Al Klappenberger

Rudy, I am no horn expert by any means. I'm really not the guy to ask! As I understand it, the advantage is in the termination of the mouth to the room. The abrupt transition is greatly reduced. Transitions like that cause reflections back to the driver. The Elliptic idea simply expands the area of the mouth so that it's big enough to support a cutoff low enough to work down to 400 Hz where the Khorn needs to be crossed over. A round Tractrix is just too big to fit. In the case of the Edgar type horn the transition is smooth in the horizontal plane only. The exponential horn has an abrupt transition to the room in every direction! The round tractrix mouth is smooth in every direction. The Elliptic is simply the best compromise. Al K.

Rudy, I'll probably be posting some polar plots next week. The news now is that Dave has finished the 2 Inch to 1.4 Inch to 1 Inch adapter. It separates near the middle where it fits a 1.4 Inch driver. The ends reduce from 2 Inch down to 1 Inch. The neat thing is that it's true round Tractrix expansion all the way to the 2 inch diameter and continues elliptic on to mouth of the Eliptrac horn. It provide the correct mounting flange for each driver size . There is no jury rigging of any sort. Al K.

Mark, The answer to most of your questions is yes. You could also use the AP12-AK3 if you opened the woofer hatch and changed the 140 Uf cap it uses to 100 Uf, like the AK-3. The upgrade path to mentioned is fine except for the "passively bi-ampable" thing. The answer to that is probably no. Anytime you bi-amp the crosser MUST be an active one located up-stream of separate low and high amps. All passive networks between the low amp and woofer driver must be removed. Al K.

"Who needs a Universal network" The AP12-xxx + AP15-6000 costs almost the same and is better, but I have built 235 sets of Universal networks to date plus all the kits. How can I stop offering them? "Does Al offer the AP12-AK3 in kit form?" No.. Only the Universal and the Forte. "Need to order the ES5800 without the orange extension cord (sorry Al, I'm an electrical contractor and can't get past this" Now you are giving away my secret stuff! I get them from Wall-Mart and cut the connectors off! Al k.

Mark, Yeah! I bet you could get one of those at you local hospital. They use them to keep a patient's head still during brain surgery! [:$] On second thought, loudspeakers are just too much trouble. Everybody needs to replace them with headphones. They don't have all these problems! Al K.

That impresses me as even more laughable than my acoustic delay pipe idea! Al K.

Ok horn experts. What's the down side of simply putting a round "pipe" between the tweeter horn and driver exactly long enough to position the tweeter driver right along side the mid-range driver? With a 1 inch horn and screw-in driver like the Selenium 220 it should be easy to do. It would simply be a 1 Inch I.D. pipe. Al K.

"Would these 2 drivers be considered time-aligned?" Unless your head is sitting at exactly mid-way between the two drivers vertically at a distance, the answer is NO! Remember just 1 inch difference represents 360 Deg error at 13.5 Khz! Al K.

EXACTLY! See, I'm not quite as dumb as I look! [8-|] Al K.

"Might be something to add to your product line!" I already to. It's the AP12-AK3 except it also has the squawker level transformer on it. "I'm assuming one can simply remove the Universal and insert the ES5800 in its place with this mod, correct" Almost. The squawker transformer you are using is on the Universal network. The ES5800 has a TWEETER attenuator instead. It feeds the mids back to the AP12 board instead which has the squawker level transformer (3619). Al K.

How you have it connected is OK for what you have, but here's how to do it. IMPORTANT: DO NOT connect the input from the rig you have now to the Bi-Amp input or you will burn up something! Only connect to the Bi-amp input from the added components. Al K. EDIT. This mod seems important enough to redraw the schematic properly.

When you do this mod, here's what your will get. Not only is the impedance now flat, but the filter slope is much better. For example, 100 Hz to the squawker was 15 dB down. Now it will be 25 dB! Al K.

Ok. Here's what you should do. It will make the equivalent of the AP12-AK3 + AP15-6000 set. On the schematic, the stuff in red is to be added, Also, move the input to the Universal network from the normal input to the "bi-amp input". I'm sure you are using the normal input or you would have destroyed the K55 already! The two 27 uF cap can be any brand you like. The 3 mHy can be of AWG 16 (which I use) or heavier. The 24 Ohm resistor can be film or wire-wound. It should be 5 or 10W That's it. I recommend anyone who has my Universal and the AK-3 network still intact inside the woofer compartment do this. A K. BTW: If you have the AK-2 network, it has 140 uF in place of the 50 + 50 uF (100 uF) of the AK-3. You must change the value to 50+50 for this mod to work properly.

