Different waterfall results every measurment

[RalphH]

Hi people. I am somewhat puzzled .
Today I wanted to check out the results of 2 resonator traps I purchased and started of with REW and changing things in the room.
Initially things seemed positive, untill I discovered that the waterfall charts were really different even when not making changes. Blamed it on the wind outside and waited for it to lay down...But unfortunately, this was not it, leaving me puzzled and now posting here.

What I also saw, is that phase, clarity, RT60 (graphs I normally do not check) are also very different with every measurement.
Tried differend versions of REW, the last being 5.20 RC7, no difference.
Using a UMIK-1 with 90degree cal file loaded
I have been using REW for quite some years now and I never saw this behaviour. Would almost think the mic is broken, don't have a spare around unfortunately.

Attached a file with some measurements. Every number is a single situation, no changes to anything and measured with one subwoofer (to rule out other subs interfering), 1 being a diferent subwoofer in the room than used with 2 and 3.

Thanks in advance for your help.

 

[John Mulcahy]

Looks like some external noise source, such as traffic. Could watch the RTA and see what that shows over time.

 

[RalphH]

Thank you for your reply John. I believe it was dead silent in and outside the room (no frige, heating, fans in the background), I even waited till the evening and performed the measurments I posted because during the day it was very windy and I thought this might cause the strange results.

Will try to check with RTA what is happening.

 

[RalphH]

Turned out to be something in the pc or with the usb extension cable to the mic (although data is data I would say). Connected the mic and AVR to a laptop that was laying around and measurements stayed consistent.