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Jims 3 way speaker build

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  • rpb
    replied
    I'm not sure if I used the right files, but here's what I came up with.

    Click image for larger version  Name:	Jims speaker.jpg Views:	0 Size:	187.5 KB ID:	1493052 Click image for larger version

Name:	Jims speaker impedance.jpg
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ID:	1493053

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  • jimbones
    commented on 's reply
    @DerZzar understood, I meant I could not save a snip as a jpg to my "Pictures" folder. I did some research and they said that a Windows security patch disabled the "save" feature. A lot of good that is ha ha

  • DeZZar
    commented on 's reply
    You can actually just 'paste' the snip directly into the text input area here when making a post.

  • jimbones
    replied
    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 lol
    Attached Files

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  • jimbones
    commented on 's reply
    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!

  • rpb
    replied
    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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  • jimbones
    replied
    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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  • jimbones
    replied
    Originally posted by rpb View Post
    I could be wrong, but it looks like your output at 20hz has increased quite a bit! Like maybe 6dB.
    yea the graphs look quite different. Is there anything else I need to do WRT the box and tuning before I even consider moving on to the XO??

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  • rpb
    replied
    I could be wrong, but it looks like your output at 20hz has increased quite a bit! Like maybe 6dB.

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  • jimbones
    replied
    zma bypassing XO
    Attached Files

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  • jimbones
    replied
    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.
    Attached Files

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  • jimbones
    replied
    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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  • DeZZar
    commented on 's reply
    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)

  • jimbones
    replied
    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
    Attached Files

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  • jimbones
    replied
    OK so I was able to create more free flowing space by opening up the windows on the braces while not totally mutilating them ha ha. I did the zma over with the recommendation of setting the low f mark lower. I will do the frd next Click image for larger version

Name:	zma remove braces stuff.jpg
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ID:	1492945

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