Electrodynamic

Nice video! I think I might pick up one of those DD-1's for the shop. PS: Thanks for the mention in your video. Made me feel all warm and fuzzy!

That's plenty of room for two 12's in a ported enclosure. I would contact DC Creations or RAM Designs about enclosure plans and/or building the enclosure for you.

I am fully aware of that. That's why I said what I said. However, it is what people don't understand which supplies the illusion of having those response curves inside of their car. Sure you can compare subwoofers to see which one will play lower in the same size box but again it is in a test chamber, not in real life. Actual responses in real life are anything but close to what WinISD shells out. The program is very good for determining port length in a vented enclosure though.

I hope you are not stating that the Obsidian woofers are designed by the same person who designed the Skar woofers because that is completely wrong. If you are listening to your woofers in an anechoic chamber then definitely look at the WinISD graphs. If you are not, however, add in a +12dB/octave gain at ~45 Hz and you will have an estimated in-car response.

And that's exactly what they were designed to do - operate over a very large bandwidth while sounding good and getting very loud if need be.

Yes indeed. He puts up respectable numbers but the camera does not do this system any justice.

Send it again and I'll keep an eye out for it. What is the email address you are using?

I'm doing fine Ryan. (PS: Nice to see you around!) I wasn't really keen on the idea of opening this up to everyone but if it raises money to help out with MS I'm all for it.

It looks like a solid box volume and tuning frequency. I don't know where the idea of X in^2 per ft^3 started but it is not a very good ideology to follow. If that were the case a single port for a single 12" driver in 3 ft^3 would be 36 in^2 for 12 in^2 per 1 ft^3 which is a 3x12" port...and good luck fitting it inside the enclosure due to the port length required. That's a huge port for a single 12"! Most drivers out there can't excite that huge port area, so that huge port is wasted for the most part. Simply stick with 12 in^2 to 18 in^2 per 12" driver and you will be fine. An adequate port for the Obsidian 15's is 30 in^2, or 90 in^3 for three 15's. The enclosure you have listed above is 165 in^2, or nearly double what you need. You can go with a huge port but your bandwidth/response will suffer as larger ports tend to peak higher than smaller/adequate, ports. Or if you had 9000+ watts and were interested in competing only, then the 165 in^2 has the possibility to put up a better score than a port that is 90 in^2. For instance, with 1500 watts of clamped power using a single 6" aero port (28 in^2) I managed 144 dB in my CRX legal on the dash sealed up using a single 15" Obsidian. Switching to the 8" aero port (50 in^2) and raising my tuning closer to the peak of the vehicle (mine peaks at 56 Hz) I managed a 145 with the same power. However, increasing the power to 3000 watts saw a peak score of 148 dB with the 8" port. If I didn't have the large 3000 watts of power the huge port was not very beneficial.

Nice response curves.

Just thought I would post to check and see if everything looks alright in my signature. I got an email from denim, so I thought I would come check it out.