The schematic of what you have would be the same as the Universal with an additional cap (100 uF) added across the woofer and the series 1.3 mHy inductor raised to 4 mHy. This results in a 2nd order lowpass connected to a 1st order highpass (the two 24 uF). The two have different reluctance slopes. They do not cancel each other properly. It might also move the crossover frequency a bit although I didn't bother to check for that. Al K.

The Faital Pro and B&C drivers are both made in Italy. They require metric hardware. The HF200 needs studs about two Inches long and nuts that are provided with it. B&C isn't that nice. You need to provide them yourself, but they are just simple metric screws. Al K.

"I built my Universals as well but kept the woofer xover in the compartment and used the universal for the mid/high only" This is a POOR IDEA. Yes, it works, but it's a half-way measure which provides squirly impedance to the amp.The attached plot shows the impedance varies between 5 and 10 Ohms. This isn't as bad as the stock AK-3 but there is a reactive component to the impedance that doesn't show on the simple impedance curve. It can be seen on the Smith chart or return loss plots that don't show on this particular plot. You need to replace the stuff in the woofer compartment with the AP12-AK3. What's in there now is not correct. You can feed the output of the AP12-AK3 into the bi-amp input of the universal for now. You will then have the equivalent of the AP12-AK3 + AP15-6000 combination. Later the ES5800 can replace the upper section of the Universal. Al K.

Moray, Look at the thread on the Forte I. Everything is very similar. AL K.

JW, The reason the 4500 Hz crossover sounds good is because the K400 squawker horn is so bad. It diverts the range between 4500 and 6000 Hz to the tweeter. Do the crossover mod later and replace the squawker horn first! Once you do that you will want to keep the 6000 Hz crossover. Al K.

Bernie, I think the biggest improvement would be in going to extreme-slope for the highs. That means the AP12 + ES5800 combination. The low crossover is secondary. There's no good way to use the Universal with the ES5800. Al K.

Guys, We now have a new option. Before we had: 3-way systems with response clear to 20 Khz but the tweeter was closer to you causing a time alignment issue but good high distribution due to a small tweeter horn. 3-way with a coaxial driver with response to about 16 - 18 KHz withOUT the time alignment issue. Both drivers are the same distance from you (B&C DCX50 driver). High frequency distribution is limited by the large horn needed to go down to 400 Hz. There is also the 3-way system with extreme-slope crossovers option. This goes a long way toward limiting the time alignment problem but has the disadvantage of higher cost due to the complexity of the networks. Now we have a new option: A single driver that will go to 20 KHz withOUT the time alignment issue. The only problem remaining is that a single large horn that will go down to 400 Hz does not have a good distribution of highs. That is the problem with any 2-way full-range system I am familiar with. Al K.

J.. The Universal will replace the AK-2 but I generally suggest the AP12-350 and ES5800 set to upgrade that network. The AK-2 and AK-3 networks both have extreme-slope tweeter filters already in them. The AK-4 and AK-5 do NOT. The Universal has a 18 dB / octave tweeter filter. The Universal has other advantage over the AK-2 or AK-3 but the AP12-350 and ES5800 set give you all those and a correct extreme-slope tweeter filter too. Dean is correct that the woofer filter of the AK-2 is inside the woofer hatch. The AK-3 is set up the same way. You need to open the hatch and use the cable going to the upper half of the AK-3 to run directly to the woofer driver. The cable from the amp will be moved directly to the new networks input terminals.The old input posts on the woofer hatch are no longer used. This is the case with the Universal as well. Al K.

Download and build the design for my AP12-500 or AP12-600 from my web site. That will run 2-way or adapt to 3-way by moving a single strap. http://www.alkeng.com/dload/ap12.zip Al K.

NO.. Put it on eBay! Al K.

The type B will ONLY work with the K55 driver. Al K

Nevermind - I just had a dumb idea and realized it while I was typing! Al k.