i have a system in my HX holden, composed of:

Cadence Z4000 amp running splits and sub

splits Focal 165V2 in custom pods

deck JVC KDSX985

rears jaycar responce 6 inch running from deck

sub alpine type S svc 12 inch in sealed bod ( around 1.8 cubes)

what i wanted to know is how can i improve the system. What is the best setup as far as gains, bass boost settings and crossover freqs ?

the problem i have is poor bass performance at lower volume levels, then overwhelming boom at higher levels.

i have a gas tank behind the seat. The sub fires back towards the rear of the boot.

pics here: http://gallery.oldholden.com/CruisEH

I think you need a head unit with sub control or an external sub controller.

The reason the bass is reduced at low volumes is because everything is reduced at low volumes and the human ear isnt very receptive to low volume 60Hz noise. To remedey this people often turn up the bass at low levels so they can hear it and exaggerate it louder than the other frequencies, then if they turn up the system, the bass is too loud.

With a sub level control, you can adjust the sub volume at the turn of a knob to suit different listening volumes or recordings.

the JVC has the extra RCA's and functionality to give sub control, and i use it.

its like the loudness control.. i dont use it at all, because it colours the music badly, and i lose the clarity.

hard to explain without hearing it, maybe i need to snap out the factory 7 inch hole in the parcel shelf, to allow space for the sub frequencies to enter the cabin, as the HX has an all steel parcel shelf, with only 4 small (3 inch) holes in it..not exactly ideal for sound transmission...

does anyone know what the ideal size is for a ported box for the type S 12 inch?

Sub control isnt like loudness. It doesnt boost certain frequencies or colour the sound, it simply increases the signal to the subwoofer RCA outputs.

i realise that. Perhaps what im trying to get across isnt coming out correctly.

The point is, i do not use loudness control.

The bass boost on the cadenc amp also has a frequency control as well as a crossover for the low pass.

Im not sure what the settings should be. Currently, i have the boost at around 3/4 gain, with the freq at around 30 hz, and the xover freq around 70-80 hz.

the focals are driven from the other two channels of the amp, at full range, and gain set around halfway.

i'd say the bass issues are due to the bass boost on the amp being up so high

turn it off and maybe readjust your gain if it seems low...this will get rid of the change in volume in subbass as the volume dial goes higher

i would also suggest using some kind of sub level control. It isnt a loudness feature of any kind and only affects the volume of the sub. You can turn it up or down and have as much control as the main volume control. It wont colour the sound at all and certainly shouldnt effect the clarity of the system

did two things today:

changed phasing of the sub = good. better low down bass, more punch.

also adjusted the bass boost, turned it nearly all the way off, and it made a huge difference. Pity i hadnt tried that before.

thanks for all the help guys...