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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?
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 👍🏼
 

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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.
It wasn’t aimed at you buddy, we have to try things to see what happens… but there is always more than one way to skin a cat was my point, if you have an 8 db null try taking surrounding down to -4db so the null is then 4db deep and shallower, sometimes that sounds better than dropping everything down by 8db so the null ‘disappears’ as the null still has the speaker making energy at the nulls freq if that makes sense and sometimes results can be better, try it a few ways and one will work out for the best 👍🏼
 

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It’s very likely it’s a room mode down to the length of the car, move the sub to the back seat and see if the nu
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
the null is present in the midbass with each driver playing solo’d, so the sub position may reinforce the 180hz dip and fill it somewhat, but that doesn’t solve the issue of the null itself

in one post I read the enclosures buzz and resonate at 180hz, this will give enough out of phase output to effect the response

enclosures should be solid and a nearfield measurement may be close enough to miss the effects of the resonance cancelling stuff out

does the null appear as you move the mic away from the driver in its enclosure

put bluntly of the enclosure isn’t sealed do that, that alone could be the root cause of your dip (use butyl from deadener with the foil removed. It’s perfect for this job and also for using like blue tack for mounting tweeters) and also you need to make sure the enclosure is deader than a dead thing, on a dead day, coming first in a being dead competition!
 

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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
Rectangle Slope Font Parallel Screenshot

in the first post he states it’s in both midwoofer playing separately

If this is the case an all pass won’t help at all as it’s present when solo’d, an all pass will only help when it’s between two drivers, it’s also unusual to get a modal dip at the same freq in both drivers in two locations

this is why I’m coming to the conclusion that maybe him saying he can hear resonance at the exact freq in the pods, and also what’s common to both drivers… the pod 👍🏼 That’s where I’d start
 

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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 😁.
If deadening the enclosures I leave the silver foil on, do the inside as you don’t see that…

if it’s for sealing the holes or anything for that matter remove the foil and make it into a malleable butyl sealer that is self adhesive and will seal it up a treat 👍🏼
 

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That looks a lot better with the deadener! Far smoother response

I will also say that you have what look like 5” drivers in enclosures that are way too small…

most 5” I’ve modelled are roughly 2.5l ish… grab a 2l bottle of coke and then compare to your pods volume, the sound will be very compromised in those for me
 

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Any speaker mounting wants to be rock solid, both it’s walls and also it’s mounting, I always aim for metal work where possible, it likely doesn’t help that the pod is so small as it naturally resonates around or over 180 and you are playing notes that act on that resonance

Now if you could cut the drivers over 180, say 300hz it would be way less of an issue, but playing around resonance of the enclosure/driver with a less than solid enclosure is never going to work out so well unfortunately
 
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