Subwoofer Surrounds: The Inverted Apex Advantage
MTX Inverted Apex Surround Animation

MTX Inverted Apex Surround

Traditional Half-Roll Surround Animation

Traditional Half Roll Surround

All MTX car subwoofers are now designed using a high performance, Inverted Apex Surround design. The surround is the material around the cone that connects to the basket allowing the cone to move up and down from its rest position in proportion to the voice coil travel.

Working similarly to the way an accordion compresses, the Inverted Apex Surround is built to fold in at the edges when de-energized, but still extending up or down as the music plays.

Most subwoofers use the traditional half-roll surround where the cone surface is attached to the basket with material wrapped in a single half circle. The circumference of the half circle provides the length available to extend the cone up or down as the circle straightens, moving the cone surface up and down to generate sound waves.

The Inverted Apex Surround design uses four folds using less space around the cone compared to the half-roll design. This surround construction provides the same extension distance in half of the width used by a half-roll surround.

The Inverted Apex Surround design provides two significant advantages over traditional, half-roll surround designs:

  1. More Volume (SPL)
    • The volume of sound (Sound Pressure Level) is proportional to the volume of air moved per subwoofer cycle and the volume of air moved is a result of the one-way extension measurement (typically Xmax) times the cone surface area (proportional to usable diameter).
    • The Inverted Apex Surround increases the cone surface area by using about half the diameter of surround width.
    • SPL is increased per a given subwoofer diameter.
    • The Inverted Apex Surround moves symmetrically through both positive and negative cycles.

      Subwoofer SPL Calculation
  2. Music Sounds Better
    • Half roll surrounds have an inherent “snap-through” distortion that occurs in the surround due to the physics of its action. (See the wrinkles in the animation)
    • Better construction methods and materials can limit this distortion but the Inverted Apex Surround eliminates this problem, resulting in better sound quality.
    • non symmetric  motion control

The MTX engineering team works on constant development of material construction techniques to overcome this complex linearization process, so you get extremely accurate music reproduction while still maximizing SPL.


MTX at Ice Thunder - Michigan Tech

Wednesday, 19 February 2014



For the third year in a row Michigan Tech University created the COOLEST HOT music party in the snow!

Each year the students of Michigan Tech University make all sorts of snow sculptures to celebrate the Winter Carnival. The highlight of the past years Carnivals was the ICETHUNDER sculpture. This year was no exception!

And we all know the word THUNDER stands for MTX Audio products.

What better way to get your self warmed up during a cold snow covered winter night than to dance to the hottest sounds coming from the worlds coolest audio system. For the third time the ICETHUNDER snow sculpture was created to not only demonstrate what cool stuff you can do with snow but also to show how MTX loudspeakers and subwoofers can perform during, and with stand, the most extreme environmental conditions.

In addition to the MTX square subs used to shake the winter landscape, the RTX ROADTHUNDER Extreme series loudspeakers made their debute to deliver the mid and highrange frequencies. Needless to say the sounds created by the DJ never before were so well balanced and so crispy clear coming from the MTX ICETHUNDER soundstage.


Car Subwoofers: SPL or SQ?

A common buzzword used in the car audio world is car subwoofer SQ or Sound Quality. SQ is much more difficult to quantify than say, SPL, the sound pressure level (the boom in subwoofer). Although there is no hard spec that identifies SQ, it is always good to talk about sound quality in a car sub.MTX 95 Series Car Subwoofer

If we define subwoofer SQ as the accurate reproduction of the low frequency (bass) signal input to the low frequency (bass) output, there are big differences from one sub to another. Generally, more expensive subwoofers are built with better voice coil control, among other features, that improves the sound by reducing distortion and reproducing the input signal more accurately. And note that this control becomes more difficult as the music is played at higher volumes.

Some subs are designed and/or tuned with enclosure design, to achieve more SPL even at the sacrifice of SQ. Some customers don’t worry about sound quality, only that their subs rattle neighborhood windows, and more power to them. But what about enthusiasts that want their music to sound like the original even at high volumes?

If the “SQ car subwoofer” is meant to be superior in sound quality, then voice coil control is an important factor to evaluate. Controlling the voice coil attached to the cone to accurately follow the tiniest input signal differences and the most dynamic signal changes makes the difference in music clarity and quality. It means your music sounds as the artist intended with nothing being lost.

And if the subwoofer is not designed well, distortion, aka noise, can be introduced into the music that further degrades the quality of the original.

MTX Audio knows car subwoofers. We have designed some of the most iconic models ever released. Competitors around the world have won numerous competitions based on SPL and SQ using MTX subwoofers. We are introducing our new 95 Series ‘Superwoofers’.If there ever was a subwoofer that could be called both a superior SPL sub and a superior SQ sub, this is the design.

Measuring SPL and SQ?

These are tricky specs to measure in any fashion since enclosure and vehicle type vary so differently from one system to the next. There are many variables to figure into the equation. But we welcome honest tests where the environment is identical and measurements are accurate. We feel confident you will be impressed with MTX.

