D-MAN Posted July 26, 2006 Share Posted July 26, 2006 I would use 2.5" depth at the throat, AND 2.5" in the non-expanding side channels - this is very close to the LS design at this point - except the LS uses 3" depth. The rest of the layout is fine. Yes, use a full-width channel reflector at the front "corners". DM Quote Link to comment Share on other sites More sharing options...
jwc Posted July 26, 2006 Author Share Posted July 26, 2006 Thank you. Will redo tonight. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted July 26, 2006 Share Posted July 26, 2006 "You started cutting?" I'm refinishing 2 pairs of LaScala's right now. They're empty, sanded, primed. I keep looking at them and asking myself if I really want to refinsh them or turn them into a set of jubilee cabs. The cabs are very nervous when ever I approach, their fate is still not final. I do have wood ready and everything else is all set to build from scratch. Quote Link to comment Share on other sites More sharing options...
jwc Posted July 26, 2006 Author Share Posted July 26, 2006 I would use 2.5" depth at the throat, AND 2.5" in the non-expanding side channels - this is very close to the LS design at this point - except the LS uses 3" depth. The rest of the layout is fine. Yes, use a full-width channel reflector at the front "corners". DM OK Dana. Doing what you quoted. Here is BFD's layout. Added is what it would do with your suggestions. There is only a distance of 1 3/4 inches between the reflector and the corner. Is this cool? Doesn't get choked does it? jc Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 26, 2006 Share Posted July 26, 2006 JW, the sound waves aren't travelling perpendicular to the line you drew, so no it doesn't get choked. In the ideal world the planar wave front will experience no effective expansion for those 2.5". In the real world the wave has a spherical front and there will be some diffraction and also a natural spherical propogation that will avoid the deflectors and get trapped in the next throat. And just a side note...don't think of it as air molecules moving in one direction. The air is wiggling back and forth - it's only the energy that is moving forward down the path. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted July 26, 2006 Share Posted July 26, 2006 D-MAN You have a PM, let me know if you do not recieve. Quote Link to comment Share on other sites More sharing options...
jwc Posted July 26, 2006 Author Share Posted July 26, 2006 Well, here you go. I think at this point, the attached should be approved by the team here. Height is 37.5". The angles aren't bad. The calculated areas are very similar to the AES paper's actual horn...not "per equation". Please let me know if you see gross errors. jc Quote Link to comment Share on other sites More sharing options...
Guest " " Posted July 26, 2006 Share Posted July 26, 2006 looks fine to me, it looks like thats what D-man recomended. My status. The Jubilees were second up after the 2 pairs of laScala's got refinished. Now Jubilees are third up, LaScala refinish is second up, and I need to knock out a quick pair of Cornwall clones this weekend. . Quote Link to comment Share on other sites More sharing options...
D-MAN Posted July 27, 2006 Share Posted July 27, 2006 Jc, there you go! that's exactly what I was talking about. SF, I sent you an email? Dana Quote Link to comment Share on other sites More sharing options...
jwc Posted July 28, 2006 Author Share Posted July 28, 2006 Update: Looks like I will be able to start a build soon. No other project ahead except for a few networks I want to try out. I have all the individual pieces drawn out separately that have the angles. It looks like two 4' x 8' x 3/4" sheets per cabinet. Here is my latest sketch from the above view. I think this may be final. I added the bracing measurements in there and added a "support" strip in the back as this area is complex and afraid of stability. Sorry for the large size. I wanted to get good overall view and always open for criticism. I unfortunately will be headin to the beach next week. I will have to visualize the build w/o actually doing anything about it. Kinda painful. jc Quote Link to comment Share on other sites More sharing options...
BEC Posted July 28, 2006 Share Posted July 28, 2006 jc, Your woofs came in today. Bob Crites Quote Link to comment Share on other sites More sharing options...
jwc Posted July 28, 2006 Author Share Posted July 28, 2006 Here is the flares on the mb. Only drawn in one set. Quote Link to comment Share on other sites More sharing options...
jwc Posted July 28, 2006 Author Share Posted July 28, 2006 jc, Your woofs came in today. Bob Crites Great Bob. Again. Just send out at the end of the week. Your stuff gets to me in 48 hours sometimes. A good thing. jc Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted August 1, 2006 Share Posted August 1, 2006 so lowoctaveacoustictransformer guys, where are you guys at on this project? someone owes me a report!! berryboy roy Quote Link to comment Share on other sites More sharing options...
