Page 15 of 30 FirstFirst ... 5131415161725 ... LastLast
Results 211 to 225 of 450

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

  1. #211
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by Robh3606
    What can you do on the 2496??
    U/C 2496 is 0.5 dB per tic. RTA display resolution is variable. I'm showing 5 dB per major division (the dotted horizontal lines) above. Full scale, then is 30 dB.

    Choices are 15, 30, 60, and 90 dB FS. You also set the max shown (the top line), which is adjustable from 0 to -60 dB in 5 dB increments. It'll display somebody a block away flushin' their toilet, if desired.

    Didn't take a pic of the EQ curve (DUH!). After dark tonight, then.

    Earl: 1 kHz wavelength is 13.56", a do-able deal in L200 box, probably. We certainly don't want upward tilt, as the baffle board is already angled up....

  2. #212
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by Robh3606
    What does the EQ curve look like??
    Well, there's a dilemma. I know for a fact that small movements of the mic when both channels are playing pink noise move stuff all around on the RTA, likely due to phase cancellations. So, the question is, "Can you get an accurate auto EQ doing both channels at once?" Seems it would only be valid for the mike position.

    U/C has a "Dual Mono" mode that lets you save separate EQ curves for left and right at the same time, after running them separately. Cool. I try it. Stupidly, it plays pink noise outta BOTH channels while doing auto EQ on each. Fine, so I shut down the right channel while doing the left, and vice-versa, aiming the mike at the active channel. Results below, along with the curve from doing both channels concurrently. Very little difference. DUH! How do it KNOW? It's smarter than your ordinary Zilchster, apparently.

    Bear in mind that these are corrections the U/C makes with 5235 and N3134 crossovers (all boosts at max) in the path, NOT corrections for the raw 2431H drivers.

    Finally, reassurance for the mighty Giskard, his 2235H's now safely ensconced behind the glue-blobbed vintage L200 grille screens. Apparently, there's no dust where he lives; these look like fresh recones.

    Installing them, I discovered there's NO bracing on the back of the front baffle (one rattle fixed with Gorilla Glue outta a hypodermic), largely due to port locations there. Gonna have to transverse triangular brace to the rear corners, probably, like yggrdrasil did here, once I'm finally done "messin'" with 'em. Don't think I'd put Sub1500's in these boxes.

    [Sound purty good as B380 equivalent subs, tho....]
    Attached Images Attached Images     

  3. #213
    Obsolete
    Join Date
    Apr 2003
    Location
    NLA
    Posts
    12,193
    Quote Originally Posted by Zilch
    Apparently, there's no dust where he lives; these look like fresh recones.
    They've never been reconed. Those are factory originals. I did blow them off with compressed air though. The boxes I shipped them in are the recone kit boxes for Mike's 2235H's he just bought from a guy in Michigan who claims his 4430's were from a very famous former JBL engineer.

  4. #214
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963

    GOODO, Guido!

    AM6212/00 crossover topology recognized by forum member Guido nearly a year ago as potential 4430 enhancement drives 2431H on PT waveguides. Two units on pink noise at ~1M shown on RTA in averaged mode, I suspected one was "hotter" than the other, but I don't know yet if it's the horn or the driver.

    Scale is 2.5 dB per dotted line. They shouldn't let us have measurement devices like DEQ2496, probably. Too easy to see what's goin' on with stuff, like manufacturing variability and defective units.

    How much of this is room response? How do I get more "anechoic," move up to like 6"?

    I think I know what I'm doin' next -- another one of these....
    Attached Images Attached Images     

  5. #215
    Senior Member Guido's Avatar
    Join Date
    Apr 2003
    Location
    Germany
    Posts
    2,503
    Quote Originally Posted by Zilch
    AM6212/00 crossover topology recognized by forum member Guido nearly a year ago as potential 4430 enhancement drive 2431H on PT waveguides.
    I just couldn't try it without the horns

    Today I got again bad news. JBL cancelled all orders for the 12x12 waveguides! Reason is their fear from copys. That's so stupid. All the far east copy cats will by an AM Speaker and then they will have the horns anyway

    Zilch, looks like you need to penetrate them for 2 more horns

  6. #216
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by Guido
    JBL cancelled all orders for the 12x12 waveguides! Reason is their fear from copys.
    That's TOO silly to be true. It's not as if they haven't had the same potential (and real) problem with all of their designs.

