MAB
Major Contributor
I dug up my measurements on a 15" paper cone woofer. I have two of them. I measured them both fresh out of the shipping carton with a DATS V3. I have been playing them for the past 6 months. I just demounted them and remeasured:
I measure 1-2% change over the first 6 months, 3% for Q(ms). The break-in as I measure it over 6 months is about the same as driver to driver matching, as near as I could observe.
Here is the impedance trace for Driver 1 in a 60 liter sealed enclosure prior to use and after 6 months:
When making these measurements I did do things like normalize for lead resistance. I let them settle to ambient room temperature. I didn't normalize for the actual temperature though, and temperature has a large effect.
So I did the next reasonable thing, I put the woofer in the refrigerator for 10 mins.
After just 10 mins soaking in the fridge I remeasured, then took a few more measurements over then next few hours as the speaker warmed up.
As @HarmonicTHD suggested, temperature is a large effect, much larger than break-in. I need to wait much longer than 3 hours to let the driver equilibrate after just 10 mins exposed to cold! I am not surprised, this is similar to previous measurements I posted.
@jackocleebrown , I hope this is intelligible. I am trying to reconcile actual driver measurements of break-in with the data you presented. I am obviously operating on a small sample size with limited variety. Am I missing something?
Thanks!
I measure 1-2% change over the first 6 months, 3% for Q(ms). The break-in as I measure it over 6 months is about the same as driver to driver matching, as near as I could observe.
Here is the impedance trace for Driver 1 in a 60 liter sealed enclosure prior to use and after 6 months:
When making these measurements I did do things like normalize for lead resistance. I let them settle to ambient room temperature. I didn't normalize for the actual temperature though, and temperature has a large effect.
So I did the next reasonable thing, I put the woofer in the refrigerator for 10 mins.
After just 10 mins soaking in the fridge I remeasured, then took a few more measurements over then next few hours as the speaker warmed up.
As @HarmonicTHD suggested, temperature is a large effect, much larger than break-in. I need to wait much longer than 3 hours to let the driver equilibrate after just 10 mins exposed to cold! I am not surprised, this is similar to previous measurements I posted.
@jackocleebrown , I hope this is intelligible. I am trying to reconcile actual driver measurements of break-in with the data you presented. I am obviously operating on a small sample size with limited variety. Am I missing something?
Thanks!