JohnA

You should see what Roy uses to demo Jubilees!

LOL! Somebody's google-fu is a failure.

There should be no need for a "rebuild". If a driver is not working it can be repaired. Test by putting you ear close to each driver to see if it's producing sound. You can test DC resistance or continuity with a volt meter. A good volt meter can detect AC voltage applied to the driver terminals to test the network, if a driver tests good, but is not playing. That same good meter can test the network components, *IF* you can disconnect enough to test it alone. Finally, if they sound recessed, laid back or "polite", consider replacing the capacitors with high quality film and foil caps as they may have gone off spec enough to affect the sound.

Aside from pretty obvious terminal strip corrosion and other visible issues with the network, I'd recommend looking for very late K-77-Fs that have a recessed flange so the mouth of the tweeter is made flush with the motorboard. That cured some grittiness my La Scalas had. PM me for more ideas.

The size, of the 4, should be selected by output and performance. There is not a recommended La Scala match, but I'll pick Large. You will not want or need additional subwoofers for any reason. If I were you, I'd replace any direct radiator subwoofers you have with these. They are easily special effects capable. You will not regret it! We were given impressive response curves and told a lot about the physics of the subs, that i won't discuss. The Medium goes deep enough for any music, the Large should cover most LFE effects, if not all and the XL is likely brown note capable. 😆 Choose the additional subs for the max dB output you require. They are powered, so you will not need an additional amp. The amplifier power is surprisingly low and the embedded amp allows some control of distortion. We were not given a release date, but speculation was not before Spring/Summer '24. You have plenty of time to try to time the Market. This is the Large.

Serial numbers are fine. Names, SSNs and DL numbers are not, now that internet based ID fraud is rampant. (I hope VISA and grubhub go broke; they don't even try to prosecute.) Your serial number is 17N159, the 16,159th Heresy made. The wood is birch and the butt joints say they left the factory raw. the "Type" was most like HD-BR and a previous owner stained them. Walnut?

Find a Type AK-2 or AK-3 and use that. A Type A is probably not a good match for any of the 3 drivers in your cabinets.

@reyerbrandt Please delete the pics with the previous owners name and SS number. Identity fraud is rampant. Having been a victim, that is a horror to me.

Were your woofers damaged? Did they rub or distort? If not, you wasted money. What made you think the crossovers were "tired"? That a really unusual description that conveys little data. Did the speakers sound distant, dull, forward? The capacitors may have degraded after 40 years, and maybe not. I had a '67 H700 that didn't need new caps and a '68 that did. Since you did not state what you "upgraded", we can't begin to offer a guess. I sincerely doubt your diaphragms need replacement. My 1980 La Scalas have their original diaphragms (and woofers). If they are deficient, I can't detect it. In fact, the old, square magnet woofers are said to be a better match to the bass horn than the newer round magnet K-33s. Now, there are improvements you might make to a La Scala that are too expensive or of too little benefit for the factory to implement but that is for another time.

The spacer is only for looks, like a Klipschorn Type B. Since the new ones are MUCH heavier, 2 pieces makes moving them easier. Do not raise the bass horn off the floor (2 or 3 inches is insignificant), consider pushing them into corners. The low bass is limited and the distance off the floor could raise the bottom limit even higher. I have mine setting on subwoofers, but .... subwoofers. There are a few worthwhile mods (PM me), but first, which crossover do you have? What are your serial numbers? If the sound is forward and out in the room, you do not need a cap upgrade. If its laid back and "calm" you should consider it. Here's a hint.

Don't turn up the volume too loud. All things have limits. Any harshness, brittleness, or obvious distortion is too loud. I'm quite surprised you found service tutorials on the Klipsch web site.

An opening is a perfect absorber at that location (no reflective surface). Consider a larger rug that comes closer to your La Scalas. Colorful rugs used as artful wall coverings at reflection points from the tweeter and squawker may be useful. You might consider building panels from a 1" wood strips with A/C duct board in the center and wrapped with an attractive woven fabric. They would resemble cubicle walls. Place them at reflection points. If your SO will accept it, add insulated drapes to the windows and perhaps 2x as much as the windows need so they'll bunch up thickly. That is what I've done to the windows behind my La Scalas. You probably won't need to do all of the above. You can find your reflection points with a small flashlight placed against the front of the tweeter or squawker and angled like the sides of each horn. I like a super dead room for Home Theater but a more reflective room for music with the wall behind the speakers reasonably non-reflective.

