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andersen09
11-20-2015, 03:32 PM
Hi,

I have just bougth a pair of 4412's and I noticed a shift in channel balance - especially for vocals and fine details.
By adjusting the L-Pads I need one speaker at -2/-2 and the other at +1/+1 to get the balance sort of ok.

Next planned step is to measure frequency response and impedance to check for any obvious faults but I was hoping for some guidance before I go further.

Thanks
Br Jesper

rdgrimes
11-21-2015, 06:37 AM
The Lpads themselves can cause that, due to dirt/smoke/age/etc. Try spinning them all the way back and forth a bunch of times and see if it makes any difference.

andersen09
11-21-2015, 03:11 PM
The L-pads may were well be the cause as the left one is pretty hard to turn.
I did measurements just now and adjustment of left tweeter is not right. Level is much higher and does not look like the curves in the manual. The right speaker follows the curve in the manual to perfection. As this happens around 4Khz and the crosseover frequency is 3.5Khz I suspect one of the filter components.

I think it is most likely the capacitors for the tweeter that are bad, but the L-pad might also be the cause?

Left (red) and Right (Blue) speaker 40 cm from baffle with L-pads in neutral position
68326

Right speaker with different L-pad positions (+1, 0, -1, -2, -3, -4, -6, -10 and min)
68324

Left speaker with different L-pad positions (+1, 0, -1, -2, -3, -4, -6, -10 and min)
68325

Left (red) and Right (Blue) speaker Left -10 / Right -3
68323

audiomagnate
11-26-2015, 11:22 PM
No two drivers are identical, and these have a lot a miles on them. The fact that they are dead equal at 10K makes me think it driver variation. I don't think a bad blocking cap would do that to the response above 10K.

andersen09
11-27-2015, 05:36 AM
No two drivers are identical, and these have a lot a miles on them. The fact that they are dead equal at 10K makes me think it driver variation. I don't think a bad blocking cap would do that to the response above 10K.

Thank you, I will swap the drivers to check this.
What do you mean by "dead equal at 10K" I see 7 dB difference at 10K? You mean 1K?