greg928gts Posted July 9, 2009 Share Posted July 9, 2009 I recently did a restoration on a pair of Khorns www.dcchomes.com/FLKhorns.html which included closing in the backs with plywood. I used 3/4" birch plywood for the braces and for the three pieces used to close in the backs. Everything was very securely glued and screwed. It ended up being a very solid cabinet. There was no movement at all from the braces or back pieces as I hefted them around my shop. I enclosed the backs by installing the pieces so that the horn size was not decreased. I did not put the pieces inside the horn, lined up with the tophat, I put them "outside" of the horn, so that the inside surfaces of the pieces were in the same place the corner wall would be on a normal Khorn. I felt like if I had made the horn smaller, the sound would have suffered. This meant that I had to increase the size of all the tophat pieces to match, so everything fit against the corner walls evenly. The whole process of closing in the backs and extending the tophat pieces added about 20 hours to the overall restoration, or about 20% more hours. I wondered if I would hear a difference, and if so, what kind of a difference. It's possible it could have been different in a bad way. Installing seals on Khorn tailboards increases mid-bass more than deep bass. Using this information, I thought it was possible that closing in the backs would maybe add too much mid-bass, which might not sound as good. Possible, but probably a stretch. What I really expected was for the bass to be stronger, making the whole speaker voiced lower. That didn't happen. I was able to compare these directly to my own Khorns in my living room. What made this comparison really cool is that these two pairs of Khorns are identical except for the closed in backs of the FLKhorns. This is why I spent the many hours it took to move Khorns all over creation and upset my household for a day to do this. This was going to be really good information. Both pairs of Khorns have the Crites woofers, ALK Universal networks, V-Trac horn, BMS 4592ND-MID drivers, and Beyma CP-25 tweeters. I used wheeled dollies, the kind that have four casters and carpeted topside that is flat. I could tip the Khorns up on their tails and slide the dolly underneath and then tip it onto the dolly. A little tricky, but it worked. I listened to my speakers, moved the others in and mine out, moved mine back in and the others out, moved the others in and mine out, and finally put mine back in for good. This audio hobby is a lot of work! Conclusion. The FLKhorns with the closed in backs had a tighter bass with better tonal definition. The bass was clearer. This was noticeable on low bass guitar notes mostly, not so much on kick drum. Both Khorns had the same low end extension and output. I didn't notice any more output with the closed in backs, and they didn't change the voicing of the speaker. This is what made it difficult to tell why they sounded different and why I had to move them in and out of my room so many times. Certainly worth it as part of a restoration, maybe not if you're not restoring them. It's too late for my Khorns, they're already restored, www.dcchomes.com/GRKhorns.html I'm not going to add backs to the bass bins. But I am seriously thinking about doing something to the walls behind my Khorns to stiffen them up, and make sure that everything is well sealed. If I'm careful about installing 3/4" plywood in my corners, I think I can get basically the same sound improvement that I noticed closing in the backs of the FLKhorns. Greg Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted July 9, 2009 Share Posted July 9, 2009 I have to wonder if you could stiffen the wall material behind your regular Khorns and achieve similar results to the enclosed backs? Or is it more complicated than just a stiffening issue. Interesting findings there. Quote Link to comment Share on other sites More sharing options...