And, in case it hasn't been plain, the La Scala bass horn is NOT a subwoofer. Subwoofers operate from below 20 Hz to as high as 80 Hz. Some can respond a little higher. A La Scala bass horn will not go much below 60 Hz, even under the best of circumstances. It will reproduce bass tones cleaner and clearer than most any other speaker.

Klipsch, maybe. An Atlas dealer, definitely. https://www.fullcompass.com/prod/027035-atlas-ied-d-20gb-diaphragm-for-pd-5vh-and-pd-5vt If your drivers work, leave well enough alone. Don't have audio nervosa. I had a pro replace a bad diaphragm in a spare K-55-V and it buzzes on piano.

I think I remember seeing the old dome rear cover in old literature for the -5VH. It will be essentially the same as the current production and should use the same diaphragm, should you ever need one. I'm sure Atlas will sell you all you can carry, too.

As new as they are, I'd expect you would ruin the sound. Ask again in 30 years.

Heresy or Forte. I'm partial to the H IVs. You will not need the sub, but it won't hurt.

You may, or may not need new capacitors. If the sound is not out in the room with you, consider it. I had a '67 H700 that did not and a '68 that did. I have an unproven theory that speakers used regularly will not need new caps as soon. At any rate, install high quality film and foil caps. They don't need to cost $250 each, but spend some coin. One very good update, was the K-77-F version of the tweeter with a recessed flange that placed the mouth of the tweeter flush with the front of the motorboard (no more playing through a hole). Not only does that eliminate the diffraction of the hole, but the tweeter itself responds to higher frequencies than the old AlNiCo tweeters you have. That new tweeter is a modification of the ceramic K-77-M the factory went to in 1980. The -F may be hard to find, but worth it. The factory added "Z" brackets the the -M to do the same thing for a while, but that would require enlarging the tweeter hole in your top section.

The square magnet K-77-M Is the better tweeter, responding to higher frequencies. Being newer than 1979, yours should have had the -Ms.

You're in like company here! Your '78s are likely made by Eminence in KY and they will have proper recone kits to restore them to OEM performance. Eminence probably will not sell to you directly. Look for a gray ink stamp number in the back side of the cones, 15162?. Also look for the EIA build code. It will be 67-xxxx; 67 for Eminence and xxxx for build week and year. The '69s may not have Eminence woofers, you you will need to start with the EIA code and determine who made them. However, early K-33-Es might well be a good match for the cabinet. compare the dimensions of your cabinets to that of mid '70s Cornwalls. If your woofers have failed, I'd recommend ebay for vintage replacements. If you want new, consult Klipsch to see if the current K-33-E is a good match to your cabinet. There is enough precision required that I would not DIY a recone. I say this after reconing a pair of Peavey 1504-4 woofers built for quick, easy cone replacement in the field, requiring no gluing.

DCR for the tweeter should be 7.2 to 7.5 ohms. If they are REALLY old and rated at 16 ohms, you might see 12 to 14 ohms. If you can hear scratching while rubbing the leads with the meter, it is most likely good. A 1.5V battery is good for this test, too, but be sure to rub, don't hold the leads against the battery terminals. Tweeters don't like DC.

Yes, H IVs run circles around H 1s (I had 7 at one time and still have 3 in my HT system). H IVs are much more natural sounding and better on vocals, especially. H IVs do not need a subwoofer, though open E on a double/electric bass is down a little compared to G, but not so much you might not think the song is recorded that way.

Since they are ported, you will not damage the sound, but surely there is a better way than damaging the finish, even if on the bottom.

I'm still looking for that 50 to 60 watts/channel. I'm driving my La Scalas with 125 wpc. While certainly more than enough, I wouldn't want less than half for the trip through "Sweet Jane", "I Don't Need No Doctor" and "Layla". 😆