input. The line-in input has a gradual roll-off at 100hz.

sealed response

Fig 1.1 - FVX12 Frequency response comparison of 1P-music and 1P-HT with LINE-IN input

For highest SPL HT playback output, users should select 2P mode with both ports opened. While the extension is only limited to 20hz, the power of the amplifier is better utilized for audible frequency band instead of less audible sub-sonic band. In the following is the frequency response of 2P mode.

sealed response

Fig 1.3 - FVX12 2p mode response with LFE input and two ports open

One of the strength of directservo subwoofers is the consistency of the frequency response. FVX12 has a frequency response very similar to FV15HP/FVX15, making it easy to mix these subwoofers in the same room without phase issue as shown in the phase response plots.


One important aspect of getting a correct integration is phase alignment. We have written a guide on how to achieve a phase aligned subwoofer. More >



These are some of the finest subwoofers ever manufactured and the difference in sound quality between these subwoofers and the typical big-box ported subwoofer is surprising. You will hear the difference the very first time you listen and as so many have said, you will never go back to a non-servo subwoofer.

Rythmik FVX12 12" Ported Subwoofer

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