Problems measuring - Freq seems to be Double

[NAC]

Hi,

I'm new to REW, still trying to work it all out.

I have a macbook pro, UMIK USB mic and a zoom recorder as mic input.
I am trying to measure impedance of drivers and all of the readings seem to be double what they should be.
eg driver fs spec is 50HZ, I measure about 100Hz. same for tweeters 900hz measures about double that. I think my freq measurements are double as well.

Any ideas on were the issue may be?

Thanks.

 

[John Mulcahy]

Are you using the 256k sweep? Try that if not, and if you are not using the latest 5.19 beta version best use that, can get it from the Downloads section of this site.

 

[NAC]

Thanks for your reply.
sweep is 256k running 5.19 beta7.

I'm now thinking that perhaps my drivers have changed due to age.
I have four Dynaudio 15w75 that I am rebuilding new boxes and crossovers. I purchased them back in 1989.
Is it possible that all four could have changed fs from 55Hz to around 100Hz?

 

[John Mulcahy]

Possible I guess, material characteristics could have changed significantly over 28 years.