If that mid is being crossed with a 5.6uF, we really don't know if it can handle a lower crossover. Thing is, a free-running 15" bass is going to naturally roll off around 1.5kHz on a simple bass coil. And that is where you would cross to the mid in this case. The mid really being a big tweeter here.
Have to sleep on this one! 🙂
Do you know, I think I have stumbled upon the right solution here... 😱
Your 5.6uF and 2uF caps are really not far away from these values:
The bass section will need some thought though. A 1mH bass coil, and 7.5R plus 10uF impedance correction is more likely to work on the bass. And we might need to add some resistors.
Your 5.6uF and 2uF caps are really not far away from these values:
The bass section will need some thought though. A 1mH bass coil, and 7.5R plus 10uF impedance correction is more likely to work on the bass. And we might need to add some resistors.
This seemed doable with the gear I have to at least establish a rough idea of impedance:
Loudspeaker impedance measurement using a multimeter and 2 resistors
So you’re suggesting a higher mid range cross because the cap value is so similar to the tweeter cap? Which makes you think the mid can’t go very low at all?
Regarding separating the mid range in the cab, would a large~6” pvc cap glued to the backside of the baffle work?
Loudspeaker impedance measurement using a multimeter and 2 resistors
So you’re suggesting a higher mid range cross because the cap value is so similar to the tweeter cap? Which makes you think the mid can’t go very low at all?
Regarding separating the mid range in the cab, would a large~6” pvc cap glued to the backside of the baffle work?
I'm not sure you need to measure the bass impedance here.
The idea of adding a bass coil and some underdone impedance correction is just to roll it off a little steeper. Which should reduce breakup.
We might assume it has a fairly benign sort of frequency response running fullrange. But usually around 1.6 or maybe 2kHz rolloff. Just how big cones like this 15" work.
The 5" mid is difficult to guage, but I would guess it doesn't have a lot of excursion, resembling more a fullranger which is quite a different animal from a midbass capable of digging deep. Nevertheless a sealed enclosure makes sense even if its just a litre or so.
The replaced 2.5" sealed back cone tweeters are another unknown quantity. Some of them have very awkward requency response.
However, whatever you do, its going to sound cleaner than this simplistic 5.6uF and 2uF jobbie. I would try a sim with a big bass, a 5" fullranger and some typical cone tweeter. See how polarity works out for one thing.
You start with the existing crossover, then save the response, and see what a better filter does. Gives you a feel for it all.
The idea of adding a bass coil and some underdone impedance correction is just to roll it off a little steeper. Which should reduce breakup.
We might assume it has a fairly benign sort of frequency response running fullrange. But usually around 1.6 or maybe 2kHz rolloff. Just how big cones like this 15" work.
The 5" mid is difficult to guage, but I would guess it doesn't have a lot of excursion, resembling more a fullranger which is quite a different animal from a midbass capable of digging deep. Nevertheless a sealed enclosure makes sense even if its just a litre or so.
The replaced 2.5" sealed back cone tweeters are another unknown quantity. Some of them have very awkward requency response.
However, whatever you do, its going to sound cleaner than this simplistic 5.6uF and 2uF jobbie. I would try a sim with a big bass, a 5" fullranger and some typical cone tweeter. See how polarity works out for one thing.
You start with the existing crossover, then save the response, and see what a better filter does. Gives you a feel for it all.
Thanks a lot for all the help! I wish I didn’t have to order all the parts, I don’t know of a local place to go shopping. Teaches patience I guess. I had already ordered the .15 and 2.5 coils from parts express. They showed up so I put the big coil on the woofer, I was expecting a bigger difference, female vocals sound a bit more cohesive, less smeared maybe, but it’s not a night and day difference. I’m leaving one side stock and tweaking on the other. I also added some bracing and lined one cab with about an 1 1/2” of fiberglass insulation, again, not a big change.
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I just had a quick look at how this speaker might work.
I imported this 12" design into Boxsim projekte folder and quickly knocked it into shape.
boxsim-db.de | Boxsim Projektdatenbank
It turns out quite well on the simple crossover. Seems to be positive polarity in the original. The Visaton filter isn't too bad on mid and tweeter, but the bass filter needs something different.
Remember we have seen something like this before: SEAS Kit 503
Anyway, here's what I got. I'd assume your original speaker is much better matched on levels than my sim, so the mid and tweeter levels are definitely select on test. I've probably overdone the attenuation, and I'd guess your 15" bass will roll off a bit lower.
I imported this 12" design into Boxsim projekte folder and quickly knocked it into shape.
boxsim-db.de | Boxsim Projektdatenbank
It turns out quite well on the simple crossover. Seems to be positive polarity in the original. The Visaton filter isn't too bad on mid and tweeter, but the bass filter needs something different.
Remember we have seen something like this before: SEAS Kit 503
Anyway, here's what I got. I'd assume your original speaker is much better matched on levels than my sim, so the mid and tweeter levels are definitely select on test. I've probably overdone the attenuation, and I'd guess your 15" bass will roll off a bit lower.
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