Z19 Crossover

LE85 is three-bolt and 16 Ohms. Put 8-Ohm diaphragms in them and solve the mounting issue, then, maybe, but at that point, I'd also be trying 4430 crossover clones.

It's 4430 with 152i waveguides in lieu of butt cheeks you're suggesting; a worthy endeavor....
 
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Zilch, you should run some impedance plots for that driver on both the 511a and the QSC W-guide .

I'm thinking the QSC plot will look something like the 3rd pic I've shown .

What's needed is an impedance equalizer to flatten those peaks below 3K .

JBL network design would dictate that one should add either a 20 to 30 ohm load resistor across the driver /or / add a coil with a DCR of @ 7.5 ohms ( mH value chosen to be effective below 2K ) .

The addition of either solution should help this network become a bit more "Universal" in it's application .

<> cheers
 
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Thanks, Earl!

I'm only just now in a position to suss this out empirically.... :thmbsp:
 
Altec 414-8B, BMS 4552nd, QSC 152i, KDT, Z19

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Zilch said:
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Well, that settles it. DE250 is significantly flatter than the D220Ti on the 511. And top end extension isn't enough different to matter, at all...

I know which way the project I have here (reconing Altec 421s to 416s, with 511B flare, DE250 horn driver and Z19 crossover) is now going to go. Time to get approval and order some parts.

Regards,
Gordon.
 
Elated to see this in it's own thread, so much easier to find for future reference.

Many many thanks to you Zilch!:thmbsp:
 
Thanks for the link education Kelly- I needed that!!

You can build the revised "Z" network on the same chasis as the old network-AFTER you strip it clean! I went with all ERSE company components as PE did not have everything at that time, but may have now. The ERSE component are very nice and everything tested perfect to spec.- but was a bit more $$$. I think I re-built both networks for close to $125, that was with new L-Pads as well. Clean up and reused your old L-Pads and save some.

The vesatility of this network is well worth the time to rebuild them. The old networks would tend to saturate, not so with the inductor upgrades here. The spec caps certainly improve the clairty and smoothness of tyhe 811's high end, lastly the flexability of dual compensation if a LARFE plus- despite adding the complexity and expense. These networks are a perfect fit for Radian drivers and QSC lens. When I finally get the networks working in an active amplification split then I will report on that effort. In the meantime- while you purchace these components to build them also include 4 post strap binding terminal cup so you can allow for and easily experience multi amplification. The network is easliy modified so when you pull the terminal straps then you can esily bi-amp to your hearts content. Great flexability and a new dimention in sound- especially if you drop in a tube amp for the upper end here.
DC
 
I am curious Zilch- do you think this network would be another good one to consider for the Econowave build ups- especially the higher model of the E-Wave, or would you only consider it as a direct replacement for the OEM 19's?
DC
 
I'm still analyzing how it works, and within what limits here. Any new driver/waveguide combination I've wanted to try, I've grabbed a vintage Model 19 XO to do that first and dial in listenable HF comp. This has a wider range of adjustability, so I'll be retiring the M19s for that use.

I'm just now finishing a PCD-designed passive XO for the Altec 414-8B/BMS 4552nd/152i combo with equivalent performance. Building custom this way, I can do somewhat better than Z19 with a lower parts count and cost, but for those who don't have the requisite tools to accomplish that, Z19 with a couple of tweaks would yield an excellent result.

I'll go on to check out how it works with Altec compression drivers and horns, but I suspect Z19 comprises a slam-dunk upgrade path for the many vintage Altecs that are so popular here on AK such as Valencias. There's more development work to do adapting Z19 to 16 Ohms for some of those, but that's in the plan, as well. As you mention, Z19's biampability is a major plus.... :thmbsp:
 
Zilch said:
I'm still analyzing how it works, and within what limits here. Any new driver/waveguide combination I've wanted to try, I've grabbed a vintage Model 19 XO to do that first and dial in listenable HF comp. This has a wider range of adjustability, so I'll be retiring the M19s for that use.

I'm just now finishing a PCD-designed passive XO for the Altec 414-8B/BMS 4552nd/152i combo with equivalent performance. Building custom this way, I can do somewhat better than Z19 with a lower parts count and cost, but for those who don't have the requisite tools to accomplish that, Z19 with a couple of tweaks would yield an excellent result.

I'll go on to check out how it works with Altec compression drivers and horns, but I suspect Z19 comprises a slam-dunk upgrade path for the many vintage Altecs that are so popular here on AK such as Valencias. There's more development work to do adapting Z19 to 16 Ohms for some of those, but that's in the plan, as well. As you mention, Z19's biampability is a major plus.... :thmbsp:
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Zilch,

I'm almost done with my JBL loaded Barzilays. I used your M19 crossover. Drivers are LE14H-3 and 2452H-SL. Hopefully we can get them measured soon.

BHamm
 
I put one of the Barzilays together today to find out how it sounds. The cabinet and driver need to be sealed and stuffing put back inside. Initial impressions are it sounds balanced. More upper end detail, but I'm used to my JBL 4430s which roll off around 16kHz. Lots more listening to do. Why can't my crossovers look like Zilch's:no:
 

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Altec 802 - 511

Altec 802-8g / finless 511 horn combo:

802 - 40.png

802 - 40 separated.png

& connected to the Z19, with an 8r dummy load on the LF:

802 net - 40.png

802 net - 40 separated.png
 
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sba2 said:
I recently measured an Altec 802-8g / finless 511 horn combo using the Z19 crossover....
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Thank you for posting this data.

Please upload your images to the AudioKarma server via "Manage Attachments" in "Edit, Go Advanced" so that they will be permanent in this thread.

With respect to Z19's HF comp flattening the response, do you agree we get very much the same result?

We can clearly see 511 beaming the top octave dispersion; at -6dB, its a 60° horn at 10kHz, but somewhat less than 40° at 20 kHz....
 
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Excellent thread!
Zilch, what does the 4uF (C5) cap do for the HF? How is it calculated?
Thanks, Kyle.
 
I worked up a Z19 copy with a couple of part substitutions: 8.2 instead of 8.0 uF, 6.2 instead of 6.0 uF, and 0.80 instead of 0.77mH.

Working with the QSC 152i and DE250 combo I came up with these curves. HF was at max and the MF L-pad was at 12, 9, and 8 o'clock positions. Obviously not bad but the bump at 2 kHz doesn't want to go away. Based Zilch's advice, I attempted to rework the highpass in PCD by flattening out the filter response below 3 kHz. I have barely a clue what I am doing but it look like I'll try C2 = 12 uF and C3 = 6.2 and see what that does. Nothing magical about the values except I have the parts on hand.

Comments?

Zilch said:
In measuring these samples, my criterion was flat within +/- 2.5 dB. DE250/152i appears among the flattest responses across the widest SPL range (12 dB) with it, actually. The peak at 2 kHz suggests that the core 3rd-order highpass (C2, L2, C3) is somewhat underdamped with that combination, which could be easily resolved in PCD for a final design, if desired:
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kyle said:
Zilch, what does the 4uF (C5) cap do for the HF?

How is it calculated?
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I forget; sets a limit. It's been a while since I modeled it in SPICE.


donprice said:
I worked up a Z19 copy with a couple of part substitutions: 8.2 instead of 8.0 uF, 6.2 instead of 6.0 uF, and 0.80 instead of 0.77mH.

Comments?
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You're getting very much the same result as I do. The bottom two curves are quite listenable, depending upon whether it matches your woofer.

Reducing C4 in the bridge to 4uF attenuates the works, a better approach, probably, than adding another L-pad for use with low-sensitivity LF. I don't know the limits in either direction, tho. I've had limited opportunity to dig into it this week, and still have to finish the second one.... :rolleyes:
 
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