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Posted

I keep reading about deriving an Xmax number from BL.

How is that done, and how acurate is it?

Please enlighten me.

I keep reading about deriving an Xmax number from BL.

How is that done, and how acurate is it?

Please enlighten me.

I think you may be confusing a couple different things.

The T/S parameter BL alone tells you nothing about Xmax. You can obtain Xmag (linear excursion allowed by the motor) from a BL vs X plot, which is a graph displaying the value of BL in relation to excursion where Xmag is defined as the point where the BL falls to 70.7% of it's rest value. This is a graph of BL vs X generated by a Klippel analyzer;

http://diymobileaudi...er%20prs/bl.JPG

Xmax is generally accepted to be the lesser of Xmag and Xsus (linear excursion allowed by the suspension). I will also say there are several methods for determining Xmax, all of them may give slightly different results. So knowing what method the company uses for arriving at their Xmax can be important before trying to compare the Xmax values for two different drivers.

  • Author

I've noticed that some companies do not offer Xmax measurements.

Now the software which i use to design my enclosures requires Xmax.

I read that some use 70% of BL or something along those line.

I might be off in left field here, i really dont know.

It'd just be nice to have the Xmax measurement to put into my software

Software is TermPak just so its clear

  • Author

Cool, thanks I will try that.

I'm not always clear with my typing out thoughts.

So I'm sorry if I confused you at all.

The three most common ways of getting Xmax are via FEA, Klippel, and Dumax. The Dumax has issues with measuring long throw drivers as it can not create enough pressure.

Andrew

The three most common ways of getting Xmax are via FEA, Klippel, and Dumax. The Dumax has issues with measuring long throw drivers as it can not create enough pressure.

Andrew

Amongst the manufacturers with budget a Laser Vibrometer is used as the FEA is based on assumptions, the Klippel isn't very accurate, and Dumax well you already took care of for me.

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