# How to solve big Dip at Crossover region?



## jianhua1975 (Sep 13, 2011)

hi,
recently i am recalibrating my HT system( Cary cinema 12 pre+Poweramp+active Sub-MK 1250+main speakers).

test SUb+RFspeaker, i got a quite big dip always at crossover region, when i move Crossover upwards till 110hz, it becomes slightly better, and move to 80Hz, it's quite worse. 

i guess it's about phase/polarity, but i don't have any handon operation idea how to adjust , 
could anyone give some support.
will be really appreciated!


----------



## sdurani (Oct 28, 2010)

Try changing the distance setting for your receiver's subwoofer output, adjusting it in both directions until measurements show the dip shrinking. IF the dip was caused by a phase cancellation at the crossover point, adjusting the delay should improve things.


----------



## fusseli (May 1, 2007)

This sounds like a phase issue. Does the sub not have a switch or dial on the back to adjust phase? If it does, set the phase to a new setting and repeat your different crossover points and see how things look. What is the room placement with respect to your mains and the sub?


----------



## jianhua1975 (Sep 13, 2011)

fusseli said:


> This sounds like a phase issue. Does the sub not have a switch or dial on the back to adjust phase? If it does, set the phase to a new setting and repeat your different crossover points and see how things look. What is the room placement with respect to your mains and the sub?


i'll try to do that to see if any help. 

i have a 35squareMeter room, sub is placed arround 1meter away from LF speaker, and 1meter to the up-left
corner. and near to the left wall(almost touch the left wall).

but if it's a phaseissue, it'll be changing if i move sub signficantly on the path towards Listening position, but last night, when i moved the sub, and mointoring the RTA, seems no obverious change on the DIP. so quite strange!


----------



## jianhua1975 (Sep 13, 2011)

problem solved now! 
just turning the phase switch from "+" to "-", the dip disappeard.

thanks for all for the valuable suggestion. 
now i got good result now, i'll post the data soon later.


----------