    They're big boys, and know how to protect technology. Locking everybody out will GUARANTEE they'll be replicated.

    I'll try to order up a couple more here....

  7. #217
    Senior Member Guido's Avatar
    Join Date
    Apr 2003
    Location
    Germany
    Posts
    2,503
    Quote Originally Posted by Zilch
    I'll try to order up a couple more here....


    We should spam them with orders

  8. #218
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by Guido
    We should spam them with orders
    Now, Guido, let's not overreact.

    We don't even KNOW if they're worth a damn yet.

  9. #219
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    5,109

    Horn to Woofer Spacing

    Hi Zilch

    Back to your question ; re 2235 to horn distance .

    - Once I started working with 24db/octave LR electronic filter slopes I had to move horns ( in boxes ) as close as phsically possible ( within 1/2" sometimes ) to the woofers edge. I find this gives the best cohesion for the highish points that I use ( @1200 hz ).

    - BTW , I don't think its' the center to center distance that's so important with a horn /woofer combo , as much as the marrying of the two polar plots.
    A horns coverage angles are determined by its' 6db down points ( for most frequencies wthin the midband ) while a woofers' polar patterns' 6 db down point shifts upwards with with frequency. ( This is definately a "What Ian said" sort of comment . )

    Center to Center :
    - Out of interest you might want to explore the reasons for the distance spreads found in the 4343/44/45 series of boxes between the woofers and the ten inchers. Then relate them back to the actual filters being used in each box type .

    - I'm still not sure what to suggest you do with your L200 boxes. ( I've always liked two box systems )
    - I guess that question has a lot to do with your recent explorations , correct ?


  10. #220
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by Earl K
    - I guess that question has a lot to do with your recent explorations , correct?
    Yup, trying to figure out the parameters here, particularly for the L200 modification. It's pretty clear to my ear (and the RTA) here that the 1.5" drivers on PT waveguides are a significant step up. We've got more testing to do before the decisions are made, though.

    From what I've been able to figure so far, as long as the combination behaves as a coherent source (alleged virtue of 4430 is that beamwidth of woofer and horn are the same at the crossover frequency), a wider spacing reduces time alignment issues. The closer the drivers are, the more coincidence (equal path lengths) is "aimed" by time alignment. That hasn't led me to any conclusions yet, but it tells me what to try using the RTA. Frequency nulls and how they move are plainly visible.

    Quote Originally Posted by Guido
    I just couldn't try it without the horns
    Again, try it on your P-Audio horns. You will NOT be disappointed. Trust the Zilchster on this now. That's what's playing here, just to confirm it for you. We're gonna have to tweak the HF crossover point down a little (to 1 kHz, maybe, if 2431H will play that). There's a notch at 1 kHz, 'cause 2235 won't work up to 1.2 kHz very well (max recommended crossover frequency 1 kHz).

    I'm playing 2235's with no crossover to let them go as high as they will. Maybe if I put the 4430's Zobel back in the LF, they'd play a little better above 1 kHz and fill the notch. It's not a difference I can hear, but it's visible on the RTA. I'm reluctant to EQ it out, as 2235 would be boosted in its "bad" area. Also, AM6212 crossover will prevent any EQ at that frequency going to the 2431H's, probably, but you're more familiar with that part from your earlier work with it. Any suggestions? Like you, I'd like to make the straight passive work without additional EQ. This is gettin' VERY close....

  11. #221
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963

    System G:

    Mating Giskard's 2235H's in retuned L200 cabinets with 2431H's running on 12" square PT Waveguides and HF section of AM6212/00 crossover (5 components). 2235's are running full range, biamped. "Presence" is adjusted simply by the relative attenuation of HF vs. LF amps. Run totally passive, a single L-Pad would do it, like in the "olden" two-way days.

