I am happy to announce that we are ready to start taking orders on the SubMersive F18 which will ship in the form of an F18 (slave) or F18+ (w/4kW power).  I have long wanted to offer a more direct path to an extreme capability, sealed subwoofer system which scales up the balance of efficiency, power, size and refinement of the SubMersive, and the F18 delivers on that goal. 


The F18 is the production evolution of the prototypes installed early this summer and detailed here.  This is a modular system using very manageable size modules measuring in at 23.5" x 23.5" x 18"D (including magnetic grill).  The removable feet add 3/4" to the height (=24.25").  The single 18" driver was selected after extensive testing and benchmarking many various candidates from many sources against our SubMersive 15" driver.  With two shorting rings in the motor, dual mirrored spiders and more than +/-2" linear travel without all the operating noise many big woofers suffer from, this beast delivers on both power and refinement.  The high excursion rubber surround and Nomex honeycomb composite, concave cone features woven fiberglass outer skins for the ultimate in rigidity and durability.  Through a great deal of testing we settled on the best driver and enclosure match to get the most from our 4000W amplifier.

While the SubMersive HP+ & F2+ can drive 2 enclosures with 4 drivers, with each 18" module being about 90% the volume of the HP/F2 models we are able to get more than double the deep bass capability from a single 4000W amplifier as the F18+ can drive itself and up to THREE (3) slave units! [eek]  The 4 total modules represent almost 4 times the box volume which allows us to design in significantly more efficiency gaining more from the same amplifier.

This means that with each F18+ you purchase, you have the ability to power a total of 4, F18 modules. [cool]

Our 4000W amplifier delivers 1300W per F18 module with the full 4000W continuous between the 4 drivers when more than 3 are used.  For 80% of use and operating conditions the amplifier drives the stack of 4 18s like a 5,200W monster delivering 12dB more than a single F18.  Only under the longest duration and lowest frequencies is a slight 1dB shed vs using a second amplified unit in the set.

While the samples were entirely utility black, production units will have no threaded inserts on the sides with the main body of the subwoofer being veneered with the black satin cover panel and a matching magnetic grill.  We are offering the same finish options as the rest of our lineup.

Here is a picture of the pre-production sample in our office, without the veneer on the main enclosure.  We will have pictures of a production sample in black maple with magnetic grill early next week:

Of course this new product will utilize the same new version of our SubMersive HP+/F2+ amplifier with the following features:

  • Four digitally programmable control knobs for adjusting Gain, LF EQ, Crossover, and Delay
  • Increased range and fine adjustment of Gain/Volume control.
  • LF EQ allowing a +/-8dB adjustment for 12-27Hz to 200Hz ground plane response (+/-3dB)
  • Variable 4th order (24dB/octave) low pass filter with a range of 30-200Hz for 2 channel use.
  • Delay adjustment of 0-20ms intended for aligning multiple powered subwoofers in a room, especially in the case of front/rear placement.
  • Summing RCA inputs and looping XLR male/female connection
  • Auto signal sensing and 12V triggered standby modes
  • Neutrik SpeakOn 4-pole, twist-locking connector to deliver power to a maximum of 3 slave modules
  • Standard IEC (C13) power inlet allowing right angle power connection and readily available power cords (was blue Neutrik PowerCon connector)


Long term pricing (we'll do more detailed cost analysis as we have a larger production sample) will be as follows in black maple and black oak + shipping:

  • F18+ with internal 4000W amplifier - $2,295
  • F18 - $1,095

Each slave module has a plate the same size as the + amplifier, so upgrading is always possible and we are able to keep both in stock more easily.  This plate will have 2 paralleled Neutrik SpeakON connectors for looping into each F18 and on to another F18 up to a total of 4 total F18 modules.

I know many have been waiting a long time for this release, and I want many to get started on their way to assembling their dream subwoofer systems.  Introductory pricing is as follows for the black maple finish:

  • Single F18+ subwoofer - $2,195 + shipping
  • Add an F18 slave module - +$995 + shipping 
  • Purchase 2x F18+ subwoofers - $3,990 + shipping
  • Purchase 4x F18+ subwoofers - $7,880 + shipping 
  • SpeakON slave cables are available and made in house to ordered length in 1' increments using premium, right angle, Neutrik SpeakOn connectors and 4 x #11 wire (5/8" diameter.  The cables are priced at a $40 termination fee + $3.50/ft length.  Ex: 20' length = $110.

Jumping on the significant discount on 2 powered units sets you on a path of assembling two massive, 3-4 module stacks in bite-size pieces, and there are few who won't be amazed at the experience of 6-8 carefully optimized, 18" woofers motivated by 8,000W of US made power. 

As an example, you could pick up a pair of F18+ units and 2 F18 modules to set an F18+ and F18 in the front 2 corners with another set at the rear of the room.  Even here you have the ability to double the system capability in the future while starting with more 
Pictures like these never get, old and look even better in person [cool] :


Those ready to order please e-mail us at with your shipping address and the specific units you are ordering so we can provide the appropriate invoice for payment by credit card (by phone), PayPal e-mail invoice online, or by check or wire transfer.  Check or wire transfer payments can save $40 per powered unit and $20 per slave.

Here are a few more pictures taken of the first production units in the shop:
[F18-p5] [F18-p1]    

Mark Seaton
Seaton Sound, Inc.
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I will be updating the first post of this thread and post a separate notice that our introductory pricing will be wrapping up on Wednesday, September 14th. To secure the introductory pricing we will need an e-mail ( ) with your shipping address and what products are being ordered by 10PM CST on Wednesday, September 14th. Payment needs to be received by Wednesday, September 21st.

We have quite a few black maple F18 subwoofers available to ship by September 12th along with a few more rosenut units (+$300). Shipping within the lower 48 states is typically $80-100 per unit.


After September 14th, pricing will be (+shipping):
Single F18+ Black Maple - $2,295
Multiple F18+ Black Maple - $2,195
F18-Slave Black Maple - $1095
Black Oak finish - +$100
Rosenut finish - +$300

SpeakON slave cables are available and made in house to ordered length in 1' increments using premium, right angle, Neutrik SpeakOn connectors and 4 x #11 wire (5/8" diameter. The cables are priced at a $40 termination fee + $3.50/ft length. Ex: 20' length = $110.

The 12V trigger on our amplifier uses a 3.5mm Mini Mono cable. We stock these cables in lengths of 6, 10, 15, 25 & 50 foot lengths for $8-15.

Thank you again for the patience of all who have taken advantage of the introductory pricing and are enjoying their new F18 subwoofers.

Here is a peek at a rosenut F18


Mark Seaton
Seaton Sound, Inc.
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