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Discussion Starter #1 (Edited)
Pretty smooth FR. The bump at 1-2khz is a measurement artifact, as is the dip at 4khz. Nice extension to about 6khz, and a smooth rolloff. Keep in mind the driver was measured in free-air, without any box or baffle.

Here you can also compare the nearfield measurement (driver measured at the cone), versus a .5 meter measurement, and the corresponding .5m 30 and 60 degrees off-axis measurements.



T/S parameters and impedance curve. A good match with manufacturer's specs, although inductance is a bit higher than advertised and efficiency a good ~2db or so lower.



Some resonance issues here at both 1khz, and again at 5-6khz.



Overall decay times seem about average, without any serious issues at these frequencies although not stellar performance either.





Distortion measurements were taken in the nearfield, and then converted to a reference 96dbspl at 1m. 96db I feel represents a good, dynamic, real world listening level.

Pretty good performance considering the difficulty of this test. In fact it's the best low bass performance I've measured from any 7" driver period.



Good performance at 80hz.



Excellent, below 1% distortion.



Very low 3rd order distortion and higher, but 2nd order is a bit high here over 1%.



Very low distortion.


Interesting bl curve, typical of all the xbl^2 drivers I've measured with a ripple in the center. Other than that, very flat curve. 1 way xmax looks to be around 8mm. Xmech about 24mm peak to peak, at 25% of rest BL and 20% of rest CMS. KMS (suspension stiffness) and LE (inductance) curves look similar to other high end drivers. Good centering and symmetry. Remember, any non-symmetry from the rest position leads to higher distortion.

Pretty good thermal results. You can see that cold or warm, the t/s parameters stayed fairly stable.




Overall, a good driver. This driver was definitely designed with several things in mind. Smooth, extended frequency response and strong, clean bass output. In fact, in terms of clean, low bass output this is as good as it gets for a 7" driver.
 

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No comments.
please post some.

although I can help myself by learning to interpret graphs some more. but comments can be helpful too.
 

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Discussion Starter #3
Take a look at the distortion and transient response threads in the diy article forum and let me know if something is difficult to understand. With those in mind, I think it should be fairly straightforward interpreting the data.
 

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some guy on SIN is trying to tell me the extremis has more linear output than my xls 8's.....

simple math is hard i guess :)
 

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Derek said:
some guy on SIN is trying to tell me the extremis has more linear output than my xls 8's.....

simple math is hard i guess :)
well thats SIN 4 ya...
somethings never change do they?

hahah
 

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Interesting! Bxl and inductance are well centered at around -1.25 mm, stiffness more around + 2 mm.

How does the Klippel system determine the rest position? Is the driver measured magnet down or at 90° to this? In the absense of external static forces (gravity), it follows from Hooke's law that the cone should sit at the very minimum of the stiffness curve.
 

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Ok so far I have the extremis in my doors and there is a total difference in sound from my CDT Eurosports. First of all I had no complaints about the eurosports in the midrange department and hoped that the Extremis would continue in that department. To be honest they are a step down. The Extremis are not as bright as the eurosports. Congos do not sound the same!!! :( But the the extremis excel in the lower 100hz and below. This is were the eurosports lack. DAMIT!!! I want a 6.5 that has it all and I thought this was it. I think I may be selling them soon. I am going to try a few more twerks to see if I can get them were I want them.
 

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I just finished make some changes to my extremis install. There is somewhat of a difference but nothing spectacular. I still prefer my CDTs. I am soon going to get a h700 so that I can tune it properly and we will see what happens then. But other wise they are going in the closet, tonight. I am thinking of trying to seas for the results that I am looking for. From the reviews they have a better midrange than the Extremis. We shall see...... :confused:
 

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I switched the phase and that did it!!! :D There is some difference in the two they have there postive and negatives. But the low end on these is great.
 

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npdang, In your opinion, would you say these drivers are suited mainly for 3-way(frontstage) applications. I bought a pair of the 8ohm versions. I am going to attempt to try them out and cross them as low as possible but cut it off at 2khz with an 18 or 24fb slope...2way application front stage..
 

