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HT-1 Series 18


Handmade in USA
Current lead times are 10-15 business days to machine and assemble Fi products


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Designed, machined, and assembled in house at our Las Vegas NV facility, the new HT1 series is a feature packed driver.

SKU: HT1-18 Categories:

Introducing the first sub in our new Home Theater series of drivers, the HT1.

Utilizing our water jet we are cutting the top plates and back plates in house as well as final machining. This new design uses a 3 stack of high grade ceramic ferrite magnets along with a solid pole and helical cooling channels for 1000W of power handling. A high excursion 8″ spider, stitched leads, a multilayer foam surround attached to a fiber impregnated kraft pulp cone helps keep things under control in both ported or sealed applications. The 3″ coil is available in single 2 Ohm or single 4 Ohm with 27mm of Xmax.

  • Single 2 and 4 Ohm

  • Cast basket

  • Wrap around gasket

  • Kraft pulp fiber reinforced cone

  • Multilayer layer wide foam surround

  • Push terminal

  • FEA optimized motor

  • 3” diameter 4 layer coil

  • Triple high grade magnet

  • Heli-cool system

  • Carbon Dustcap
Weight 45 lbs
Dimensions 20 × 20 × 14 in

Thiele-Small Parameters

  HT-1 18
FS 20.7 Hz | 20.9 Hz
RE 1.35 | 2.85
QMS 6.89 | 5.75
QES 0.59 | 0.57
QTS 0.53 | 0.51
MMS 525 g | 518 g
CMS 1.083 mm/N | 1.083 mm/N
SD 1210cm^2 | 1210cm^2
VAS 222.1 L| 222.1 L
SPL 87.5 1W/1m | 87.6 1W/1m
BL 12.89 | 18.77
XMAX 27mm (One Way)
RMS 1000W

Technical Specifications

  HT-1 18
Overall Diameter 18.500”
Cutout Diameter 16.750”
Mounting Depth 6.500”
DriverDisplacement 0.18cuft
Sealed Box 4-6 cuft
Ported Box 6-8 cuft @ 26Hz

This is a complete list of options; not all options are available on all models.
See drop down selections for options available with each speaker model.

Cooling Stage: The new cooling stages are aluminum rings or plugs that aid in cooling and reducing the inductance of a coil (as well as linearizing it to further reduce distortion).  The first stage is a machined aluminum sleeve over the pole.  This has better thermal conductivity than steel alone does and reduces the effect of the coils inductance increase being an iron core inductor.  The second stage includes the first pole sleeve and adds an aluminum pole cap that increases compression and cooling.  The third is the first two stages along with the large visible heatsink that surrounds the outside of the coil and transfers heat to the ambient environment as well as greatly reducing the inward inductance of the coil.  The overall effect increases cooling/thermal capacity as well as linearizing in vs outward inductance shift reducing distortion ad increasing bandwidth

Cooling: Self explanatory, the cooling channels are machined into the inside of the sub to help cool the coil FAR better. This option is available for subs that do not have staged cooling.  While it is not a visible option, it makes a huge difference in long term thermal capacity.  

High QTS: This option is for users who intend on using the subwoofer in only a sealed enclosure.

Low QTS: This option is for users who intend on using the subwoofer in only ported enclosures.

Extra Spider: This option adds an additional spider to the spider pack to help with mechanical power handling and keeping the moving assembly under control.  It can have small detrimental effects on the sound quality of the sub if the sub is made too stiff (reducing excursion ability and low frequency bandwidth).  But in some applications the losses are offset by the ability to use extra power.  An extra spider is not a bandaid for improper subsonic filter settings on your amp/DS with respect to the box tuning (should be 2-3 Hz lower than box tuning to avoid mechanical issues when the port unloads).

Internal Lead: This option is for 8 lead per coil, increasing the current flow from coil to terminals.  It is sandwiched between the spiders to keep it linear and from flopping around under extreme excursion.

Plus Coil Pack: This option adds an extra spider and the larger/higher power handling Omega/TeamV3 coil.  This well bump thermal capacity from 3500W to 4500W or more depending on other options and application.  The extra spider helps keep the additional moving mass and power under control while the coil has much higher current carrying capacity over the standard 4″ coils.


Speaker Terminals

We have two terminal options on selected subwoofers.

Our Standard Push terminal using 144 strand count sewn tinsel leads Or our new Hybrid+ lead system with ring terminal attachment for high power systems.



