use of multiple sweeps in measurement

[terry j]

Hi all

just for 'kicks' (aren't I a sad specimen ha ha) last night for the first time I tried a few things, comparing the results from the short sweep (128 ?) then each one up to 1M, and was happy to see that they were all pretty consistent in my room at least, so as I will be doing a lot of dialling in on my new subs soon for the most part I will stick to the short sweeps.

I did also for the first time check out the use of multiple sweeps, and I must say the results were totally unusable, even on two sweeps. I think there was ONE combination that produced a sensible result, maybe it was 500 @ 4 sweeps, but in any case that result was no better than a single sweep.

I didn't keep any graphs to show (and in any case it's a trivial matter to run a sweep again if needed) but am wondering, is it only me that gets rubbish when a multiple sweep is run?? or is it some sort of program glitch, issues particular to my setup or what.

As I say it's not super important as I'm more than happy with what I get from the short sweep, but it HAS become an 'interesting question' if you know what I mean. So could someone else (Bruce?) do a quick multiple sweep and see what they get??

[brucek]

is it only me that gets rubbish when a multiple sweep is run??

IT certainly works fine for me. The more sweeps will result in random noise being eliminated and an impovement to the S/N ratio.

brucek

[terry j]

let's have a little 'game' here, ....."Who thinks I can reproduce the rubbish measurements of the other night or does it all work fine now?"

Please accept my apologies, I start up REW so I can capture the stupid graphs i was getting, and of course now multiple sweeps work as they should. Hmmm. Funny thing is that I simply cannot get the input level up to the old readings, hard to imagine there is a link, maybe my computer is juat starting to play up.

Thanks Bruce, sorry for the muckaround, and if it does it again then you can rest assured that I will take a screen shot of it ha ha.

[terry j]

Just got my second sub in tonight, so wanted to have a look.

First thing was my input levels were 'back', and so immediately wondered if i could repeat my 'garbage' multiple sweeps, and it did.

So I quickly grabbed a screenshot, lets hope I get over the next hurdle and manage to upload it. I took note of where REW sent the picture, and found a graph of a mates system that I thought I'd lost!! I KNEW I took it ha ha.

multiple sweeps.jpg

The purple graph is actually two measurements of different size (ie I mean 125 and 250 in the dropdown sweep menu), and the loopy ones (both offset for clarity) are two sweeps in one case and four in the other.

It worked yesterday, yet with 'something going on with the input level', today I got my input level back and now the multiple sweeps are wonky.

It is probably something stupid with my computer, but it is curious.