Why different ETC-values for the same measurement?

[Adhoc]

The ETC-values for one and the same measurement show different figures depending on if I have also pushed the RT60-button or not. Sems strange to me. Is there a good explanation for why this happens and which value would be more true if one is chasing reflections?

If I save the measurements, closes down the program and opens it again, I get back to the original more "jagged" ETC-diagram -22,5 dB at 19,5 ms. Then if the RT-60 button is pushed and I go back to Overlay ETC I get the value -28,7 dB at 19,5 ms, just like before.

Another question: In a previous REW-version I could set Sweep Retitions to 3 or 5 etc. That button / option is now "greyd out". Where is the command to get that option back?
(REW V5.20 Beta 59 is used together with a UMIK-1 microphone)

 

[John Mulcahy]

I can't reproduce that, perhaps you could attach the mdat file. When you say "pushed the RT-60 button" do you mean selected the RT60 graph on the main window?

Multiple sweeps cannot be used with a USB mic because the mic clock is independent of the replay device clock so there will be slight differences between the clock rates, which means synchronous averaging will not work properly.

 

[Adhoc]

Thanks John. Regarding the Sweep Repetitions-options; I made those sweeps several years ago so it must have been before I bought the UMIK-1. -Good (but regretable) to know Sweep Repetitions is not avaliable together with UMIK-1.

I made some new Test-measurements as the original mdat file contains a lot of measurements. The Test-measurement contains only 2 but the same thing happens. It doesn't matter if I choose Main Menue or Overall Menue..

It appears to me Impulse figures and ETC figures are extremely close both in the Main Menue and The Overall Menue before I have clicked on the RT60-button. After the RT60-button has been selected the ECT-figures changes dramatically when I go back and check them again.

 

[John Mulcahy]

I don't get any change to the ETC with your data or mine. I'm not sure what could be going on, there must be some other contributing factor in your setup. Please attach screen shots of the graph controls for the RT60 graph and the Impulse graph, after that it may help to use the "Delete preferences and shut down" option in the Preferences menu in case there is some problem with a preference setting from an earlier version.

 

[Adhoc]

Thank you for your very prompt reply John and my apologies for my late answer. (-Vacation time, so I have been away.)

Whatever the cause was for those "funny" ETC-changes, your suggestion to: "Delete preferences and shut down" was the cure. Everything seems to be OK after that and the ETC looks fine. Enclosed JPG from today 200818 (orange/brown) show the same setting in the Impulse as for 180813 (red), but ... there are no changes for the figures in the diagrams when flipping back and forth in the menues

ps in Preferences -Equaliser it is mentioned XP-2040. I guess that would be for Xilica XP-2040. Do you happen to know it that box could be ticked also if Xilica XP-4080 would be used instead? (I am thinking about buying XP-4080.)

 

[John Mulcahy]

ps in Preferences -Equaliser it is mentioned XP-2040. I guess that would be for Xilica XP-2040. Do you happen to know it that box could be ticked also if Xilica XP-4080 would be used instead? (I am thinking about buying XP-4080.)

I would have thought so. They are part of the same series so should have the same filter definitions.