tkot Posted December 16, 2004 Share Posted December 16, 2004 i have been taking all this info in over the last few weeks and have vacation next week. i plan on ropeing my horns and recableing the the motor leads. i saw on a thread here that someone had added a 1 inch thick board to the rear of his cornwalls. anyone know if worth the effort, while i have the corns apart?? i also want to put a felt seal on the back board jay Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted December 16, 2004 Share Posted December 16, 2004 Welcome to the Forum. I short while back I was compiling a list of popular Cornwall modifications in this Updates column. Go to the SEARCH area in upper right corner and type in Cornwall Mods Glossary. You should find a nice thread. The back stiffener is a doubling of thickness (usually 3/4 ply) glued and screwed to the inside back panel. It should be slightly small, NOT touching the side panels at all or it may buzz. While inside, there is a 1x2 or metal 'L' bracket bolted to front panel between woofer and squawker that stiffens up the motor board a bit. Good luck, Michael Quote Link to comment Share on other sites More sharing options...
Good2BHome Posted December 16, 2004 Share Posted December 16, 2004 ---------------- On 12/16/2004 9:18:28 PM colterphoto1 wrote: ....... The back stiffener is a doubling of thickness (usually 3/4 ply) glued and screwed to the inside back panel. It should be slightly small, NOT touching the side panels at all or it may buzz. While inside, there is a 1x2 or metal 'L' bracket bolted to front panel between woofer and squawker that stiffens up the motor board a bit. Good luck, Michael ---------------- Welcome, I know Michael just mis-spoke. The "back panel" stiffener should go on the "outside" screwed and glued. Otherwise, 1)you would significantly reduce the interior volume, 2) have to deal with moving the dampening material and 3) have to cut a hole in your new stiffener to accomodate the Midrange driver. Avoid screws in the area of the Midrange which should be touching the "back panel" currently. There is a correct picture in the thread he refers to by I. B. Slammin (I think). The reference to the "L" bracket is commonly called angle iron. You can also use a 23" x 1" x 2" piece of Hardrock Maple, milled very smooth on the 1" side. The brace should go on the motorboard halfway between the woofer and the midrange. The thread Michael refers to is good, but not all inclusive. I'm reasonably sure it does not mention the use of felt to seal the back panel. I have been giving serious thought to how to seal the back panel for sometime (which I believe can be a serious problem depending on the individual speaker). Felt, as you mentioned, is one of the viable solutions I settled on. However, I have been unable to find felt thick enough (IMHO) to do the job. I think it should be about 1/8" thick, 1' wide and be attached to the back panel. I want the extra 1/4" to be inside the enclosure and for practical purposes uncompressed. If you have a source for the felt I would appreciate a hint. I'm currently considering using "Sill Plate" foam, which is what builders use between the concrete foundation and the first 2x4 plate. Enough to do 5 Cornwalls is $3.47 @ HD. Good2BHome Quote Link to comment Share on other sites More sharing options...
ricktate Posted December 17, 2004 Share Posted December 17, 2004 Andy has talked about making the back board thicker,he said you should just make another back board and make it thicker then you would have the original to switch back to.You should try the gripper idea to if you have smooth floors.Since the Cornwall is not airtight i dont think it needs a seal but you could just use window weather stripping.Rick 1 Quote Link to comment Share on other sites More sharing options...
boom3 Posted December 17, 2004 Share Posted December 17, 2004 From the discussion of removing the back panel, I'm presuming we are talking about the CW I here. (although we all know now that the line between the I and the II is blurry). As a configuration management specialist, this kind of vagueness drives me nuts. Ah well... As Lawerence Welk used to say, "Ah Wun Ana Too!" He even had a license plate that read A1ANA2. McMaster-Carr is the ultimate industrial supplier and I've bought felt from them for speaker projects over the years. They carry all grades and thicknesses. They will sell you a sampler book also. The sampler is part number 9248K222. http://www.mcmaster.com/ Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted December 19, 2004 Share Posted December 19, 2004 Tim Babb (No Disc) did this mod on his CW I's and it sounded great. Best I've heard Cornwalls sound. Quote Link to comment Share on other sites More sharing options...
Good2BHome Posted December 19, 2004 Share Posted December 19, 2004 ---------------- On 12/17/2004 3:08:02 AM ricktate wrote: ................. Since the Cornwall is not airtight i dont think it needs a seal but you could just use window weather stripping.Rick ---------------- I have SERIOUS problems with this part of ricktate's statement. I hold the belief, that the Cornwall was designed with just ONE port. ANY other "openings" degrade the bass produced by the official port. The air pressure, sound or whatever you want to call it, produced by the backside of the woofer is meant to exit through the designed port. Anything else is a "Swiss Cheese Cornwall", with a resultant loss of bass. This loss may be so small as to be unhearable (but a loss none the less) or large enough to be detectable. Now I'm off my soap box, Mike Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted December 19, 2004 Share Posted December 19, 2004 ---------------- On 12/19/2004 1:43:49 PM Good2BHome wrote: ---------------- On 12/17/2004 3:08:02 AM ricktate wrote: ................. Since the Cornwall is not airtight i dont think it needs a seal but you could just use window weather stripping.Rick ---------------- I have SERIOUS problems with this part of ricktate's statement. I hold the belief, that the Cornwall was designed with just ONE port. ANY other "opennings" degrade the bass produced by the official port. The air pressure, sound or whatever you want to call it, produced by the backside of the woofer is meant to exit through the designed port. Anything else is a "Swiss Cheese Cornwall", with a resultant loss of bass. This loss may be so small as to be unhearable (but a loss none the less) or large enough to be detectable. Now I'm off my soap box, Mike ---------------- DITTO! Quote Link to comment Share on other sites More sharing options...
ricktate Posted December 19, 2004 Share Posted December 19, 2004 Ok,,,I was kinda slammed in my post on K-horn bass bin airtightness,,,some said leave well enough alone..some said oh the air will take the path of least resistance...some said the woofer cone is not airtight....some said motor board didnt have a seal on it so airtight didnt matter.So if the bass bin of a K-Horn need not be airtight why does a Cornwall....i didnt say the Cornwall should not be airtight i just said its not real important to it or they would have put a gasket on the back panel.I see they did put a gasket on the K-Horn door ,,huh.Rick Quote Link to comment Share on other sites More sharing options...
mike stehr Posted December 20, 2004 Share Posted December 20, 2004 I'm using wheather stripping, I figure it gives a good enough seal, I dunno...maybe not. JMHO, but I think the best way to get tighter bass from a Cornwall is to stiffen up the cabinets and get rid of some resonance. The back panel Mod from HDBRbuilder Andy makes sense, because the back Cornwall panel is just 3/4" piece of plywood or MDF screwed to the back. I'm sure it moves and resonates. More corner joints, or run a 1" x 1" piece of harwood in the corners of the cabinet where the panels meet. Running a brace on the front baffle between the woofer and midhorn is a good idea, I have some Hickery to maybe try. Then another brace from the front baffle brace to the back panel. Affix some sort of bracket to the back panel to hold the brace in place when installing the back panel. (Maybe another cross-brace on the back panel) Another brace can run from sidepanel to sidepanel around the center, possibly affixed to the front and back panel brace around midpoint where they would cross. There would be some loss in internal volume from the bracing, but it could be made up with polyfil, making sure not to block the ports. And get a good seal on that back panel... This should tighten things up, but then it wouldn't be the traditional Klipsch Cornwall sound. My ponderings...... Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted December 21, 2004 Share Posted December 21, 2004 ....Back Brace.... Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted December 21, 2004 Share Posted December 21, 2004 thankyouverymuch, I shall add it to the Corn Mods Glossary, pretty soon to be published. Got a good photo of the rope caulk mod? What do your cabinets look like? I'm seriously thinking about the cane grilles- Soooo retro! omigod, Ellen Degeneres has HEART on this am. should be a hoot! Seen it before, Nancy is a WHALE! Thanks, Michael Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted December 21, 2004 Share Posted December 21, 2004 ....first layer rope caulk.... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted December 21, 2004 Share Posted December 21, 2004 "omigod, Ellen Degeneres has HEART on this am. should be a hoot! Seen it before, Nancy is a WHALE!" I thought Ann was the fat one..... Quote Link to comment Share on other sites More sharing options...
Klewless Posted December 22, 2004 Share Posted December 22, 2004 Folks, I just gotta chime in on this one! You may take what I have to say with a grain (or more) of salt. The Khorn compression chamber must be air tight. Notice the word compression. The horn itself also needs to be air tight. The Cornwall is not air tight because of the port. Within reason, a little leak would not cause a problem. I agree with the statement about air taking the path of least resistance (the port not a little hole). Enclosures which depend on high compression for it's performance requires no leaks. A good example is todays acoustic suspension systems. The Cornwall is not an acoustic suspension speaker. I am not trying to say one can be sloppy in construction. A well made enclosure will not have small leaks. Relative to modifications of any speaker system means you have deviated from the original designer's intentions. It is important to not change internal conditions if you want to preserve the original. Of course, if change is what you desire, then change anything you want. As for the Cornwall, adding more internal lining will change the damping charactistics of the design (meaning no longer a true Cornwall voiced the way Paul Klipsch wanted it). Now I can get off my soap box. Hope I did not offend with my strong opinion. Quote Link to comment Share on other sites More sharing options...
tkot Posted December 22, 2004 Author Share Posted December 22, 2004 testing Quote Link to comment Share on other sites More sharing options...
tkot Posted December 22, 2004 Author Share Posted December 22, 2004 test post Quote Link to comment Share on other sites More sharing options...
tkot Posted December 22, 2004 Author Share Posted December 22, 2004 sorry about the test posts but the system keeps telling me im banned from the forum??? sometimes it will let me in , like now, and sometimes it wont. anyone else, or is it just me?? any suggestions thanks jay Quote Link to comment Share on other sites More sharing options...
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