KT88

The photo is from an early Quad advertising brochure.

Some of the still best speakers on the planet today like the Khorn or the UK Quad ESL57 were designed to be a mono speaker at first in the early days of hifi.

The khorn has a very good impressive bass. As Coytee says, you are "in" the bass horn. But the LaScala has the better punch. The nice thing about the Khorn is that about 32 Hz is all I would need for my kind of music. But everything has to be right with the room regarding the Khorn. I would never spend the money for a Khorn and then have to handle with false tinkered corners. If the Khorn is not in the corner from my point of view the LS is the better choice what this aspect is concerned even if the low bass is gone. The determination of the placement re the Khorn is an issue even if you want to finetune the mids and treble. The LS can be aligned so that the stage cam be calibrated exactly. When the Khorn was developed PWK wanted to get a nice roomfilling sound even as a mono speaker. Therefor it radiates 45 degrees from the corner.

Apart from this specific case, what can generally make overheating caused by the load of the speaker output of a tube amplifier? I have not heard of this phenomenon. Would a short circuit or a too low impedance of a speaker cause this?

Mike, next time when I'm in the States I'll bring you some good German beer as a ticket so I can experience your set up for an hour and with a coffee, if you'll allow it.🙂

There is a German rock band from the 1970s, the guys are still together today and recorded a new album in the Covid era. The band is called Kraan. They were even known in the States in the late 70s. The bass player played a Rickenbaker bass with a plectrum back then. The sound was incredibly dry, powerful and unique. When I think back to live concerts from that time, today LaScala can reproduce that fire and those super fast attacks. Here is a live recording from 1974. This is pure LaScala music, also because it does not go so deep in the frequencies, but fully trumps in the LaScala spectrum. And why I like still like them a lot 50 years later, here is how they sound today.If you like rock with some rockjazz and fusion elements. LaScala music😀

I haven't heard the Heritage Jubilee yet, I own the UJ since 15 years combined with K402/ TAD 4002. But I blindly believe that a speaker that goes more than an octave lower produces a different, fuller and more intense sound experience. As for the high frequency differences between HJ and UJ described by various posters here, I think there could be several influences. First, did both speakers have the same drivers in the respective comparison, e.g. in Hope? And even then, it is a difference due to the use of Roy's second phaseplug in the HJ. Then there is the fact that even the same K402 with exactly everything the same, phase plugs, drivers, everything, can still cause a different sound impression when the bass reaches much lower. In the end, we always hear a holistic sound that is added together by given parameters. Regarding the three-way constellation. I know the K510 and it sounds very good on its own. But with three ways you destroy the most important goal that PWK had...the most point-like sound source of the Jubilee two-way system. Three way only works at a greater distance than any private listening room. But when you sit so far away we are no longer talking about hifi but about public address like in the cinema. So more sound pressure and less nuances through this kind of setting.

Ok, thanks for info. I was just thinking about the capacitors of the network which are nowadays polyester types Klipsch uses like I used them to restore my old LaScalas. And in my experience they need some time to open up which means clearer and more spatial high frequencies. (The „burning in“ is not a privilege of boutique expensive parts:) But within 250 hours it should be done.

Another idea. Have your AL5s been running for a while, or do they just have this cosmetic flaw but have barely run?

I don't want to be too schoolmasterly in the sense of giving too much advice, sorry. After some time of acclimatization I would try it once without these rubber pads because the AL5 then has less "micro wobble", which can also benefit the high frequencies. Regarding your CW4, if they stay in the room, would it be me, I would put them together in the way that the two front baffles "see" each other. That would make the effect as a possible bass trap much smaller. They would mutually eliminate this effect each other.

Mike has chosen this quasi Khorn placement, not tight in the corners but with an almost similar 40 degree angle as it looks in his photo. So I think it will work good, but I am curious what Mike will reply himself.

