Measurement accuracy and noise

[thexder]

Hi,

I've been doing a lot of measurements and never thought they might not be accurate. A guy involved with studio designs suggested measuring with other gear as he is convinced my measuring setup is somehow generating a strange noise.
Can someone confirm this?

P.S.: The microphone was not in the exact same spot but the noise he is mentioning should be visible.

Thank you!

 

[John Mulcahy]

The "studio gear" measurement has a very high noise floor before the measurement - you can see that on the Distortion graph. The UMIK1 measurement has a normal noise floor. Can't really say any more than that unless you can explain in more detail what is meant by "a strange noise".

 

[thexder]

Kind thanks for your thoughts, John. Actually he said noise floor is the problem. And some anomalies UMIK1 measurements has provided in the waterfall if you extend the window/time to 2500 ms.

I'm surprised you are saying UMIK1 measurement has a normal noise floor. I think 40-45 dB is rather high given the fact there is absolutely no outside noise. His measurements showed much lower floor noise, appprox. 30-35 dB.

 

[John Mulcahy]

That's normal for USB mics. Analog mics can have lower noise floors if used with a low noise preamp.