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Thread: Quick & Dirty 4430-Inspired Two-Ways Part II

  1. #181
    RIP 2011 Zilch's Avatar
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    Y'all can see it took all of 2.5 hours to do that.

    The hard part was deciding to do it....

    [You CAN test yur drivers, folks, it ain't difficult.... ]
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  2. #182
    RIP 2011 Zilch's Avatar
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    Listening to Vintage Aluminum:

    I've completed the second NL200t3-16 crossover and am playing the venerable vintage LE85's 1 & 3, above, on S3100 horns after EQ'ng flat with UltraCurve Pro. In spite of full HF boost, they sound smooth and natural. They have a bit more HF extension than 2425/6 to begin with.

    I've invited Mr. Widget over for a listen, as he's particularly sensitive to, and critical of, the harshness of titanium diaphragms when the top end is pushed like this, which harshness seems to be gone. I'm wondering if the dusted titaniums will handle HF boost as gracefully now....

    Here's what UltraCurve did to make them perfectly flat. These crossovers are really optimized for 2342/2344A horns; playing them on H3100 requires further correction (+/- 4.0 to 5.5 dB) as shown here. Dot is left channel, circle is right. AutoEQ'd separately, they virtually superimpose:
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  3. #183
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by B&KMan
    What is ( y ) scale please ??? 1.5 or 15 DB...
    That's 15 dB. You can see the corrections at the cursor for 6k3 Hz of -4.0 and -5.5 dB, respectively.
    Quote Originally Posted by B&KMan
    mmmmm titanium sound sweet ???
    good news....
    No, no. LE85 is vintage aluminum. See the title of the post. LE85 = 2420.
    Quote Originally Posted by B&KMan
    but diaphrams it is completely news or reclycling used ???
    Diaphragms are original. The red wax seals are intact on these.
    Quote Originally Posted by B&KMan
    it is possible to explain little bit more what is ultra curve pro works ???
    Behringer UltraCurve Pro 24/96, an inexpensive (>$300) combination RTA and digital equalizer, including an "Auto-equalization" function which will listen to the speakers and adjust the 1/3 octave equalization bands to make them play whatever response curve is specified.

    UltraCurve is often ridiculed by the pros as a cheap knock-off of better tecnology, but there's a furtive underground cult here using them routinely.

    Me, I use it for research....

  4. #184
    RIP 2011 Zilch's Avatar
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    Up from the dungeon, 4507 "Utility" enclosures come with 2226H installed as 4647A. With 1" thick MDF front baffle and cross-braced with 2x4's (see pic), they're about the same size as L200, but with more internal volume (5 cuft.) as the front baffle is only recessed 1/2" and not sloped.

    Closing two of the four 2-7/8" dia. X 6-1/4" ports in each will retune them from 40 Hz to 28 Hz. Closing just one in each will bring them to 4430 standard 34 Hz tuning. They'll be getting 2235H's installed, and maybe PT waveguides or 2342's cut in (inverted). 2344A's won't fit in the baffle; there's only 11-1/4" below the woofer cutout there. Everest horns are merely for "illustration."

    Ref: http://audioheritage.org/vbulletin/s...ead.php?t=7480

    Compare to the current version Citation 7.4-based Mini-Everests, middle.

    [Dwarfdom. ]

    Available unassisted 2235H bass tuning options, bottom. Two ports open = blue, three open = red, and four open = black. There's unexploited versatility in these humble boxes....
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  5. #185
    Senior Member DavidF's Avatar
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    Zilch, there is an old Laurel & Hardy short film where the boys go to sea to get Hardy away from the job. It seems the ole boy goes into a rage whenever he hears a horn. A condition prompted by his constant immersion in sound at his job in a horn factory. Hmmm...

    DavidF

  6. #186
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by DavidF
    Zilch, there is an old Laurel & Hardy short film where...


  7. #187
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    Re: Laurel & Hardy

    You can see that the Everest horns are a "challenge."

    From the results with H2600/H3100, tho, I'm now committed to giving them a good listen with proper EQ.

    Cudos to the Everest builders here. I ain't up to the task.

