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  F25 Direct Servo subwoofer
15" sealed audiophile sub with dual drivers

Dual driver sub

F25 matches the low frequency output of our vented subs and for music use the output is even higher. The dual driver design increases efficiency so that only half the power is required for a given output level. Like our other high output options, a 800WRMS amplifier is included.

Direct Servo Technology

All our subwoofers use our patented Direct Servo technology. The servo enables precise control over the cone which is essential for tight, dynamic and accurate bass. It also counteracts many different driver non-linearities and allows us to use lighter drivers which avoid the need for excessive amounts of amplifier power.

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

Read more about Direct Servo in our technology section.

View animation demonstrating how Direct Servo works >

The standard amplifier of F25 is H800XLR3. It has two Hypex 400WRMS power amplifier modules in one heat sink so that each module independently drive one driver with servo control. The quickguide of the H800XLR3 amplifier for sealed subs can be found here. Regular price is $1499. It is on sale for $1399 (price reflected in shopping cart). We currently only ship these to within 48 continental states via UPS freight. These subwoofers are very heavy so we will include furniture mover pads (for either carpet or hard floor). Customers can only select one of them. Limited silver cone drivers are available for $50 extra.

The feet are sold separately. All cones are made of anodized aluminum.

These subwoofers are shipped via UPS freight. They are not time definitive. So we cannot guarantee delivery time. In addition, the shipping charge of $180 per sub is valid for business address delivery without the need of lift gate service. For residential delivery with a lift gate service, UPS now charges us $220 for both. It is an issue starting happening this summer. We are now looking for another carrier with more reasonable delivery charge. For single F25 subwoofer purchase, please do add the residential delivery/lift gate to the shopping cart (which we cover half of what UPS charges us on residential delivery and lift gate service). For multiple subwoofer purchase, we can cover this charge at our cost.

  Description: Price  
  Residential delivery/lift gate for Single F25 purchase $100 buy it now
  F25 black oak with black aluminum cone drivers and H800XLR3 amplifier $1499 buy it now
  F25 black oak with silver aluminum cone drivers and H800XLR3 amplifier $1549 buy it now
  2 large furniture mover pads for carpet $0 buy it now
  2 large furniture mover pads for hard floor $0 buy it now