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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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This route isn’t for everyone but it’s a short read and on the second page it gets to the point. My doors are still not ideal and I’m planning under dash midbass but I managed to significantly improve the response by fiberglassing over most of the inner doors.

 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Another thought after reading the original post again is that something like the roof or other big-ish panel might be resonating. This seems to make more sense than the door deadness as I noticed the subwoofer dips seemingly in ratio to the spl produced.
Automotive tire Hood Automotive lighting Motor vehicle Trunk


Here’s a photo of when I first installed my UM12 through the floor. The circled area is a cavity where I couldn’t screw the 3/4 mdf down. I had a very noticeable dip around 80hz and when I put something heavy on the spot it completely went away. I ended up bracing underneath and now it’s all but gone.

Perhaps you can set up your measurement gear and feel around for something resonating and press on it to see if it stops.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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I want to revisit this thread, It’s been a while and I’ve forgotten the specifics but I’m seeing some measurements with no null.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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I’m just waking up and will read through again but

Do the speakers shown in the graphs with the dip have an open back? That’s to say does the sound from behind the cone have an easy time getting into the listening environment to mix with the front sound? Even if it travels through the dash in some void, is it finding a way out?

I seem to think I remember there’s a subwoofer that’s also subject to the same null, am I remembering correctly?

Have we tested at all around the cabin with a smaller sealed woofer yet?
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Also, I don’t know if anyone else has mentioned it but ~7db nulls are childs play with eq. Did you say that making high q cuts around that null makes the null deeper with careful enough q usage that it’s definitely not acting on the null?
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Open that subwoofers lowpass my guy!! Let’s see the response up to 500hz.

I really have come to highly value test enclosures man. There has to be a cheap way for you to get response down to 100hz in a 6”x6”x6” mdf cube. Move the subwoofer around with a very high crossover and test the footwell, by the doors, everywhere it fits.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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If you’re making the point that you can eq everything else down around the null then that’s all good… but… you can’t cure the null and if you drop the rest to match your null will still be there and have two lots of phase at your ears both at a higher level and you will get worse results in some cars than just leaving a deep narrow null as it is and levelling the rest to suit at the higher level than the null

the other solution is relocate midbass to somewhere without a null where we need to use the driver, and see what happens after than 👍🏼
So test enclosure it is, try it in every possible midbasse location wouldn’t you say?
 

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Ahhhhh, I see. It's not ideal, not what I want to do, but it was attempt, and I'll admit the attempt didn't pan out very well 😕.




I'll have to see where I can buy a cheap one, then. I have zero woodworking tools, so no way of building one myself at the moment.
If your subwoofer enclosure isn’t too big hopefully it’ll work in a pinch.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Actually, it's a truck box, so I could probably throw that in a few places 😁 I can put it in the passenger footwell and test like normal, though I'll have to sit in the passenger seat when I test the driver's side. Though I could just prop myself up cross-legged. Give my middle-aged knees a workout 🤣.

So just open up the sub crossover (I can only go to 240 Hz since the amp's built-in crossover kicks in there), test with the sub alone playing through 180 Hz, test again with the woofers + sub, test all drivers. Anything I'm missing?



Oh I didn't take that personally. I'll take any advice at this point. I know I'm going to have to throw a little money at this, just want to make sure I'm not wasting any of it.

So far I figure I'll either be buying replacement drivers, additional drivers, enclosures, amp, or a combination thereof. Just annoying since I planned to get a much better sub box and second sub and was really looking forward to have decent sub-bass.
Test the sub alone everywhere it fits
 

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You talking us all on a wild goose chase there Flint🤔

Next task is to have the mic at the listener position and test each speaker location one at a time wan enclosed driver.
 

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When the sub is in the cargo area I have a null. I thought it was just the mid woofers because I had taken near field measurements and they were bottomed out at 180. Now I'm taking near field and they're fine.

With the sub right behind me the null is gone. Fun thing, though: it might be related to the timing. I have to test it more to be sure, but with a few minutes of playing it seemed like the null returned when I moved the timing input by a few inches.

I'll take some measurements after my class tonight or tomorrow morning.
If the subwoofer alone has a null one place and not another it’s not a time issue, unless I’m misunderstanding something.
 

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Hmm, hadn't thought of that. I'll test when I get home in a few.

Question: I know you aren't supposed to hold a tone on a subwoofer for extended periods, something about it not allowing the sub to move enough to cool. Does that apply to regular woofers?
I don’t know anything about that bud. If you’re talking about testing for a few minutes at reasonable levels I can’t see any problem. But maybe someone is gonna be like hell na, don’t do that yo🤷🏼‍♂️
 

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That null is in almost every test measurement, in an open vehicle. I’m curious about a panel resonating. When I built my IB floor baffle there was a small spot that was resonating creating a null somewhere around 60-80hz. I braced it and it’s cured. I’m taking about a 16” by 6” area in 3/4 mdf screwed to the floor.
Automotive tire Hood Automotive lighting Motor vehicle Trunk

I knew I had this marked picture, I may have mentioned this to you weeks ago but it’s a thing.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Okay, at 180 I hear things rattling. Honest to God it sounds like the speakers themselves are trying to rattle out of the pods.
Feel around and press hard against all surfaces. When I found that spot in my IB baffle I put my emergency jump box thing on top and measured again and it was a lot better.
 

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Hmm, not sure how to do that. I've seen the waterfall option on REW but haven't fiddled with it. I'll pull it up and look for the sweep option.



Tried the windshield, the dash, all around the speaker pods and the speaker itself. The only thing that's helped slightly is pressing hard on the metal surround of the speaker, but it was just a slight improvement. I swear it sounds like something's rattling around in the speaker or pod. Would the speaker wire vibrating in the pod be enough to cause a null that severe?
Na, it’s a floorboard or footwell or cargo area or door if anything.
 
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