21 Inch Subwoofers – Hand Built in the USA | EM Audio

21″ Custom Hand Built Subwoofer 3500rms (Mini Team 21)

Adam — Tue, 31 Mar 2026 14:46:54 +0000

EM Audio 3.5K 21” Subwoofer

The EM Audio 3.5K 21” was built for one thing—serious output with real-world reliability. This isn’t a watered-down “big sub.” It’s a purpose-built driver designed to handle daily abuse while still delivering the kind of low-end that turns heads and flexes metal.

Every part of this subwoofer was engineered from the ground up to balance efficiency, excursion, and durability. Rated at a conservative 3,500 watts RMS, this platform is capable of handling massive power while maintaining clean, controlled bass response across the entire low-frequency range.

At the heart of the 3.5K is a triple 34mm slug, triple-stack motor structure, designed to generate serious motor force and maintain high flux density under load. This gives the sub incredible control, even at extreme excursion levels.

We paired that motor with a 3” (86mm) 8-layer American-made aluminum flat wound PE voice coil, delivering excellent thermal capacity and efficiency. The 10” progressive spider pack keeps everything aligned and controlled during heavy excursion while still allowing smooth, daily play.

Cooling is a major focus in this design. With pole venting and perimeter voice coil cooling, heat is pulled away from the motor and coil efficiently—reducing power compression and allowing longer play time at high power levels.

The ventilated motor structure and basket design improve airflow and thermal dissipation, helping this sub stay consistent whether you’re on music or pushing it for demos.

Finished with EM Audio’s aggressive styling and premium materials, the 3.5K 21” delivers high output with low distortion, making it a serious contender for any high-power build.

If you’re trying to move real air, flex your build, and be heard from down the street—this is it.

Key Features

3,500 Watts RMS Power Handling (Conservative)
Up to 25,000 Watts Peak Power
21” High-Output Platform
Triple 34mm Slug, Triple-Stack Motor Structure
3” (86mm) 8-Layer American-Made Aluminum Flat Wound PE Voice Coil
10” Progressive Spider Pack
Advanced Cooling System (Pole Vent + Perimeter Coil Cooling)
High-Efficiency Motor Design with Strong Flux Control
Low Distortion, High Output Performance
4 Gauge Push Terminals
Heavy-Duty TI Frame
4th Order and 6th Order Friendly

Recommended Enclosure

Ported: 5.5 – 6.5 cu ft
Tuning: ~30–32Hz

For best performance, we recommend working with a professional box designer.

The post 21″ Custom Hand Built Subwoofer 3500rms (Mini Team 21) appeared first on EM Audio Subwoofers.

21″ Custom Hand Built Subwoofer 5000rms (Team 21) shown with full carbon option and direct leads

Adam — Fri, 14 Jul 2023 03:27:06 +0000

The Team EM audio 21″ is without question the most insane street, daily, SQL or SPL subwoofer ever developed! Every component of this subwoofer was custom designed to deliver the deepest, loudest, and clearest sub-bass available out today. Weighting in over 100lb we added incredible reliability and unbelievable power handling coming in at 5000rms, and 20,000 MAX! the Team EM audio 21″ comes in D2 or D1 Made in the USA coil. These subs was built for efficiency while still having a high amount of xmax daily. We use the latest in Development and technology of softparts goes into all of our subs. Numerous R&D hours went into designing this subwoofer. we use a 11″ wide triple stack y35 low carbon steel motor structure with durable and attractive black powder coat. smooth extended bumped backplate allows for a longer voice coil winding length. 75mm to be exact. A 5 layer 10″ suspension was used to keep everything align during extreme high excursion. Pole vent cooling was added to keep pressure off the dust cap on high excursion. And perimeter rear direct coil cooling to help keep this beast cooled during high power handling. The powerful magnet assembly we use assures high flux concentration. The ventilated basket designed between the spider and magnet structure significantly improves thermal connection and heat dissipation, further increasing power handling and lowering power compression. This driver is capable of high output and low distortion, which is unheard of in these off the shelf brands. A newly designed Mega roll stitched surround are now used in our Team line. A 650oz motor that was designed to have extreme motor force backed by some of the best softparts available today, makes this team line something to reckoned with! Want to Be Heard? Or out do your friends? Piss off the town? This is the sub for you! Get you one today before its to late! The Team 5k is a top pick for extreme level SPL and daily ground pounder enthusiast!

5,000w rms conservatively rated

20,000w for burps!

21″ frame gray is standard (over 100 different colors optional upgrade)

over 3″ of xmax (38mm 1-way)
half roll surround
black poly dust cap (real carbon fiber dust cap optional upgrade)
10″ progressive spiders 4-layer (stiffer optional upgrade 6-layer)
triple Xl flat oversized leads
4″ 75mm 8-layer American made PE coil
4ga. push terminals (direct 8ga. ofc leads optional upgrade)
stainless steel hardware and lock washers bolt this beast together

2-tone EM audio logo standard
650oz black triple stack 1″ thick slugs and 11″wide motor (over 90lbs just motor)

Mounting Depth:

Motor Width: 11.0″

Cutout diameter:

outside diameter:

total weight: 102lbs

Box requirements:

6-7.5cu. ported to 32hz

*4th order and 6th order friendly *

We recommend you Get with your favorite box designer.

The post 21″ Custom Hand Built Subwoofer 5000rms (Team 21) shown with full carbon option and direct leads appeared first on EM Audio Subwoofers.

21″ Competition grade Hand Built Subwoofer 8000rms (Super Team)

Adam — Fri, 14 Jul 2023 03:08:27 +0000

Do you want the Biggest and Baddest subwoofer out on the market today? Then look no further than the EM audio Competition Grade Super Team subwoofer! You want to have the biggest subwoofer in your town? Want to have that edge over your competition? Then you came to the right place! this Monster will move crazy amounts of air! pressure unheard of in normal smaller drivers. coming in at over 148lbs and 8000w rms yes 8k with ease. Super Massive 8-layer 4″ American made PE coil with over 4″ of wh. 13.5″ wide motor over 850oz! This subwoofer comes in full carbon fiber only because paper cone would just Shred under extreme conditions!

hand built to order here in North Carolina with pride

MADE IN THE USA!!!!

over 148lbs the 21″

8000w rms conservatively

over 35k on burps.(been tested)

6-layer Tan EM audio custom tooled progressive spider pack

triple xL leads to take over the 8000watts rated power

Massive American made 4″ 8-layer PE coil with over 4″ wh

one of the biggest 4″ coils out on the market today!

true 4ga. push terminals to feed massive amounts of power to this beast!

real carbon fiber cone (one of the strongest out on the market)

big roll surround extra thick and tuff to take extreme abuse with string Reinforced surround

real carbon fiber dust cap pressed 3-layers

Mounting Depth 13.25″
Cutout 19.25″
Outside Diameter 22″
Weight 150
Displacement .4cu
motor width: 13.5″
Box recommendation:6.0-7.5cu
recommend tuning:24-32hz

Super Team 21 TS

The post 21″ Competition grade Hand Built Subwoofer 8000rms (Super Team) appeared first on EM Audio Subwoofers.