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<blockquote data-quote="T3mpest" data-source="post: 6703892" data-attributes="member: 560148">Thought I would chime in.&nbsp; Anyway xmax does NOT change as xmax is a large signal parameter that is based upon the changing of other parameters.&nbsp; The point that audioinformer is missing is that BL is defined as a drop of below below 70.7% of it&#039;s RESTING VALUE.&nbsp; Whatever amount of BL product you have with the coil essentially resting in the gap is defined as 100%.&nbsp; As you begin to lose BL as the coil moves, once you&#039;ve lost more than 29.3% of it, you&#039;ve reached xmax.&nbsp; However far the coil could move from it&#039;s centered position and still maintain over 70.3% of it&#039;s magnetic strength will determine your xmax.&nbsp; Xmax cant&#039; increase or decrease with drive levels as it&#039;s parameter that&#039;s based soley on the shifting of another parameter.BL product as Klippel is using it isn&#039;t truly a measurement of motor force so much as motor force product...&nbsp; The key different being as you pointed out, current.&nbsp; Klippel worries about simply B*l in order to do this they test the driver at fs where current demands and therefore impedence shifts will be minimized.&nbsp; This truly doesnt&#039; give you a competely accurate picture of what&#039;s going on, obviously, but impedence irregularties usually only account for 10% distortion at best.&nbsp; Coincidentally that&#039;s also where distortion is usually audible in the sub-bass region. However, BL irregulaties generally cuase 30% of the distion within a driver, so overall just doing B*L is probably the safest bet.&nbsp; If we were truly concerned with actual SPL potential and distortion we would need to know BLI and look at things three dimensionally, with current being the third.&nbsp; However this creates different levels of xmax at different frequencies and various box arrangments, so we would get&nbsp; useless value unless we knew exactly how it was derived.&nbsp; Anway the last interesting thing to note about the various T/S parameters is that given 2 drives with the exact same T/S, xmax values can be drastically different.</blockquote>

[QUOTE="T3mpest, post: 6703892, member: 560148"] Thought I would chime in. Anyway xmax does NOT change as xmax is a large signal parameter that is based upon the changing of other parameters. The point that audioinformer is missing is that BL is defined as a drop of below below 70.7% of it's RESTING VALUE. Whatever amount of BL product you have with the coil essentially resting in the gap is defined as 100%. As you begin to lose BL as the coil moves, once you've lost more than 29.3% of it, you've reached xmax. However far the coil could move from it's centered position and still maintain over 70.3% of it's magnetic strength will determine your xmax. Xmax cant' increase or decrease with drive levels as it's parameter that's based soley on the shifting of another parameter. BL product as Klippel is using it isn't truly a measurement of motor force so much as motor force product... The key different being as you pointed out, current. Klippel worries about simply B*l in order to do this they test the driver at fs where current demands and therefore impedence shifts will be minimized. This truly doesnt' give you a competely accurate picture of what's going on, obviously, but impedence irregularties usually only account for 10% distortion at best. Coincidentally that's also where distortion is usually audible in the sub-bass region. However, BL irregulaties generally cuase 30% of the distion within a driver, so overall just doing B*L is probably the safest bet. If we were truly concerned with actual SPL potential and distortion we would need to know BLI and look at things three dimensionally, with current being the third. However this creates different levels of xmax at different frequencies and various box arrangments, so we would get useless value unless we knew exactly how it was derived. Anway the last interesting thing to note about the various T/S parameters is that given 2 drives with the exact same T/S, xmax values can be drastically different. [/QUOTE]

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