KT88

Perhaps Klipsch has changed the wiring. But honestly, does that make a difference for 20 cm of cable? I have like Klipsch expensive Stirling Broadcast LS3/6 and Tannoy Canterbury. They are wired exactly as in your picture I quote. In my opinion, using a brand for 20 cm of cables is just marketing blah blah.

Some dealers advertise that the Heresy 4 uses Audioquest cables. Here in German in the second last section. I don't know where the dealer got the information from... https://www.elektrowelt24.eu/shop/Lautsprecher/Standlautsprecher/Klipsch/Klipsch-Heritage/Klipsch-Heresy-IV-alle-Farben::7105.html

Yes, you are right.

Put simply, the base plate of the Lascala is removed and an enclosure with two bass reflex tubes is built underneath. This gives you the horn down to approx. real 80 Hz and bass reflex down to approx. 40 Hz. Powerful enough for a large living room, with a little EQ.

…Even if it is true that the 140 Hz peak should be smoothed out. But I would not saw a very recent AL5 into parts, only an old LaScala.

When it comes to searching in a forum, google is your friend. Take any site, e.g. community.klipsch.com. Then put the word "site:" in front of it with a colon. Leave a space after .com and enter your search term. E.G.: site:community.klipsch.com lascala vented bass This method is 100 times more productive than the internal search function of any forum I know. Just try it out. BTW I am very inclined to rebuild my 1977 LaScala in this way since my Lascala cases are no longer completely original anyway due to the sanding of the side panels by a stupid carpenter (without asking me) 18 years ago.). It is a very interesting approach.

I'm very happy with my 2002 MC275 MK IV, it has better OTs than the Commemorative model before it, plus the classic speaker binding posts. It sounds wonderful, even if it is built on a PCB and not point to point. The biggest technical difference to the MK VI is that the feedback loop on my MKIV is in front of the OT, so it's classic. The MK VI has the feedback loop behind the OTs. Ron C, a longtime Mcintosh employee had explained this in another forum. Supposedly this produces a better damping factor. I haven't heard it yet, according to reviews it sounds "cleaner" stronger bass etc.. But I really like the classic sound of my MC275 MKIV very much.

Your Khorns look really nice. I see the rollers under the speakers. Are they temporary or should they stay there? The bass could be better if the speakers are on the floor without the wheels after final positioning..

Yes, that's exactly what I mean. The metal tongues should be firmly tightened, not with too much force of course, you do it with your hands and without pliers. If the metal tongues are nice and tight, there will be no micro-vibrations and the sound will be stable. You can try it out by ear whether you plug plus and minus into the connections for the tweeter or for the bass. I have found that it sounds "rounder" if you use the bass terminals. But some manufacturers, such as Tannoy, recommend the tweeter terminals. It's up to your ears. The difference is only very subtle.

I understand that there are separate connections for bi amping. Biwiring should be done by whoever wants, I have not recognized any advantage in 40 years, only disadvantages, you get a pseudo sense of space and sacrifice timing. The most absurd thing is that today there are extra short cable bridges from HF to LF that can cost 300 USD instead of the metal tongues from the factory. The best connection if you do without biamping would be one pair of cables to the crossover, or both internal pairs of cables to one contact point each for HF and LF.

A question about the correct connection of the mains cable. On old devices with transformer power supplies, you can measure the voltage at the housing vs. earth. If I turn the mains plug 180 degrees in Europe, I have a worse sound if the AC voltage between the housing and earth is higher and I have a better sound if I measure a lower voltage. This type of measurement does not work for devices with a switching power supply without a real transformer. The Node is such a device. I have found out which way round the mains plug has to be so that it sounds better to me. I would like to know whether my subjective impression corresponds to the correct recommendation. So my question is, on which side of the two-core Euro cable should the "hot" wire be regarding the Node? Looking from the back, left or right? Or is there a general way to find out the correct polarity of the power cable for switching power supplies, other than by ear?

Do you drive the AMT actively to compensate for the lower efficiency?

Does the AMT1 have to be open at the back @babadono? Or could it also be placed between the bass and the K402 so that it is positioned center center, so to speak, and only protrudes slightly? I have seen 100dB efficiency 1w1/m. So that seems to be enough to hear a difference? A really interesting project. It remains the two-way principle but with a little more "air". Do you hear a change in the spatiality? The staggering of the instruments etc.?

From what I see on Decware's website, the main difference is that the SE84UFO25 uses three separate rectifier tubes, one for each tube in the signal path. The "simple" UFO and UFO2.1 do not have this complexity and they use only one rectifier tube. I wonder if that has anything to do with the hum?

I do not know the H4 so I am just curious. Which freq. region do you address concerning box resonances?