MCM Electronics

8'' High Excursion Woofer - 120W RMS 4ohm By MCM Audio Select (55-2421) MCM Part #55-2421

4.5 stars 22 ratings and 21 reviews
MSRP: $64.95
You Save: $34.96 (54 %)
Qty.Volume Price

8" High Excursion Woofer

This high performance woofer features extremely long throw design for outstanding low frequency response, thought impossible of drivers this size. Optimized for vented enclosures, it is great for home theater or autosound applications, as a compact subwoofer, or as a woofer in a three–way design.

Specifications Top

  • Rigid lightweight paper cone
  • Treated foam surround
  • Bumped magnet and vented pole piece
  • Heavy duty stamped steel basket
  • Power capacity: 120W/240W RMS/peak
  • Frequency response: 25Hz ~ 1KHz
  • Nominal impedance: 4Ω
  • Voice coil diameter: 2"
  • Magnet weight: 47oz.
  • Sensitivity: 87dB W/M
  • Fs: 25.7Hz
  • Re: 3.4Ω
  • Le: 2.47mH
  • Qms: 14.0
  • Qes: 0.22
  • Qts: 0.22
  • Vas: 30.43 liters
  • Mms: 59.78g
  • Xmax: 8mm (one-way)
  • Magnet gap height: 8mm
  • BL: 12.99
  • Piston diameter: 163mm
  • Overall frame diameter: 8.25"
  • Required cutout: 7.125" diameter
  • Mounting depth: 4.5"
    Part Numbers
    MCM Part #:55-2421
    MCM Audio Select Part #:55-2421
    Package Specifications & Dimensions
    Weight:8.57 lbs.
    RoHS Comp:Yes
    Warranty:365 days
    Need to Return?
    Length:9 in.
    Width:9 in.
    Height:8.6 in.
    Shipping Information
    Extra Shipping Charge:No
    Drop Ship:No

Product Reviews Top

  • by chadatterberry

    on 7/26/2016

    Works in a variety of applications (be conscious of power input if using in large vented enclosure)

    Overall: 5 out of 5

    These woofers LOVE vented enclosures!!! Not ideal for sealed unless you are using as a midbass driver. I see many people on here complaining of overdriving the motor structure to mechanical failure. If you are using these in a HUGE box or a TL or open baffle you need to keep in mind that these are NOT free air subs. You will notice significantly lower power handling just above the ported frequency. I have used these woofers in small vented enclosures with multiple units, large vented enclosures ported low (my favorite, just use less power), they also work GREAT in a 6th order bandpass enclosure for car audio or home theater if you have the space. The enclosure is quite large, but I have built bandpass enclosures on three occasions for these. One for an ex-girlfriend with 2 of these in the trunk and ports forcing all bass into the cabin through the rear deck speaker locations. That is STILL being driven by a 4 channel Alpine MRVF400 bridged to each driver (200W x 200W), That was installed in the summer of 2005 and is still going strong. 11 YEARS AND STILL GOING!!! It has outlasted her last 3 cars!!! To this day nobody has guessed that there are only 8" drivers in the car. Goes to show how dependable these can be if you power them correctly in the proper enclosure. The only one that has failed was totally my fault, (I was in such a hurry to get it installed behind the seat of my work truck in a downfiring vented enclosure ported to FS (25Hz). I forgot to clean the sawdust out of the box and the sub snarfed it up into the VC vent. It lost volume and sounded blown... It smelled too much like burnt wood and not enough like voice coil, so I flushed the VC out through the vent in the backplate with some electrical contact cleaner (NOT RECOMMENDED). It did work. The sawdust is out of the coil, but it also reacted with the foam surround causing it to warp badly. THAT sub is still working as well. I honestly don't remember having ever blown one of these. My current build is for my 2 channel line array using (24) Tymphany 2" midrange drivers open baffle and (8) Beston RT-002 Dipole ribbon tweeters. Two pairs of these woofers are running from 350Hz down to 60Hz as midbass drivers to match up with my (4) 15" drivers. I have 3 laying around, so I'll be buying another to round it out. I'm sure they'll impress again, they always do!

  • by dennymcclain

    on 2/9/2016

    8" High Excursion woffer

    Overall: 4.5 out of 5

    Just installed two 55-2421 woofers in a pair of BIC Formula 2 cabinets. All original components work fine, but thought that upgrading the woofers wouldn't hurt. All I can say is WOW ! What an amazing difference ! I am using a Crown IC 150 preamp w/ Crown DC 300 for power, so pure and accurate signal is not a problem. Seriously, a world of difference at an amazing price ! I would, and do highly recommend these to anyone wanting to upgrade their older (or newer) cabinets. Smooth, efficient low bass at an awesome price !

  • by prizment

    on 4/9/2015

    Jukebox operator

    Overall: 5 out of 5

    Great replacement for bose 301 speakers. Really beef up the sound and bass. Put them in many speakers we use for our jukebox locations.

