Bob, Al, Dean, Others - need crossover info

[rplace]

I need a crossover education. I have 87 Khorns with AK-2 crossovers. While I am not unhappy with them I think they could be better. In my opinion they are a tad lacking in bass and the highs/mids, over longer listening times, tend to be a little harsh. Dont get me wrong they sound really goodbut I think they can sound great.

In searching I have read that the AK-2s can easily be converted to AK-3s. I also have come to understand that crossovers have a life of approximately 20 years. Mine are rapidly approaching that mark.

I have also read that if going to the latest AK-4 you need to upgrade drivers as well. This I am not interested in at the moment.

I read a lot of good things about freshening up As or AAs just to bring them back to factory specs. I also read a lot of good things about Al Ks universal A network.

It was my understanding that the A and AA network were a lot alike with the AA providing some additional protection at perhaps some sonic loss. Is this true?

Where do the AK, AK-2 and AK-3 crossovers fit in here? Do I have the option of putting original (old) A/AA or newly built A/AA clones by Bob or others in my AK-2 equipped speakers? Or would this be wrong in the sense that the AK series of drivers were so designed to work only with some flavor of AK crossover?

If I need to stick with an AK variant am I best to go with AK-3s that are totally reworked and made like new?

If I am able to use any crossover (A, AA, ALK, etc.) what do you all think is the best bet for my particular situation? Money might be an issuebut second to the fact that I am looking for gains in the sound department.

BTW, My 87 Khorns are doing double duty. Mains in my 7.1 HT set up driven by Sunfire Pre/Pro and a Carver TFM-25 amp. For 2 channel they will be driven by a NOS Valves reworked Scott 222C.

[Frzninvt]

My '88's have AK-2's that I upgraded to AK-3 functionality and they sound good to me. The changes to make the AK-2 to an AK-3 will fix a couple of the problems you noted.

Changing from 140uf (70uf X 2) to 100uf will tighten and improve the bass response, I left the 4mh iron core inductor alone.

Changing the T5A to the T4A will bring the squawker up 2db.

Not sure what changing the 4mh to a 5mh in the midrange circuit does but mine smoothed out quite a bit by doing this.

I got the T4A's from Klipsch parts, and the 5mh air core coils and 100uf caps from Parts Express. I got a single Solen 100uf, however Dean said going with two 50uf's would have less loss.

You can use a Type A or AA, but you would have to do some rewiring since the AK-2 has no terminal block and everything is hardwired to the drivers.

I have thought about changing my updated AK-3's to DHAOxer's (John Albright's Type A design) but they sound good right now and I just don't think that it is really necessary. I even thought about putting a better quality 13uf in the midrange circuit but on Dean's advice didn't since he has had people change it out with a better cap but they noticed no improvement.

I have also thought about replacing the three 2uf caps in the tweeter circuit as that may yield some more improvement but the caps aren't cheap and I just have not felt the need to do so.

[rplace]

Thanks Frzn, I take it that you noticed a difference going from AK-2 to AK-3 and that you liked that difference? I would expect as the khorn evolved over the years that the changes were made for a reason. Hopefully that reason was better sound not cheaper to produce. My gut was telling me that AK-3s would be my best course over As or AAs. However, Ive read so much praise for reworked A/AA and new ALK xovers it got me wondering if the whole AK line of networks was perhaps a mistake in the mid 80s.

I appreciate the parts list. However, given that my free time is so miniscule lately and that I dont think much of my soldering skills I would prefer to buy a new set of networks if that is my best solution.

Do any crossover builders out there take in trade your old ones for new ones or are the old parts pretty much just thrown away? It would be nice to perform a swap like you do for brakes or starters on a car. You get the new one, pay a core charge then get that core charge back when you provide your old, tired crossovers for freshening up for the next guy in line? Probably not the case though.

I did notice that my AK-2s looked to be a bit more work then my Heresy E-2s to swap out. On the Heresy everything is an easy screw and lug to attach/detach. Not so on my khorns everything is soldered in place.

Can my current AK-2s be transformed into an AK-3 with A/AA type connectors so I could simply attach lugs to my current khorn wiring and bolt the new ones into place?

Keep the info coming...Thanks!

[Frzninvt]

Bob Crites has a new AK-3 network with GE Oil caps that you could sort of drop right in, you will have to put spade lugs on the snipped off Monster Cable leads when you sever them from the old network.

You will still have to remove the caps and coil inside the woofer bin door and resolder the leads so that they go directly to the woofer.

He is waiting for some folks to try them and see what they think at present. Sounds interesting to me!

[Deang]

Let's see, we have a massive iron core strapped across a driver covering almost four full octaves of the music, and a tweeter filter that rings and spits so bad that half the people that own them cut out the elliptic portion of the filter.

[rplace]

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On 6/9/2005 3:20:08 PM DeanG wrote:

Let's see, we have a massive iron core strapped across a driver covering almost four full octaves of the music, and a tweeter filter that rings and spits so bad that half the people that own them cut out the elliptic portion of the filter.

