[cdgatti]

Wondering if anyone has experimented with different slopes for the low pass on their underseats? I am currently running at 150Hz and 24dB. Sounds fine but thinking that 12dB may give a little more oomph to help out the pathetic little 4" speakers. For mids I am running Morel ovations, High passed at 110Hz and 12dB.

[6spdcoupe]

Yup, we use a good bit higher and more shallow as default. Then again, I personally would never run a 4" driver that low though.

[AW335TT]

Low passed at 155 18db .. Mid is high passed at 160 12db

[cdgatti]

Thanks guys, that guidance helps. 6spd what is your default for a morel 4"?

[cdgatti]

I think I'll try playing with the crossover points and slopes with an RTA and see what settings allow me to hit my reference curve with the minimum of EQ work on my Helix DSP, more to come.

[cdgatti]

As follow up to my own request, I did some experimenting with an RTA and a RS SPL meter and think I hit on some pretty good settings that are making the bass in my car very strong and is not located, sounds like it is coming out of the dash.

For the under seats (Kicker ssmb8 with 150w/channel (JL HD) I have found low passing them at 180hz and 12db slope to work pretty good. I think this is better than I had before (150hz and 24db) because it adds a little more oomph where the 4" morels (or any 4" for that purpose) lack in that 150-250 range.

For the morels, even though they can be pushed to give some SPL in the 100-125 range, why strain them, I have upped the high pass on these to 140hz at 12db.

After making these changes, I then got out the RS SPL meter and played with the phasing on the Kicker under seats to get the maximum SPL measurement while playing a 180hz tone in conjunction with corresponding mid. This was illuminating at the significant difference I could measure as I went in and out of phase between each kicker/morel combo. In the end, the driver side under seat ended up at a phase of 168.5 degrees and the passenger at 68 degrees. This manipulation is made possible with the Helix DSP. The left and right morel were already time aligned to give a good center.

I have heard others say that when they get this right it seems like the bass is coming from the mids, I think I have done better than this... none of my speakers, including the mids give their location away, the bass just comes from inside the dash somewhere and the mids/highs are just floating above it. You can't shut your eyes and point to the speakers they are acoustically invisible. I have read about this but never achieved it till now.

[jeffb335]

hhhmmm.....this got me thinking so I checked the RTA and yeah, my car is down a couple db at 160hz, my crossover point.....seeing how well the jehnerts blend in at that crossover point Im betting there is room to go higher and with a shallower slope....getting more output near the crossover point AND the mids wont have to work as hard. I know I played around with higher crossover points back when I originally put this system together but at the time I just couldn't bring myself to cross over the jehnerts that high! It just felt so wrong, haha, now that the jehnerts and I have "built some trust" I think its time to try again!