merkin Posted July 10, 2009 Share Posted July 10, 2009 When you extended the tophat piece so that the enclosure was where the wall was why did you add the strip of wood instead of just making a new top hat piece the size of the top hat piece with the strips of wood added. Wouldn't that have been a lot less labor. You ended up veneering over it anyway. I just thought cutting and gluing those strips would be harder than just cutting a whole new piece. Maybe the cost of the extra piece of plywood? Just wondering. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted July 10, 2009 Author Share Posted July 10, 2009 When you extended the tophat piece so that the enclosure was where the wall was why did you add the strip of wood instead of just making a new top hat piece the size of the top hat piece with the strips of wood added. Wouldn't that have been a lot less labor. You ended up veneering over it anyway. I just thought cutting and gluing those strips would be harder than just cutting a whole new piece. Maybe the cost of the extra piece of plywood? Just wondering. LOL. More than once when I'm doing a restoration I wonder the same thing. Why not just build new speakers! Trying to keep the original parts intact is part of any restoration, whether it be a table or a speaker. So that's the main reason why I just fill, sand, add to, fill, sand, etc... It does seem like more work sometimes. It's not as easy as you might think to cut the top piece of a Khorn. It takes a very large saw to make those cuts, or I have to take the time to set up straight edges clamped to the piece and use a circular saw. Circular saws are famous for shredding plywood veneers though (although I know there are some very good ones out there made for this). So what I usually do is cut close to my line and then set up straight edges and use a router to clean up the cut. It actually would take more time to cut out a new top than to add the strips to the backs. I guess we could have sold the tophat pieces as is and built new ones, that would have paid for the labor and materials probably. Greg Quote Link to comment Share on other sites More sharing options...
CIGARBUM Posted July 11, 2009 Share Posted July 11, 2009 If this thread stays around long enough, I'll let you know. I am in the process of enclosing the backs of my KHorns. When I get a little further along I'll srart a new thread with lots of pictures. CB Quote Link to comment Share on other sites More sharing options...
The Dude Posted July 11, 2009 Share Posted July 11, 2009 When you guys talk about reinforcing the corners with plywood are you talking about just nail plywood over the sheet rock or taring up the walls to add more studs, braces then plywood then drywall,etc.... Nick Quote Link to comment Share on other sites More sharing options...
greg928gts Posted July 11, 2009 Author Share Posted July 11, 2009 When you guys talk about reinforcing the corners with plywood are you talking about just nail plywood over the sheet rock or taring up the walls to add more studs, braces then plywood then drywall,etc.... Nick The latter would be the best. I don't know what I'm going to do yet. I suppose putting plywood over the drywall would be ok. I would glue it as well as mechanically fastening. I would go to the top of the Khorn too. Actually I might consider going larger than the Khorn all around and then putting a bit of trim around the edge and making it more of a feature. I would still paint it the same as the walls to blend it in. Still thinking about it. Greg Quote Link to comment Share on other sites More sharing options...
The Dude Posted July 12, 2009 Share Posted July 12, 2009 The latter would be the best. I don't know what I'm going to do yet. I suppose putting plywood over the drywall would be ok. I would glue it as well as mechanically fastening. I would go to the top of the Khorn too. Actually I might consider going larger than the Khorn all around and then putting a bit of trim around the edge and making it more of a feature. I would still paint it the same as the walls to blend it in. Still thinking about it. Greg Can't wait for the build thread on that. Quote Link to comment Share on other sites More sharing options...
theplummer Posted July 13, 2009 Share Posted July 13, 2009 When you guys talk about reinforcing the corners with plywood are you talking about just nail plywood over the sheet rock or taring up the walls to add more studs, braces then plywood then drywall,etc.... Nick I've often wondered about this also. I don't have Khorn's and the WAF is absolutely against even entertaining the mere thought of considering the possibility of allowing herself to consider the possiblity of listening to me mention the thought that someday I might want a pair.But, I still daydream. I've often thought that the reason the closing in the backs gives a better result may be the more dense back corner, I.E. when shoved into a corner, the normal plaster, or drywall is augmented by another layer of reflective material. Be it more dense, thicker, stronger, more stable, who really knows. My thought would be to go to the local cultured marble shop and have panels made like a shower wall and install them in the corners. Plenty dense, and gives a finished "Marble" look. Just a thought. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted July 14, 2009 Share Posted July 14, 2009 Thanks for taking the time for a thorough and complete listening evaluation Greg. Great report and build. M Quote Link to comment Share on other sites More sharing options...
