Do someone have tried to calculate voice coil inductance with the Kr, Ki, Xr and Xi parameters published in ZMA files, as those published by Parts Express for Dayton Audio woofers?
I tried with bad results.
You may like to see my calculations in attached Excel spread sheets. I do hope you don't mind that are in spanish.
I tried both models: one from J. R, Wright (An Empirical Model for Loudspeaker Model Impedance) and other from Marshall Leach (Loudspeaker Voice-Coil Inductance Losses: Circuit Models, Parameter Estimation, and Effect on Frequency Response).
In the file named "Leach-Wright_3a" I've tested Kr, Ki, Xr, Xi Wright's parameters of the DSA175-8 woofer to calculate real and imaginary values of Zem of the motor impedance model, but when I add them (as complex numbers they are) to Re (the DC coil resistance), and Zms (the electric equivalents of mechanical mass, spring and damping of moving parts), the values obtained for Zvc of the voice coil, they disagree with those published in the ZMA file. This is evident in the plot of the calculated values over the impedance graph published with the specs.
In the same file, I calculate the n and K parameters of the Leach's "lossy inductor" model. With them, I get good agreement with the ZMA file values for the cited woofer.
In the file named "Leach-Wright_3b" I get my own values for Kr, Ki, Xr, Xi Wright's parameters, in accordance with his paper. The situation changes to "good agreement" with published data.
I did a second test with published and calculated values for the RS150P-8A woofer, also from Dayton Audio. Again, I got good agreement with values of Wright's parameters calculated by me and not with those published.
What could be happen?
I would like to read your comments.
Kind regards.
I tried with bad results.
You may like to see my calculations in attached Excel spread sheets. I do hope you don't mind that are in spanish.
I tried both models: one from J. R, Wright (An Empirical Model for Loudspeaker Model Impedance) and other from Marshall Leach (Loudspeaker Voice-Coil Inductance Losses: Circuit Models, Parameter Estimation, and Effect on Frequency Response).
In the file named "Leach-Wright_3a" I've tested Kr, Ki, Xr, Xi Wright's parameters of the DSA175-8 woofer to calculate real and imaginary values of Zem of the motor impedance model, but when I add them (as complex numbers they are) to Re (the DC coil resistance), and Zms (the electric equivalents of mechanical mass, spring and damping of moving parts), the values obtained for Zvc of the voice coil, they disagree with those published in the ZMA file. This is evident in the plot of the calculated values over the impedance graph published with the specs.
In the same file, I calculate the n and K parameters of the Leach's "lossy inductor" model. With them, I get good agreement with the ZMA file values for the cited woofer.
In the file named "Leach-Wright_3b" I get my own values for Kr, Ki, Xr, Xi Wright's parameters, in accordance with his paper. The situation changes to "good agreement" with published data.
I did a second test with published and calculated values for the RS150P-8A woofer, also from Dayton Audio. Again, I got good agreement with values of Wright's parameters calculated by me and not with those published.
What could be happen?
I would like to read your comments.
Kind regards.
Is the inductance measured with the coil in free air, or in the gap it will work in? Results would be quite different in the two settings. I am unable to open the files to see if the answer to my question is in one of them due to software limitations on my end.
Hi egellings,
Thanks a lot for your reply.
I tell you, I didn't any measurement. I only calculate the inductance values with those parameters published in files to download, offered by Parts Express at "Manual and resources" pages.
I attached *.7z compressed files as per requested by diyaudio. Excel files *.xlsx are not allowed.
I am able to send them to you by email if you send me a message to hugorodart@hotmail.com.
Thanks a lot for your reply.
I tell you, I didn't any measurement. I only calculate the inductance values with those parameters published in files to download, offered by Parts Express at "Manual and resources" pages.
I attached *.7z compressed files as per requested by diyaudio. Excel files *.xlsx are not allowed.
I am able to send them to you by email if you send me a message to hugorodart@hotmail.com.
Measured values reported in ZMA files, are measured with the coil into the gap and the unit working in "normal" conditions,. Could be "free air" or "baffle mounted". I believe, such information is not provided in the files.