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npdang, In your opinion, would you say these drivers are suited mainly for 3-way(frontstage) applications. I bought a pair of the 8ohm versions. I am going to attempt to try them out and cross them as low as possible but cut it off at 2khz with an 18 or 24fb slope...2way application front stage..
I know it wasnt directed towards me, but by looking at the graphs and plots i wouldnt go that high with them. They seem to exhibit noticeable distortion around 1kHz, but im not saying it would play but i dont think that was the intent of the design. Their lowend response is indicative of a dedicated midbass IMO. But hopefully members with personal experience will comment :)
 

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I had good results with mine crossed up at 2kHz.

Now the main striking feature with the Extremis is its bottom heavy nature. This makes the midrange sound quite weak, especially compared to many other midrange woofers out there, a lot of which have a natural rising midrange response.

The biggest part of getting them to work and work well will be understanding their complete lack of sensitivity. Don't be fooled by the strong bass response and the overpowering tweeter when you first set up the Extremis in a 2-way. You'll need to get used to the heavy bass, but you'll also need to understand that you'll have to dial the tweeters waaaay down. The Extremis has a sensitivity in the low 80s. Most tweeters will be around 90dB. This is a huge difference, and you do have to attenuate the tweeters down far enough, more so than you may think you do. For example, my Seas tweeters were a good 9-9.5dB down from the Extremis to match and blend well.

I didn't notice much of a trouble with EQing. However, the bass response is somewhat overwhelming at first. EQ it down or just get used to the full nature. It's not bad, but it's not what you're used to. Most midwoofers have a strong midrange and a falling bass response. The Extremis has a pretty flat midrange but the bass response doesn't taper off and is actually slightly exaggerated, at least in my doors. It's a very different feel that creates a perception of no midrange.

I was content on my Extremis/Seas combo for over half a year, enough so where I was never compelled to start on the 3-way setup I had planned, lol.

If I had one gripe about the Extremis, it is simply the lack of detail. The woofer has a smooth, full, and bottom heavy presence. It sounds monsterous, but it's not as open and crisp as a person might like. This can make for a somewhat mild midrange, but the setup is still very much useful. I used a 2kHz crossover point on both the woofer and tweeter with the tweeter cut a solid 9dB down from the woofer. EQing was pretty minimal with only a very minor boost approaching 2kHz. I left the low end full and heavy. Well I have one more gripe, and that's just its low sensitivity. It does take a lot of power to get loud, so don't skimp. I've got a 150w at 8ohm(or whatever 300w at 4ohm goes down to), and that's sort of where I'd suggest to be able to push it to its full limits and not strain the amp. 100w rms is definately the minimum, and you will only be limiting yourself with anything lower.
 

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Have fun with them. I miss my second one, but...I think the XLS8s will make up for them...as soon as I build the door pods for them.:(:p The weather's finally warm, but there's all these pesky tests I gotta study for. If next week isn't raining, I might finally be able to get around to them. I'll have some reviews coming up too after a little run time including the Ural HU that's been a long time in the waiting.:eek:
 

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Where did you get them from, Mir? A big problem with the Extremis is that the soft parts were changed without notice on different runs; the result are drivers that don't measure to published specifications and the potential for two very different drivers from one channel to the other.
 

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Where did you get them from, Mir? A big problem with the Extremis is that the soft parts were changed without notice on different runs; the result are drivers that don't measure to published specifications and the potential for two very different drivers from one channel to the other.
I bought them from a friend. He lives in Louisiana, ha came to dallas a few times. He goes by the name AlpineInstaller on ca.com. I believe he bought them from Acoustic Visions, i pmd him just now to get a legit answer from him. :)

I also can get one more set of extremis cheap, 6.8s though. They were owned by Undercoverpunker(so they are first generation mids iirc) and now JNtar owns them.



edit: got a response from the pm, it was Acoustic Visions he bought from
 
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