XXX's over-rated...a challenge to you.

[Ryan from Ohio]

If you run the linear displacement numbers of these two subs you can see an easy winner by that test... This might be a fair comparison.

I think Elevation is purposely under rating their equipment.

Before we get into this any further lets look at a few definitions for those of you following along and already dont know it.

XMAG- Excursion limit due to the magnetic limitations of the driver's motor. Xmag is defined as the displacement at which the BL product has fallen to 70% of its value at the cone's rest position.

XSUS- Excursion limit due to the driver's suspension. Xsus is defined as the point at which the compliance of the suspension has decreased to 25% of the value at the cone's rest position.

XMECH-Maximum excursion of driver, peak to peak.
usually in millimeters, or inches.

And finally:
Xmax/Xmech- Short for Maximum Linear Excursion. Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap. Although suspensions can create [lull-linearity in output, the point at which the number of turns in the gap (see BL) begins to decrease is when distortion starts to increase. Eminence has historically been very conservative with this measurement and indicated unly the voice coil overhang (Xmax: Voice coil height minus top plate thickness, divided by 2). Xmech is basically the lowest of four potential failure condition measurements: Spider crashing on top plate Voice coil bottoming on back plate Voice coil coming out of gap above core Physical limitation of cone Take the lowest of these measurements then multiply it by two. This gives a distance that describes the maximum mechanical movement of the cone.

As you can see, Xmax is a very deceiving number. It can physically be measure or calculated. This can in a sorts "fudge" the numbers.

All I can say is if the Elevation subs are truly hitting 3" peak-peak that is 38.1 mm one way.

Elevation needs to publish some better specs. They might get a bit more respect if they did :)

[squeak9798]

Linear excursion is different from an X-max rating, and in many cases they don't necessarily relate to each other.

Xmax = Linear (one-way) travel of the cone

Xmax: The measurement of how far a diaphragm can move while still maintaining linear behavior.

Xmax Short for Maximum Linear Excursion

Hmm...I would be to disagree that Xmax is different then linear excursion. In fact, the term "linear excursion" is present in the definition of Xmax.

However, there are different ways to measure Xmax. Amount of coil overhang is one. But there is also the method of measuring Xsus and Xmag, with Xmax being equal to the lesser of the two. This method being much more accurate, as it gives you an accurate measurement of when the speaker actually starts to exhibit non-linear behavior.

[squeak9798]

All I can say is if the Elevation subs are truly hitting 3" peak-peak that is 38.1 mm one way.

But is the driver still within what's to be considered it's "linear" range of motion when hitting 38.1mm one-way?

[Ryan from Ohio]

But is the driver still within what's to be considered it's "linear" range of motion when hitting 38.1mm one-way?

I dont know, and I have asked for any DUMAX sheets that may be available.

There are a few ways to measure Xmax that is found to be acceptable and is widely used.

Im going to have to disagree with Jonathan also.

Xmax has everything to do with linear displacement. Xmech has nothing to do with it :)


BTW why were all hashing this little topic out its nice to hash out the technical topic behind it- Xmax....

[Jonathan]

I wasn't referring to it by the sense of definition, I was referring to it in the results you would achieve. While by definition x-max is considered maximum linear excursion of a subwoofer because a fraction of the voice coil still remains within the gap, this is only theoretical and doesn't indicate true performance at that point. Just because the coil is within the gap doesn't mean the speaker is necessarily in a full linear motion, the motor strength and flux density also determine that. While yes, remaining somewhat within the gap will be capable of controlling the subwoofer to a small degree, you will still consequently have non-linearities at that point. In the real world you very rarely have true linearity at the rated x-max since the motor strength is so low and has much less control over the coil, especially if you were talking about only a fraction of a percent of the coil remaining within the gap. This is shown in Dumax reports and even more easily shown with distortion levels, even with XBL^2, the Brahma being an example, you'll see that even around 15-20mm of excursion (one way, depending on forward or rearward motion), you have already begun a sharp rolloff of BL when compared to it's resting state, by it's rated 28mm you've lost a buttload of motor strength. With other subwoofer designs you'll lose even more.

[Jonathan]

And I was referring to X-max being rated by gap height and coil length, BTW :)

[Ryan from Ohio]

kewl...

Hey Justin send me a set of Pros to test to! I promise to send them back after testing

lol, Im sorry that doesnt make much business sense. Only a complete fool would do such a thing. The challenge is at Detroit Bass, which it clearly states.

[xloudcivicx]

that is that persons first post, also....

[Justin from Detroit1]

Holy shit look what i got started.

I STARTED THIS THREAD TO GET THINGS STARTED ON THIS BOARD. I MADE HALF OF THAT SHIT UP. THE XXX'S MAY VERY WELL BE LOUDER THEN MY PROS, AND I DON'T CARE. I MADE HALF OF THAT SHIT UP.

All I wanted to do was spark a fire in this palce and get things going, and it seem to worked. Yes, I still say my Pros can be louder then XXX's, but there is no "challenge" to make Detroit Bass money. I had this all planned from the start, ask Chris from MI and Basstronics, they both knew about my plan from the start.

READ AGAIN : I MADE SHIT UP.

[GlassWolf]

people, let's stay objective here and not turn this into something hostile please.

that being said, I'd like to say there's been a lot of good information posted so far in this thread. a lot of it explains exactly why I'm using two XXX subs for a SQ system, in an AP enclosure, and with about 1300 watts each to drive them. the enclosure yields excellent driver control, and allows for increased mechanical power handling. it allows me to compensate for the -3dB loss compared to a sealed enclosure for SPL by just throwing more power into the setup and getting a very loud, very clean system as a result.

I get a lot of comments from people asking me why I used two XXX subs in a SQ system, so I thought I'd point this out. They're suited to the application very well. Far more so than if it were an SPL event car.