I have to agree with those who say there should only be one pair of speakers in the room. The CW4s work like two giant bass absorbers with their bass reflex ports. They are practically exactly like those bass traps some people put up against unwanted frequencies. Only that here desired frequencies might fall victim. If it's not too much trouble, I'd put them in another room for a day. As for the sound of the AL5. Yes, the ear gets used to some things in a very amazing way. But there are also sound additions that you can't get used to. On the contrary, some undesirable characteristics of some speakers or rooms can even become more annoying over time. It remains to be seen...I personally have "LaScala ears" :-). I am very curious about your experiences and impressions. Especially if you go back to the CW4 after a week or so, that would interest me the most. I feel like I find radial speakers quite obfuscated after being spoiled with a full horn for a longer period of time. Another quick question. Did you put the rubber pads underneath to protect your floor from scratches or because you think it improves the sound of the AL5?

I think the AL5s look very good in your living room. They have that coolness factor that only a few speakers offer. I agree they should not be too far apart. In my experience it can work if they are further apart but then they should be angled in more. For comparison, the Khorn is in the corners (using the same mid and high) and it works with the 45 degree angle. The way you have the AL5 set up now I would try with the angle in and go a bit over the target and then slowly go back to see where is the sweetspot of the best angle. There is a magic spot that matches your personal idea of width of the stage while projecting a focused center along with depth staging. I'm excited to see what you may report further on.

As for the Lascala, they do not need to be moved away from the back wall. They are also spatial in sound when placed directly against the back wall and angled in slightly. I think the reason is that they are so deep that the midrange horn and tweeter horn are far from the back wall anyway. Did you get the AL5 today?

The angled inside front edge of the LaScalas is about 2.80 meters and I sit about 2.70 meters away. The angled in of the LaScala is very critical and they really should be right up against the back wall. My LaScala are close to the wall with the inside back. They do not have to be in the room, they are so deep that it simultaneously brings a lot of space and the best bass when they are on the back wall. The angulation you have to try according to your taste. If the angle is too small, the stage will be wide but too flat. If the angle is too big, the feeling of spaciousness is not so good. See my photo as a starting point (if you don't want to do it completely different). Surely you can put the speakers closer together than I do. Try it out. I have the impression that the bass is better and more open when they are a bit more apart. But also not too close to the side wall because then it can drone. Just try it. Every room and every ear is different:) You won't find any Underground Jubilee in Marktplaats. To my knowledge, I have the only Underground Jubilee in Germany. Roy was so kind and sent me a pair in 2008😀 I remember that another pair was in the Netherlands at a dealer (I remember that he wanted to prefer three ways but I forgot the name of the dealer) and a pair was in London at a dealer who used it to demonstrate his high end turntables. That was all in Europe.

In my view, the LaScala is the smallest possibility to acquire an adequate full horn for normal rooms. With enough low frequencies for most music and as the best compromise between size and performance. Plus a bass that is excellent where it exists when there is no sidewall resonance. With the new LaScala this is always the case.

Flevoman, it is not so easy to put into words. The UJ are in their own class as far as sound is concerned. I really can't compare them to the LaScala in the disciplines you describe. But there is one point that I don't mean as a criticism of the UJ, but it is simply due to the size of the UJ in my view. The LaScala does not have that large and highly impressive serenity of a UJ. But in a normal living room size the LaScala does an excellent job of integrating the room. This gives that 3D effect that I love so much...in combination with the natural clear and lively horn sound. Depending on subtle fine tuning of the speaker placement, the sound in the sweet spot is very spatial and has that layer from front to back. You can say the LaSala is best suited for just one listener. The UJ sounds very good from many points in the room, you can hear (that's how I feel) the recordings with all their subtleties, very musical, with good timing and absolute resolution. And above all the airiness you describe. But to achieve the effect of marriage with the room I think the Jubilee would need a slightly larger room than mine. Now in the US many people have a larger room than I do, and for that the UJ and especially the new Heritage Jubilee is made in excellent fashion. The unpleasant resonances of the old LaScala have actually been eliminated with much thicker MDF used today on the LS2 and AL5 side walls. I am already quite curious about your sound impressions of your soon arriving AL5!

