I think I finished with the saw dust today. I ended up making some adjustments and additions to the cut sheet. Someone suggested I should use a double baffle, and that got me thinking about the details of the bracing. The braces I initially designed reach from side to side and top to bottom across the back, but leave the baffle secured only to the sides and top. I added a wide post in the center, redesigned the vertical brace to reach all the way to the baffle, and prepared some cleats to secure the baffle to the sides with a little more beef. Any thoughts before start gluing? Fred
Fred, I like those side braces that you use to stiffen the single front baffle, might steal that idea. Now are those pieces lying to the left of the box going to span top to bottom, tying into the wide brace running front/back? IMO it looks good to start gluing and FYI you can use spackle/bondo, etc. to fill those gaps/holes/imperfections and MDF will need the edges sealed prior to painting. Just had a thought, but if someone wanted the double baffle and was not able to cut the second they could use 2 of Erich's baffles, one with roundover and one w/out to get a double baffle? Also I have to say the price on these Cel15's is tough to pass on, might pick up a pair for...well just because. I doubt they will replace my JBL 2226H/SEOS12/DNA 360 combo planned, but they might make a good present. joebuddyguy, I've used that program for several projects and it's been very helpful.
The two pieces on the left will be glued to each side first first, flush with the front edge. That way they will provide more surface for the baffle to glue to when it goes on. They won't interface with any other braces - just the baffle and the sides. I have also added a post (around 3 inches wide, 3/4 thick) to go left to right in the cabinet. I make no claims whatsoever to this being the best, or even a totally adequate way to do it, but it seems good to me. That said, I've piddled and considered and reconsidered enough. I'm gluing Sunday. I'll take plenty of pictures. A few days later I'll get a router on some edges and start prepping for finishing. I expect the backordered XO parts from PE next week. I'm hoping for shipping confirmation either tonight or Monday.
I've got my cabinets built, and my crossover parts that were back ordered are due in tomorrow. I've got some clean-up to do before I start finishing. Is there a good rule of thumb or a specific recommendation about poly fill or any damping that should be used here? I'd like to seal these things up once and not remove the drivers again.
Crossover board material I've got the world's dumbest question, but I swear I've been sweating this; what kind of material should I put my XO parts on? My problem is that I've been THINKING about it. Do I want a thick piece of wood that may vibrate? What about material like a mouse pad? Won't vibrate, but it may fall apart some day? How about plastic, like cutting up an old laundry basket? I think some people like using whatever is laying around the house, and I've seen some people really make some nice, clean looking XO's, so I know there's some latitude and philosophy involved. I don't have much wood laying around, but I've got some 1/2" drywall material, old laundry basket, some 1/2" thick rubberized pads, a 1/8th thick painted stock (like from the back side of a furniture project, and I think I have an old 3/4" 2x4 laying around. This can't be as difficult as I am trying to make it.
wvu, You are correct....it is not as difficult as you think. There are a lot of different ways to do it, don't worry too much about it falling apart. Personally, I just use some scrap thin plywood, with all components hot glued to it then solder the connections. Just lay them out, cut out the piece of wood and go to town. Usually the second one comes out better than the first. I then use industrial strength Velcro (bought at your favorite Wally World or home improvement center) to hold the assembly to either the bottom or a wall. The pic below is from one of my Karma 12's built last year.
Hey, while we're asking silly crossover building questions - I have one! Did I mess this up by putting the iron-core inductor too near the air-core inductor? I've seen that helpful sheet about positioning air-core inductors, and I understand that iron-core is better at rejecting interference (is that true?) - but I wasn't thinking about the iron-core inductor when I laid this out. I just used the OSB, cuz I had it laying around.
Here is another option for the Crossover layout. I placed all the inductors at the outer edges of the board to maximize separation.
Thanks, WVU! It took a lot longer to wire it than it did to do the layout. I went a little overboard using 12g solid copper... I had hoped to finish the second of three today, but life intervened and I had to fix our dryer and one thing led to another...Once I test the X-Over, I plan to glue all the components down with hot melt glue. For the resistors, however, I will just stabilize the ends so I don't reduce their thermal dissipation. Mike
Sure does. Sorry. I realized that there was an error elsewhere on that board, so I tried to edit the picture at photobucket. How about this: I moved the cap as indicated, but I'm still not sure about the spacing of the air-core to the iron-core.
