I was wondering what ppls opinion on this subject.. i.e. use HU's xovers or the AMP's xovers.. say the HU has adjustable slope 6,12,18 dB/oct and the amp has only 12 dB/oct.

when using the HU's xovers, would u just set the amp's xover setting to flat or ...???

Most amps should have defeatable crossovers (read : you can switch them off)

Unless you have a top knotch headunit and a poor amp, you'll probably find the crossovers on the amp are of better quality... Having said that, i bought a Pioneer DEHP8650 specifically because in network mode it has one of the best crossover networks i've seen on a headunit for its price... low/high/bandpass filters on high/mid/low outputs with variable slopes from -6 to -36dB/octave... its hard to argue with that...

The only thing i HAVENT seen on too many affordable headunits is a subsonic filter from removing ultra-low bass and subsonic frequencies, does anyone know if any affordable (sub $1500) headunits have this feature?

how abt to make it more specific..
comparing Alpine CDA7998R's xovers, and SS Tarantula amps' xovers... any opinions?

Try both and see which sounds best. If you cant tell the difference, pick one and be done with it, or use both.

I've cascaded the head unit's 12db/octave LPF and my amp's 12db/octave LPF for my sub to give it a nice steep 24db/octave slope.

how do u do that? so say if i use the HU 18db/oct + 12db/oct on my amp i can get 30db/oct?

Yep. Play around with it and see how it sounds.

Using a steeper slope on your sub can help to reduce boominess in the upper sub bass/midbass region, and when used to high pass midbass drivers you can use a lower cut off point while still maintaining decent power handling. Most systems sound best with a gap between the midbass/sub crossover of 5-20hz to reduce overlap, with steeper slopes you can close that gap up a little, which may sound better, or it may sound worse. There are also phase issues that come into play with different slopes, so take that into account.

6db/octave = 90 degrees out of phase
12db/octave = 180 degrees out of phase
18db/octave = 270 degrees out of phase
24db/octave = 360 degrees out of phase (back in phase)
and so on.

Whenever you change the slope, try switching the phase on your sub (via the head unit or switch if the amp has that feature, or switching the +ve and -ve leads) and see if it sounds better or worse. It all comes down to experimentation, but the difference can be quite noticeable.

would I set both xovers cutting point at the same frequency to get that cascading effect u talking abt??

you certainly can cascade the filters to increase slope as it is cumlative but you really need an RTA to do it properly as the markings for each crossover may be out a fair bit. An RTA will let you see what the crossovers are doing and make sure they are crossing over at same point

There are no right and wrong answers to this question but if you can get a phase correct filter arrangement then its all good. Using 12 dB slopes can provide great results if the speaker is kept in phase, but ideally steeper is often better when using active filters
peace
Cyberpunky

use the headunits x-over

its quick easy and you can play with them for weeks

its just darn horrible to use the x-over in an amp unless you sit the thing on your lap and adjust it .....good luck with that :-)

also remember the marking for x-overs on amps are logarithmic rather than linear = top fun to adjust

stik79, how r u setting ur system? The only diff is dat my hu is cda7998r and my SS is TR800.5. Right now I'm using my amp's xovers for both the front and the sub.

i'm not... (amps are on workbench receiving TLC )

But I was (before everything went pear shaped!) using the deck with pretty steep filters (9815 have variable slope etc)

do you guys know the slope of the pioneer 5550 x-overs by any chance?

pretty sure theyre 12db/oct steve iirc, but check any site or the manual it will tell you

ahh yep, only few sites had the slopes
18db are the sub x-overs and 12db for the other outputs.

Thanks

I am also having the same headache.. but mine is with an additional passive crossover for the front speaker. Which crossover should I set first, HU or AMP?..that's if I want to use both filters.