Electrodynamic

Thanks for the reply's guys - they were all spot-on. 1200 watts on a previous Mag 15 is just fine. Can it sound good? Yes. Can I get it insanely loud with 2k watts and a fart box? Yes. Will it sound good in the fart box? No. Just like Stratus said - mid 140's from a single Mag isn't un-common...all while still sounding better than anything else out there.

I'll listen to anything you guys send me. I don't have anything by D'Angelo.

I have been listening and listening and listening to the new Mag for a few weeks now in our '94 Civic hatchback with the woofer in 1.3 cubes sealed off two channels of a SAZ-100.4. I wrote the following first bit after I spent 4 or so hours with the driver. The more I keep listening the more I feel like I should update the review. So what I'm going to do is keep this thread open and keep adding to the original text. What you will see is not reply's, but the text will grow as time goes on. I'm not going to lie though, a lot of the material I use for testing subs isn't in a lot of people's CD libraries. Having said that, I will post the album title and artist of the material I am using so you can either download the song/album (legally of course...you don't want the RIAA on you (note the sarcasm)) or buy the CD. I got the driver hooked up in 1.2 cubes in the Civic tonight!!! It

^ What he said. Ok, instead of having you (or anyone) model something up to help explain what I was about to explain I'll model it up real quick and post a graph. I'm going to use a PA 12" driver in 1 cube sealed and the new Mag 12 in 1 cube sealed to show you what Jake and I are talking about. Like Jake said, above 200 Hz, sensitivity means a lot if you're talking about a midrange. When you're after output below 100 Hz, high sensitivity is a bad thing. Like Jake said, high sensitivity drivers have moving mass's that are too low, Xmax's too low, and usually Qts's that are too low to provide any real output in the subwoofer region. Concerning the driver you are talking about (the DIY), take a look at the Great 12 Challenge results. The driver didn't fair well at all. It's a neat looking driver, but output wise it provided very little and proved to be a brittle driver (mainly the cone). The light moving mass approach is a good one...if, and only if, you have the other parameters in check so that you still have good output. Like Jake said above, and I've said before, if you have that kind of mass you need a high Qts in order to regain output down low. Low Q, high BL, low moving mass drivers are not good subwoofers. Anyway, here is a graph of an Eminence 12" high-efficiency woofer (97 dB) against the new Mag 12" (86 dB). Both are in 1 cube sealed. The green horizontal line is 0 dB, the red trace is the Mag and the blue trace is the Eminence. The Mag's F3 is 40 Hz compared to the Eminence's F3 of 79 Hz. The thing to keep in mind is that there is a clear difference between efficiency and output. Two completely different things. What the new Mag was designed for was output in 1 cube sealed or 1.5 cubes vented. It wasn't designed to hit a great 1W/1M number because if it was designed for that, it wouldn't produce any real sub bass.

They might be able to play that high, but not without encountering breakup first. Anyway, I was experimenting with such a high x-over to see how the driver sounded. It sounded so good with it being that high I just left it for a while. The x-over is now at 100 Hz, and will probably go down to 80'ish this weekend.

Sensitivity is rated lower than the previous Mag. The result is more output while using less power from 100 Hz on down. I'm going to post Fs, Qts, Le and Re graphs over excursion / power delivered. I'll also post up the same graphs with the previous Mag, which will be VERY interesting to a lot of you guys.

Same 'ish, different day. Shops all around get brain-washed by the companies they deal in and industry magazines on a daily basis. A lot of shops also are so money concious that they will turn a cheek to anything that doesn't get them any commission. And to their credit (what little credit I do give the majority of shops) they only know what they have been told. It's quite simple really...except that they seem to be more opposed to learning new information if the information doesn't have the seal of approval by the companies they carry. Unfortunate, really.