From time to time I like to divulge information that helps people understand subwoofer performance. For this particular post I'm going to copy an article from Adire Audio on subwoofer speed. "There's a common misconception out there that heavy woofers must be "slow", and light woofers must be "fast". If a woofer A's moving mass is higher than woofer B's, then woofer A is probably going to be sloppy, or slow and inaccurate. Can't keep up with the bass line. Woofer A simply can't respond as fast as woofer B. There's also this concept that the "acceleration factor" (BL/Mms) is an indicator of woofer speed/transient response. High BL, combined with a low Mms, should give great transient response, right? Well, on surface these might sound like logical assumptions. However, they are in fact incorrect! More to the point, moving mass has precious little to do with woofer speed or signal response! And we'll prove it... Go back to good old Newtonian physics... We're going to start with the famous law: F=ma (eq 1) Or force equals mass times acceleration. Anyone who's been through introductory physics (or watched a bit of PBS) should be familiar with the equation above. It's pretty much the bedrock equation of Newtonian physics - it's number 2 of the Big 3 Newtonian equations (the first being about interia, and the third being about complementary/opposed actions). Now, let's look at a loudspeaker... What do we have? We have a coil of wire which creates an alternating magnetic field which interacts with the static magnetic field in the gap (see our page on DVC subs for a bit more information on this). How does the alternating magnetic field of the coil come into being? Well, the magnetic field is created by passing a current through the voice coil. As the current through the voice coil changes, the magnetic field created by the coil changes. This field interacts with the static magnetic field of the permanent magnet, and you get a force - the cone moves in and out. Just like two permanent magnets will attract/repel each other depending upon how they are oriented. And a bigger current means more force. Just like bigger/stronger permanent magnets mean stronger attraction/repulsion. Additionally, what if we make the field of the permanent magnet stronger? Well, that's call the B field in the gap. Increase B, we increase the force as well. Or, what if we could somehow make the magnetic field from the voice coil stronger? We can - increase the number of turns of the voice coil (increase the Length of the wire in the gap). Guess what - in both cases, we increased the BL of the speaker (yes, this is the BL of the T/S parameters - now you know where it comes from!). Now, let's go back to equation 1... Let's define each of the terms in that equation so we know what we're talking about: F= Force m = mass (moving mass) a = acceleration So, what is the Force (NO Star Wars jokes, please!). From above, we see that the force on the cone is the motor force factor (BL) times the current. So, let's rewrite equation 1 in these terms that are applicable to the loudspeaker: BLi = ma (eq 2) So, the Motor Force Factor BL times the current i equals the moving mass of the driver m times the acceleration of the driver a. Note that we have italicized i and a. There's a reason for it! Now, back to the original question - transient response of a driver. What is transient response? Simply a measure of how fast the driver can respond to the input signal. That means that - inherently - there is a time dependency on the driver. How much TIME elapses before the driver responds. So, let's look at equation 2, and cancel out all terms that are not based on time. After all, if a quantity is time-invariant, then it won't affect time-variant effects like transient response (think of this as a simple offset). Or, to put it in an analogy, does the 1/4 mile time of a vehicle depend upon where you start? No, the distance over which you measure is still 1/4 mile. So whether you start in front of your house and go straight 1/4 mile, or motor on down to the dragstrip and go 1/4 mile doesn't really affect the car's 1/4 mile time. The 1/4 mile time is strictly dependent on how fast the car can accelerate from a dead stop over a 1/4 mile length. So, looking at equation 2 we see that: BL is time invariant, assuming small excursions (assume an ideal motor with a flat BL curve; I know, most drivers don't have that, but assume that it does, like our XBL2 enabled motors). So BL is essentially a constant. i is the current into the driver (we used italics to indicate a parameter that is time-variant). This is the music, or test tone sweep, or whatever signal is coming from the amp. It's an AC waveform so by definition it changes with time. m is mass. Well, if the moving mass of the driver is changing as you operate, you've got big problems! The weight of the cone, dustcap, former, voice coil, surround, and spider are pretty much fixed. The don't change either. So m is essentially a constant. a is the acceleration. This is what we're after. After all, the rate of change of acceleration IS the transient response - it's what dictates how fast the driver can change speed, which also means it dictates how fast the driver can move from position to position. And note that it's in italics, too. After all, acceleration in the time-variant parameter we care about here! So, let's rewrite equation 2, and replace the time-invariant parameters with a simple "C" to indicate a constant (a parameter that does not change with time): Ci = Ca (eq 3) or i :: a (eq 4) (note: the "::" symbol is the mathematical symbol for proportionality; that is, i is proportional to a). Interesting! This says that the change in acceleration of a driver - how fast it can change position - is strictly a function of the current through the driver. In fact, if you could make the current change infinitely fast, then the driver would accelerate infinitely fast, and we'd have infinite transients - zero time to change between states. Infinite frequency response. So, now that we know that current is the driving force (pun somewhat intended) behind driver acceleration changes, let's look at what limits how fast we can ramp current through the driver. Because if we are not restricted in how fast we can change the current, then we are not restricted in how fast the driver can accelerate - transient response is not limited at all. So, back to that loudspeaker model... A loudspeaker is a coil of wire wound on a former that attaches to the cone. The current flows through the coil, creating an alternating magnetic field that interacts with the static magnetic field of the permanent magnet. So, what could limit current flow? Well, what does a voice coil look like? How about an inductor? You know, those coils of wire (hey, isn't that what a voice coil is) that you use in crossovers? Guess what - a voice coil IS an inductor! In fact, an inductor stores its energy in the magnetic field (as opposed to a capacitor which stores its energy in the electric field). It is this magnetic field of the voice coil "inductor" that interacts with the permanent magnet field we talked about above. Hey, a loudspeaker is an inductor hung on the end of a cone in a static magnetic field! So, what about an inductor will alter the way current flows? Well, inductors don't like to have the current flowing through them change. They like to hold the current constant. They will allow you to change the current flowing in them, but the bigger the inductor (or, the higher the measured inductance) the longer it will hold the current before it starts to change (I'll leave it to the reader to go research inductance on their own, to learn why this happens). So, the voice coil is an inductor. And we see that inductors don't like to change current. But we also see from equation 4 above that we need to change the current if we want to change the acceleration. So, the voice coil doesn't want us to change the current. How good is it at holding the current? Depends upon the inductance! The higher the inductance of the driver, the longer it can hold the current flowing through it. Which means the more time elapses before it starts to respond to the amplifier's applied voltage. Which means we have slower transient response. Guess what - we just answered the original question! It turns out that transient response of a woofer is not a function of the moving mass, as is commonly espoused (one of the most infamous audio myths). In actuality, it is based upon the inductance of the driver. And the greater the inductance, the slower the driver - the lower the transient response." There is a graph and measurements that follow the above information. I need to host the image, however, in order to show it to you. The information / text won't really help without the graphs. The final paragraph of the article reads: "Mass isn't the problem - inductance is. So if you want faster transient response, ignore that moving mass parameter that some manufacturers push - look at the inductance! And if they don't list the inductance, ask yourself why - is there something they don't want to show? Inductance is the key to driver transient response - ask for it when transient response comes up!"

