Daan

Thank you for this link Moray, I will read it here on my vacation-adress with a cold beer in the shade Always nice to have something new to try out after coming home again. Just before leaving on holiday I received a pair of eighteen-sound neo drivers to try out; this way I can listen to other drivers while I'll be looking at the K55-V's again thinking about this mod.[Y] Daan

You are right Moray. I prefer to keep it like this as it sounds great! Using taps 0 and 2 on the transformer gives best results here [that's 3,3Db down from the taps used on the original horn].

I use the ALK universal crossovers and no EQ since the CT125 tweeter takes care of the high frequencies and it sounds great without the need for a EQ. Everything remained the same, only used different taps on the transformer for attenuating the higher efficiency of the EV horn. Daan

Endresult with the "big white" mounted flush with the motorboard. Combined with the machined K55-V on the adaptor, it produces the most lively, natural sound I ever heard in our room. The Crites cast woofers, K55-V 's with EV HR-60's , Crites CT125 tweeters plus the ALK universal filters together produce a kind of MAGIC that makes us watch less t.v and spend more time listening again.

Glad I can make a small tribute here ; I learned so much from all you guys! After about 20 years of listening to my stock La Scala's I found this site and people not only describing the shortcomings I heard for years, but also providing a solution. This in the end ,led to my current system , using the LS cabinet but for the rest holding all the modifications that solved the shortcomings that bugged me all those years. Ofcourse you can say I destroyed a pair of original LS's , BUT I never had so much fun upgrading my system and listening to music like in the past few years! Oh, and ofcourse I could be fooling myself that "a upgrade must sound better" but my wife set me straight when needed. We often listen to our music for the whole evening and occasionally she says; "it sounded better last time, put back what you replaced". So with the help of all the info and the posts made here, and my wife beside me, I look forward to a musical evening at home every time! Daan

And the endresult; a smooth transition from driver to adaptor.

Has to fit this original EV adaptor.

After making the throat conical , leaving the original opening intact and going to the adaptor's size on the outside it looks like this. Also provided a seal so both parts are joined airtight without the need for a [not conical] gasket; this way the transition is without any disturbance.

Resulting in a bad transition on the EV adaptor.

And here's what you can do to get a smooth transition between the driver and another horn/ adaptor; stock K55-V throat [mesh removed].

While disassembling my K55-V drivers for modification I found one of the phase plugs had a bit free play in it's fitting. So for everyone replacing the diafragms of their drivers; be sure to check the fitting and give all of the three points a gentle "tap" with a small hamer and a suitable steel [round] tool. I replaced the diafragms a few years already but never noticed it , now I machined them to fit the EV adaptors of my HR60 horns. Better safe than sorry. Nico

And this is the front, waiting for the gasket to set before I can fill in the thin free space around the flange left on purpose; this space is filled with wood-coloured elastic putty. This way the only physical contact between the EV horn and bassbin are the four screws through the front flange. Even the vibrations coming through here will be absorbed by the thick foam gasket underneath the flange of the EV horn.... I'v heard the [bad] effects of vibrations before and always try to avoid them since. Experimenting with the Beyma CP25 and Crites CP125 this evening.

Here's one of the horns installed, the horn is supported by a silent block which is under just a bit pressure. I hope this reduces vibrations going from the basshorn into the midhorn.

This thread is going...I don't know where to, but here some more pics of the HR60 build. After filling the back of the "front expansions of the horn" so to speak, and covering the horns with liquid rubber. Also added rope caulk to the 13/8 adaptors.

I will keep on using the system as a three-way with the tweeter on top of the cabinet. Although the horn specs show it will not go low enough, integration of the midrange as well as musical details are much better using this horn over the much smaller Fastrack. The fastrack however is THE drop-in replacement horn for those who do not want to change the orignality of their La Scala's. Just completed the make-over this evening and I'm very pleased with the appearance as well with the sound, only not sure I'll keep the K43E ; it does exactly as described earlier as having more "body" in the 400Hz region which in my case is a bit too much. More listening to do and finetuning. Nico

One panel mounted for fitting. BTW; the ALK filters did not fit easily into the upper section anymore as I also opened the doghouse. Later I put them on a nice speakerstand next to the cabs, between the cab and amp which made a very short speakerwire possible and finetuning on the crossovers themselves. The ALK 's are beautifull to look at anyway, so no prob. here.... The closed backs look just the same as the ported ones, with a set of WBT speakerterminals in the middle. I dyed them with teak-oil later which made them look almost OEM.

I used flared ports as recommended by people who build reflex cabs on a regular basis.

A few pics of the porting.

Bruce; I tried the closed back first, then tried the ports in several lenghts. 7 inch was about right indeed, but even although the speakers are not positioned in corners this gave too much bass. After closing the back again everything seemed to "sound right" with the right amount of bass, which also sounds tighter to me. Looking for the pics. Nico

You are right about the midhorns I used; after more than 20 years of listening to the stock LS's [with the K-400] I swapped them for Dave's Fastracks. These horns were the first evidence that I needed to move forward.... In my opinion the best upgrade I made amongst the others [ ALK universals, crites cast woofers and tweeters]. Dave's horns made the biggest difference, then AL's filters and then the tweeters from Bob. I replaced the woofers because the original [square magnet] ones were a bit out of center, though they still play fine for their new owner! I will look up some pics of the porting I tried; with them in place I experienced too much bass and found the bass a bit "slower" .... maybe because of the room, don't know exactly but after closing the back again I immediately heard what I liked more again. At some point my LS's actually were not LS's anymore.....but sounded much more natural, and suddenly I could listen to them all day ! Nico

Thanks for your reply's; I will put the K43E woofers in when re-assembling. For the real low frequencies I use a REL STRATA 3, which can be fine-tuned to every system IMO. When the midhorns are put next to each other, the difference in size is....well HUGE ; the difference in sound is accoardingly. Most appearent is the coherence with lower frequencies, lyrics can be followed all through a song [ some words and "the meaning " of a song I never understood] and these EV's sound much more "lively" than the other midhorns. Using the K-55-V gives really great results, these horns have a 2 inch throat and they came with a set of original aluminium cast adaptors for 1 inch drivers. After re-assembly I will post some pics here on the forum for others to maybe benefit; these horns seem to be cheap on Ebay. THANKS for your help! Nico

Just wanted to add that I show these pics for the first time to anyone; this conversion is the result of years of listening [23 as a matter of fact] before I could not live with the original sound anymore. Reading a lot on this forum, and becoming a member enabled me to learn more about the shortcomings of the LS, other people describing JUST what I was hearing as annoying colouration and such. DO NOT think I'm just another guy who can not appreciate what Mr Klipsch has achieved with building this speakersystem; it's just that in the end I think a speakersystem should do what it's made to do.... produce sound that's as close to reality as possible. The original LS just don't do that IMO. I spend hours and hours deciding wether to stay with the original looks [and performance] of this system; in the end I choose for better sound with materials from ALK, Bob Crites and the help of everyone here who helped me. Before raving about "upgrades" I read about what other people's experiences are, think about it for a while, then buy,let my ears decide, then my RTA analyzer. This has brought me closer to a "real life experience" than I ever could imagine possible with my good old LS's. Thanks Nico p.s; K43E woofers, found local

After removing the long flanges with the holes and the hole routed to mount the horns flush with the motorboard, these horns look like they're tailor-made for the La Scala... and sound awesome with the K-55-V drivers!!

Wood cutting after some sleepless nights...

Work in progress here as well..