Daan

Hi Bruce, The midhorn I finally chose is a EV HR-60 constant directivity horn. I found them local [new] for very little money. After putting them on top of my LS's and listening for a few weeks I just couldn't go back to the tractrix horns I used before [which were a huge upgrade already over the stock K-400's ]....

Thank you Marvel ,for posting this explanation. I do understand most of it....but not all. I get confused where the text starts about D2, SC4, C6 and a "two pole high pass filter ahead of the power amp". As I like to keep things [ my install] simple, do I understand correctly that with using the K43E woofers I already gain 3Db at 30Hz , compared with the K33E [stock woofer] ? Also the so called "D2 " alignment is what I use [having opened the doghouse and closing the high freq. cabinet] , giving a Qtc of .577 and 4.5Db more output at 30Hz than with the stock woofer chamber ? Forgive me for maybe asking for answers that are obvious , but the language is sometimes a barrier when it comes to technical explanations... And I do use two SET monoblocks [Decware Zen] btw. Thank you for your help, Nico The Netherlands

Thank you for sharing your thoughts about this subject. I realized that my message was not complete since I have opened the doghouse accoarding to the suggested bass mods for La Scala's by DJK. I've been experimenting with just the upper chamber added to the volume of the basscabinet [closed the upper chamber at the back], added ports in this extra panel and also tried the bass mod suggested by Dave [bass port in chamber under the cabinet]. In all cases this resulted in more and extended bass response; best configuration for my ears and room is only the upper chamber added and closed at the back. I also use a very good REL sub that dials in very nicely for the remaining frequencies that the LS's never will be able to reproduce. After reading your post I understand that it might be worth in my case to try the K43's, to listen [and measure] if they are better suited for my system, more comments regarding this are very welcome as I'm always keen to learn! Thanks again, Nico

Hello fellow members, I recently stumbled upon a set of mint K43E woofers [as used in the industrial La Scala's as I believe]. Is there any benefit in changing the Crites cast frame woofers I currently have for these K43E's ? At the moment I have my cabinets empty for changing out the midhorns [routing a bigger opening in the motorboard] so it would be nice to know what woofer to put back in without having to A/B them. If you have any thoughts about it, please share. Thanks, Nico

Just wanted to share that I heard and saw these beauty's "live" yesterday evening at Peter's house in Amsterdam. Peter invited me after buying the speakerunits from me some time ago, and I emailed him once or twice in the past two years, asking if he already had made the cabinets..... It was very nice to be at his place, listen to some music and seeing these smooth cabinets. Even when looked at closely, one can only admire the quality of the woodwork. While driving home, I realized that Peter's LS's impressed me just like my own LS's impressed me, hearing them for the first time 25 years ago. They fill the room with a lively presentation of what's spinning on the Lenco. My visit felt too short.....a good sign.[] Way to go Peter!! I hope we'll meet again. Nico

.....or buy a set of "FASTRACKS" from Dave and discover all the musical details the K400's hide from you. [experienced first hand what I've been missing ,listening to the K400's for years]....

I know what you mean Bruce, making the box and just putting the LS on top would have been MUCH easier and I recommend it to anyone who wants to try the mod..... But...My wife has never complained about me dragging huge stereo-related objects into the room...until she saw the drawings for the plint. Putting those boxes under the LS's was just a NO-GO..... Since we don't have a huge livingroom and the LS's already dominate it; he box would have added 10 inch to the height which would just have made them, well ....JUST TO BIG. So I agree with you and recommend making that box to everybody who wants it the easy way, has a room big enough, or is single. Thanks everybody for your comments. Nico

Thank you. I asked seller for pics of midhorn and crossover;.... clearly visible the AA-type, midhorn beeing the aluminium K-400, so the speakers must be defenately older than seller claims.[1995] So at this point I will not buy them since I am looking for a newer produced set. Thanks! Nico

I have a chance of buying a set of klipschorns with serial 161361 on one speaker, what would be the date of manufacture; seller claims 1995..? Please advice, thanks.