Cool deal!

I just replied to an email to someone about the same exact thing. Displacement is 0.1 cube.

True. I need to host a pic of the surround on the cone to give you guys an idea about what it looks like.

Click here: Mag and BM pics!!

Cool.

LOL! Haha, I didn't even check the date. So who brought this thing up from the dead anyway? I swear it was at the top!

http://stereointegrity.com/oldmag.php

First you need to let us know what your goals are and how much room and power you have to play with. Without any of those, this topic really won't get you a solution to your querry.

Very light, on the order of 20-25 lbs for the Mag and less for the BM I'm sure. Yep, the Mag weighs in right at 20 lbs. The BM's are in the 15 lb neighborhood.

Bigbang - search this forum. The prices and all the information regarding the new Mags are on this forum.

Like I said before, the 1800+ watt, power-soaking monster market is flooded. If you want a driver like that that requires 2+ cubes ported, then buy something else. That is NOT what the Mag is designed to do, period. Read what I've written before - the new Mag sealed has the output of most ported 12's. Case in point. Why go incredibly larger (most of the time over 2X the enclosure size and double the weight) when you don't need to? And if you feel that you can hear the 0.6 dB difference going from 1000 watts to 1200 watts, then by all means throw that smidge more power on a different driver. What you'll end up doing is coming back to a Mag after 6 months of fooling around with settings, making 3 different enclosures, and spending 4x the money on a subwoofer system that you could have avoided the entire time just by purchasing a new Mag in the beginning. I'm not making the new Mag a 1500 watt do-anything-you-want-to-to-it driver. The new Mag is for small sealed, phenomenal SQ, 1k watt power handling, good SPL, light weight. Period. It solves more sub-bass problems than the previous Mag's could have ever fathomed solving. Much more specific, much more wide-range problem solving.

Thanks for the replies guys. Haha, the thread got fairly interesting on page 2 for sure. I know it might seem like it's a gamble to do a small enclosure, sealed only, lightweight driver on roe and ca.com, but keep in mind that a lot of people who post about ported post questions to whether or not they can use 1800 watts on a single driver. That's not what the Mag was designed to do at all. A lot of people don't post too - those are the ones who typically ran them sealed. There are a lot of Mag users that wanted the best sound possible from the smallest enclosure possible. Listening to my customers lead me to design the next Mag for small, lightweight, shallow mounting depth, and sealed. That's what people wanted. They wanted a solution to bass without taking up the entire trunk. The new Mag is that solution. If I make a 1800+ watt ported bad boy it's going to be a 15 that will be completely different than the Mag. Like I said on ca.com, the Mag was originally designed for small sealed enclosures. Back in our beginings we thought we made a good sealed driver. Come to find out it worked really well ported. We found out why it did so well ported and continued to make it work both ported and sealed. Making it a true SQL, shove-1500-watts-on-it-and-nothing-is-damaged, big-boy was cool, but it was still a big, heavy, power hungry beast. People wanted something like that, and that's what I built. Sure it still sounded good, but it sounded good, not REALLY good. But now the market is flooded with drivers that will do what those customers want. The Mag slowly lost some of it's SQ and gained more SPL roots. Not entirely, but the tables went from something like a 50/50 split to a 40/60 split. And that's fine for people who want that, but that isn't where we are focusing anymore. It's time to take the Mag back to its roots - small sealed. ...but now the new Mag sealed is as loud as most drivers ported. And it takes up half the enclosure size. And it weighs 2/3 if not 1/2 what other woofers do. And it's 2" shallower. And it still handles 1000 watts. And it sounds better...a LOT better. I know it might look risky, but I don't see it that way. There have been a LOT of people email me over the past few years asking for a shallow version of the Mag, and when I look at the market it makes total sense to do one. The new Mag hits 100% of the design goal. Not only our original design goal back in 2000, but also our new goal for 2008. I'm stickin to it! And Chad is right - I'm an OCD bastard that won't settle for anything other than perfection. Jim knows that too. How many other companies would sit for 2 years without any product to sell because they would rather wait for the best than to jump on something that would get them by? In car audio, I don't know of any other than us. PS: Asia is shaping up nicely. (I'm in Shanghai right now). I spent all day yesterday meeting with the owner of a metal extrusion facility, eating lunch and dinner with him before making my way back to the hotel. Tomorrow I'm going to start my 3-day stay with the build house that's doing the final assembly work on the new Mag's and BM's.