What is "X-Max" and does it matter?

[chpthril]

My boy wants a new sub/amp set up for the Jeep. He is split between the W/S-XXX and the Kicker Solic L7. He keeps talking/asking about this X-Max measurement, and I don't know what to tell him. The W/S is listed @ 11mm and I cant find a spec on the L7.

Can someone explain what this really is, and is it something that needs to be taken into consideration when choosing a sub.

Thanks guys

[philwsailz]

VERY basically...

x-max is the measurement of the distance that a speaker can move linearly in one direction from rest. Lots of times considered half of the voice coil winding length. That is a simplist view of what x-max is, but gets a job done from an uderstanding basis.

X-max is one measurement of a loudspeaker's parameters. It contributes to the understanding of the speaker's application, its parameters, (sealed vs. vented, vs free air), and it gives a very small indication of its construction, and maybe quality.

Be cautioned, it is only one consideration, and to pick a woofer based on x-max alone is sort of like buying a hi-performance sports car solely on it wheelbase...

[philwsailz]

One needs to make a decision not solely on x-max, but rather on many factors that are much more relevant...
* Efficiency
* recommended enclosure design, and size, (the woofer and the box BOTH have to fit in the vehicle)
* Power handling
* Sealed? Vented? Bandpass? What is the woofer optimized for?
* Budget, (if you can't afford it, does it count?) not that either of the two are wallet crushers...
* Personal preference: Which one sounds better to you?

[G-MONEY]

x-max

The x-max specification is the speaker’s excursion capabilities. This number, usually in millimeters, describes how much 1-way linear excursion the driver has. Depending on the motor and suspension designs, some speakers can exceed their x-max and still provide reasonable (albeit more distorted) sound. Others may get very nasty or have audible bottoming at any excursion above x-max. Since the maximum output of a subwoofer is determined primarily by how much air it can move, the x-max along with the speaker’s cone area (Sd) can help you determine a speaker’s theoretical output capabilities, although there are many other factors that weigh in as well.

[philwsailz]

here is a link to a PDF that has X-max for L7 woofers.

http://www.kicker.com/06/tech-suppor...rs/pdfs/L7.pdf

The 10 and the 12 have x-max measurements at roughly 14mm...

[philwsailz]

x-max

The x-max specification is the speaker’s excursion capabilities. This number, usually in millimeters, describes how much 1-way linear excursion the driver has. Depending on the motor and suspension designs, some speakers can exceed their x-max and still provide reasonable (albeit more distorted) sound. Others may get very nasty or have audible bottoming at any excursion above x-max. Since the maximum output of a subwoofer is determined primarily by how much air it can move, the x-max along with the speaker’s cone area (Sd) can help you determine a speaker’s theoretical output capabilities, although there are many other factors that weigh in as well.

where did you find that?

[G-MONEY]

I knew it........

[G-MONEY]

http://www.iroczone.com/technical/Subwoofer/

[philwsailz]

http://www.iroczone.com/technical/Subwoofer/

I knew it....

[G-MONEY]

I knew it....

[spharis]

X-Max matters.

[Timmy!]

Is he thinking that if the X-Max parameter is larger it will move more air and thus have higher SPL than other speakers?

[philwsailz]

spharis is right, it does matter.

It is technically correct to realize that as a piston, the greater the X-max, the higher the SPL probably will be for a given Sd.

That being said, I want to caution from anyone oversimplifying their thinking and making a buying decision based solely on X-max.


* I know for fact that the absolutely loudest sound that a vented subwoofer enclosure makes is right at the enclosures resonant frequency. It is at that point that the woofer is moving at its very least...

* I have also seen infinite baffle installations and very leaky boxes where the woofer was moving a ton, and yet the subwoofer was making very little output...

Hopefully these two extremes help to further clarify it is not ONLY about X-max.

[Timmy!]

I used to run Orion XTR 15 DVC's in my S10 Blazer and they didn't move all that much, very minimal excursion and I still managed 146 db with a single 150 watt amp (in 1995)

[chpthril]

Ok, would it be safe to say that this is not a spec that you would use in comparing one sub to another, but use it in relation to the subs other specs?