Low inductance subs, do you adjust your lowpass slope accordingly?

[BuickGN]

This is kind of a general question that I have since going with the larger midbasses and trying to cut the subs off a little lower. When I use a 24db slope, they tend to "push through" the crossover with more of the upper frequencies coming through than my 12W6s did with the same setup. I've started using my amp's crossover in conjunction with the MS8. For example, when I was running a 63hz highpass/lowpass, I used the amp's 24db lowpass on the sub set to 70hz. Seemed to help with sub localization and you don't realize how much higher material gets through until you slap another 24db lowpass on it. Currently have the subs and midbass cut off at 50hz and I don't feel the need to do this anymore.

Tomorrow I might go back to a higher lowpass on the subs, it's a shame to have subs like these playing only 20-50hz. I've traded tactile cues from the subs to the back of my seat for vibrating the whole seat from the midbasses at 50hz, bringing the stage down. I can't win and 50hz seems to light this car up no matter where the source is and with a couple hundred pounds of deadener and sound blocker. Maybe going back to a 70hz lowpass on the subs with an additional 24db filter will be what I'm looking for. Now I'm just rambling.

Back to the original question, I was more or less wondering if it's normal for low inductance subs that play the upper frequencies with ease to require a steeper slope than a "normal" sub?

[fish]

Since we have the same subs I'll chime in with kind of the same results that you're dealing with. If I cross them @50hz 24db they're fine, but 63hz 36db they bleed through. If I cascade the low-pass @63hz with the HD600/4 with 24db (sum of 60db/octave @63hz then it tames it down pretty well. 80hz... forget about it.

What's weird is I had a pair of Audiomobile MASS 12s in a sealed box just over 1cf each that wouldn't play much of anything above 60hz. I saw measurements of the inductance being .5mH, so I dunno. Unless it was because the lowend was so over-extended it just washed out the higher bass frequencies.

[sqshoestring]

I've always had that with efficient (usually cheap lol) subs that like to play high, the LP needs to be lower and/or more slope. While even the sub range spl may be higher with some, they are still a PITA to work with. There is something to be said for choosing drivers tuned to your install needs. I can play my pyles with no EQ or LP (class D amp only plays to 200hz, but still) and they don't sound bad. With my infinity everything below about 45Hz would have vanished due to them loving to play high. By high in sub I mean they are stronger around 50 and up. Same thing can happen with mids/tweets that give a FR in your install that is not ideal. You use them you just have to deal with it, sometimes double xovers and EQ only on those are things you have to do. I had an old xover that went down to 35hz and that worked well on the infinity subs I ran, it was comparable to two 50Hz LP (one of the 50lp was my 880prs 50 is low as it goes) on them. Yes its a pain to add more equipment you wish you didn't need, I eventually tore them out and put these 15s in instead. Got lucky the model was right and they tune very close to what I want. I don't look only at certain specs, even the cone design can affect FR of a sub.

All that said, a PEQ is the master at fixing this stuff. You should try to find one that covers that frequency and plug it in on those amp channels just for kicks. The one I used would flatten those infinity out like nobody's business. Of course you still have to mostly cut with them so you don't clip/etc., and if you never used one it takes some work to recognize what its doing to be able to tune by ear.

One time someone posted here how they could get these great and efficient subs, Kef subs. They modeled like a giant 15" midbass. They were more efficient even at 30Hz, but I sure don't want to be the one to tune them in the curve still dropped like a brick. High efficiency is great on paper but can trash your FR. Seems like some people don't realize pro sound uses a driver at its high efficiency range, that is the game. If it is falling off then you use a horn/porting/etc to level it out. But you don't try to use it where it does not work, and that is why car subs/drivers tend to have a smoother roll off so they don't flat out suck when you do use them that way. I know many people here know all that, just saying due to some stuff I read here....

Also might be the car. I could not get any low bass in my car with boxes that should have worked better. Finally went to IB to get it. Funny thing with these pyles is they are just a hair too much at 50Hz or so, after some listening time it just needs to cut down a little more. I have to LP them at 50 or 63 to get that last little bit. Certainly could be a sensitive frequency in that area in this car, would explain a lot.