We have 4 Dustcap options on selected subwoofers.

Our regular Dry Carbon composite dustcap and new Gloss Carbon. Both variants are available in 6″ and ‘Big’ 7″ diameters to further your customized experience with Fi.



We have a wide array of color options to choose from, with over 10 colors to choose from we’re sure you’ll find something to enhance the look of your Fi subwoofer.


Subwoofers & Recones are dispatched via FedEx Ground. Small goods such as sticker packs, various apparel items are shipped via USPS. Upon dispatch of your goods, order status will be updated from “test/pack” to “shipped” which is accompanied with tracking details.

General Information

All orders are custom made to your selected options.  Each order is machined from raw steel and hand made after it is ordered.  This normally takes 10-15 business days, but due to unforseen issues it can take longer. We will note much of this directly on the individual product pages and try to update this weekly.  There are a couple of times a year that we simply can not keep up with sales and these “normal” time lines will not be in effect.  These times normally include Black FiDay and tax season.  During these times we will run batch orders per series and not individual orders.  This increases our overall efficiency, but can put your order into a later build date.  Fi will maintain reasonable communication should an item take longer than our normal 15 business days to make during our normal build seasons.  Often we will post through Facebook and Instagram our batch sequences to give all customers a better time line.  We also note for each item the current lead times (which can be longer than our normal 10-15 business days. Should an item take longer than normal, all refund policies still are in effect.

Delivery Location

Items offered on our website are only available for delivery to the verified billing addresses in the US and Canada. We also accept orders from international customers who are shipping to addresses on an individual basis.  All items will ship direct from our Las Vegas, Nevada location.

Delivery Time

An estimated delivery time will be provided to you once your order is placed. Delivery times are estimates and commence from the date of shipping, rather than the date of order. Delivery times are to be used as a guide only and are subject to the acceptance and approval of your order.  Deliveries will be made through FedEx Ground unless otherwise noted.  Delivery times in the US generally take from 1 to 5 business days depending on how far you are from our facility in Las Vegas, Nevada

Unless there are exceptional circumstances, we make every effort to fulfill your order within [15] business days of the date of your order. Business day mean Monday to Friday, except holidays.

Date of delivery may vary due to carrier shipping practices, delivery location, method of delivery, and the items ordered. Products may also be delivered in separate shipments.

Delivery Instructions

We will only ship to the customers billing address.  No exceptions.  All orders are shipped with direct signature required.  We will not ship orders without direct signature, sorry if this causes any inconvenience.  Fedex will send an email to your customer supplied email address once the order has shipped.  This normally happens after 6PM PST on the day it is picked up.

Shipping Costs

Shipping costs are based on the weight of your order and the delivery method. To find out how much your order will cost, simple add the items you would like to purchase to your cart, and proceed to the checkout page. Once at the checkout screen, shipping charges will be displayed.

Additional shipping charges may apply to remote areas or for large or heavy items. You will be advised of any charges on the checkout page.  

All shipping rates are pulled directly from our FedEx rate chart.  We do not charge extra over our actual cost from FedEx.  Fi also pays from its own pocket for DSR (Direct Signature Required) and Insurance for any order over $500.

Damaged Items in Transport

If there is any damage to the packaging on delivery, contact us immediately.  A claim will need to be filed with Fedex.  In contacting us please have your order number (it has been emailed to you and is on the shipping label) and your tracking number (emailed to you and on the shipping label) ready to expedite the claims policy.


If you have any questions about the delivery and shipment or your order, please contact us.

  • Overlord1330@yahoo.com

    I got the ht1 to replace my dayton audio um 18-22 and let me tell you. The sound quality is 100% better…… same enclouser same amp same location picked up 2db build quality no comparison!!!! Fi customer service every question answered. Build and shipment times were sent out i was in the loop from day 1

  • blaze2051@gmail.com

    Little back story I wanted more bass started with an 8in yamaha HITB sub moved to dayton 1200sub then a 1500sub. then dual custom 15s 2.6ft3. I heard from others dual 18s was the way to go. So i was going to order the dayton um18s then i read about Fi and there HT1s. Performance and looks was my concern i went to check out Fi Audio and after the owner answered all my questions and concerns i was sold i ordered 2x HT1’s and had someone built custom 10.8cuft3 net ported enclosures. ran REW and i hit 113dbs no compression and dual subs produced decent measurement with little to no major peaks or nulls without any adjustments to peq. will consider buying another set of HT1s

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