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  • mattp
    replied
    Originally posted by Wolf View Post
    I would still likely place an LC across the woofer and see if you can't get to -50dB on the breakup. As low HD and resolving these should be, I would remove all doubt and kill that blemish. This also might allow you to shift the xover higher, as I think Xmax could be your issue, not HD. I would try some higher output with xover and see, but 1500+ w/o waveguide is probably recommended. I have a set of TL, but not that model.
    Wolf
    Thanks Ben. What I put in bold were exactly my thoughts for this design. The design I came up with was very similar to his first which was a surprise to me, the main difference being the values for the woofer filter since he accounted for baffle step. He sent me a 4th order with notch and a XO around 3k that I think I will try next.

    Otherwise I will always have that mild panic thought in the back of my head that these will just shatter one day.

    Originally posted by Wolf View Post
    And a cap of about 1uF across your padding resistor will lift the top.
    Wolf
    This is very useful info. I might try it to see if I hear any real difference, My ears are only good to about 14k but it's cheap enough to try. And according to my sim you nailed that 1uF value BTW. I have this sneaking suspicion you have done this once or twice...

    Originally posted by rpb View Post
    Click image for larger version

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ID:	1419606 I'm puzzled. My sim ends up at 90dB. Johns is at 85dB. In PCD, the response of Johns filter looks much different below 1k. The transfer function shows 1k to be down 12dB. It looks like he was correcting for baffle step, but that is already in the measurement. Or maybe I'm doing something wrong here.
    I know he accounted for baffle step but he did use his own corrected/blended response using a NF measurement I sent him for everything below probably 600-700 Hz. I did not correct the file I posted earlier in the thread so the phase was probably not accurate. Hopefully John will chime in and shed some light on his reasoning for this. When it comes to proper XO design I don't know what I don't know - so I am all about learning from you veterans.

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  • rpb
    replied
    Click image for larger version

Name:	jh sim.jpg
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ID:	1419606 I'm puzzled. My sim ends up at 90dB. Johns is at 85dB. In PCD, the response of Johns filter looks much different below 1k. The transfer function shows 1k to be down 12dB. It looks like he was correcting for baffle step, but that is already in the measurement. Or maybe I'm doing something wrong here.

    Leave a comment:


  • Wolf
    replied
    And a cap of about 1uF across your padding resistor will lift the top.
    Wolf

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  • Wolf
    replied
    I would still likely place an LC across the woofer and see if you can't get to -50dB on the breakup. As low HD and resolving these should be, I would remove all doubt and kill that blemish. This also might allow you to shift the xover higher, as I think Xmax could be your issue, not HD. I would try some higher output with xover and see, but 1500+ w/o waveguide is probably recommended. I have a set of TL, but not that model.
    Wolf

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  • mattp
    replied
    Since I cannot edit my other post...here is overall measured with individual driver roll-offs.

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  • mattp
    replied
    For anyone curious this is 0-45 degrees.

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  • mattp
    replied
    Actual measurements. Distortion was taken at 5v with 1/24 smoothing.


    Top is overall, bottom is tweeter only with XO.

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    Last edited by mattp; 08-17-2019, 01:19 PM. Reason: Smoothing ratio was wrong.

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  • mattp
    replied
    Quick question for anyone who has used TL N26CR2-A tweeters in the past (I don't think there are many...)

    Due to the peak in the woofer, in order to get away with a minimal-component XO with no notch these really want to be crossed around 1300 Hz second order. Is this a safe XO for these tweeters? My listening tests don't show any real strain even at higher levels but I know these are fragile and I realllllly don't want to literally break one.

    John Hollander has been graciously helping me get these as good as I can get and proposed asking anyone that has used them before. Here is the first sim he came up with. I have only listened to this one so far. I do not see any issues in the distortion plots at all... and nothing is shouting at me during listening tests.

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  • rpb
    replied
    Originally posted by mattp View Post



    Ben is correct, this is the chamber here in the lab at PE. Not so much a booth but an actual room (~1500 cuft) with a non treated floor. It's good to around 450 Hz and yes that distortion was gated at 5ms. We usually blend our FR curves for spec sheets around 500-600 Hz. The tweeter for this test was about 61" off the floor on two stands stacked.

    I have attached frd and zma files for anyone who wants to fiddle. Everything is 2.83V/1m, woofer is blended to nearfield at about 720 Hz.

    [ATTACH]n1419249[/ATTACH]
    [ATTACH]n1419250[/ATTACH]
    [ATTACH]n1419251[/ATTACH]
    [ATTACH]n1419252[/ATTACH]
    This was fun playing with. My x-over uses a lot of parts to smooth some bumps. Probably isn't practical, but If you like big x-overs.....

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  • Vader540is
    replied
    Beautiful work.

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  • Wolf
    replied
    That's bigger than it used to be then.
    Wolf

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  • JoeCaWWW
    replied
    Wow! That's awesome, man!

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  • jhollander
    replied
    Matt I would need the T+W file to be able to find the offsets between the drivers.

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  • mattp
    replied
    Originally posted by jhollander View Post
    Nice, might play if you have the T+W file...
    Sorry John, if you are asking for a different file than I posted I'm not sure what that would be. Can you elaborate?

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  • jhollander
    replied
    Nice, might play if you have the T+W file...

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