Flevoman, I'm very curious about your listening impressions. It is a rare opportunity to have two such exceptional speakers in the same room at the same time. Personally, I am in the second spring with my old 1977 LaScala. Paradox is, since I brought in the Covid 19 years with much love the LS in almost original condition, diaphragm, Xover original parts etc. I hear the resonnance in the upper bass even more clearly because the „new original“ sound is so clear and pleasant. My next project is to reinforce the side panels and the top with multiplex by 6 mm and 4 mm respectively. I would leave the Lascala as it is because I value originality very much but a carpenter had sanded it down a bit on the side walls to eliminate paint that the previous owner had applied. So I go a little beyond the original thickness of the sidewalls because I have to do something anyway. This will be closer to the characteristics of the new Lascala 2 without resonances in the upper bass, even if the new one uses different material. As has been said here, a full horn is something unique, and the LaScala with its old-school K401 still conveys the Klipsch magic and a fantastic spaciousness. Unfortunately, my post is not for comparison with a CW4. But I do have the comparison with my Tannoy Canterbury 15, which as some may know is also a combination of high-mid horn down to 1000 Hz and bass reflex, though almost everything is a bit different. And despite all the competencies of the Canterbury with almost a whole octave more bass range, it is in the end the LaScala that moves my heart and my bobbing foot more. I said it in another thread, the seamless connection of the bass to the K401 is simply world class. A word about the tweeter. I have not heard the AL5 yet. I tried other "more modern" tweeters with my old LaScala. Without expanding on that, I have ruefully returned to the original K77 alnico. If the AL5 as well as the AK6 have a newly developed tractrix tweeter then I'm sure it took Roy a few sleepless nights to realize it the way he envisioned it....a modernization while retaining the original character and with the best possible connection to the K401 exponential horn. Roy knows much better than I do that you can't just take any other tweeter. I think it is high art to design the right tweeter or to choose it. Many a good speaker has been designed from the tweeter down to the bass. Now I've digressed a bit, but I rave about these speakers. PS Since yesterday I have my Underground Jubilees back in the living room after a break of a few years. This is a fantastic, breathtaking and unique speaker in its own right. If I were forced to go to the famous lonely island I would chose between the Underground Jubilee and the LaScala. Both are so impressive musical but for different reasons. The Underground Jubilee is unbeatable with its serene and at the same time powerful impulsive sound as if from one source. It is the "big block" speaker. But even here you must not deceive yourself about the bass. On the one hand, incredibly clear, fast, articulate. On the other hand, not lower than a little below 40Hz...which does not bother me. The LaScala on the other hand is just as satisfying for me in the bass for jazz, acoustic music and rock music. It is not the "big block" but it is unique how the LaScala can visually and acoustically marry with many rooms. What LS and UJ have in common is that the horn bass of both is miles ahead of any normal radiating bass in a speaker cabinet…in my view.

Thanks for the advice, Randy. I will take it into account and choose 6 mm for the sidewall reinforcement accordingly.

My conclusion is that I reinforce the sides with about 4mm birch multiplex/veneer. This compensates for the fact that my LS already have 1mm thinner sidewalls in original condition than the usual 19mm to reach reasonably the LSI standard of the 80s The top I reinforce with about 3mm. Do you have any objections to my plan, Randy? Then say it with pleasure. Thank you very much for sharing your exceptional and historically accurate knowledge of Klipsch products. I am very happy with the info you have shared. I owe you a good tasty German beer or an American quality bourbon, whichever you prefer.

does it make an effect soundwise?

left and right speaker, this should be ok regarding the horn length?

What means routed tweeter /midrange openings ala LSI? And do you think that the slight shortening of the bass will have an effect? I would say, it has not, I hope, by reducing the length by 0.25 mm.

I hope it doesn't affect the bass response if the bass horn got a little shorter this way. I had the same impression as you that it was slightly abraded....

Last question in this topic, Randy, was the front/motor board also sanded, please see the pic above in the post where you can see the K400.