The Mag can actually play clean up to 900 Hz before it starts breaking up. If you ignore the 3 dB dip it can play out beyond 1.2kHz. You're right on the x-over settings though. I usually run around with mine at 80 Hz for fun and 65 Hz for more discerning listening. Higher points do localize the driver more because mids start coming through.

I just updated again, the x-over is at ~100 Hz now. I started the test (before the first writeup) at 50 Hz and kept bumping it up and up and up so I just said screw it and lowered it back down to 150 Hz because it still didn't muddy anything up. But like I said, the x-over is at ~100 Hz now.

I just updated the post with two songs. I'll see if I can get my hands on som Pink Floyd. I've heard Pink Floyd on other peoples systems (mainly home), but never in a car.

HHawk, check your PM's. I burned the tracks last night and have listened to them all about 5-6 times over.

No new updates as of now. I am going over to China in mid March to visit the build houses that we are using. When I return I will bring back with me the finished, final, Mag. I will also bring back the proto BM (and hopefully the final BM). Stay tuned to the forum for more udpates! PS: I'll be writing an article with pictures of my experience over in China. I'll be visiting other build houses besides the one's we are using too - mainly Tang Band. For those of you who don't know - TB even makes their own glue! They make EVERYTHING themselves. It should be a really cool experience.

The higher the inductance, the narrower the bandwidth and poorer the transient response will be with all factors remaining equal. However, like Neil and others have pointed out, the box that you put the sub in makes a difference as well.

If all goes well, hopefully the new Mag's will be released this spring.

Cool! Strong cones FTW! Jake and I were just talking and we think the Nightshade cone is stronger than a "special" paper cone we have laying around here. The thing is heavy (about double the weight of a "normal" cone), but it sure is strong!

In addition to what Adrian said (which is correct, by the way), inductance is the rise in voice coil impedance. Inductance in the "super woofer" category usually ranges from 2.5 mH to 6 mH. The lower this number is, the higher the driver will play (which is where your blending comes into play) and, of course, the other benefits as described in the Adire article apply too. But 1.8 mH is really low for a woofer of that calibre, which is a good thing.

Good post. I see this is where they have all the DUMAX files for various drivers too.

Same here. I've had articles like these for a while now and a lot of the articles on Adire's web page had been taken down last time I looked, so I decided to post one up on here.

True. But you went to the extremes. 800 grams of mass is quite a bit with a motor that wasn't designed to accomodate the mass. When you build to meet your design goals with the appropriate materials the probaility of it breaking should be mimimized. Over-building with lots of mass just to avoid failure is just as counter productive as is under-building with as little mass as possible. If you have a driver with 46tm of bl and 400g of moving mass and try putting it in a small sealed enclosure the LFE is going to suffer quite a bit. All you've got is a tough, tin-can sounding subwoofer. In the link that Jim provided to the actual document (which includes the graphs), you can see that they almost doubled the mass of the Extremis and when that "heavy" Extremis was compared to the Extremis with added inductance, the transient response of the added mass example was still better than the increased inductance example.

I'd sell the drivers to you Jim, without passive Xovers. ...if we made them.

I'm surprised it's still there. A lot of the files they used to host are gone now.

It's 0.8 mH on the new Mag. The previous Mag was 3.5 mH.

Haha, not at this moment. We might do some components, but nothing is set in stone right now. Thanks for the enthusiasm though!

I know you'll be satisfied with the SAZ's and the Mag's. Right now the Mag has been powered with just the rear channels of a SAZ-100.4 for lisening tests. But like Jake said, we'll use a 1000D on it this weekend. The SAZ line is the most performance-packed amplifier line I've ever dealt with. I'll be running complete SAZ amps in the Civic when it's all said and done. I don't know if I'll be using 1500's or a 3000 yet though. It all depends if I go two Mag's or four BM's.

Haha, I didn't overlook it. Sorry for not responding to it yet. I was gone for the past 4 days and haven't had the time to burn the CD. I did get the recordings though. I'll burn the CD and take a listen before this coming weekend.