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rplace

Basic KHorn XO Question

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My 87 Khorns came with AK2 crossovers. They are clearly labeled with "Audio Input" and "To High Frequency Cabinet". When I had some Super AA XOs built for me I was told more or less to remove the "stuff" inside the bass bin, replace the AK2 up top with the new crossover and connect the main input to the bass bin and run the wires from the To HF Cabinet to the XO. All well and good. Things have been humming along ever since.

 

Now I am working on a two way set up with an active crossover in my future and bypassing the passive XOs all together. I get the basics that in that configuration I'll set the active DSP setting so only send lows to the bass bin and mids/high to the big horn up top (for argument sake lets say it ends up with 20-350 to the bass bin and 300-20K to the horn's driver). What I am now unclear about is what has been happening with my bass bin all these years with the AA passive? I'm assuming in the AK2 days that stuff in the bass bin filtered out the HF signal going to the woofer, correct?

 

It would seem to me that with nothing in the bass bin of the khorn it has been getting a full range 20Hz-20KHz signal all this time and only the squawker and tweeter has had any filtering from the passive XO. If that is correct why would you not want to make it so the bass bin only sees the appropriate low end signal, not everything?

 

What am I fundamentally not understanding on the swap between AK2 and AA passive crossovers?

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34 minutes ago, rplace said:

 

 

It would seem to me that with nothing in the bass bin of the khorn it has been getting a full range 20Hz-20KHz signal all this time and only the squawker and tweeter has had any filtering from the passive XO. 

 

What am I fundamentally not understanding on the swap between AK2 and AA passive crossovers?

 

Why would you come to this conclusion?

 

 

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1 minute ago, Schu said:

 

Why would you come to this conclusion?

 

 

 

Because in my mind there is nothing between the signal from the amp to the woofer in the bass bin. I can see, or at least think I do, that the signal up to the HF section has to go through all the XO bits prior to Mid driver and tweeter driver.

 

In my mind bass bin is Pre>>AMP>>driver while Mids/Highs are Pre>>AMP>>XO>>Drivers

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8 minutes ago, baron167 said:

Does this help?

AK-2

 

No, not really. Curvy lines and funny arrows are beyond my layman's grasp. I get on the surface that capacitors/transistors/coils of wire/etc. filter out unwanted ranges of signals prior to the driver seeing them. I also believe they can lower or attenuate the signal as a whole.

 

When I had the AK2 it would seem that stuff in the bass bin I removed did that. I can't envision in my Super AAs how anything is removed from what the woofer sees. Isn't the stuff inside the dotted lines gone with my current configuration?

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Maybe post some pics of current configuration (if it's all still together).
But, why do you care about what's happening (now) with the bass bins?
You're moving to active crossovers, correct?


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1 minute ago, baron167 said:

But, why do you care about what's happening (now) with the bass bins?
You're moving to active crossovers, correct?

 

I like understanding what I am doing not just doing it because I'm supposed to. As I've been digging into the active thing I think I got a better understanding of how a speaker works. The Active (or passive) is like a traffic cop letting things go where they are needed. That got me to think about my AK2 to AA swap. There is no cop on the beat for the woofer. Isn't it a free for all?

 

I'll get some pix of the top of the Khorn, but I think it would be like any other AA set up. Wires from the amp to the bottom, jumper wire to the top and passive crossover, wires in crossover to each driver in the HF section.

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OK, but to clarify, you are currently running Super AA's, correct?

This Should help and yes, it requires some reading comprehension 🙂 If you really wanna know, let this sink into your grey matter lol.

From Al, himself:

 

Mike,

The reason the high filters are tied to the 40 uF and not the input is very simple and very fundamental. My networks are two completely seperate "diplexers" tied one to the next. The 40 uf and 2.4 mHy forms the woofer / squawker cross and the rest of the network is the squawker / tweeter cross. This is true for the "Super AA" and all my network designs. To move the high crossver input to the common input completely louses up the low crossover! The is the main thing Klipsch gets wrong on ther networks. You can NEVER connect two similar type filters together and get a flat impedance. It can be done using two singly terminated filters of the same type but the impedance will ALWAYS be the parallel combination of the termination impedances over the common frequency range of the filters and will change as you go out of the range of one of them assuming the have different cutoff frequencies. BTW: It's my opinion that "group delay" is a red herring and makes no difference to anyhting. It's just a way of quantifying phase linearlty. Propogation delay, on the other had, is a major concern. May people confuse the two.

