Daan Posted August 12, 2014 Share Posted August 12, 2014 Though I sometimes do not understand everything said, I LOVE this project! Why? -After hearing a OB system on a audioshow nothing else seemed to come even close that day while listening to many other [ expensive!] setups [ in terms of clarity, dynamics and realism]. -I'm always trying to get my few braincells to understand loudspeakerdesigns, and looking at the pics provided together with the comments in this thread it helps and is great fun. -It shows I'm not the only one that has tried many,many things to recapture a experience, it's like a curse sometimes . There are days that I think it can't get any better and then I read another interesting story on this forum that starts me thinking again..... I've been offered a large batch of drivers , small to large, now and then but did never buy them for there was no purpose. Next time, I might just see my wife shaking her head again when I come home with a car filled with speakers... Keep up the good [experimenting] work ! Nico Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted August 12, 2014 Author Share Posted August 12, 2014 Though I sometimes do not understand everything said, I LOVE this project! Why? -After hearing a OB system on a audioshow nothing else seemed to come even close that day while listening to many other [ expensive!] setups [ in terms of clarity, dynamics and realism]. -I'm always trying to get my few braincells to understand loudspeakerdesigns, and looking at the pics provided together with the comments in this thread it helps and is great fun. -It shows I'm not the only one that has tried many,many things to recapture a experience, it's like a curse sometimes . There are days that I think it can't get any better and then I read another interesting story on this forum that starts me thinking again..... I've been offered a large batch of drivers , small to large, now and then but did never buy them for there was no purpose. Next time, I might just see my wife shaking her head again when I come home with a car filled with speakers... Keep up the good [experimenting] work ! Nico Had I never built the open baffles, I would never have believed that they would even work! Ever since, I have been stuck in the realm of the OB. The sound, to me, is just fantastic. Dynamic, and very 3 dimensional. BTW, my center channel is a pure OB speaker with a Tang Band 1808 8" driver from 270Hz-20kHz and the same dual 15" open baffle for 40-270Hz. It is by far the best center channel I have used in my home theater. Crystal clear dialog and it just sounds great. I will say that my recent changes to my acoustic treatments have helped quite a bit in maximizing the OB potential. Making a simple OB is easy and doesn't take much time. Next time you have a few drivers lying around, give it a shot. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted November 30, 2014 Author Share Posted November 30, 2014 I guess it's time to bring this thread back to life now that I have decided to start another build. I wanted to improve the OB LF baffle in several ways. First, I wanted to reduce the vertical size of the panel. Second, if possible, improve the performance a bit. Third, move the top woofer out from under the Oris horn flare. Finally, improve the aesthetics if possible. Spent about a month or so building various OB prototypes. H frames, U frames, Linkwitz W frames, M frames etc. All the prototypes had some good things and some bad things. There was no perfect solution to the problem. Based on my testing and after several reads of Martin King's papers, I decided to go with the basic H frame build. So, built a more robust prototype and got to cutting lumber. Here is the prototype. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted November 30, 2014 Author Share Posted November 30, 2014 Next decision was what material to use for the H frame. Usually I would have used Baltic Birch, but I wanted a thicker and heavier material. That led me to 1" MDF or something else. I hate working with MDF, so scrapped that option. Decided to try 1.5" butcher block counter tops from Ikea....just to try something new. Price is very competitive with BB and the solid wood counter tops seemed appealing. Here are three counter tops, ripped and ready for cutting. 1 Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted November 30, 2014 Author Share Posted November 30, 2014 Overall I found the counter tops very acceptable. They are heavy and void free. I did find they were not 'perfect' and had some slight warping, but nothing I couldn't live with. It just means I'll need a little extra sanding and touch up work to get them to look right. I wanted to minimize the amount of external hardware, so decided to mostly use glue for the build. Going for locking rabbets on the corners and inserting the baffle itself in a dado to ensure good seal between the front and back of the H frame. Still a work in progress. 1 Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 30, 2014 Share Posted November 30, 2014 Just when you think your done, you start right up. Can't wait to see the finished product. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted November 30, 2014 Author Share Posted November 30, 2014 Just when you think your done, you start right up. Can't wait to see the finished product. I can't myself. I hate seeing the shop sitting idle.....just have to have a project. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 3, 2014 Author Share Posted December 3, 2014 Moving right along with the center channel H-frame. Here is the completed build, ready for paint. Overall, working with the butcher block was not too bad at all. Very dense hardwood at 1.5" thickness. I might suggest this kind of lumber for something like a box subwoofer build. As I mentioned earlier, it is not dimensionally perfect, but it is close enough that you can sand or fill the imperfections....as you can see in my locking rabbet corners. For the curious, the baffle has a sanded area which originally was an 8" hole in the baffle, housing the center Tang Band driver. I decided to try and 'repair' the hole and see if it would work vs. building a whole new baffle. It turned out better than I expected. Used Gorilla Glue to fill any imperfections and create a strong fill. I really don't like using that stuff, but for his application, it was just perfect. Next on the agenda will be tearing down the main channel LF baffles and cutting them to fit into the other two H-frames. If I get motivated, I would like to do an outdoor sweep comparison between the new H-frame and the old 'vertical' baffle. 2 Quote Link to comment Share on other sites More sharing options...