seti Posted August 2, 2006 Share Posted August 2, 2006 so lowoctaveacoustictransformer guys, where are you guys at on this project? someone owes me a report!! berryboy roy Well Roy it looks like good Scotch may have gotten in the way. I see a nice full bottle of Ballantyne on the table accompanied by a glass with a generous pour [] Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 2, 2006 Share Posted August 2, 2006 bodcaw boy JC is requirements planning a non-drone version. I'm in it for the long haul on the drone version. DrWho did some modeling at around post 767343 using both a single drone and 2 drones. The 2 drone version got my vote. 1st drone will be at the cabinet core with the drivers, but using independent exit paths. The second drone will be mounted on the top driver access plate. An additional exit path will be created for the top drone that travels from the top of the cabinet, down the back, and underneath the cab so as to open toward the listening area. Current status of this project is # 3 on take off. Currently working on a cornwall clone project, followed by 2 pairs of lascalas that need refinishing. Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 2, 2006 Share Posted August 2, 2006 I wouldn't recommend non-symmetrical loading of the drones. The models were assuming that the passives were benefiting from the same transport function of the bass bin. The shorter the effective horn length for the passive, the less output you're going to get from them. There are also going to be phase issues with different pathlengths not to mention that passives can't be mounted vertically (or at least these ones can't because they're not designed for it). In the name of experimentation I would sooner try two unflared 4" ports between 8" and 10" long. Not only is it cheaper, but it's a reversible mod in the chance that porting ruins the design. Just build a removable motorboard for the middle section between the two active drivers. Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 2, 2006 Share Posted August 2, 2006 Just wanted to add that a single PR (35Hz tuning) doesn't look that bad once you've got EQ implemented on the bass bin to knock out the 100-200Hz peaks. Quote Link to comment Share on other sites More sharing options...
Marvel Posted August 2, 2006 Share Posted August 2, 2006 so lowoctaveacoustictransformer guys, where are you guys at on this project? someone owes me a report!! berryboy roy Well Roy it looks like good Scotch may have gotten in the way. I see a nice full bottle of Ballantyne on the table accompanied by a glass with a generous pour [] Good Scotch can get in the way of a lot of things.... Quote Link to comment Share on other sites More sharing options...
jwc Posted August 6, 2006 Author Share Posted August 6, 2006 so lowoctaveacoustictransformer guys, where are you guys at on this project? someone owes me a report!! berryboy roy I was at the Beach for about one week. Back now. My update is this. I guess I'm ready to build one of these. Yes I will do the non-ported version. Again, already got all the pieces mapped out. Now hear this. What are you guys thoughts on MDF. Now I'm not looking for the usual war here on MDF vs Plywood. Been talking to a couple of cabinet guys here seem to like the MDF option better. Think they can cut me sharper angles. I planned on plenty of glue and thinking of getting a nail gun verses all the sink/countersink stuff I've done in the past with #6 x 1 1/4 screws. The cabinet guys also like the way vennering works well with the MDF. I have no experience with this. The Home Depot MDF is right at 3/4 inches thick vs all the plywood they have that isn't right at 3/4 inch. The one down side I am seeing with the MDF is the weight. Lots heavier than plywood. Not concerned with resonance and solidity. Now my original plan wasn't to build a Jubilee clone but I have seen to have migrated to this. The only "real" noteable difference that I can pick out between my layout and the Jub is the reflectors at the first turn. It looks to me like the AES paper, and the recent Jub build thread, and BFD's Jub clones all used the RADIUS CORNER REFLECTOR at the first turn vs the DIAGONAL CORNER REFLECTOR. Now from what I have been reading, it would seem to me that the Jub would suffer from the Higher frequencies (we know it doesn't...right?) by using the Radius reflector. I know that Edgar in the monolith and show horn paper emphasized the importance of the DIAGONAL CORNER REFLECTOR. I have decided to go with the DIAGONAL CORNER REFLECTOR. Now this takes away from the fact that the AES article wants "point B" to be a depth of about 2 5/8. It won't happen this way with my build but I feel it makes good sense to do it this way. One other interesting thing. Now this will be one cabinet with two drivers evenly spaced...like the paper. I decided not to do "stacking" cabinets for now. Now what do you think of the one driver and one drone option? After I test the two driver option....outside with WinISD and a Microphone, why not try out the drone in place of one of the drivers. I know my SPL won't be high like 110dB but may be able to boost up that roll off in the low end. It would be easy to add mass to the drone or even change the slot this way. Any comments on this? jc Quote Link to comment Share on other sites More sharing options...
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