Here's a graphic that may help explain the idea of 2-port "diplexers" tied together to make a 3-mort "multiplexer":

block.gif

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Oh, and @rplace, if you want to sell the Super AA's, please let me know, thanks! 😎

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15 minutes ago, baron167 said:

OK, but to clarify, you are currently running Super AA's, correct?

 

I believe so. They did not come from Al, Dean built them. Perhaps I got the name wrong. Thinking they had a few names. Super AA, ALK Jr., etc. At any rate I can't see how anything modifies what the woofer in the bass bin gets. Surely I'm missing a key concept. The real reason I'm asking is because it got me to thinking if by chance I was right about this then why would I need to do anything with the future active crossover with respect to the low end? Seems like the XO could give a full signal to the bass bin's amp. And that just seemed to not makes sense at all - based on what I thought I had figured out. If the 2-way active is a winner I'll keep you in mind for the passives. We are close to each other.

 

Not the greatest pix my room is very dark. To be clear I opened up the access door in the first picture and removed some things. One being a very large capacitor (I think). Its been a wile so my memory could be wrong but I don't think there is anything inside that bottom cabinet besides the woofer and wires going form the bottom jacks to the top jacks.

 

AAFromAmp.thumb.jpg.e29b8b44057fa39fec8f9a719fc9d4ef.jpg

 

 

AAXO.thumb.jpg.383fd1ec72e046202a065e09e1e07f8f.jpg

 

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I believe so. They did not come from Al, Dean built them. Perhaps I got the name wrong. Thinking they had a few names. Super AA, ALK Jr., etc. At any rate I can't see how anything modifies what the woofer in the bass bin gets. Surely I'm missing a key concept. The real reason I'm asking is because it got me to thinking if by chance I was right about this then why would I need to do anything with the future active crossover with respect to the low end? Seems like the XO could give a full signal to the bass bin's amp. And that just seemed to not makes sense at all - based on what I thought I had figured out. If the 2-way active is a winner I'll keep you in mind for the passives. We are close to each other.
 
Not the greatest pix my room is very dark. To be clear I opened up the access door in the first picture and removed some things. One being a very large capacitor (I think). Its been a wile so my memory could be wrong but I don't think there is anything inside that bottom cabinet besides the woofer and wires going form the bottom jacks to the top jacks.
 
AAFromAmp.thumb.jpg.e29b8b44057fa39fec8f9a719fc9d4ef.jpg
 
 
AAXO.thumb.jpg.383fd1ec72e046202a065e09e1e07f8f.jpg
 


Thanks!

This is Interesting! I'd like to see what is behind that input panel.



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Maybe @Deang will be able to input something here.  Then again, maybe not.

 

If you removed the door and removed "some things" and it being large....I would think that was an inductor/coil/autoformer, etc., of some sort but I don't know Khorn crossovers.  Caps don't generally go on woofers by themselves as they are a high pass filter.

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I have the exact same question with my La Scala splits..........I have not looked behind the cable inputs on the bass bins....but the xo is in the top section.  So what is filtering the signal to the bass bin?

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3 minutes ago, avguytx said:

Maybe @Deang will be able to input something here.  Then again, maybe not.

 

If you removed the door and removed "some things" and it being large....I would think that was an inductor/coil/autoformer, etc., of some sort but I don't know Khorn crossovers.  Caps don't generally go on woofers by themselves as they are a high pass filter.

 

I totally could be wrong about what was removed. It was a while ago. How about a more general question. For those of you with AA networks how are they hooked up? Do you have your wires from the amp to the crossover then three sets out to Low/Mid/Highs?

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Yep.  That's exactly how they're hooked up and designed to be.

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1 hour ago, rplace said:

 

Because in my mind there is nothing between the signal from the amp to the woofer in the bass bin. I can see, or at least think I do, that the signal up to the HF section has to go through all the XO bits prior to Mid driver and tweeter driver.

 

In my mind bass bin is Pre>>AMP>>driver while Mids/Highs are Pre>>AMP>>XO>>Drivers

 

Also, in this scenario of no inductor on the woofer.....this was quite common to let the woofer "roll out" on its own natural mechanical roll off plus them being in a folded horn also was an "order" in the network and factored in.  Many companies did this.

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There should have been a 4mh inductor and two 70uf capacitors in the bass bin.  If you removed them, and have only wire between the input and the woofer driver, than yes the woofer is receiving all frequencies.  

 

 

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I hardly ever throw anything away. This is what was removed from mine when I swapped them out. "Things"  to the right of each were in the bass bin

 

IMG_20180717_120330.thumb.jpg.fc6489793944281c296b39c7846cdfbf.jpg

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