Rythmik F12-400 12" Subwoofer

F12-400 SUBWOOFER FEATURES

Features & Options

Product features include:

• Patented Direct Servo technology
• 12" black/silver anodized aluminum high excursion driver
• Solid and very inert enclosure available in a range of finishing options
• Bass extension controls allowing adjustment of bass extension and excursion control
• Selectable 12/24 db/octave crossover filter slope
• Balanced XLR connections for professional use (XLR version option)
• Parametric EQ
• Choice of finishes - black matte, black oak or piano gloss (signature edition)

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.

Learn more in our technology articles 

12" black anodized aluminum high excursion driver

Driver features include:

• Rigid one piece anodized aluminum cone ensuring control at high SPL
• 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

While designed primarily for their sound quality, these custom designed drivers are also stylish in appearance with a one piece anodized aluminum cone and rubber surround. Unfortunately, it's not possible to judge the accuracy of a driver by observing its appearance. There are other drivers on the market which in fact look quite similar, and it's tempting to think that they are comparable. Many of them are inferior in performance due to a heavy moving mass, the absence of shorting rings, wider gaps around the voice coil and high inductance which limits the useable high frequency cut off point. Many aren't suitable for a crossover point higher than 50 Hz. This is very limiting when one considers the large number of home theatre speakers which perform better when relieved of bass duties.

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. Black piano gloss finish is also available in our signature edition.

Bass extension controls

All of our subwoofers feature unique bass extension controls which are not normally provided on subwoofers. This enables the user to customize the output and extension to achieve the best compromise in any room. Most subwoofers neglect to provide bass extension control, and the result is that dynamic headroom is compromised.

The bass extension controls enable the user to customize the frequency response of the low end. The controls customize a high pass filter, which attenuates frequencies below a given frequency. If set to 14 Hz, bass below this point will be filtered. 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. The combination of 28hz and low damping is recommended for maximum SPL output for all of our sealed subwoofers.

Crossover options for PEQ3/XLR2/XLR3 models

A370PEQ3/XLR2/XLR3: For customers with an AVR or pre-processor, we recommend LFE inputs which bypass the crossover control. In this case, the crossover should be controlled via AVR. If you are still using stereo receiver or conventional pre/power amp setup with no bass management, then we recommend LINE input and set the crossover/phase controls to where the front speakers start to roll-off. Please refer to quickguide of the model for recommendation. To understand more about how to correctly integrate your subwoofer, read our phase alignment article.

A370PEQ: A370PEQ has extra 80hz 2nd order high pass filtered RCA outputs. For customers with an AVR, we recommend LINE inputs with AVR/12 LP filter switch setting, the crossover should be then controlled via AVR. If you are still using stereo receiver or conventional pre/power amp setup with no bass management, then we recommend LINE inputs, HPF outputs, and set the crossover/phase controls to crossover at 80hz. Please refer to quickguide of the model for recommendation. To understand more about how to correctly integrate your subwoofer, read our phase alignment article.

Balanced professional version

For professional use, a balanced input version is available. The outputs allow multiple subwoofers to be connected. Simply daisy chain the connections, running output from the first (master) subwoofer to the input of the next. For home use, balanced connections are not normally required. However, for those using studio processors and EQ units with balanced outputs, this option may be more convenient. If connection to a source with RCA connectors as found on my home audio equipment, an adaptor may be used. In this case it should be noted that the connection can no longer be considered balanced.

Shown above is XLR2 option. Slave subwoofer units each have their own phase and PEQ adjustment, allowing for placement apart from each other. All other controls will use the same settings as the master sub. Therefore you can adjust the gain on the first and it will control the gain on all the others. The servo will still function normally, correcting any non linearities in each individual subwoofer. We also have XLR3 options with two XLR inputs and no XLR output.

For more information, including charts showing response with different settings, view our amplifier page 

PEQ parametric version

Our PEQ version comes with a few extra options which aren't provided on our standard amplifier. First, there is one band of parametric EQ with adjustable frequency, gain and bandwidth. This means you can not only control the boost or cut, but also the width of the filter. Additional bass management options are also provided. A switch allows the user to select a 12 or 24 db/octave crossover slope setup option. Where the higher slope (24db/octave) is selected, the amplifier uses a variable 12db/octave filter in addition to a fixed 12db/octave filter. One can choose with a switch the corner frequency of the fixed filter as either 50 or 80 Hz, which will suit most situations. The variable filter can be used for fine tuning.

F12-400 SUBWOOFER SPECIFICATIONS

We use high quality high excursion drivers which make it possible to achieve high output in a relatively compact enclosure. Only with Direct Servo is it possible to achieve such deep bass extension, high output and very high damping simultaneously. The effective system Q is 0.3. A lower Q factor represents a higher level of damping, indicating control of the cone. A typical sealed subwoofer has a Q of 0.9 and then equalized to Q of 0.7 by DSP or other equalization means. However, that does not alter the native Q value of those subs. Only our direct servo subs achives a native Q value of 0.3 with close-loop servo feedback control.

The bass extension controls allow the user to customize the deep bass extension and the rumble filter to control cone excursion. For high SPL, one can set a higher cut off. For music one may prefer a lower cut off. Changing the settings can also result in a better integration with the acoustic gain of the room.

F12-400 SUBWOOFER MEASUREMENTS

The extension filter in F12-400 is simplified to 3 positions: Low-Music, Low-HT, and high with frequency and phase response shown below. Low-music has the lowest extension, -3 db @ 17 Hz. The response is flat and extended. For high SPL in movies, we recommend Low-HT mode with built-in rumble filter that preserves the FR to -3db@18hz while reducing potentially damaging subsonic energy.

Fig 1.0 - F12-400 Frequency response in Low-Music mode

Fig 1.1 - F12-400 Frequency response in Low-HT mode

The high extension setting further reduces the extension and thermal stress for extended duration of playback

Fig 1.2 - F12-400 Frequency response in High extension mode

Integration

With many subwoofers, it is difficult to get a correct and seamless integration with the main speakers because the amplifier settings are often very different to the measured response. You may set the crossover point to 80 Hz, but the actual crossover point may be anywhere between 60 and 100 Hz!

With our subwoofers the upper and lower -3 dB points are a very close match to the settings selected. If you set bass extension to 14 Hz, that is exactly what you will get. All this is possible because Direct Servo ensures a stable and flat response.

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

F12-400 SUBWOOFER SUMMARY

Many of our customers marvel that we are able to produce such exceptional subwoofers at such a low price. Our Direct Servo technology makes it possible, allowing us to get the most out of a 12" driver without the need for kilowatts of power. Don't be fooled into thinking that other more expensive subwoofers with much more powerful amplifiers will offer more output. The output of a subwoofer is determined by how much air the driver can displace, not the power rating of the amplifier. We could supply a more powerful amplifier, but there would be no increase in output, only extra cost.

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.