[ctviggen]

I plan on purchasing the ETF program (once I get it to work -- which is harder than anticipated due to my failure to follow directions!  By the way, why do they have to use symbols on sound cards?  Can't they fit "line in" on the stupid card?), but I'd like to know how to use it for comparisons.  What I'd like to do with the software is compare old curves with new curves, preferably using the program to highlight differences between old and new curves.  Does the program do this, or do you manually have to do this?  

For instance, I'd like to use the ETF program to see how well my real traps work, to see if I hurt or help when I add additional acoustical materials such as foams, and to better integrate my two subs with my RM40s.  The program seems to operate so quickly that I could change something about my system, analyze the room acoustics, then perform a comparison between the beginning and ending room acoustics to see whether I've improved or worsened the situation.

[ted_b]

I plan on getting ETF as well (and comparing it to the readings I got while I had the DEQX).  ETF has a repeat function (icon on screen) that allows you to easily check the results after each change, etc (I think that's what it's for).   Ethan knows ETF very well; I'm sure he'll respond.

Ted

[davejcb]

You can overlay curves to compare, I have it shown in this thread.

[ctviggen]

Thanks.  I think the analysis that I want to do might be harder than I anticipated.  I'm going to have to be careful to use the same level each time or else comparing levels is going to be a bear.

[Ethan Winer]

Bob,

> Can't they fit "line in" on the stupid card? <

Worse, on many sound cards the labels are stamped on the metal back plate with no ink, so you have to view it in exactly the right light to read it at all.

> What I'd like to do with the software is compare old curves with new curves <

Dave beat me to it. But I'll add that for comparisons made the same day in the same run of tests you should first click the lower Calibration button to establish a baseline for all subsequent measurements. Otherwise all the graphs are normalized putting the highest peak at the 100 dB line. So if you add traps and the peaks are reduced, you'll miss most of the effect.

Also, when assessing the improvement of adding bass traps, the most important display is the 3D waterfall plots. That shows much more than the raw low frequency graph.

--Ethan

[ctviggen]

Thanks, Ethan.  I'm going to try to take some measurements this weekend.  We'll see how that works out.