If you set them to run the full spectrum, you have to keep the volume very low. The midbass drivers can't handle the really low stuff. So if you want it at normal volumes, you have to do a high pass filter.

For no subwoofer, a compromise is sometimes to drop the volume somewhat and drop the frequency somewhat, ie 50-60Hz @ 6dB slope instead of 80 Hz at 6 or 12 dB slope. (The higher the slope the faster the frequencies disappear.) And the frequency respone of midbass speakers already typically drops off at around 80 Hz.

But it's always a compromise until you get subwoofers. Midbass speakers aren't designed to go much below 80Hz with any real volume.

 

How do you adjust the slope?

 

Ace, you got the slope backwards.

6dB slope means the volume drops 6dB/octave after the cutoff.

12dB slope "..." 12dB/octave "..."

using a lower frequency for the crossover, you'd want to increase the slope to compensate.

Hellspare, your best bet is to set the frequency on your woofers for 80-100hz (I would lean toward 100, tbh). The amp should have a switch for slope next to the frequency dial.

 

As of right now my sub is set at 100hz and my speakers are set at 80hz. It seems to work well for the delay. Maybe my ears just weren't working correctly last time, but lowering from 100 to 80hz on the speaker amp really did seem to help.

What do you guys suggest I set my slopes to?

 

12dB should be fine.

You might try setting your speakers to 100Hz and 6dB.

See which setting has more fill without causing distortion.

 

I will try that.

 

Oh, I wasn't trying to imply they were equivalent--my post must have been unclear. I though he asked what people can do when they have no subwoofer and decent mids--that was a question, right?

For that case, you can compensate for the lack of low end by runing more bass through the midbasses, but you'll have to reduce the volume or you'll blow the speakers in a hurry. I'd at the minimum run 6dB @ ~50-60Hz on midbasses just to protect them speakers, and you can't play it loud, but it will sound more full that way.

I'm biased since I can adjust all this on the HU and on the fly, so when I'm tooling around town on low volume I can let more through to get better bass response, but on the freeway with the road noise I want the volume up so I increase the crossover points. (And I'm on factory speakers, so if I screw up and blow them, they're still coming out next month.)

With a subwoofer, I'd expect something like 12dB @ ~80-120Hz, just like hellspare is doing from the sound of it.

 

Would I run any risks of blowing my sub at 3/4th gain and 100hz when I crank it up on the freeway?

 

ACE:

You still have your slopes backwards.

At 50-60Hz, you should be running 18dB slope on stock speakers (you shouldn't even be this low).

An 18dB slope drops off faster than a 6dB slope.

When you use a lower slope, the frequencies should shift up on a high pass xover. On a low pass xover, a lower slope should be paired with a decrease in xover frequency.

i.e. woofers: 100Hz, 6dB or 80Hz, 12dB or 63Hz, 18dB
subwoofer: 100Hz, 12dB or 80Hz, 6dB



Hellspare: Listen for distortion. If you're hearing distortion at that level, then you need to turn down the gain or adjust the xover freq/slope to eliminate it.

 

Anyone mind doing an in depth explanation of slopes/high pass tuning/low pass tuning? Would be helpful for the FAQ's. I've got a link to one about adjusting gains using a multimeter.