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Have you taken a near field measurement to compare to? If the dip isn't there when you take a measurement an inch or so from the speaker, than it's due to your cabin geometry(most cars have a dip somewhere near that frequency) and seating position. This can't really be fixed unless you change up some serious stuff. Like change location of the speaker to the kick panels for example.
If it is there in the near field measurement than it is probably caused by door resonances causing some cancelation. In which case you may be able to remedy by doing more treatment on the doors.
 

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Interesting! I'll certainly test that in the morning. So, run test near each speaker and compare to seated position. I am considering getting another amp to hook to the overhead speaker bar (it's disconnected at the moment) to run 80 - 200 Hz to fill that midbass. However, that might take a little while for that purchase (I have mechanical issues to fix as well), so I'd like to address it however I can in the meantime.
Exactly. It will tell you what's from the legit frequency response of the speaker, and what is the car.
 

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So maybe I misses this, but you said moving the sub fixed the issue. And I saw you were going to attempt moving the time alignment to see if it helped. But I never saw the results to the test.
180hz is 6 ft long. That's pretty long but, not really. That means if you moved the sub 3ft closer to you when you moved the box, you effectively made the phase 180°. If we take that to the world of time alignment and delay, that is 2.6 ms to get the same 180° rotation at 180hz. Thats not a ton of movement in delay that would cause a massive null within the crossover. And of course if you are off on time alignment, it is going to show up in the highest frequencies of the sub aka 180hz. But much less so the longer frequencies like 80hz which is over twice as long. Since it is roughly twice as long at 80hz around your crossover region, you could easily get fairly good summation at the crossover point that may only be hypothetically 80° out of phase at the same time that 180hz is 160°.
So I would attempt starting there if you have yet to test it. Cause that's where I would put my money if I was a betting man.
 

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Leaning that direction, for sure 🤣


That's where I'm leaning, friend 🤣. Might take my boss' idea and replace the lower third of my door panel with MDF and mount. Probably will create resonance issues, but it's a start.



So, when I moved the sub to the floorboard passenger side the null stayed. When I put it in the passenger seat facing me it was improved but still present. Passenger seat but firing up was the best of the bunch, but still somewhat present. I now have the sub behind the driver's seat firing forward and the time delay correctly set by measurement.

I can toy with the time delay, certainly. Run some tests and see if anything changes. I played with the polarity of the woofers earlier with sub in its current position and the null only became worse, so 180 isn't the way to go.

So do you think it's time delay or my crossover settings? My crossovers are figures and slopes that I toyed with until the null improved, so it's possible it's tied up in that.

View attachment 316609
I would start by flipping the phase of the subwoofer and playing a test tone at 180hz or some bandwidth limited pink noise centered there. Then play with the time alignment of the sub until you hear that 180hz note basically disappear because of cancelation. Then switch the polarity of the sub back to normal and see what the measurement looks like.
Another idea would be to verify polarity of the speakers. If the sub is reversed polarity, the tape measure dealy is going to make you have a null
 

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🤣🤣🤣

Clear as glass, now 😆



Am I leaving the LPF above 180 on the sub or keeping it at the 120 I have now? Heck, I can do both. I'll test this in a few hours.



The sub is between the back seat and front seat now, I'll move it directly on the back seat and test.

Okay, I was wondering if that pod rattling could be something. Pushing on it doesn't seem to improve anything, but I guess if it's the whole darn pod it might not make a difference.

The enclosures are strange. The portion where the screws mount feels a little hollow, because when I tightened them to the dash the material collapsed where the screws bolt down. It's solidly held, but I thought that was odd. The pods themselves feel solid. The null appears as the mic moves away, but I've only tested moving it towards the listening position, not moving it towards other positions.

As for using the butyl (I have some spare deadener since I never fully started my deadening project) am I putting that on the inside of the pods or the outside? Do I peel the foil off first and then lay the rubber, or lay it with the foil and remove the foil afterwards? I haven't played much with it, but I might have time to do it on my lunch break. I'll make sure to knife it until the bleeding stops 😁.
I would keep all settings the same for the moment. Your doing an audible test of phase alignment by trying this out.
I did also just do a quick skim of the rest of the thread and didn't see that you already have a null at 180 with only the midbass playing that dumdum was speaking of. If that's the case you will probably need an allpass to help remedy the problem. But I would try the thing I mentioned first to see what happens
 

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I'm really not sure. It was sudden. This morning I noticed it buzzing, thought it was the same resonance issue, but realized it was only that speaker. The other one is fine. I'll pull the speaker tomorrow, but I'm not sure what would have detached other than maybe a piece of CLD.

I'm not entirely sure how to go about testing the speaker.
Lightly push on cone and feel for any sort of scratching. Other than that, inspect the speaker. Surround, spider, tinsil leads, connections to speaker wire. Sometimes something as simple as the speaker wire moving and touching the cone can cause a buzzing issue.
 

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Yeah, I'm starting to learn this 😕. I have a tester amp I'm going to install tomorrow (who needs turkey? It's tinker day!) running to the overhead speaker bar, going to see how badly it throws off imaging. Though maybe I should be less concerned with imaging and more concerned with killing that ungodly rattle.

My buddy was checking out the speaker earlier. He pointed out that the enclosures are leaking badly (Can't believe I didn't think of that. I checked my sub box thoroughly for leaks and added sealer to the seams even though there weren't any) and recommended using the butyl later of CLD or window sealing foam strips to make a gasket. It seems like the butyl wouldn't work if I had to pull the speaker and replace it, but the foam seems like it wouldn't be as effective. I could be wrong, and I do have a few square feet of CLD left, so I could easily try it.
I would NOT use butyl to seal against the pod. Can you, yes, but you just stated it's downfall. It's going to be absolute hell to get out and make a mess of your speaker. Most times I've seen people do it, they used way too much and there is a huge amount squished out. Then it ends up all over grills, interior panels, speaker basket, surround, ect.
You really just need something soft around the mounting area. Soft CCF, window gasket foam, thin neoprene sheet, or something of the sort works well. Anything soft that will conform easily.
As far as the leak, I'm assuming you mean where the wires run through? You can use some butyl rope, or butyl pulled from a sheet of CLD to seal that up no problem. It may actually be helping you out a bit by acting like a sort of aperiodic port though. I've heard of people needing to drill a few holes in small pods to help cone backpressure via venting. Typically firing them into something like a pillars stuffed with insulation or carpet though, making them act similar to an aperiodic membrane of sorts. But only one way to find out! Seal it and measure!
 

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Ahhh, glad to have that confirmed before i tried it. Just seemed to be a bad move, unless I plan on nearly permanent speakers.

So anything that is soft will do it? Okay, I'll see if the hardware store is open tomorrow 😁.

The leak is around the speaker where it meets the pod. I've felt the air move around it, but I always dismissed it as the air moved by the outer face of the woofer. As soon it was pointed out to me I realized. To be fair, I had mostly inspected it before sealing the wires, so I'm sure that's forcing more air out of the gaps with it being sealed.
Yeah that will make quite a noise typically. That may be your noise issue right there.
 
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