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x-max measurements

Old Jul 10, 2003 | 10:54 PM
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x-max measurements

aside from RMS and max wattage a sub can take, a sub with a large x-max measurement generally yields more bass right? since the xmas measures the amount of cone movement in one direction while maintaining linear cone travel. i'm just gathering all my facts before i go and get me another pair of tens.
Old Jul 10, 2003 | 11:42 PM
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More cone movement means = more spl typically. Some of the subs out there have huge surrounds and it's hard for the larger subs to react to faster bass. Just a thought
Old Jul 12, 2003 | 12:16 AM
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jmax
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X-max ia not a measure of linear travel, merely a measure of maximum travel. Some subs have large linear displacement, JL W7, Adire XBL^2, IDQ IDMax, JBL GTI, Diamond TDX. But most with huge X-max are simply SPL monsters.
Old Jul 12, 2003 | 07:20 AM
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You also have to look at the SD which is the surface area of the cone. Convert everything to centimeters and use XMAX*2*SD to get the total displacement. Here's a site showing their subs are the best value in dollars per liter of displacement. They are fine drivers made by TC sounds but they don't take in other factors. The XBL^2 motors by Adire Audio are getting great reviews. By having a very linear BL curve, it cuts distortion and has the same amount of magnetic power throughout the cone movement. Adire has licensed this technology to Destijl Engineering who actualy builds the Adire Brahma series and Tumults and Resonant Engineering drivers.

it's hard for the larger subs to react to faster bass
It's not the driver size, it's the motor. Adire has a white paper on this subject.

aside from RMS and max wattage a sub can take
The power ratings for subs are thermal ratings before a voice coil starts burning. Well, at least for the reputable companies. You can destroy a sub with less than the rated power in a properly designed enclosure. Drop a sub in a vented enclosure tuned to 35Hz and feed it a 100 watt sine wave at 18Hz. Since the input signal is less than the tuning frequency, the enclosure is offering no resistance to the movement of the driver. Depending on the XMAX (and other factors) it could easily bottom out bending the voice coil fomer. I use WinISD Pro when building my subs and always check the max excursion first.

X-max ia not a measure of linear travel, merely a measure of maximum travel.
Not according to this site.

-Robert
Old Jul 12, 2003 | 09:11 AM
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jmax
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Originally posted by Robert_J

Not according to this site.

-Robert
I guess it depends on what you consider linear and what you consider to be audible distortion. There are many woofers with 15mm X-max that start sounding like crud at the 10mm point. In my person glossary that is a linear X-max of only 9.9mm. I have also seen manufactuers refer to both an X-max and a distortion limited X-max.

http://adireaudio.com/diy_audio/driv...ire/tumult.htm

If you look carefully at the chart at the bottom of the page you see a listing for one-way X-max. As well as a distortion limited one-way X-max. This is where the differences between the engineering definition of a term and the marketing definition of a term is important.
Old Jul 12, 2003 | 09:22 PM
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thanks for the informative replies, appreciate it
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