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Jims 3 way speaker build
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Here is a current version of the XO. I didnt have all the correct values so I have to order some parts. For some reason snip wont give me the option to save images anymore..just vanished lolAttached Files
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33 is what I was aiming for. The things that affected it the most as far as I can see was the woofer break-in and stuffing. Yes the woofer has the XO on it. I measured it both ways. I did have to pad the mid and tweet quite a bit. I think I padded just a bit too much now but thats OK I will back some out. I will also do as you suggest with the mid and the woofer and reverse polarity looking for a null. Happy Thanksgiving All!
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I was going to stay out of the way while you and DeZZar got the tuning, and bass figured out. It looks to me like you are tuned to about 33hz. Is that where you want to be?
You have a filter on the woofer, mid, and tweeter, right?
The mid, and tweeter were padded down more, right? Check your sim. The mid should be padded about 4dB lower than its raw measurement. Tweeter is then padded to match the mid. How does the impedance look? Safe?
How does the mid response look now? Smooth like before I hope.
I'd check to see how the woofer and mid sum together. Measure from about 12", with the mic half way between them. Try switching polarity on one driver. You want flat one way, and a null the other polarity. The null would be at the xo point, but can be very wide. The theory is, if they are in phase, and sum well, when you reverse the polarity, they will cancel where they overlap. This is not an exact procedure, but it's what I do to get in the ballpark.
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BTW I tried summing the 2 curves to see how they would sum but I am not getting it. any instruction is appreciated.
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Originally posted by rpb View PostI could be wrong, but it looks like your output at 20hz has increased quite a bit! Like maybe 6dB.
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I could be wrong, but it looks like your output at 20hz has increased quite a bit! Like maybe 6dB.
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I stuffed the area behind the woofer pretty good. I measured the woofer and port again. Also I am trying to break the woofer in by playing some tones on repeat on the cd player.
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My bad, when I modified the braces I didn't put the stuffing back. I spoke to madisound and they said with that amount of bass energy I should have a decent amount of stuffing behind the woofer. I am sick today but will correct and measure
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Well....I don't know what to make of this. Impedance looked better in post 214 above where that peak @ 150hz was mostly subdued. Now its back in full force. The aligned sum between the attached port and woofer response shows an f3 all he way up at 55hz and a steep roll-off from there. Port tuning looks to be on or just over 40hz. I'm really struggling to trust these measurements and I have no experience with OmniMic...
From here all I can recommend is:
- Ensure the box is sealed up tight, no leaks and that the internal surfaces are all padded with felt. Top and bottom surfaces should have a decent amount of wadding in place.
- Re-confirm your NET internal volume is in fact 70L and if it is, lengthen the port until your impedance shows box tuning is at 32Hz.
- Trust that the SPL of the drivers is per their spec and try the crossover I suggested which assumes they are playing at expected levels and that the woofer will result in an SPL target of 85db and see if it creates a better balanced sound overall (if you just plug my values into your sim it'll look strange because I have scaled your files to match an expected output level)
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things look like they are going in the opposite direction lol The zma is woofer only (no XO) the frd include a 8.4 mh and 80uf 2nd order
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