Thanks for your replies, as for making the decision; I have been thinking this over and over again since I always wanted to keep them as original as possible... Anyway, after the first step [replacing the woofer, tweeter and crossover] and listening to the results, there was no way back anymore. I even sold all the old components mentioned above and used them to buy the new parts; never would go back to the K-400 for example! After trying Bob's tweeters and a recap-set for the AA filter, I decided to go for the ALK Universals, which I have to admit indeed sound the best [with the mids at position 0-4] . Now it's finishing up the basreflex-mod, and then to a active control which will allow me to boost the lows a bit and at the same time provide a subsonic filter that moves with the choosen frequency and cuts off just below it. [phoenix gold basscube]. I collected, refurbished and sold Phoenix Gold oldskool-gear all around the world and this device is really one of their best products when it comes to enhancing and controlling deep bass. Link; http://www.teamrocs.com/reviews/processors/basscube.html It operates on the same 12Volts battery as my passive ARRAY P-1 pre- amp and TRENDS T-amp do. Will update with more results..... nico

A quick first-look, after taking this pic I applied the sealant, and put all screws into place... first I just HAD to hear it. First impression; no "booming", in fact the extended bass blends so well I had to listen some time to tell it actually IS THERE. The more I listen now, the more I am pleased and all thoughts about ruining the actual sound of the basshorn etc. are behind me now. I have these LS's for 20 years now, and for the first time I FEEL a orchestra in full swing [the neighbours might so too] . Still have to coat the rear-panel and route the wires to the outside, since I'll be placing the ALK's outside the cabinets [reducing vibrations beeing transferred to the components have prooved to be usefull IMO. I won't go back, listen to music with more joy, and...the wife is happy too! A story with a happy ending therefore, I have made a lot more pics than shown, documenting various problems along the way, plus if anyone has questions I'll be able to help out, just as I was before doing this. THANKS to you all! Nico, The Netherlands.

And after fitting them into the rear-panel all measurements prooved to be correct; the rear panels can [o.k, "just" ] be inserted into the back of the cabinet.

Ports cut to size [7 inch], now that's more like it.

Making the rear panels fit, and routing the holes for the bassports was a lot of thinking-where-and-how so that everything fits afterwards.... The size of the ports is ...well... huge. I wanted these ones because when you do something...do it good! These ports are known for good results while adding no port- noise.

Placing the inside-mounted braces for the rear-panel had to be done after installing the fastrack; the opening now is just way too small.

Next the tweeter and midhorn are placed with sealant to make the enclosure airtight.

Baff- wadding applied, woofer back in place.

I still wanted to be able to go back on this mod; by leaving a edge it would be easy to place a triangular piece into the woofer-cabinet to close it again... won't be used!

Also made some room for the Crites tweeter-magnet.

Result of which....

Next was the first cut....

After preparing the port-section that will be placed in the back, the speakers and crossover were removed.

After reading almost everything there is to read [?] about the subject and trying to decide what-to-do regarding which version to make.... my wife decided for me. The inside mod it would be, and preparations were made for [ouch....] putting the saw into my beautifull cabinets. I admit that the first cut was the most difficult; thinking and re-thinking it from all angles [what if I want to reverse it again...?] but while working on it I even started to enjoy this modification-to-be. Here are some pics like promissed to all people who helped me with additional info, and giving their opinion ,without I would not have started this. [And NO..... I DO NOT WANT TO GO BACK TO STOCK....]

Thanks, so finally it's going to happen. Thanks for showing the position of the filter DizRotus, might bee a good idea if placing it behind the fastrack proves to be impossible. I'm off to work now, have to get this thing off my mind for a few hours! [can't wait to start..] Nico

THANKS everyone, the LS's are the only part of my install that has not been replaced in the past 20 years... Still, I always desired some more extention to the lower frequencies but after trying a few subwoofers without good results I gave up. It annoyed me having two big 15 inch woofers in my speakers, and just lacking this low- end extention. So I'm considering trying out the porting methode from the start it was mentioned here, but never had the guts to begin..... So I thank you all for helping out; after looking at the various methodes suggested I'm going to.....make my wife happy. I'll go for the "stealth" option, though I prefer the way like shown on Dave's site. Since I use Dave's fastracks I agree I'll benefit from the shorter horn compared to the K-400; I'm going to look if it's possible to position the ALK's behind it, and to fit the two ports on either side mounted in a removable backplate which will seal the back. If there is a need for pics I'll take them along the way and post them as a way to say "thanks"to you all for sharing the mod, plus helping me to decide which one to go for. Greetings from The Netherlands! Nico