B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm

Brand:|Model: 21SW152-4
B&C's 21SW152 21" subwoofer driver features a massive 260 square inches of diaphragm surface area—nearly 40% more than an 18" driver and equal to double the Sd of a typical 15".
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List Price$1,081.65
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Part # 294-689
  • 4,000 watt continuous program power capacity
  • 6" diameter, 1" long split winding copper voice coil wound on fiberglass former
  • 15 mm Xmax, 60 mm peak-to-peak excursion before damage
  • Neodymium ring magnet allows a very high force factor and linear excursion
  • Ventilated voice coil gap for reduced power compression
  • Aluminum demodulating ring decreases distortion
  • Double silicone spider with optimized compliance

Product Details

B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm

The B&C Speakers 21SW152 21" subwoofer's 6" diameter voice coil with a 1" copper winding length provides great Xmax (15 mm) and impressive power handling (2,000 watts RMS). Despite the driver's size, a high-strength neodymium ring magnet keeps overall weight as low as possible. The 21SW152 will deliver nearly unmatchable low frequency output when loaded into vented or horn loaded enclosures. Perfect for high output concert and nightclub applications.

Product Specifications
  • Nominal Diameter21"
  • Power Handling (RMS)2000 Watts
  • Power Handling (max)4000 Watts
  • Impedance4 ohms
  • Frequency Response30 to 1,000 Hz
  • Sensitivity96 dB 1W/1m
  • Voice Coil Diameter6"
Thiele-Small Parameters
  • Resonant Frequency (Fs)32 Hz
  • DC Resistance (Re)3.4 ohms
  • Voice Coil Inductance (Le)1.5 mH
  • Mechanical Q (Qms)7
  • Electromagnetic Q (Qes)0.31
  • Total Q (Qts)0.3
  • Compliance Equivalent Volume (Vas)7 ft.³
  • BL Product (BL)32.5 Tm
  • Diaphragm Mass Inc. Airload (Mms)460g
  • Maximum Linear Excursion (Xmax)15 mm
  • Surface Area of Cone (Sd)1680 cm²
Materials of Construction
  • Cone MaterialTreated Paper
  • Surround MaterialCloth
  • Voice Coil Wire MaterialCopper
  • Voice Coil FormerFiberglass
  • Basket / Frame MaterialCast Aluminum
  • Magnet MaterialNeodymium
Mounting Information
  • Overall Outside Diameter21.5"
  • Baffle Cutout Diameter20"
  • Depth10.3"
  • Bolt Circle Diameter20.7"
  • # Mounting Holes8
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
  • Sealed Volume0.93 ft.³
  • Sealed F393 Hz
  • Vented Volume2.22 ft.³
  • Vented F358 Hz
B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm
  • BrandB&C Speakers
  • Model21SW152-4
  • Part Number294-689
  • UPC844632086144
  • Product CategorySubwoofer Drivers
  • Unit of MeasureEA
  • Product Rating
    (4 Reviews)
  • Weight48.45 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

View similar products to the B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm
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B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm
B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm is rated 5.0 out of 5 by 4.
Rated 5 out of 5 by from Professional monsterI bought this speaker 5 months ago. Works excellent.
Date published: 2015-03-05
Rated 5 out of 5 by from Incredible subwoofer. Very durable.I use two of these, each in its own "Othorn" Tapped horn. In this enclosure it is extremely efficient. I'm getting measurements of 130+db from 30hz-40hz with only 1000-1200 watts if that (a pl380 with input sensitivity in the green). I'm new with an RTA but it sure sounds and feels like it. They sound quick and snappy, not like you might expect a 21" to sound. If I remember correctly I ended up using a 5/16th bolt for mounting, these things WILL break wood screws. I'm not sure how they would sound in a BR but I have heard good things.
Date published: 2015-01-26
Rated 5 out of 5 by from Perfect bulletproof subwoofer for extreme performanceAs a DIY speaker designer striving for ultra high fidelity sound for live sound and public DJ performance to a small outdoor audience within 100 feet of the speakers, I chose the B&C 21SW152-4 21" Subwoofer due to its incomparable specifications that match my custom acoustic suspension subwoofer cabinets perfectly. The B&C holds the bottom end of custom three way line array system that is like the Bose L1 Model II - live sound/portable DJ performance line array speaker system, for a fraction of the cost, with deeper bass, better clarity and imaging, and far greater max SPL. This fall I ran the B&C 21SW152-4 ran in one sub cabinet and a Pyle 21" ($200 Performance sub) in the other and the B&C completely trounced the Pyle with deeper bass extension and far greater excursion with the same power. I run a DBX DriveRack PA+ and four Crown digital XLS-1000 and XLS-2000 amps to drive the system. Each line array is composed of a 21"sub in a 24"w x 24"t x 20"d sealed and braced MDF cabinets. On top of the subs are four excellent Peerless (830991 like, previous generation) 5 1/4" mid woofers in a seperate aluminum frame cabinet running 80hz thru 4000hz and topped with ten feet of midrange and tweeter each with nineteen 1" x 4.5" dual magnet / voice coil panel TV speakers forming a single 1 inch by ten foot tall line array radiator. I love the B&C sub and will be replacing the Pyle with a second B&C before next BurningMan 2012.
Date published: 2012-01-09
Rated 5 out of 5 by from Good looking; powerful; bulletproofI utilized two of these woofers in a pair of Jensen Imperial horns (built-in version) and have been nothing short of amazed. At full volume (2000+ watts RMS); the hair on my arms flutters 15 feet away! They're also smooth on the ears--I didn't hear much distortion, regardless of volume.Power is provide by a pair of QSC RMX 2450 power amplifiers in mono-bridge mode. EQ comes from a Behringer DEQ2496 Ultracurve. These components are also available from Parts Express.I EQ'd the bottom end (parametric with 6db boost at 20hz with a slow roll off to 100hz) and have no trouble getting first octave bass extension. There's so much acoustic power available that I had to perform extensive panel bracing on the Imperials--double plywood panels everywhere and half a gallon of glue & 5 lbs of screws per horn. There's no mercy... This is one incredible machine.
Date published: 2010-06-19
  • 2015-10-13T06:46CST
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Product Q&A

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B&C 21SW152-4 21" Neodymium Subwoofer 4 Ohm

this can be horn loading?

Asked by: rb57
Yes this could be horn loaded.
Answered by: MattP
Date published: 2015-08-14

What would be a good size for a sealed enclosure in a car trunk?  The 0.93cf in the item description sounds like a misprint for a 21" driver.

Asked by: zacjones99
I would recommend a volume of 3.5 to 4 cubic feet for this woofer sealed. This will provide an F3 of ~80 Hz and in car response into the 40's.
Answered by: MattP
Date published: 2015-05-28

what is the recommeded crossover setting for this woofer

Asked by: DJ CURT NICE
There isn't one recommended setting for this, it will depend on the rest of the system and application requirements.
Answered by: MattP
Date published: 2015-03-17

Do you think this driver would be suitable or survive being played at 30hz or less? Just sub frequencies only.

Asked by: cartoman
This depends on application, box alignment and output levels required. This driver isn't designed to play much below 30 Hz, but in the right box alignment and proper EQ it can, but with limited output.
Answered by: MattP
Date published: 2014-12-18

cabinet configuration for 2 of these in same cabinet,in home,700sq,ft.room,music use.what type of damping,how much?

Asked by: bobbo410
I would say 8.9 cubic feet total for both which will provide in room response into the upper 30's and handle full RMS power without excursion problems.
Answered by: MattP
Date published: 2014-03-04
  • 2015-10-13T08:13CST
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