Wrong Harmonics calculation and view

[moesmann]

Dear John Mulcahy,


First of all: Thank you for a great measurement tool! I use it for headphone measurements, and it is easy to use and I have quick good results, easy to work with!

Unfortunately, I have seen a bug, I would like to hear your feedback on.
See attached screen dump - It shows the same measurement.

On the right we have the RTA view with the frequency curve applied a 7 kHz sinus to see the harminics. Cursor set at the 2nd harmonics at 14 kHz about 75 dB under fundamental frequency. 3rd harmonics is aboud 25 dB down. The left window shows the Distortion view. Here we see the 2nd harmonics at 7 kHz around -55 dB relative to fundamental frequency. 3rd, 4th, 5th and 6th are shown around -10 dB relative to fundamental frequency.

So we see some discrepancy between the two windows - still the same setup and measurement.

How can I get the right Distortion view? Do you have a work around?
I hope you can help me out.


All the best,
Ole Moesmann



Additional information:

• Repetition: 1 (at the measurement on the left)
• The signal is going through an AD/DA circuit, so I do have a unknown certain delay. I have tried to use Timing (Use acoustic timing refernce) without any change.
• If I do the measurement without the AD/DA circuit the calculated THD and Harmonics are correct.
• Sample Rate: 192 kHz
• DAW: Focusrite 18i8 3rd Gen. Analoge in/out ASIO driver used.
• No calibration file is used.

 

[John Mulcahy]

In the graph controls uncheck the option to use harmonic frequency as ref for a different view.

 

[moesmann]

Thank you for quick answer. And we apologise. That option was not on the radar. We are sorry to inconvenience you.

/Moesmann

 

[John Mulcahy]

No problem, there's an explanation of the settings and the pros/cons in the help.