    The best-sounding system assembled thus far (including full-blown 4430 emulation), I ran them most of today with 2435H's (Be diaphragms); they also work fine with this crossover topology, according to RTA.

    Both driver types (Al & Be) apparently incorporate new two-stage phase plug and dome design, which shifts rolloff up to 7 kHz rather than ~3 kHz of earlier drivers. Less compensating EQ boost is required with these, and HF distortion is allegedly therefore lower. 4430 pushed 2425H harder in boosting the HF.

    More info here @ Fig. 29, 30, & 40, also text description of 2435 at #7:

    http://www.jblpro.com/vertec1/doug%2...%20rev%20c.pdf

    Yes, I can hear the difference, but wait for measurements to confirm this. The tradeoff seems to be LF response. I doubt these would play down to 500 Hz, though Giskard asserted earlier here that, with a larger back cup, they'll do 800 Hz very nicely....
    Attached Images Attached Images  

  12. #222
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Four-bolt 1-1/2" PT Waveguides may be mounted via JBL thread-on throat adapter to varous 1" drivers such as LE85 (with thread adapter, left), 2418H-1 (right), and exposed "snoot" of 2426 or 2427 (rear).

    A two-piece assembly, as TimG observed, adapter incorporates engineered compound race-track oval throat constriction similar to that in the waveguides themselves, and alignment studs to establish the requisite orientation. With waveguide mounted, there are double constrictions, yes.

    Note safety gear in top photo.
    Attached Images Attached Images    

  13. #223
    Senior Member Guido's Avatar
    Join Date
    Apr 2003
    Location
    Germany
    Posts
    2,503
    Quote Originally Posted by Zilch
    Four-bolt 1-1/2" PT Waveguides may be mounted via JBL thread-on throat adapter to varous 1" drivers
    What is the part number please?

  14. #224
    Senior Member Guido's Avatar
    Join Date
    Apr 2003
    Location
    Germany
    Posts
    2,503
    Quote Originally Posted by Zilch
    I'm playing 2235's with no crossover to let them go as high as they will. Maybe if I put the 4430's Zobel back in the LF, they'd play a little better above 1 kHz and fill the notch. It's not a difference I can hear, but it's visible on the RTA. I'm reluctant to EQ it out, as 2235 would be boosted in its "bad" area. Also, AM6212 crossover will prevent any EQ at that frequency going to the 2431H's, probably, but you're more familiar with that part from your earlier work with it. Any suggestions? Like you, I'd like to make the straight passive work without additional EQ. This is gettin' VERY close....
    We should wait for widgets mighty measures


    Basically I would go with the 4430/4435 crossover but modify the HF part such as the boost around 7kHz is lower. See my voltage drive curves. I'll try to figure this out tonight with my spice program. Will post the results when you having lunch
    Could you please post (again) a detailed RTA with the 4430 crossover and 2235 and 2431+Waveguide without ANY correction of this digital doohickey?

    We should take into consideration the 4435 too as this is my next project

    BTW:
    I need 4 such adaptors (mentioned earlier here):

    http://store.steelsound.com/Detail.bok?no=428

    They are not available here in Germany. I mailed them but no response. Seems the order is too small for them.
    The P-Audio PC25 does not work as it adds 2cm in length!

    Who can help? I pay with paypal instantly.

    Zilch, maybe you can ship them together with the Waveguides if you'll get them?

  15. #225
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    5,109
    Guido

    - It looks to me that Steel Sound is still in the process of building that web-page. I'm sure you can get some help on a purchase like that .

    - That's a different page from the one found at my last visit ( January maybe ).

    - I'd just give it a bit more time and try buying from them again .

    - Did you try to purchase through the automated "shopping cart" ?

    - Or did you just send an email ?

    - ( I also think you should buy some of these small round/square horns - just because they're cheap - $ 7.00 ?? )


    BTW Zilch,, great thread !
    Attached Images Attached Images   

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •