khix Posted May 2, 2012 Share Posted May 2, 2012 Hello, I am the new proud owner of a pair of late 70's La Scala's, all original components, AA crossovers. I absolutely LOVE them, as I have wanted a pair since my first hearing them in the late seventy's. I love the tight clean bass that they produce, but have noticed the ported bottom modification that extends the bass down 35 or so hertz with out any other modification to the original, (except for removing the bottom cover). This may seem like a silly question, but what if you designed the bottom box with the same doghouse style folded horn? I am a musician, not a technician so I don't really understand all of the math and science involved here, I just know what sounds good to me, and I've always perfered folded horn bass cabinets to others. If I am going to build these, it would be pretty simple to just extend the doghouse by 10". What do you think?. I know I do not want to modify anything else, (components) so please don't suggest that or just adding a sub. I'm just kicking aroiund ideas. Thank you for your time. Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 2, 2012 Share Posted May 2, 2012 To do the ported cabinet, you need the volume made by the approx. 2 ft x 2 ft x 10 inches. This is the easiest way and totally reversible. I don't see the point of just extending the doghouse, as you still need a base for the rest of the cabinet to sit on and you don't want to get into changing the whole horn geometry of the LS cab. Unless I don't understand what you mean by extending the doghouse. Bruce Quote Link to comment Share on other sites More sharing options...
khix Posted May 2, 2012 Author Share Posted May 2, 2012 I guess what I'm asking is why the ports in the extended 10" box can't be the same design as the la scalas, instead of tubes? And isn't adding a box with tubes changing the geometry of the folded horn? Quote Link to comment Share on other sites More sharing options...
garyeanderson Posted May 2, 2012 Share Posted May 2, 2012 They (the ports) don't have to be round but I think its been said that a round port can be bit more quiet than a square or rectangular port. My clone build http://forums.klipsch.com/forums/t/137782.aspx?PageIndex=1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 2, 2012 Share Posted May 2, 2012 I guess what I'm asking is why the ports in the extended 10" box can't be the same design as the la scalas, instead of tubes? And isn't adding a box with tubes changing the geometry of the folded horn? I think I understand now. Those aren't ports on the horn of the regular LS. The woofer faces the rear of the cabinet, and splits left/right and comes back toward the front. The doghouse isn't ported. The bass mod makes the doghouse larger and adds ports to tune the cabinet. It makes a sealed cabinet a reflex cab.Bruce Quote Link to comment Share on other sites More sharing options...
sootshe Posted May 2, 2012 Share Posted May 2, 2012 Here's a plan of the LS so you can see how it works..........this is the view from the top......the speaker sits in the chamber (dog-house) & fires to the rear & then out the sides. La Scala Plans 1.pdf La Scala Plans 1.pdf La Scala Plans 1.pdf La Scala Plans 1.pdf Quote Link to comment Share on other sites More sharing options...
Brac Posted May 2, 2012 Share Posted May 2, 2012 I thought the Lascala mod involved cutting open the top of the dog house and closing in the back of the top section, then adding a port? Is this not it? Quote Link to comment Share on other sites More sharing options...
sootshe Posted May 2, 2012 Share Posted May 2, 2012 I thought the Lascala mod involved cutting open the top of the dog house and closing in the back of the top section, then adding a port? Is this not it?Yes, that's one way to do it......or you can add the additional volume underneath the horn cabinet, just by removing the bottom access plate.......this makes the mod completely reversible & requires no modifications to the original cabinet. Quote Link to comment Share on other sites More sharing options...
garyeanderson Posted May 2, 2012 Share Posted May 2, 2012 I thought the Lascala mod involved cutting open the top of the dog house and closing in the back of the top section, then adding a port? Is this not it? I dun no, I cant foll'er directions. Tough to read the stuff ya know? I just build what I want or mod what I have bought. Quote Link to comment Share on other sites More sharing options...
djk Posted May 2, 2012 Share Posted May 2, 2012 "I thought the Lascala mod involved cutting open the top of the dog house and closing in the back of the top section, then adding a port? Is this not it? " The early LaScala was a top loader, the top came off, you removed the midrange horn, and a door for the doghouse. Those are easy to change, leave off the door, add a board with ports across the back. The newer ones can be made like the older ones, or the ported riser base may be added. The ports could be a slot or round, whatever looks good to you. Quote Link to comment Share on other sites More sharing options...
