Originally Posted by tuxedocivic
Well Brad. I have some good news and some bad news. The good news is I can get the impedance files no problem. I have the waveguide and CD on hand. I also can ask Bill for it. And I'll just find the JBL impedance somehow. More good news is you did everything exactly right. I can't see a single flaw in anything you did looking at your photos and the measurements. I also have already processed the files in REW and have them ready to go in PCD.
I like the good news.
I also downloaded PCD and loaded up the REW FR measurements, and went looking for impedence measurements to load as well - all I could find for the JBL was the embedded graph in the JBL data sheet, which I could plot and map to a data file, but not sure if that's close enough; for the SEOS/360, I saw this thread on diysoundgroup, but didn't see any ZMA files in the zip file: http://www.diysoundgroup.com/forum/index.php?topic=56.0
Now, the bad news. The results have an issue.... And I don't know why. Let's take a look at what I mean.
Here I applied an 8ms gate window in REW to shut out the reflections from the ground and then screen captured the result.
I've circled some very regular peaks and dips in the response in red using Paint. See the pattern? I don't think this is driver related. I think it's measurement related. But how, I don't know. The microphone does look close to a tree or something? Is there a reflection point somewhere near the mic? The other thing, unlikely in my opinion, is the plastic bins that the speaker is sitting on.
For now, don't sweat it. I'll work on getting the impedance files and I'll work on this assuming those peaks and dips are anomolous and see what happens. Don't drag your gear back out there until we can figure out what it is.
Right, as I mentioned the back yard is not ideal for doing outdoor measurements, its not very big to begin with (lot is like 55' wide, with that planter box right smack in the middle. About 10' behind the mic is a dog ear fence, so about 16' from the speaker; maybe 20' to the right is the house; 15' or so to the left is the garaage, door was open, but still some obstructions; a couple feet back from the mic were a couple more of those storage bins where I had the test gear set up (laptop, etc.); MDF under the top box right under the enclosure was sticking out a couple inches as well; there's the table top ~2.5-3' below the speaker; and of course me pushing the button and then hiding off to the side.
Re: maxmercy's comment, the box is not lined yet, and my bracing is fairly minimal (one side to side and one front to back brace between woofer and waveguide).