Question on X-over filtering

[RooTxBeeR]

So here's my question. When using the LPF on my HU or my amp, bass above the Hz setting play quieter but it is still there and easily noticable. My question is, does the DB slope of the X-Over adjust how much it turns it down. So lets say for example, which I don't know just rhetorical. I set my x-over on my subs to LPF of 50, and I play anything from 60-80Hz, I will still see the woofer move, and hear the tone, just isnt as loud as it would be with the LPF off. So lets just say my LPF is a 12db slop, now if I had an xover that is a 36db slope, would it roll off faster, thus making notes played behind the filter point less audible?

Also it is the same for any of my 6.5's or 6x9s with the HPF settings. I have the HPF set to 80hz, but playing any tone under I still can hear it audibly.

[Kevin M]

That is exactly what happens. The steeper the rolloff the less audible it will be. Most people in CA use 24 max but I have seen 36 db on home audio systems when people run Maggies or large ribbons. Power handling and freq. response of the driver has a lot to do with this.

[RooTxBeeR]

Sweet thanks!

[kickass audio]

Yeah the x-overs will never fully like dead on cut the frequencies outside the range they are set to. The higher the slope (from least to steepest 12, 24, 36, 48db) the less frequencies outside that range will play. This is normal but normally i set my x-overs at 24db but its preference. I had them at 12db but the door speakers rattled too bad from the panel vibrating so i did away with 12 and went to 24 and it fixed it. The whole concept of the db of the x-over slope is how steep the runoff would be for frequencies out of where you set the range. Think of it like a hill, if you set it to lets say 12db you have a pretty flat hill to go up and you can overcome it. Now if its a 24db slope you will have a steeper hill and it would be more difficult to overcome and thus frequencies that cannot make it over will be dropped off. Again you will still have bleed through on it but it wont be bad.

Another good point to make is that for ported enclosures the good rule of thumb unless you know how to do it properly is to not go more than 2 or 3Hz lower than the tuning of your subwoofer enclosure for the infrasonic (or incorrectly called the subsonic filter). The reason for this is that if lets say you have a box tuned to 40Hz but the subwoofer will bottom out at 36Hz, if you set the infrasonic to 38Hz at 12db you would have quite a bad chance of making that sub bottom out on low tones, if you had it at 38Hz on 24 db it would have even less of a chance to bottom out.

I hope i made it clear for you and im sorry if i confused you. If you have questions feel free to ask me and ill let you know.

[RooTxBeeR]

Nah dude that just helped solidify what ScottishBear said. I was always wondering because when I didn't have subs in, and HPF on all speakers I could still hear low notes and I was like wtf? But thanks, that is awesome. Now I need to find some 36db/oct slope crossovers! I want my shit on point!