The Dude Posted April 1, 2014 Share Posted April 1, 2014 If I use a piece of 3/4" plywood wood that is 19"x9", would 1 1/4" wide bracing be good. Or could I get by with 1" wide bracing. Quote Link to comment Share on other sites More sharing options...
moray james Posted April 1, 2014 Share Posted April 1, 2014 three times the thickness is about optimum. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 5, 2014 Share Posted April 5, 2014 What are you bracing? What are you bra ing against? Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 5, 2014 Share Posted April 5, 2014 Speaker bracing width and thickness will depend on the thickness of the wall, length of the wall, the number of cross sections on the brace, and span across. Not counting an additional 10 parameters.. I'm not sure there is really an optimum but the thicker usually the better. A simple h brace on a large span should be thick. If you do multiple cross sections and using a thick edge connecting to the panel, you don't have to be as thick. Any bracing usually better than no bracing. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 5, 2014 Author Share Posted April 5, 2014 (edited) What are you bracing? What are you bra ing against? Its a center brace on a Jamboree, its I was told to keep the volume as much as possible but keeping the bracing sturdy. 3 out of the 4 sides will be glued and screwed to the walls. The 4th will just rest against the outer wall, in the plans it shows 2 cross sections. I have seen 3 holes approx 4 1/2" diameter drilled for the air flow. But I thought if I had taken the openings a little bigger to allow more air flow it would be best. But don't want to make the cross sections to week. Edited April 5, 2014 by duder1982 Quote Link to comment Share on other sites More sharing options...
jason str Posted April 5, 2014 Share Posted April 5, 2014 What panels are in question? I will have a look. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 5, 2014 Share Posted April 5, 2014 What are you bracing? What are you bra ing against? Its a center brace on a Jamboree, its I was told to keep the volume as much as possible but keeping the bracing sturdy. 3 out of the 4 sides will be glued and screwed to the walls. The 4th will just rest against the outer wall, in the plans it shows 2 cross sections. I have seen 3 holes approx 4 1/2" diameter drilled for the air flow. But I thought if I had taken the openings a little bigger to allow more air flow it would be best. But don't want to make the cross sections to week. So are you are building a set of Jamborees? Is this the center brace between the woofers? If so since you are not really looking at air flow that should be different between the two woofers (same pressure each side of the brace) but you do what them coupled. I don't think need to be worried about the few inches you will save by cutting the support differently. This is not a small ported cabinet. It is a very large horn. It has significant bracing anyway based on if you do the design correctly so I wouldn't be too worried about the couple of cubic inches saved to not do it as shown in Volti's picture. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 5, 2014 Author Share Posted April 5, 2014 What are you bracing? What are you bra ing against? Its a center brace on a Jamboree, its I was told to keep the volume as much as possible but keeping the bracing sturdy. 3 out of the 4 sides will be glued and screwed to the walls. The 4th will just rest against the outer wall, in the plans it shows 2 cross sections. I have seen 3 holes approx 4 1/2" diameter drilled for the air flow. But I thought if I had taken the openings a little bigger to allow more air flow it would be best. But don't want to make the cross sections to week. So are you are building a set of Jamborees? Is this the center brace between the woofers? Yes, and Yes. If so since you are not really looking at air flow that should be different between the two woofers (same pressure each side of the brace) but you do what them coupled. I don't think need to be worried about the few inches you will save by cutting the support differently. This is not a small ported cabinet. It is a very large horn. It has significant bracing anyway based on if you do the design correctly so I wouldn't be too worried about the couple of cubic inches saved to not do it as shown in Volti's picture. Got it, so the bracing could be 1" wide as anything wider would be over kill. Something like 1" wouldn't vibrate to much, or do to so much proper bracing through the cabinet there wouldn't be that much flexing in this area. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 6, 2014 Share Posted April 6, 2014 If you have a way to easily make it as show, I would do it that way. Looking at the size of the front panel on that horn it could use that brace done with the three holes or like a double H brace. Additionally looking at the front panel and possible resonance, I would put something like this across the front panel at the center of the woofer. I don't think it would take mush real volume thou it should reduce the likelihood of the front panels resonating. Only problem is attaching and detaching in case of a blown woofer. In that case a set of simple 45 degree blocks at several locations to shrink the front width may be easier to do. Something like a 3" by 3" right angle cat at a 45 to avoid hitting the woofer. I'm sure you get the idea. Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 7, 2014 Share Posted April 7, 2014 What are you bracing? What are you bra ing against? Its a center brace on a Jamboree, its I was told to keep the volume as much as possible but keeping the bracing sturdy. 3 out of the 4 sides will be glued and screwed to the walls. The 4th will just rest against the outer wall, in the plans it shows 2 cross sections. I have seen 3 holes approx 4 1/2" diameter drilled for the air flow. But I thought if I had taken the openings a little bigger to allow more air flow it would be best. But don't want to make the cross sections to week. So, A Jamboree is a variation on a Jubilee? In structural engineering, a brace that carries no load on its own is designed to take 1/10th of the load of the braced member. That shows effective braces are quite small. It sounds like you are bracing the woofer back air chamber. An unattached brace resting against a panel is an invitation to buzzes and rattles. You need to attach the 4th side to the brace with screws no further than 12 inches apart. If the panel needs to come off for woofer service, perhaps a permanently attached panel with woofer access plates is a better choice. I'm pretty sure the woofers come out the top and bottom of a Jubilee. In this case, the size of the holes is unimportant. Do what is easy to build. If you can place the brace off center you will avoid reinforcing the 2nd harmonic of the unbraced panel. That is, a panel, like a guitar string will vibrate at twice the frequency if braced exactly in the middle. I'd recommend shifting the brace at least 5% of the long length away from center (5% of a 30" long panel is 1.5". So, put the brace 13.5" from one end). Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 7, 2014 Share Posted April 7, 2014 John, Thanks for the good recommendations. Bracing should never evenly spaced and if possible screwed/glued/attached on all sides if possible. The Jamboree does not look like it was screwed in the central brace and for sure should be, or attached to the front panel. It seems like the way it was done was the easier choice though likely to cause more problems than solved. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 7, 2014 Author Share Posted April 7, 2014 So would 2 braces, over the woofers be better. All so I will look and see if there is room to make acces wholes like the Jubilee, one on top and one on bottom. But would make it tough if there were braces around the drivers. That would all most make it to tough to access drivers in case of failure. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 7, 2014 Share Posted April 7, 2014 If you go with the front panel/brace as normal, make sure the front panel is screwed to the braces and the braces in turn, screwed and glued to the cabinet (if you go that way). Make sure of a tight fit and there are some products that don't harden to put between the brace (or braces) and the large front panel that when screwed in from the front, will make it almost as good as screws and hardening glue. Because of it's tackiness, it may make the front panel interesting to get off. Considering you are using 2 15" woofers horn loaded, if you blow them or need access to them, you must have been putting out some serious volume or using them for pro use. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 7, 2014 Author Share Posted April 7, 2014 Thanks for the input. I think I have a good idea what to try, as for power usage, I won't be putting more then 50 watts to these, unless needed. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 8, 2014 Share Posted April 8, 2014 Too much bracing of the wrong type can actually be detrimental..... http://www.kefamerica.com/july12/LS50%20White%20Paper.pdf Quote Link to comment Share on other sites More sharing options...
pzannucci Posted April 10, 2014 Share Posted April 10, 2014 Too much bracing of the wrong type can actually be detrimental..... http://www.kefamerica.com/july12/LS50%20White%20Paper.pdf DrWho, Thank you for the pointer. I need to reread it but some of the information makes perfect sense. I would think most any locking down and dampening of that front panel resonance, as large as it is, would be a good thing. With much smaller panels would be a little different. 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.