So is it useful to talk about SQ versus SPL subwoofers? Yes, sound quality is important. Your ears literally get tired listening to distorted music. And the bass instruments and reverberations just don’t sound as crisp or hard hitting as the original performance. That’s not good. And the best subwoofers can hold control even at loud volume. That is why great musicians spend a lot of dollars on their concert speakers.

So whether you are into SPL or not, SQ is something to pay attention to as you choose a car subwoofer. There is no spec that will you tell which sub has better SQ than another, but pay attention to subwoofer technologies that can help predict performance before you make your decision.

Polaris ACE Final Update

So after a couple of solid weeks working extremely hard the ACE is finally done and ready to debut at the Mud Nationals next week. This thing turned out way meaner that even I thought it was going to be. Who would have thought you could put this much audio onto an ATV style machine? Great job to our master craftsmen on delivering a product that everyone is going to be excited about. Can't wait to see some video from Mud Nationals that shows off just how loud this little machine is. Make sure you come by the Polaris booth at the show to see both the RZR1000 Ground Pounder and this new ACE for yourself. Final audio product list for the build: (3) MUD100.2 amplifiers, (2) WET500.1 amplifiers, (2) 5510-44 subwoofers, (2) WET65-W coaxial speakers, (4) WET77-W coaxial speakers, and (1) ZN1-1FD capacitor plus a bunch of other items including dual XS Power batteries, colored LEDs and a Polaris source unit and winch. Check out these pictures of the finished pieces.

ACE with Seat and Enclosures Installed    Overhead Enclosure with Speakers Mounted    Enclosure and Rear Roll Cage Installed

Custom Front Scoop and Speaker Pods    Completed ACE Ready to Be Loaded for Mud Nationals

Polaris RZR1000 MTX Audio Promo Video

Polaris ACE Update

So it seems our crew is really serious about taking this ACE down to the frame. It looks like all the parts have gotten a sealer coat, an army green primer coat, and hopefully a finishing coat in the not too distant future. Looks like Heidi added a Polaris 2500HD winch to the front and as you can see they have taken this pristine machine down the bones in order to resurrect it to the next level as a serious offroad AND audio machine. Can't wait to see when they start putting it back together.

ACE Winch Install   Sealer Primer

Army Green Primer Layer   ACE Disassembled

New Polaris Machine Taking Shape MTX Style

So if you don't know, MTX and Polaris, manufacturer of awesome off roading machines, like to get together and build some crazy things. If you haven't seen the RZR1000 Ground Pounder our boys put together last year for Polaris you are missing a serious piece of offroad terror. Polaris has recently released their new Sportsman ACE single passenger 4-wheel machine, similar to the RZR Series just smaller and with room for only one.  Well I happened by our R&D department the other day and saw that our team somehow had gotten ahold of one of these machines and are working on turning it into an audio beast to match the Ground Pounder. As I understand it, they are going to be adding a custom fiberglass roof with four 7.7" marine speakers, a fiberglass hood unit that houses two 6.5" marine speakers, and an amp rack that is going to live on the rear cage. We are going to be taking both the RZR1000 and ACE to the ATV Mud Nationals in Jacksonville, TX March 26th-30th and showing them off with Polaris.

MTX ACE and RZR          ACE Hood Speaker Pod

ACE Roll Cage       ACE Roll Cage Amp Rack

What a Great Fight!

I was watching UFC reruns the other day on FX and they were replaying this fight. This was the first fight for female UFC fighters on primetime TV and it introduced the world to Gina Carano. Kaitlin Young represented MTX like a warrior. What a great night that was, I am still sorry she lost!

The New 95 Series SuperWoofers Are Coming!

Our new 95 Series SuperWoofers will be available in the second quarter of 2014!  This new series is designed with premium aesthetics and innovative engineering that outclass all other subwoofers.

MTX 95 Series Car SubwooferTrue to its heritage the performance of the new 95 is going to shock a lot of people. It can make the windows flex for those that like it loud and reproduces every bass drum slam and guitar stroke flawlessly even at amazing SPL levels.
The new 95 Series car Subwoofer will be available in both 12" and 15 sizes and with either a dual 4Ω or dual 2Ω voice coil configuration. Each model is capable of handling 1500 watts RMS power.

The 95 Series features the Inverted Apex Surround that we released in 2013 on the 55 and 35 series woofers. This surround increases xmax, 1.25" on both models, and surface diameter allowing it to produce impressive competition level bass.

A 4" high temperature voice coil is cooled using our proven spider plateau venting technology as well as an internal voice coil heatsink and a t-yoke with integrated heatsink, giving it a three-layer thermal management system.

Our engineers have also incorporated a layered, progressive spider that eliminates the break in period that subwoofers normally require.

Out of the box these subs are ready to deliver the boom. Finally a glass fiber cone offers excellent stiffness to weight ratio-increasing efficiency for greater SPL.

The 95 Superwoofer will be available 2nd quarter, 2014. We can't wait!

Solving the Mystery of Subwoofer Power Handling

MTX 95 Series Car SubwoofersMost car subwoofer enthusiasts start shopping for their new system once they have decided on the quantity and size of subwoofers they want to buy. After all, subs are the main part of the system that creates the window rattling, body-panel-flexing bass they crave!

But a common mistake when choosing subwoofers is that the higher the power handling rating, the louder it will sound. This assumption is perfectly logical, but not always true.

To understand this tradeoff, you need to know what makes a subwoofer loud (SPL) and some basic physics. Now, don’t expect this post to be a science lesson with a bunch of technical equations and diagrams. This is a basic explanation of SPL and subwoofer power handling.

First, some definitions you need to know:

  • SPL = Sound Pressure Level
  • RMS Power Handling = Continuous amount of power your subwoofer can manage without damage
  • Peak Power Handling = a measure of power that could potentially be managed for short bursts.
  • XMax = The distance a subwoofer voice coil can move in one direction without leaving the magnetic zone a.k.a. how far the woofer can move.

As a disclaimer, remember that a manufacturer can put any incredible number they want for their "Peak" or "Max" power ratings and many manufacturers do this as a marketing tactic to get customers to believe their product will be louder, better, more powerful, etc… You can't cheat physics; anyone afraid to publish their data is probably not being 100% honest about their ratings.

Sound is created by vibration of an object. The vibrating object causes air molecules nearby to move in waves. The more air molecules that are moving, the louder the sound waves will be. As the number of air molecules moving within the interior cabin of your vehicle increases the air pressure increases. This is called sound pressure. The Sound Pressure Level (SPL) is the measurement of this pressure in decibels (dB).

So in the simplest terms, the more air you move, the more SPL will be generated. So go buy a bunch of 18” woofers and you will be loud. Right? Not necessarily. There are other factors to consider. An 18” woofer has a lot of surface area to move air molecules, but can the woofer move a lot of air? This is where Xmax comes in. If the 18” woofer can only move 1/16th of an inch, it’s not going to move much air and therefore will not be very loud.

What dictates a woofer's Xmax you might ask?

Well… A lot of engineering! It takes a good suspension (spider) that can handle the movement while maintaining linear motion. If a subwoofer does not stay linear, it will create distortion, or worse cause a rub or short of the voice coil against the pole piece causing damage to the subwoofer. A quality suspension is very important.

Additionally, you need a strong magnetic field which uses AC current to push the woofer forward (positive) and pull the woofer backward (negative). This magnetic field is created by the interaction of the magnets on the woofer’s motor structure and the electrical current being transferred through the voice coil from your amplifier.

At this point many people get caught, logic would tell you the bigger the magnet, the bigger the magnetic field. The more power through the voice coil, the more Xmax the subwoofer will have. The more Xmax you have, the louder the subwoofer will be. Right? Not necessarily.

You could build a subwoofer with HUGE magnets weighing 200lbs each and a voice coil that is capable of handling 10,000 watts. That’s easy. But designing a suspension that can keep that power under control is the hard part.  If the suspension is too tight and rigid to control the power, it will limit the Xmax.

Mass is another factor that must be considered. Subwoofer A has a RMS power rating of 2,000 watts and includes huge magnets with a cone assembly made of aluminum that has a mass twice that of the cone assembly of Subwoofer B which has a RMS power rating of 500 watts with magnets half the size. Which subwoofer has the potential to be louder? This is in fact a trick question. 

You can’t determine which subwoofer would be louder simply from this information. Subwoofer A can handle more power but it’s cone assembly is heavier and therefore it requires more power to move it. Xmax could suffer as a result. Subwoofer B can’t handle as much power but it’s cone assembly is lighter and therefore, it’s Xmax could be as good or better than Subwoofer A, thus moving more air. This is called efficiency or sensitivity and is rated in decibels (dB) and should always be measured at (1W/1m). After all, you don’t want to spend the extra money for a HUGE amp or tax your vehicle’s electrical system to power it, right?

As you can see, comparing the performance of car subwoofers purely based on the power rating is not a fair comparison. There are many other factors to consider.

And once you start the installation, consider enclosure design, speaker wire size, and power wire gauge to ensure your subwoofers perform to maximum potential. If you buy a subwoofer with an RMS power handling rating of 2,000 watts, put 2,000 watts to it. Under powering a subwoofer is often times worse for it than over powering.  Also make sure your vehicles electrical system can support a 2,000 watt amplifier. And remember a 2,000-watt amplifier (that truly produces 2,000 watts RMS) will generally cost you more than one rated at 500 watts.

So if you are in the market for a subwoofer, don’t be fooled by peak power ratings created by crazy math. These numbers don’t mean much. RMS Power ratings are what you want to notice. This spec doesn’t always reflect performance either, but I will leave this discussion for another article. Call our MTX Support Team if you want to discuss “the loudest subwoofer for your budget" further at 800-225-5689. To read more about choosing speakers, see our MTX Library

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