It's not too bad, you have them point the right way as to minimize coupling. If you are worried about it you could always flip it over so it is sitting where the "Move" word is at on your picture.
Thanks for the feedback. I think I may leave that one the way it is, but I'm going to split the other boards in two - woofer and tweeter separated.
Fred, how in the WORLD did you figure out you had that cap wrong? A person almost never sees their own mistakes. I have studied and studied that schematic Bill had back on page 1, and I swear I have more anxiety about mounting and soldering that stupid XO than anyone has a right to have! If I keep this up I'll qualify for a diagnosable mental illness! I don't think it's that hard, but yeah, I am that dumb!
Come on, WVU. Have more faith in yourself!! It's not much different than following a road map. Think of each branch as different exits from the highway. Be methodical and follow the path of the electricity from the input to each speaker as it traverses the various inductors, resistors and capacitors. Try to create landmarks to identify key points in the circuit, for example, the little 1.5uf capacitor straddles the 12 ohm resistor, not the final 6.2 ohm resistor. Compare each junction on the schematic with the connections of your parts to ensure you have the same number of parts that connect together as on the schematic and that they are the same value. You could even print out the schematic and lay the physical parts on the schematic to help visualize the connections. Just make sure you connect all the grounds together and to the (-) terminal of your speaker input from the amp. Once you start, you will soon realize it's not that hard and the anticipation was way worse than the actual doing. Also, rest assured that these components are pretty hardy and are difficult to damage during handling or soldering. If you are particularly worried about your soldering technique, you can place an alligator clip on the wire lead between the component and the solder joint to act as a heat sink to protect your part from overheating. Go for it, Dude !! 8) Mike
Mike has given great advise. Go forth and follow the "map" in the schematic as if you were tracing each of the routes to their destination. Draw the same paths on your crossovers board and label all the key parts and connection points.
When I was putting the second board together, I had the diagram up on the computer monitor, and the first one I built sitting on the table. I was sorting resisters and grouping them, and I'm like, where's the 6.2 ohm resister go - I couldn't read the numbers on the monitor from where I was sitting, so I was comparing everything at once. And since most of them are small, you have to look closely and actually read the stamps on them. It was kind of a miracle that I found my error.
Thanks, Mike! And in your honor, I'll try not to set my hair on fire while soldering. +++ Update: My son is STILL not home from the Air Force, so our father/son project is in limbo for the moment. I have now ordered all my parts from PE and from Erich, so I'm just waiting to get them in the mail. I still don't have a box, so I'm pondering my next move. So I will have something to do with my son who will be home shortly I hope, pending a 2 year stint in Germany, I ordered the Fusion 10 Pure, with flat pack, so I will be able to put something together that we can plug in and listen to. There's no such thing as too many speakers, right guys? -Dave
Hi Eric, 1st post and new to this project. If I want the DNA-360 per the above quote, do I just put a note on the order? The schematic shows both compression drivers. Is it safe to assume that I do not need to modify the crossover at all? Someone asked that if you could hear the differences between the two, but I am not sure if that question was answered. Anyone else care to comment? Thanks. John
John, you might want to PM the thread starter, Bill Waslo (bwaslo). By a happy co-incidence, he designed the darn thing! I PM'd him regarding a similar question, and he PM'd back a very helpful answer in short order. A lot of the guys who are doing these projects are really knowledgeable on the spec's, and I think we've also got some really good trained "ears" from the guys who post here. I have a feeling Bill is probably both, and can tell you in both technical and practical terms the differences between the two. FYI I have also asked for Erich to substitute the DNA-360 for the 350, which is what you want to do. I am waiting for Erich to tell me how to pay the extra $40 or so for both CD's, since there is no apparent way to do that through the web site.
Here is what Erich had to say about my request to sub the DNA-360: "I go through each CD and make sure the 350's test good. Bill crossed this speaker over high enough so that the 350 could be used. And the 2 CD's sound the same from that point on up. It really would be a waste of money. But if you still want them, just let me know." I deferred to Erich's judgement and asked for the 350's. I'm still waiting to hear back about the flatpacks for this kit... Mike
210flyer and wvu80, