BL Series – BL12v3.1

$438.00 $329.00

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Handmade in USAEstimated despatch time of 10-15 business days

The BL v2 Series fills the gap between the all out SPL monster and a solid daily driver.

SKU: BL12 Categories:

The 2019 BL v3.1 Series fills the gap between the all out SPL monster and a solid daily driver. Featuring a chamfered solid pole piece and standard double stack motor structure with 8.660″ magnets as the foundation for a truly tough subwoofer, you can choose from a variety of options to custom tailor the sub for your exact application. New for 2019 is the addition of a revised top plate geometry along with a higher Xmax coil. With the addition of the heli-cooling channels you can bump up the subs thermal capacity for long term daily driving abuse. Looking for an ultra tough SPL sub? Choose the extra spider option, integrated leads, carbon cap, add power, and let it rip.

With head cracking upper bass and brutal low end, the BL handles the extremes with ease.

  • Dual 1 and Dual 2 Ohm

  • Cast basket

  • Wrap around gasket

  • Dual curve reinforced cone

  • Single layer tall foam surround

  • Push terminals

  • Double lead(Integrated option)

  • FEA optimized motor

  • High Flux density design

  • 3” diameter 4 layer Xmax coil

  • Double stack magnets

  • Three heavy progressive spiders

  • Optional Heli-cool systerm

  • Machined in house at Fi
Weight 51 lbs



Dual 1, Dual 2




Cooling, Flatwind Coil, Hyper Pole, Internal Lead, Universal

Thiele-Small Parameters

  BL v3 10 BL v3 12 BL v3 15 BL v3 18
Coils DUAL 1 | DUAL 2 DUAL 1 | DUAL 2 DUAL 1 | DUAL 2 DUAL 1 | DUAL 2
FS 38.0 hZ 36.6 Hz 34.8 Hz 33.6 Hz
RE 0.7 | 1.4 0.7 | 1.4 0.7 | 1.4 0.7 | 1.4
QMS 6.22 7.46 7.81 8.21
QES 0.29 0.33 0.36 0.42
QTS 0.27 0.30 0.34 0.40
MMS 206g 225g 269g 338g
CMS 0.851 0.837 0.740 0.699
SD 310cm^2 480cm^2 810cm^2 1210cm^2
VAS 11.5 l 27.0 l 68.1 l 136.0 l
SPL 85.3 l 88.2 l 90.9 l  92.8 l
BL 15.5 N/A | 21.9 N/A 15.5 N/A | 21.9 N/A 15.5 N/A | 21.9 N/A 15.5 N/A | 21.9 N/A
XMAX 20mm (One Way) 20mm (One Way) 20mm (One Way) 20mm (One Way)
RMS 1750W 1750W 1750W 1750W

Technical Specifications

    BLv3   10   BLv3   12 BLv3 15 BLv3 18
Overall Diameter 11.000” 12.500” 15.625” 18.500”
Cutout Diameter 9.250” 11.125” 14.125” 16.750”
Mounting Depth 6.250” 6.750” 8.250” 9.750”
Driver Displacement 0.16cuft 0.18cuft 0.21cuft 0.26cuft
Ported Box 0.7-1.5 cuft 1.5-2.5 cuft 3-4 cuft 5-8 cuft

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.

P Chamfer: This is a chamfer on the end of the pole, it helps to bring the air down around inside of the motor and helps cool the coil better. It also helps relieve the pressure underneath the dustcap. We recommend at the bare minimum to get this option if you choose this series of woofers.

Hyper Pole: This is an extended version of the standard P Chamfer. It has 1.250” more pole and chamfer resulting in an increased compression ratio for better cooling.

Cooling: Self explanatory, the cooling channels are machined into the inside of the sub to help cool the coil FAR better. But there are some things that you sacrifice. There is less metal inside of the motor so it is a little weaker. If you are looking for a fart/burp only scenario for SPL we suggest that you do NOT get this option. Stick with only the P chamfer. Now if you are looking for a daily sub to beat on and you have less then 2000 watts then this is the option for you. 2000+ watts you need to look into the BTL series.

Flatwind: The flatwire coil option simply helps the power handling of the sub. The coil has more surface area to dissipate heat and will take more power then the regular round wire coil that comes in the ‘stock’ version of the sub. This option will also make the sub tend to be more prone to ‘peaking’. If you are looking to do an SPL install we highly recommend that you use choose the flatwound coil option. In testing it is louder then the regular roundwire coil and takes the thermal abuse much better.

BP: “BP” option which was a machined aluminum compression plug to the pole which helps channel all of the air under the dustcap around the coil for better cooling. To aid with this increased airflow we also added 6 axial cooling channels in the top plate. Along with increased thermal capacity comes the addition of an extra spider and a changed spider pack. All of these features increase power handling from 200-500 Watts depending on the application.

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.

I Heat Ring: This option is a machined aluminum ring in the gap that lowers the inductance of the voice coil which allows it to play up a little higher in the frequency range and have better overall transient response. Please note that you can NOT select low Qts and the I Heat Ring options together.

Internal Lead: This option is for 8 lead coit per coil, increasing the current flow from coil to terminals.

Inner Heat Sink: Its a machined aluminum ring in the gap that lowers the voice coils inductance (allowing it to play up higher and have a little better overall transient response). It also reduces the volume inside the magnet gap of the motor increasing air speed with the cooling as well as allowing the coil to kick off heat to a more receptive thermal mass rather than magnets.

Daily or SPL: Simply put, if you plan on listening to any type of music you MUST choose the daily option. If it is strictly for a fart/burp scenario then choose the SPL option. The reason we have these options is the gap tolerances between the two are different. The gap in the SPL woofer is much tighter and FAR less forgiving in comparison to the Daily option. The Daily option simply gives the coil more wiggle room inside of the gap to deal with the non-linearity tendancys that you can get into when you are using a sub in a daily driving scenario. Typically SPL applications deal with 1 note and it does not change, therefore we can make the gap much tighter and get all of the motor strength that we can out of it.

Spider Spacer: Adding this feature mirrors the spider layers and in turn reduces rock ratio helping keep the voice in line at extreme excursion.

Universal: This option gives you the choice to later chance the impedance of your voice coils. You can change from dual 2s to dual 1s and vice versa by reconing them. If you do not choose this option your motor(s) will be optimized per the coil resistance that you have chosen. (Dual 2s will forever be a dual 2 motor, Dual 1 will forever be a Dual 1 motor).


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.  This normally takes 10-15 business days, but due to unforseen issues it can take longer. Fi will maintain reasonable communication should an item take longer than our normal 15 business days to make.  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 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.

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.

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.


    Best street beaters around takes way more then rated. FI all day!


    Dudes……..The wait was well worth having these built. I am throwing 1200 RMS on each of these and they are still saying “Feed Me” Only issue I have is I put them in around 4 cubic foot, shared chamber (to include all displacements) and tuned to 29 HZ, and turned up it sounds like it doesn’t have enough airspace to breath. I suggest reviewing your specs and minimal air space at that amount of RMS wattage………….. I am about to throw them in a custom enclosure with roughly 5.5 cubit foot (yes – to include all displacements). Great Job guys for an awesome Sub……and by the way my room flexed out of its sunroof seas at around 26HZ…..LOL

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