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Discussion Starter · #62 ·
Really interesting, wonder what the spl headroom is like to flatten it out. Does look like it's best 10-40 then a front sub 40-80 before handing off to midbass.
I wondered the same thing too. This setup has a ton of headroom below 40hz. It'll be interesting to see if some cut below 40hz will level this thing into a nice rising response curve and still have enough output.

In the unfiltered response I'm seeing:
20-30hz -6db
30-40hz -8db
40-50hz -1db
50-55hz -1db

I must be missing something -- why would I need to transition to front sub at 40hz? It looks pretty flat to me from 40hz all the way out to 55hz -- only a 2 db drop from 40-55hz, but then it really starts to drop off.
 

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Yeah I hear you, and looking at the natural falloff pretty much following a xover curve anyway. Someone with more knowledge than me bring some experience to the table here.

I'd have thought you could get a mid bass down low to meet it but only if it's in a substantial box / build.

The more headroom you have, the more you can extend the working zone of the sub. Maybe a DSP mode for SQ and one for SPL
 

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Discussion Starter · #64 · (Edited)
Maybe a DSP mode for SQ and one for SPL
That's what I was thinking too.

I did a very rough freehand approximation with the snipping tool of the sub with it's natural rolloff and a midbass with flat response (like that ever happens) and a 24db crossover at 75hz and came up with this:
Rectangle Slope Plot Font Parallel


The overall response in red doesn't account for the IB sub's recovery from 70-95hz -- it should add a fair amount of boost in that region when summed with the midbass. It'll be interesting to see the effect of how leaving that in vs taking it out affects the response.

The graph is likely far from what would actually happen with a 75hz 24db xover, but it sure looks nice. Wouldn't it be nice if all we had to do was sketch things up so they look nice to actualize them? Now all I have to do is get a perfectly flat midbass response :).

Time to start in on a little cutty-cutty for the midbass!
 
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Discussion Starter · #66 ·
I think at this point it might be best to move this topic on over to another thread for tuning. I'll keep updating this thread when I start finishing up the cosmetics of sub install...
 

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YOu're running two 12" subs IB ? I'm really surprised it rolls off that early. You sure there isn't a crossover activated in there somewhere ?
I've never seen a non filtered sub roll off that early but maybe its your drivers.
 
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