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






  FM8 Direct Servo bass and midbass subwoofer
Sealed audiophile sub with dual 8" drivers and a selectable 50hz HPF

The subwoofer for audiophiles with the need to play up to upper bass

For audiophiles looking for uncompromising accuracy in both bass and upper bass frequency range and higher crossover frequency up to 250hz, our F8 subwoofer is the ultimate choice. It features two light cone weight 8" drivers with our Direct Servo technology to ensure accuracy and definition. FM8 is a variant of F8 subwoofer with a slightly different extension filter arrangement. The Low-music and Low-HT positions on the extension filter allows FM8 to be used as a regular subwoofer. The "high" position implements a 4th LR filter to allow FM8 only play down to 50hz and crossover to low bass subwoofer unit at 50hz (for instance, the 50hz/24 setting of our larger subwoofers). For upper end extension, this sub is designed to effortlessly play up to 250hz . Customers should note signals above 80hz can be localized and therefore placement is important if FM8 is used above 80hz. While there are already many subwoofers on the market which can play deep bass, their sound quality and transient response degrade as the frequency goes up above 120hz. FM8, when used as a subwoofer, can cover more than a decade of frequency range of servo control from below 20hz to 250hz.

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 memory effects, such as spider hysteresis and creep effect of surround material, is 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

FM8 uses two Hypex Ucd class D modules in the power amplifier with each module independently driving an 8" driver. Hypex Ucd modules are considered as one of the best sound quality class D modules available. The standard amplifer is HX585 (300WRMS x 2 for a total of 600WRMS), It has two RCA inputs and one highpass filter output. Three different finishes are available: piano black, black matte vinyl, and black oak vinyl. Price includes shipping to 48 US continental states only. Shipping to other region or country should inquire us for actual cost.

FM8 is particularly suitable for pairing with front speakers with small woofer or planar/ribbon speakers with limited extension. Customers are tempted to use them as speaker stands. This usage method severely limits the placement choice and hence also hinders the efficiency. For front speakers with 8" or larger woofers, we recommend other 12" or larger models such as F12.

In addition, FM8 does not have speaker level inputs. It also has only one channel HPF RCA output which means to use 150hz built-in HPF, customers need to buy a pair to work. For customers with AVR or out-board crossover, a single FM8 will still work.

Integration guide

  Description: FREE SHIPPING to 48 STATES (RCA inputs only) Price  
  FM8-SE dual 8" subwoofer with piano black finish with RCA inputs only (last one available) $1109 buy it now
  FM8-BO dual 8" subwoofer with black oak finish with RCA inputs only(back order till further notice) $985 buy it now
  FM8-BM dual 8" subwoofer with black matte finish with RCA inputs only(back order till further notice) $985 buy it now