greg928gts Posted July 14, 2009 Author Share Posted July 14, 2009 Thanks for taking the time for a thorough and complete listening evaluation Greg. Great report and build. M It took me a while to figure out what I was hearing that was different. I threw my back out switching Khorns in and out by myself, so I'm hobbling around now. This is a tough hobby sometimes! [8-)] Greg Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted July 14, 2009 Share Posted July 14, 2009 I can't wait to hear these! They are supposed to be delivered on Thursday and I get home on Saturday. I need to pick up some dollies at HD and hope to have them hooked up on Sat night. Unfortunately, I don't have corners (hence the closed in backs) so not real sure what they will sound like, but I have a contractor coming next month to remedy the situation.In the meantime I will get them as close to a corner as possible and see how they do. Hope to have some results shortly. Mike Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted July 16, 2009 Share Posted July 16, 2009 When you guys talk about reinforcing the corners with plywood are you talking about just nail plywood over the sheet rock or taring up the walls to add more studs, braces then plywood then drywall,etc.... Nick The latter would be the best. I don't know what I'm going to do yet. I suppose putting plywood over the drywall would be ok. I would glue it as well as mechanically fastening. I would go to the top of the Khorn too. Actually I might consider going larger than the Khorn all around and then putting a bit of trim around the edge and making it more of a feature. I would still paint it the same as the walls to blend it in. Still thinking about it. Greg This is what I love about my 1950 home. With fire blocks between the 16 OC studs and TWO layers of 1/2" PLASTER board, my Khorns sit in some very stiff corners indeed. No drywall bounce here. Quote Link to comment Share on other sites More sharing options...
laager Posted July 26, 2009 Share Posted July 26, 2009 The real question is this: Did enclosing the backs make the unit truly 'portable'? I presume that many would like KHorns but due to corner placement are precluded from it, either by corner construction or inconvenient spacing and losing the ability to toe in or out to suit the room. Did they still benefit from corner placement or was there no significant difference in their performance when located out of a corner? Quote Link to comment Share on other sites More sharing options...
greg928gts Posted July 26, 2009 Author Share Posted July 26, 2009 The real question is this: Did enclosing the backs make the unit truly 'portable'? I presume that many would like KHorns but due to corner placement are precluded from it, either by corner construction or inconvenient spacing and losing the ability to toe in or out to suit the room. Did they still benefit from corner placement or was there no significant difference in their performance when located out of a corner? Sorry, I did not explore that. My experience tells me that it will still benefit from corner placement as all speakers do. I also believe they would perform better than stock Khorns out of a corner. Greg Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted July 26, 2009 Share Posted July 26, 2009 I have them out of the corners right now (don't have any) and they sound phenomenal! I do plan on having a false corner built next month and will reply back with my thoughts at that time. Mike Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted December 3, 2011 Share Posted December 3, 2011 bump for Tom according to Trey, the loss of lf froma Khorn pulled from corner isnt' in the lowest bass but in the 200-300 Hz region. I would think that would be an even worse issue then. Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted December 8, 2011 Share Posted December 8, 2011 If this thread stays around long enough, I'll let you know. I am in the process of enclosing the backs of my KHorns. When I get a little further along I'll srart a new thread with lots of pictures. CB Update...... I have been listening to Khorns for 40+ years. Bob's closed back units with horn, network, driver upgrades just blew me away. I never thought that a corner horn could have so much impact! tc Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted December 9, 2011 Share Posted December 9, 2011 Update......I have been listening to Khorns for 40+ years. Bob's closed back units with horn, network, driver upgrades just blew me away. I never thought that a corner horn could have so much impact! tc Yep, I've never heard a better pair than mine either. Does Cigarbum's have Greg's V-Tracs/BMS 2" driver? Just curious, since thats what's in mine. Mike Quote Link to comment Share on other sites More sharing options...
The Dude Posted February 3, 2012 Share Posted February 3, 2012 Coming back to the this thread, as I recently came into the Khorn world, and a fellow member was over a couple of weeks ago telling me how much it made a difference with closing the backs in. Plus you didn't have to deal with trying to get the corners tight and sealed. One of the problems I have is that one of my walls is only 2-3 feet long not the appropriate distance for a solid corner. But I will be adding some reinforced corners since it will be new construction. What do You guys think, just enforce the corners or close in the backs. If closing the backs in, any good threads how to do it properly. Thanks Nick Quote Link to comment Share on other sites More sharing options...
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