  • by misterman15

    on 1/21/2015

    Excellent speaker for the money

    Overall: 5 out of 5

    I bought this 8" high excursion woofer by accident when i thought my 8"pioneer powered sub-woofer speaker blew- Fizzed out but it turns out it was the plate amplifier ...having invested and not wanting to go thru the hassle of returning it i matched it up with a new plate amp and sub-woofer Box /Cabinet and whoa i used a class D amp and the bass is outstanding low and handles the power easily

  • by rivilee

    on 10/31/2014

    Been using this for years in numerous builds- easy mod to make it last longer

    Overall: 5 out of 5

    The weakest thing about this driver is they are prone to cone separation from the spider. Easy fix. Just use 5 minute epoxy where the the glue has failed. I use a wooden tongue depressor to get to it. In fact I do it as a preventative fix on new drivers. Pretty bullet proof after that.

    As far as burning the voice coil... well, there is such a thing as observing the power rating.

  • by Blaise170

    on 8/25/2014

    Sounds good but does not last

    Overall: 2 out of 5

    I've had three of these and all three of them have blown. The first one ended up with burnt tinsel, the second with a bad coil, and the third with burnt tinsel. They do sound really good, I won't deny that, but their longevity is questionable. I finally purchased some Rockford Fosgates that have lasted me far longer and also sound better. As they always say, you get what you pay for.

  • by eastmtmike

    on 2/18/2014

    You get what you pay for

    Overall: 2.5 out of 5

    I have two tapped horns each loaded with two of these woofers. They sound great for about an hour of moderately loud music. After that the burning smell begins. I have gone through 8 of these woofers. The cone detaches from the spider and they're toast. I will be upgrading to something with a little more power handling. For what they cost you can't beat these, they're just not for me. On the other hand, I had nothing but great experience with MCM customer service.

  • by TheGDog

    on 10/29/2013

    Wish I knew about this driver before...!

    Overall: 5 out of 5

    This driver replaced a Kicker Comp 8" I originally used in a TLine enclosure for my home theater application. This driver having a much lower Qts value and Fs value lends itself much better to getting excellent lows. Just swapped-out the driver today. Wish I'd known about this company and this driver earlier so I could have saved money AND gotten the better woofer for the job right from the get go! I originally purchased this driver with intent to build an AutoTuba folded horn. After my free-air listen I got impatient to check this lil guy out. No doubt in my mind I will buy another one of these to build the AutoTuba.

  • by seanmcguire

    on 10/10/2013

    Good 8" Woofer

    Overall: 4.5 out of 5

    I experimented with making clones of the JBL 2800 model. The 2421 is good in a 2-way design, but would be better with a lower frequency tweeter than the Ultra 1230 (crossed @ 2.5kHz), or a 3-way with a little more help in the upper midrange. These are power hungry! I could see these handling 200w clean power daily. The sensitivity and range is nowhere near as good as the JBL 508, and not as crisp either (DUH!). I tuned the ports to 25Hz with satisfactory results, not subsonic bass, but it will quietly fart out the lows and play nicely up through the lower mids. The 2421 will tear up a small box and move it across the room, so do give it PLENTY of volume - 1.0746 ft3 is probably the MINIMUM MCM calculated for these. Give these plenty of time to break-in as well, and the paper cones will sweeten up. I am impressed with what this woofer can do, especially for the price and the crappy job I gave it to do.

  • by nigelrajah

    on 11/12/2012

    8" subwoofer

    Overall: 5 out of 5

    This sub thumps! No midbass coloration. I like it. May have to buy two more for the home speakers.

  • by decampo

    on 9/19/2012

    8" Long Throw Woofer

    Overall: 5 out of 5

    Great woofer for 8". The long excursion means it moves more air than another 8", with a shorter throw. In a ported box it will play the lowest frequencies as clearly as a much larger woofer, without taking up the room a larger woofer in a larger box would. Great for sub, or 2 or 3 way speakers. Home or automotive. Just a great combination of features, to make a variety of possible builds, and also replacements for your old 8" woofers. Just about guaranteed to be an upgrade. If they are on sale, grab a couple like I did. Check your mounting depth, they sport a giant magnet!

  • by D.J.RSB666

    on 5/17/2012

    omg it pounds

    Overall: 5 out of 5

    excellent quality for money with a 200watt sub amp 50-6263

  • by MarleyMarl

    on 1/13/2012


    Overall: 5 out of 5

    Great sound, deep bass. Made a big difference in my surround sound. Great vaule great price.

  • by Perfecto57

    on 5/25/2011

    Nice Little Sub

    Overall: 2.5 out of 5

    Ok, so I got this little work horse back in December for a car audio application and I was very happy with the performance of this speaker. However, after just 3 1/2 months of use it failed on me. I think next time I'm going to go with another brand for a replacement sub. Not quite durable enough for me. -Jeff

  • by Odougbow

    on 12/13/2010

    Extraordinary Bass

    Overall: 5 out of 5

    Extraordinary bass - use two woofers in an Isobaric design box (face to face). For example, construct a simple, slotted box: 11”W x 14- 3/4D x 18-1/4" T (outside dimensions) - using ¾” MDF. Install a 3/4" slot port at the bottom, 9-1/2”W x 10-3/4”D (inside dimensions). This will tune the box at 31 hz. Space the woofers 1/2" apart so they have plenty of room to move, wire the speakers in series (8ohm) and use a MCM 200 watt plate amplifier. No need for damping material. I have built two of these cabinets and the results are amazing, the lowest and most detailed bass that I have ever heard. This design will astonish any home theater enthusiast, even if they have sub-woofers that cost much much more.

  • by jcmbowman

    on 3/15/2010

    Great woofer - great price.

    Overall: 5 out of 5

    I bought this woofer for a horn-loaded car subwoofer (An Autotuba designed by Bill Fitzmaurice, to be specific) and was amazed at the output of this box. It went over so well that my wife stole mine until I built a second one for her car. I love the look on people's faces when I explain that all I've got running is a 100 watt 8" driver that cost less than $50. It replaced a dual-10" loaded sealed box that cost $600 altogether and used 1200 watts. And the new box is louder and cleaner. Awesome driver.

  • by tsloms

    on 1/9/2010

    MCM 55-2421 Tapped Horn system

    Overall: 5 out of 5

    I purchased this sub to build a tapped horn enclosure for it. I am using a cheap 115W amp to power it in a tapped horn enclosure about 2 cubic feet in size. This system by itself is powerful enough to hang with most 10" and 12" subs in much larger enclosures. For the price this sub cannot be beat.

  • by Odougbo

    on 12/16/2009

    Very Powerful Woofer

    Overall: 5 out of 5

    I was impressed with this woofer in a 2 cubic foot ported enclosure tuned to 30 htz and a MCM 200 watt amplifier, the bass bubbles down extremely low. However, I decided to try two woofers face to face in a 1 cubic ported enclosure (excluding the slotted port, again tuned to 30htz). The results are incredible, tremendously low, powerful bass. I did switch to a 200 watt stereo amp set in a bridged mode. Speakers are connected in series so the speaker load is 8 ohms. This speaker has a noticeably smooth response from 25htz – to 100htz. A wonderful speaker and a great value, I may try the cast iron version next.

  • by hooviemoto87

    on 2/8/2009


    Overall: 4.5 out of 5

    I installed this 8" woofer in a Toyota RAV4. I mounted it in a .24 cu. ft. ported enclosure (along with an 8" grill MCM 50-525 and matching blue carpet). It was hard installing a 13" port in that small of a box, but it was worth it! I powered this woofer with a Power Acoustik OV2-420 car amplifier. Let me tell you, this speaker surprised me after I installed it. It handles the 190 watts RMS well and complemented the stock speaker system well. I couldn't believe you could hear the woofer outside the RAV4. The stock system had too much midbass, so to balance it out, I turned down the bass knob and turned up the subwoofer. I would argue that this sub has better sound quality and more deep bass than some more expensive subs that I have heard that require much larger boxes. Why would you take up your whole cargo area when you can build a box the size of a sheet of paper? Only complaint I have is the paper cone. Hopefully it holds up to the elements and 140 degree heat. Great Speaker.

  • by chwojdak

    on 5/14/2008


    Overall: 5 out of 5

    The high excursion along with the low Fs made this driver in a 1 cu ft enclosure outperform larger subs I have built. This guy and your 100watt module for less than $100 will wipe out way more expensive units.

  • by pemrich

    on 11/23/2007

    Part of good <$100 sub for home theater

    Overall: 3.5 out of 5

    Great small vented design from AudioXpress produces outstanding crisp clear bass using the speaker and an MCM subamp like the 50-6272. Really shakes the floor. I built several of these, one speaker failed after a year, thus the low quality rating. Wait for these to go on sale for <$25 and the amps for ~$50, that's value!

Associated Products

Image of Acoustic Dampening Pad

LS00916 - Acoustic Dampening Pad

Perfect for internal speaker enclosure dampening, this wadding provides the perfect solution to eliminating problematic low frequency internal resonance. Made from 2/3 sheeps wool and 1/3 polyester fiber, this material is a must for any speaker building or...

Limited Stock


Buy Now

Others Also Bought

Image of Double Sided Foam Tape

28-955 - Double Sided Foam Tape

•Thousands of uses •Fasten accessories to car dash, etc. •3/4" x 61/2' roll

In Stock


Buy Now
Image of 22

22-24120 - 22" Black Tactical Weatherproof Equipment Case

Durable equipment case provides maximum shock protection for contents making it useful for instruments, audio/video equipment, tactical gear, photographic equipment and test equipment. Pre-cut cubed foam insert (top layer only) is easily customizable to fit nearly...

In Stock


Buy Now
Image of 10MM High Performance Earbud

35-5170 - 10MM High Performance Earbud

High Performance Earbud Lightweight, stylish, high performance earbuds give crystal clear sound as well as a comfortable fit. Ideal for use with CD, MP3, MP4 and any other small portable audio players.

In Stock


Buy Now