> Home
> Products
> Technology
> Plans & DIY
> Ordering
> Reviews
> About us
> Contact






  F15 Direct Servo subwoofer
15" sealed audiophile sub

The subwoofer for audiophiles

For audiophiles looking for uncompromising accuracy, our F15 subwoofer is the ultimate choice. It features our Direct Servo technology to ensure accuracy and definition. As an audiophile you appreciate that bass is the foundation of a satisfying music or home theatre experience. You also appreciate that there is more to a home theatre subwoofer than shaking the room, and that music can be far more satisfying with a subwoofer that can play deep.

What makes our subwoofers suitable for audiophiles? It's not that they can plumb the depths with authority. There are already many subwoofers on the market which can do that. The difference is that they reproduce bass with a level of realism that is normally only associated with much more expensive high end full range loudspeakers.

Direct Servo Technology

You may have heard about other servo subwoofers which are generally well regarded for their accuracy. It is a well established technology, most often based around an accelerometer which measures cone movement. Our Direct Servo technology has significant advantages over other servo technologies. We use a sensing servo coil which acts like a microphone which compares the original signal to what the subwoofer is actually reproducing. The signal is then corrected instantly to compensate for any differences. Once you understand the concept, you may wonder like we do why anyone would make a subwoofer any other way.

All our subwoofers use our patented Direct Servo technology. The most significant benefit is that it provides high end performance at an affordable price. Conventional subwoofers require heavy drivers in order to achieve deep bass extension. Direct Servo allows the use of a lighter driver which is more efficient so that a very high powered amplifier is not necessary. At the same time, Direct Servo reduces detrimental memory effects which detracts from the realism of reproduction.

Some of the benefits of Direct Servo include:

  • Reduction of the effects of thermal compression are eliminated under normal operation
  • Higher efficiency allowing output which would normally require a more powerful amplifier
  • Deep bass extension can be achieved using a low mass driver with superior transient response
  • Mechanical and thermal memory effects are reduced, further improving transient response
  • The effective Q value is 0.3 resulting in much tighter and accurate bass than conventional designs
  • Dramatic reduction of the re-radiation of bass from inside the box

Many audiophiles aren't aware of all of these issues, but we believe they are critical to the design of an accurate subwoofer. While it's not necessary to understand them to enjoy accurate bass, for those who wish to understand how we do it, we have articles to describe our unique approach.

Read more about Direct Servo in our technology section.

View animation demonstrating how Direct Servo works >

View animation demonstrating the reduction of bass re-radiation >

Better value through intelligent design

Many of our customers marvel that we are able to produce such exceptional subwoofers at such a low price. One Direct Servo technology makes it possible, allowing us to get the most out of a 15" 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.

To understand further how this works, you may wish to read our article on smart Q.

Amplifier options

The standard amplifier is H600PEQ3 (600WRMS PEQ). The quickguide of the PEQ3 amplifier for sealed subs can be found here . PEQ3 amps do not have high pass filter RCA outputs. But it does have dedicated LFE inputs allowing for easy integration of a 2-ch-plus-HT system setup. PEQ amplifiers are available for those who still need high pass RCA outputs. The quickguide of PEQ amplifier for sealed subs can be found here. Please order this amplifier as an option in the table below. The response curves with various extension frequency/damping combinations of both amplifiers can be found in our EQ page.

The feet are sold separately. All cones are made of anodized aluminum. Silver cone driver is available for $50 extra.

  Description: Standard with A370PEQ3 amp (with both LFE and L&R inputs) Price  
  F15 black oak grain finish with A370PEQ3 amplifier and black cone $974 buy it now
  F15 black matte finish with A370PEQ3 amplifier and black cone $974 buy it now
  Upgrade to A370XLR2 (with one XLR in and one XLR out) $40 buy it now
  Upgrade to A370XLR3 (with two XLR in) $40 buy it now

Spike Feet

Our subs can be placed directly on carpet floors or matching spike feet are available. These are 1.2" in diameter and 1.75" in height. The thread size is M10-1.5 where 1.5 is the thread pattern distance. Spike feet are not recommended on hard surfaces where we recommend the standard rubber feet which inlcuded in our subwoofers. Free shipping in the shopping cart is only valid when ordered and shipped with subwoofers.

  Description Price  
  Metal spike feet for carpet floor to match F15 Black oak/matte/SE (4pcs) $45 buy it now

Continue to Options & Features >