I bought a Dayton Audio DATS V3 system a month ago. Mostly so I wouldn't have to build the correct jig for impedance and TS parameter testing in REW...
But I also got it for the Rub and Buzz test capabilities. Their theory on it seems sound - shifts in impedance and resonating frequencies with different input levels indicate voice coil drag. Seems simple enough.
The issue is that if I test one driver and it passes with say 10% Zmax variance, if I immediately test it again I'll get a completely different set of numbers. The next several tests back to back will show Zmax variance - 30%, 40%, then 15%, 50% - all over the place. Same with the F(s) numbers. If I test one driver up to ten times, I'll even get one test that fails.
Makes me question the validity of the test. I would expect the same driver tested back to back to produce similar results.
Anyone else have this issue or concern?
But I also got it for the Rub and Buzz test capabilities. Their theory on it seems sound - shifts in impedance and resonating frequencies with different input levels indicate voice coil drag. Seems simple enough.
The issue is that if I test one driver and it passes with say 10% Zmax variance, if I immediately test it again I'll get a completely different set of numbers. The next several tests back to back will show Zmax variance - 30%, 40%, then 15%, 50% - all over the place. Same with the F(s) numbers. If I test one driver up to ten times, I'll even get one test that fails.
Makes me question the validity of the test. I would expect the same driver tested back to back to produce similar results.
Anyone else have this issue or concern?
Are you testing in free space or mounted?
I'm no expert but I believe that is subject to where you put the driver.... like on a table, or not and of course whether the back is vented.
I'm no expert but I believe that is subject to where you put the driver.... like on a table, or not and of course whether the back is vented.
It's free space - sunny side up. The back is not vented - these have a screen dome for venting.
I would think if you don't move the speaker and test it repeatedly the position/mounting shouldn't matter with respect to the variability I'm seeing.
I would think if you don't move the speaker and test it repeatedly the position/mounting shouldn't matter with respect to the variability I'm seeing.