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I'm guessing that is a bad thing, right? Are you saying I don't want to go from old tired AK-2 to fresh new AK-3?

I fully admit I know very little about crossovers. I also don't want to make a move in the wrong direction. I think from Frzn's post I can conclude that A/AA is an option, but is it an option I should consider?

[BEC]

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On 6/9/2005 3:20:08 PM DeanG wrote:

Let's see, we have a massive iron core strapped across a driver covering almost four full octaves of the music, and a tweeter filter that rings and spits so bad that half the people that own them cut out the elliptic portion of the filter.

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Dean,

Please elaborate. What the heck are you talking about?

Bob

[Deang]

This is the only thread I have bookmarked on the subject here at home.

http://forums.klipsch.com/idealbb/view.asp?topicID=15088

Plenty more at the Asylum.

As far as the 5mH iron core goes, it's probably just audiophile voodoo -- but I've read that iron or ferrite cores shouldn't be used for frequencies above 3kHz. Something about evil eddy currents I think. I don't know, I look at the thing and it just looks silly. It's basically being used as a frequency dependant resistor, and since it's scaled for 32 ohms, it's the size of Rhode Island.

[BEC]

Dean,

I have been listening to AL-3s for years and never observed one to "spit" or ring. Not sure I personally prefer it to the AA but it is a design that Klipsch stayed with for a very long time and one that Klipsch used across the top of the heritage line with minor differences. I don't think that it would have survived for the 12 to 15 years in the flagship products if it was common opinion that it was a poor design. To me it sounds more like an ALK type A than any other Klipsch crossover I have heard.

Bob

[Al Klappenberger]

rplace,

I suspect that you would be happy with my universal replacement network mainly becasue it has the adjustable squawker level feature. As I see it, there is very little difference between the AK-2 and the AK-3. The advantage between the two is that converting to the AK-3 renews the parts which always helps.

Dean,

The business of "ringing" in the "elliptic filter" is a myth! It is totaly inaudable and only a tiny fraction of the ringing that happens all the time in a mechanical contraption like a moving tweeter diaphragm. That filter is in fact an "extreme-slope" filter. It's just that it's only half of what it could be if the morror image filter was there to roll off the squawker and provide a constant impedance. The "AK" series netwroks, like all the Klipch networks, have no upper limit on the squawker. It runs full range above 400 Hz.

Al K.

[Deang]

Thanks Guys.

Here's another good thread on the subject:

http://forums.klipsch.com/idealbb/view.asp?topicID=19854

There are a lot of complaints regarding sibilance problems with this filter both here and at the Asylum. I thought the problem might be related to ripple in the passband, or possibly the group delay characteristics of the Chebyshev alignment.

I read that all filters "ring", just some worse than others. Yes?

[Al Klappenberger]

Dean,

Yes, some filters ring more than others. Chebyshev and Butterworth WILL ring. Gaussian and Bessel do not. BUT the ringing is NOT the casue of anything you can hear. Group delay is NOT time delay. It is nothing more than a way to express phase linearity. This relates to the phase relationships between the components (harmonics) of a waveform. Your ear is also deaf to that! As there is no such thing as a linear phase highpass filter, using Bessle and Gaussian filters in a tweeter filter is a waste of parts. It makes a very slopy filter. Making a linear phase bandpass is possible but very difficult. Linear phase lowpass filters are easy. They are just not practical. Sibilance is NOT casue by filters. It's recorded on CDs and is a natural part of some peoples voices. Listen with headphones once. There is no filters or crossover networks in headphones but you will still hear sibilance!

Al K.

[Deang]

I should probably hear the thing for myself before shooting my mouth off. It's more fun to shoot my mouth off though.

Bob -- Charles B. says the autoformer change on the AK-3 raises the output of the squawker 2db. Another post I ran across says it drops the output. Which is it?

"I don't think that it would have survived for the 12 to 15 years in the flagship products if it was common opinion that it was a poor design."

I don't think it's a "poor" design because I'm not to a point yet where I can always tell a poor design from a good one. All I can say right now is that some things just sound better to me than others, and have decided I really prefer a bandpass on the squawker, and a conventional alignment for the tweeter section.

[Frzninvt]

The AK-3's T4A autoformer raises the squawker output 2db as compared to the T5A in the AK-2.

[BEC]

Dean,

The T4A is 4 db. (Measured).

Bob

[Frzninvt]

The T4A & T5A are fixed value autoformers correct? I know the T5A was not adjustable which is why I had to replace it with the T4A.

[D-MAN]

"I don't think that it would have survived for the 12 to 15 years in the flagship products if it was common opinion that it was a poor design."

This is a matter of debate - the market place and what it will bear is not much of a validation of any particular product or design. Rather it was an economical consideration, not an engineering one, i.e., design a crossover that costs X to produce and still sounds good enough to sell in a particular price point.

Take Bose for instance. 'Nuff said.

DM

[BEC]

Charles,

Yes, the T4A and T5A are fixed value. Any of them can be replaced with the new 3636 that I have UT build for me. It is adjustable in 1 db steps from 1 to 12 db attenuation.

Bob Crites