New to IEC711 measurements, how to determine what is correct?

[AncientMariner]

Hi,
I bought a 711 clone from Aliexpress, and followed some YT videos how to get it set up.
Did a few meassurements of a Truthear Nova, and the shape of the curves all come out pretty similar but at different levels.
- Used an Apple dongle for both output/input
- A sound card that was provided with the 711
- A Qudelix 5k for output
- A mix of the above

What do I need to look for to determine what is most likely to be correct? The supplied USB soundcard created the result I was most likely to expect, but the was very loud when calibrated to 85 dB. The apple dongle was much quieter when calibrated to 85db.

Any ideas what I'm doing wrong perhaps, or what I could do better?

Thanks!

 

[DVDdoug]

but the was very loud when calibrated to 85 dB. The apple dongle was much quieter when calibrated to 85db.

How did you calibrate them? 85dB SPL should be 85dB SPL (except for frequency response variations). If you calibrate two (or more) things at 1kHz they will match at 1KHz but could mismatch at different frequencies.

A sound card that was provided with the 711

I don't know anything about it, but that one might be calibrated.

 

[AncientMariner]

Thank you for the reply

How did you calibrate them? 85dB SPL should be 85dB SPL

That's what I would have thought. I can't figure it out, because apparently I can turn the microphone gain down and input volume up and get 85 dB, or I can turn the microphone gain up and the input volume down and get 85 dB as well.

As you said 85 should be 85. How do I know what is really truly 85 dB?


Anyway, if I stick with the Apple dongle for the microphone, and the Qudelix 5k for output, and use a low microphone gain in the system setting I get consistent measurements.

With the systems volume at max, and the Qudelix 5k at -27.5 dB the Qudelix software claims max 95.5 dBSPL. I know the Qudelix measurement is unreliable and from listening always reading high.

I don't know anything about it, but that one might be calibrated.

With the provided USB soundcard, I can't turn the gain of the microphone low enough, so I have to turn the input volume down so much that I get a very high noise floor.