Filter sweep automation problem

[GillyDJ]

I'm doing an 8 bar high pass filter sweep automation using a Simplon (like you would use Autofilter or EQ8) into a breakdown but part way through the automation the kick starts sounding horrible but not sure why?

I've tried reducing the peak (res/Q) but no difference so I only imagin it is filtering frequencies out the kick that is conflicting with the way I've EQ'd it.

In the mix it sounds ok but if I solo the 'low end' group with sub bass and bass tracks it sounds bad and I would imagine on a big system it would sound dreadful.

Kick is quite EQ'd and has a Sonnox Transmod on it.
My group has and EQ8 with 275Hz 1db and 30Hz roll off, a Glue compressor, Sonnox Limiter, the the Simplon automating.

Turning off the plug-ins and devices makes no difference.

Any ideas please?

Thanks

[GillyDJ]

Anyone???

[Spectrumdisco]

try ammending the cut-off frequency and see what effect that has

[GillyDJ]

Well I'm starting at 30Hz (so I don't affect the kick or basses) then sweeping up to 500Hz or so until they fade to the break in arrangement.

The issue is happening in the middle say from 80Hz to 300Hz.

It's not a smooth sweep. It's starts farting and sounding distorted!

Masked in the mix slightly but horrible when I solo it.

[AquaNova]

I know it's kinda late to comment, but maybe it's limiting off too steep, because the part gets too loud? I usually get that "farting" sound with that situation