A shout out to @MickD.
Check out Bill Falconer's podcast Mastering Rod Building.

This particular episode is about true natural frequency with Mick Danek.
True Natural Frequency: An Additional Tool for Better Defining Rod Performance

49 minutes ago, Chris Catignani said:

A shout out to @MickD.
Check out Bill Falconer's podcast Mastering Rod Building.

This particular episode is about true natural frequency with Mick Danek.
True Natural Frequency: An Additional Tool for Better Defining Rod Performance

Thanks, Chris.  I appreciate your comments.  

I haven’t found anything to work on an apple phone though. 

13 hours ago, Delaware Valley Tackle said:

I haven’t found anything to work on an apple phone though. 

Micheal...have you looked at Gauges?

Gauges on the App Store

No, I have an Android and the recommended app works for it.  Is Gauges an Apple app that can record the period of a vibration by sound?  I'll take a look.  thx

Just now, MickD said:

No, I have an Android and the recommended app works for it.  Is Gauges an Apple app that can record the period of a vibration by sound?  I'll take a look.  thx

Yup, Apple app. Don't know if it will do it or not.  Has to record the period of a vibration using the mic on the phone.  Other Android devices, like Kindles work fine.  You don't have to have a phone.