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Z19 Crossover

^^^

That's the way to do a setup like this. Simplify to the minimal variables, get those right first. Then, start adding the other elements back in, only at as much of a level as needed, and no more.

It's no surprise that it sounds a lot better! You did it right!

Regards,
Gordon.
 
Thanks, Gordon, much appreciated!

Your avatar always intrigues me: is that an E Wave horn in an 846B cabinet? Your cabinet looks almost exactly like mine, which has about seven coats of tung oil on it and a very similar grill cloth.
 
Seeburg DDS1 cabinets, with my own concoction in it. Dual JBL 15" (custom reconed JBL M115-8A PA woofers, done up to my own specs) in 2.5-way mode, with a Selenium D210Ti on a Pyle PH714 horn, and a MB Quart MCD19E titanium dome supertweeter used only above 15KHz.

It was done before E-wave really "came of age" here... but there were some similarities. Other than some of the resistors in the E-wave highpass, the topology was very similar. I did the "CD EQ" thing a little differently (more relying on low-Q highpass, than 'gapping' the frequencies between lowpass and highpass like the Ewave does), but it's also basically a second-order highpass with a RC "shelf filter", like the Ewave basic topology. Instead of "full EQ" on the highest octave, I chose to add the supertweeter to handle where the horn started to roll off. Somewhat more complex than the Ewave in that sense, but still, not a whole lot of parts required...

Regards,
Gordon.
 
Zonker, I don't have any equipment other than my ears to tell me what sounds right to me.
The upper knob definately controls the HF and the lower one the midrange.
I just dialed it in to where it sounded best. I don't know any other way.
What is the proper way? My Altec 19's seem to be singing nicely but if there is a better way...
 
Cool, Gordon; thanks! Most of that is over my head, but I look forward to learning more about E-waves and related topics.

[EDIT: Ricoh was responding to my mistakenly mixing up LP1 (MF) and LP2 (VHF).]

Ricoh, iF you want to try what I did, albeit without a frequency generator:

Note where you have the knobs now, in case you want to go back.

If you have a sub, turn it off. Ditto any tone controls.

Turn both L pad control knobs to their lowest settings.

With some sort of well-balanced reference source playing (maybe a favorite well-produced recording?), adjust the MF knob until the woofer and horn sound well balanced at your listening position.

Then bring up the VHF knob to suit your preference. Finally, blend in the sub if you have one.

Anyway, just see what you think and report back here. At least for me, I know I had my knobs set way too high, which meant that the horn was shouting out the woofer and the treble was really cranked.
 
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I'm really confused.
I built them according to Zilchs board layout the l-pad with three wires definately controls the amount of treble coming out of the horn. And this is the l-pad I have on top. I don't want to swap its position as the HF should be on top, I think. And the l-pads are orientated vertically.
The lower l-pad with two wires seems to control midrange out of both the horn and the woofer, if that makes any sense.
Now I'm even more confused.:scratch2:
 
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I'm not even sure which one is L1? All I know is the l-pad with three wires definately adjusts the amount treble, the other add volume and midrange. But your right about these controls having any big effect on the woofer of my Altec 19.
So what did I do?
I put on Steely Dan greatest hits, sat down and had a listen. Sounds good to me!
 
Steely Dan = audio goodness. So what, you're going to trust your own ears? :D On the schematic, L1 is the one on the left, marked LP1 (L-pad 1).

All I know is, whichever control does whatever, my speakers sound a hundred times better with them now turned most of the way down, and the bass is much more pronounced. How far up are yours set?
 
The mid is about 20% and the high is about 65%. Seems to sound very nice. My 19's may sound different than your speakers though.
 
Yes, and different rooms have different effects, too.

I found a lot more on the original Model 19 crossover settings, which translates to some degree to the Z19. (A relatively minor difference, though, is that the stock crossover has the compensation interacting with the woofer, whereas Zilch wired the Z19 to separate the two drivers electrically, so as to enable biamping.)

http://www.audioheritage.org/vbulletin/showthread.php?18913-Altec-9844-8B/page4

http://audioheritage.org/vbulletin/showthread.php?12305-Altec-Model-19s-gone-wrong...&p=128826

http://audioheritage.org/vbulletin/showthread.php?12305-Altec-Model-19s-gone-wrong...&p=128689

Here Zilch says: "LP1 is balance[d] with LF, then set LP2 for VHF level."
 
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In your first reference Zilch says, "L1 establishes the slope of the HF compensation, and L2 balances it with the woofer...."

In your second reference he says, "LP1 is balance with LF, then set LP2 for VHF level".