Arash Posted December 3, 2014 Share Posted December 3, 2014 Rudy, finger joint massive panels are so sensitive to climate change. better to use some wood shield on'em. good luck Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 3, 2014 Author Share Posted December 3, 2014 (edited) Rudy, finger joint massive panels are so sensitive to climate change. better to use some wood shield on'em. good luck My plan is to paint them in the usual black lacquer to match the rest of my gear. I certainly hope I don't start running into problems with the material. I expected that the butcher block construction would provide a stable wood surface....much like plywood. BTW, it is not a finder joint as I understand a finger joint. This joint is simply a locking rabbet. Edited December 3, 2014 by Rudy81 1 Quote Link to comment Share on other sites More sharing options...
Arash Posted December 3, 2014 Share Posted December 3, 2014 (edited) Rudy, finger joint massive panels are so sensitive to climate change. better to use some wood shield on'em. good luck My plan is to paint them in the usual black lacquer to match the rest of my gear. I certainly hope I don't start running into problems with the material. I expected that the butcher block construction would provide a stable wood surface....much like plywood. BTW, it is not a finder joint as I understand a finger joint. This joint is simply a locking rabbet. I didn't mean the joint you made. I meant the connection between different pieces of the wood panel itself. if you look carefully you'll see some Zig-Zag cuts on the wood. these panels are built out of hundred smaller parts joint together. as you probably know better than me, woods sensitivity to environment depends on their inner chemicals and density. even different pieces cut out of different parts of an individual tree may differ in term of density and percentage of oil, gum, percentage of shrinkage, distribution of grains, etc. this will result in a jig-saw puzzle structure that every single element of it treats heat and humidity in a different manner so no wonder if the panels takes some cracks during seasons. it's somehow like putting a glass bowl into a microwave oven and then try "Ice bucket challenge" on it! Edit: nailing down parts with nail gun may be a good solution to keep parts steady Edited December 3, 2014 by Arash Quote Link to comment Share on other sites More sharing options...
Rick J B Posted December 3, 2014 Share Posted December 3, 2014 Rudy, you can control wood movement a bit by using a couple of coats of shellac under your lacquer finish. Shellac makes an excellent sanding sealer and slows down moisture transfer quite well. It also makes a good general purpose finish, just don't spill vodka on it. For sealer, a thin one pound cut works great. 1 Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 3, 2014 Author Share Posted December 3, 2014 Arash, I now understand what you are referring to. Yes, one would expect the different pieces to behave differently. Since this product is designed for and used in kitchen counter tops, I hope the wood has been engineered to be rather stable. Not many folks I know would accept kitchen counters that split and move very much. Time will tell if this product will work. 1 Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 3, 2014 Author Share Posted December 3, 2014 Rudy, you can control wood movement a bit by using a couple of coats of shellac under your lacquer finish. Shellac makes an excellent sanding sealer and slows down moisture transfer quite well. It also makes a good general purpose finish, just don't spill vodka on it. For sealer, a thin one pound cut works great. Interesting idea. I have never sprayed lacquer on top of shellac and don't know if shellac could withstand the chemicals in lacquer. Not many coatings do well with lacquer and its chemical makeup. Quote Link to comment Share on other sites More sharing options...