Brac Posted May 3, 2012 Share Posted May 3, 2012 So, what type of speaker is this, once the mod is done? Is it still considered a folded horn? Does it become a bass reflex, and the openings are just port? Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 3, 2012 Share Posted May 3, 2012 Is it still considered a folded horn? Does it become a bass reflex, and the openings are just port? YES...Bass to 32Hz, with slightly lower efficiency. Remeber, below 125-100Hz, the LaScala acts like a direct radiator. Porting the cabinet will increase the bass respons in room. Quote Link to comment Share on other sites More sharing options...
khix Posted May 7, 2012 Author Share Posted May 7, 2012 Thank you all for your information, but I still don't think I've explained myself correctly. What I was thinking of was adding a box similar to the ported box but with the same design as the folded horn, in other words adding to the height of the bass bin. I know little about the sceince of sound, so I was hoping someone would chime in and tell this would extended the range of the bass or not. I don't think I want to change my la scala to a reflex cabinet. Once again thanks for all of you replies, I am still just kicking around ideas. Keith Quote Link to comment Share on other sites More sharing options...
djk Posted May 7, 2012 Share Posted May 7, 2012 Making the bass horn longer and making the mouth bigger will make it go lower. This can be simulated in Hornresp. What you propose will not do much, and you would need ramps in the side passages to go from the internal ~22" height to the new height (of whatever you have in mind). The result of making the mouth larger without changing the length will make it a bit smoother above 90hz or so, and no change below there. Quote Link to comment Share on other sites More sharing options...
LenE Posted May 8, 2012 Share Posted May 8, 2012 Just finished my bass bins, results so far exceeded my expectations.Lowered output of mid with 15ohm resistor in parallel with driver.L Quote Link to comment Share on other sites More sharing options...
khix Posted May 8, 2012 Author Share Posted May 8, 2012 Thank you djk-that answered my question. I still think it might look cool. I'll probably just add a subwoofer because I LOVE the way the La Scalas sound unmodified, (it seems on newer recordings the bass is somewhat lacking, but on 70's 80's stuff they blow me away, seems the newer stuff is engineered with lower frequencies, correct me if I'm wrong) and with the right sub, it will make it just what I want. Keith Quote Link to comment Share on other sites More sharing options...
mungkiman Posted July 31, 2012 Share Posted July 31, 2012 I realize this thread is a few months old, but I have a question regarding the rear-ported La Scala mod. Mine are '73 models, with the top doghouse woofer access panel, and I intend to use one as the center between horizontally placed "vertical" Cornwall speakers. The three would be fronts for the TV room, which is why I'm asking: How far from the wall would the La Scala need to be for the rear porting to be most effective? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted July 31, 2012 Share Posted July 31, 2012 The problem is as you get closer to the wall......a bass reflex speaker changes behavior from bass reflex to infinite baffle.....the good news is that the lascala rear port mod involves two ports so the infinite baffle effect is minimized........so how far away should it be....I would start with 3 times the diameter of the port as a min. A consideration.....when you connect the dog house to the upper horn chamber you gain approx 3db anyway even if you don't port......so you add ports and you can pick up 4 more db.....so if the wall causes you to loose 2db...your still ahead 5db...approximately Quote Link to comment Share on other sites More sharing options...
mungkiman Posted August 1, 2012 Share Posted August 1, 2012 Thank you! Quote Link to comment Share on other sites More sharing options...
Mrtie Posted August 5, 2012 Share Posted August 5, 2012 I have done the top box mod, though I am usuing a K402 now so I simply replaced the horn motor board and ported it using 4x7.5" pvc, and sealed the rear. It certianly does add more bass and I'm fairly happy with it plus I can dail the bass up or a down a bit with my DX-38. I will say however the bass I get is not quite as clean as it was before, but they could also be perception due to the fact it was quite anemic before, I also replaced my woofers with Crites cast frames if that in any way matters. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.