Those statements seem contradictory. I believe the first one is the more correct explanation and it bears out in the frequency resonse graphs you posted. The two controls are intertwined but LP2 would more be considered the mid control and L1 the high control.
 
Oops. You're right; they are contradictory. I was copying and pasting without reading. I'm glad someone is paying attention. Those graphs I posted didn't say which one did what; I was just guessing. [EDIT: I was confusing LP1 (MF) and LP2 (VHF).]
 
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OK, now I'm trying to listen without preconceptions, and I'm thinking Ricoh's right. It sounds to me like LP2 (three wires; right-hand on the schematic) is VHF and LP1 (two wires, on the left) is MF, which is what I thought back when I built these things. Oops. (I need to figure out a better way to mike my iPhone, and start listening a little more carefully. :tongue: It doesn't help that my hearing stops at about 14KHz. I went back and annotated my posts above to clear this up a tiny bit.)

With that in mind, I wound up with my controls set similar to Ricoh's, subject to more fooling around later. Sounds like the best plan is still to set them both to 0, then bring MF up so it's balanced with the woofer, then adjust the VHF to preference.
 
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Starting to make sense now. I thought the references on your frequency plots were direct from Zilch. LP1 is a T-filter and was used by Altec as essentially a mid level control. It's very similar to what ZIlch used for the econowave compensation filter only with a fixed resistor instead of the lpad. LP2 then controls the highest frequencies.

I now change my vote to agree with Ricoh.
 
Hey, what does Ricoh know? All he did was actually listen to them!

If no one minds (or even if they do), I'm going to go back and clean up my last four or five posts (mixing up the MF and VHF controls) lest someone (1) believes my idiocy; or (2) figures out how stupid I was. I hope that doesn't make Ricoh's responsive posts nonsensical, but I'll figure out a way to clarify that issue.

Thanks, Doc, for helping me figure this out! And Ricoh, for the reality check!
 
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Dr. Beaker said:
In your first reference Zilch says, "L1 establishes the slope of the HF compensation, and L2 balances it with the woofer...."

In your second reference he says, "LP1 is balance with LF, then set LP2 for VHF level".

Those statements seem contradictory.
Click to expand...

After thinking about it some more, the two Zilch statements are confusing but not really contradictory. LP1 is the mid control and it does change the overall slope of the HF horn response be flatening the lower half (or mid) of the HF horn response. That slope change is used to match up to the woofer response in the mid frequency range. LP2 then tweaks the highest frequencies to match the woofer and mid level output.

LP1= Mid Control

LP2= High Control
 
OK; I guess I can see that. So Zilch is using the term "HF" to refer to the entire horn curve, rather than just the VHF part of it. That corresponds to the schematic's designation, so now that makes sense to me. (Before, I thought that by HF he meant VHF.)

So I guess the best approach is still adjusting first LP1 (MF) and then LP2 (VHF). Thanks again!

PS: I was racking my brain to figure out how I originally (and correctly) figured out that LP1 was the MF and LP2 was the VHF control, a month back when I built my Z19s. These pictures from Zilch reveal why. They're clearly labeled Mid and High! No wonder! :sigh:

attachment.php

Z1920Board20Layout1.jpg
 
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I am very glad I came back to this thread as the more I thought about it the more I wanted to pull an xo and have another look at how I assembled it. But it turns out that all is good.
L-Pad 2 (three wires) is HF.
And I think I may buy a mic as my son has volunteered to set it up on his laptop. But I need to do a lot more reading before I can actually determine what the measurements mean.
But more tinkering will lead to more knowledge and I think thats what this is all about anyways. That and enjoying the music.

And I think we should somehow mark the updated board layout as the correct one. A newbie like myself would build the layout in the post above and find that the new Z19 does not work or worse....
 
Good idea. To that end I just swapped my link above, to the corrected image. And I'm really sorry I was so stupid mixing up the L pads and confusing you.

I just ordered an adapter so I can use a high-quality mic on my iPhone. I plan to use my wife's iPhone with a frequency generator app to send a few test tones through the speakers (some in the woofer's band and some in the horn's) and use my iPhone dB meter app and with the L pads try to get the horn and the woofer at about the same output with the MF L pad, then flatten the horn's VHF as much as possible.

Once I've done that I may put little marks on the L pad cover plate as reference markers, then adjust them to suit my pleasure.

http://www.kvconnection.com/product-p/km-iphone-mic.htm

http://itunes.apple.com/us/app/ifrequency/id309563072?mt=8

http://itunes.apple.com/us/app/audio-kit/id376965050?mt=8

http://itunes.apple.com/us/app/decibel-meter/id289219810?mt=8
 
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