brians7 Posted December 7, 2014 Share Posted December 7, 2014 Though I sometimes do not understand everything said, I LOVE this project! Why? -After hearing a OB system on a audioshow nothing else seemed to come even close that day while listening to many other [ expensive!] setups [ in terms of clarity, dynamics and realism]. -I'm always trying to get my few braincells to understand loudspeakerdesigns, and looking at the pics provided together with the comments in this thread it helps and is great fun. -It shows I'm not the only one that has tried many,many things to recapture a experience, it's like a curse sometimes . There are days that I think it can't get any better and then I read another interesting story on this forum that starts me thinking again..... I've been offered a large batch of drivers , small to large, now and then but did never buy them for there was no purpose. Next time, I might just see my wife shaking her head again when I come home with a car filled with speakers... Keep up the good [experimenting] work ! Nico Had I never built the open baffles, I would never have believed that they would even work! Ever since, I have been stuck in the realm of the OB. The sound, to me, is just fantastic. Dynamic, and very 3 dimensional. BTW, my center channel is a pure OB speaker with a Tang Band 1808 8" driver from 270Hz-20kHz and the same dual 15" open baffle for 40-270Hz. It is by far the best center channel I have used in my home theater. Crystal clear dialog and it just sounds great. I will say that my recent changes to my acoustic treatments have helped quite a bit in maximizing the OB potential. Making a simple OB is easy and doesn't take much time. Next time you have a few drivers lying around, give it a shot. I was playing around this summer and I built a pair of H frames. I was going to put some Audio Nirvana super 8's on top of them but never finished them. Well I decided to try them with my Belles. It started out rough because I could get them to match the output of the Belles. I tried several amps to find the right gain amp to match and 15db on the Belles and 29db on the H frames works. And let me say well these things are awesome sounding they easily beat out my SVS-SB-13-Ultra. I would like to thank Dave Harris for inspiring me to build them Quote Link to comment Share on other sites More sharing options...
Rick J B Posted December 7, 2014 Share Posted December 7, 2014 Rudy, you can control wood movement a bit by using a couple of coats of shellac under your lacquer finish. Shellac makes an excellent sanding sealer and slows down moisture transfer quite well. It also makes a good general purpose finish, just don't spill vodka on it. For sealer, a thin one pound cut works great. Interesting idea. I have never sprayed lacquer on top of shellac and don't know if shellac could withstand the chemicals in lacquer. Not many coatings do well with lacquer and its chemical makeup. Um, it'll be fine. Over the 30 years I owned a cabinet shop the amount of precat and conversion varnish I've sprayed over shellac is measured in the thousands of gallons. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 7, 2014 Author Share Posted December 7, 2014 Yes, it turns out you can spray lacquer on shellac, although several woodworkers convinced me it was really not necessary. I am reaching the final stages. Sprayed the H-frames and Oris horn stands yesterday. Currently sitting in the garage letting the paint cure. I don't like entire house smelling like lacquer. The H-frames turned out pretty well and boy are they heavy! Hopefully this will all have been worth it. I also decided to build a stand for the Oris horns that would be separate from the LF H-frames so as to have flexibility in Oris toe-in etc. 1 Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted December 8, 2014 Author Share Posted December 8, 2014 (edited) Finally got everything installed today. Still waiting on a last set of Parts-express spikes for the right channel LF OB, but otherwise it is all coming together. Next will be some performance measurements, in-room, timing measurements vs. the Oris horns, crossover set and adjust, and finally the Audyssey Pro runs. These OB -frames sound very good with no tweaking and look much better than my previous iteration of the OB concept. In case anyone is curious as to why the center channel is raised on legs, it my way to keep an open space below the center OB to allow the dual SPUD subwoofers hidden behind the screen to have room to play the LFE channel without interference from the center channel. Edited December 8, 2014 by Rudy81 Quote Link to comment Share on other sites More sharing options...
davis419b Posted December 9, 2014 Share Posted December 9, 2014 Rudy,Rudy,Rudy, I really thought you were satisfied this time !! Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted December 9, 2014 Share Posted December 9, 2014 Great work as always Rudy...!! miketn Quote Link to comment Share on other sites More sharing options...
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