    [Maybe out in the yard.... ]

  8. #188
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    O.K., O.K., "Lowboys," then.

    I am nothing if not determined to play these beasts....

    Dollys aren't good for bass response, but they let me finesse the orientation easily.

    $38 at Grainger....
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  9. #189
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    Some interesting additional information regarding Everest/Mini-Everest/S2600/S3100 appears over in the "Test Ride" thread, beginning here:

    http://audioheritage.org/vbulletin/s...page=2&p=70936

  10. #190
    RIP 2011 Zilch's Avatar
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    Old and new:

    Newly acquired 2420 pair ($200) with tangential surround aluminum diaphragms on 2344A horns play nicely with LE14H-3 in Citation 7.4 boxes, DIY NL200t3-16 crossovers.

    Clean, clear, crisp, more keepers here!

    [Infredible made me do it.... ]
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  11. #191
    RIP 2011 Zilch's Avatar
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    For those unfamiliar, here's what 4430's are all about, technically speaking, that is:

    http://audioheritage.org/vbulletin/s...ead.php?t=7551

  12. #192
    Senior Member Uncle Paul's Avatar
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    Help Please, Mr. Wizard

    Can anybody explain the LF section of the NL200t3? It looks suspiciously like a second order Butterworth... but the 20 uF cap and 3 mF inductor would give an Fc closer to 600 Hz than 1200 Hz.
    "Zobel is as zobel does"

  13. #193
    RIP 2011 Zilch's Avatar
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    Yup.

    http://audioheritage.org/vbulletin/s...858&#post49858

    They intersect at about 1.1kHz.

    LF gotta be rolled off lower 'cause the HF is one pole and is playing lower.

    Gotta read the driver AND the horn response to see what's happening there.

    See HF RTA curves two posts above that one.

    Also: http://audioheritage.org/vbulletin/s...age=24&p=49973

    That'd be MY guess....

  14. #194
    Senior Member Uncle Paul's Avatar
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    Ahhhhh!

    Thanks, that was driving me crazy, as well as the apparant Fc of the high pass section at 12000 Hz, too. One half as much, the other ten times the other way. The graph helps.
    "Zobel is as zobel does"

  15. #195
    Senior Member DavidF's Avatar
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    Quote Originally Posted by Uncle Paul
    Can anybody explain the LF section of the NL200t3? It looks suspiciously like a second order Butterworth... but the 20 uF cap and 3 mF inductor would give an Fc closer to 600 Hz than 1200 Hz.
    Can’t say for sure that this is the specific answer here, but you can tune the components for a desired effect. You could use a higher value inductor to start a roll off at some frequency below the desired xover point. The roll off combined with rising woofer response and/or impedance will net a shallower roll off than expected in a first order xover. The intent here may be to compensate for the diffracting effect of woofers response going down from about 1,000 cycles. This would be needed if the systems are expected to be used away from walls, etc. Then use a value of the shunt cap to effect the “knee” of the xover roll off. Helps here if there is some natural roll off in the woofer near by to complete the effect.



    Looks like the high end is similar but in a different direction. The typical response of the horn approximates flat up to a certain point then droops at some frequency up to where it falls off sharply. Since you want the horn in a 2-way to cover the high treble regions flat (or better with some slight fall off) you can use the efficiency in the midrange band to your advantage. The low value cap on the high xover will pass frequencies over a higher than expected frequency. Say you target 15,000 cycles where everything above is passed, everything below is attenuated. Now the electrical effect of the cap is attenuating the response as it falls below somewhat above 15,000 cycles and, according to design, this falling electrical response will negate the rising acoustic response as you move down in frequency. The result will be a flatter response from the mids through the highs. The shunt coil with its high resistance value is probably used to tame a resonance in the low end response of the horn/driver. The natural tweeter's low end roll on is used to compliment the woofers high end roll off to complete the expected xover point somewhere around 1,100 cycles.


    Simple and effective, probably not advisable for high volume applications to protect the horn driver and keep distortion levels down.

    Suggested reading. Could be helpful in thinking through the xover design process where its not all textbook results.

    http://www.pispeakers.com/Speaker_Crossover.doc


    David F

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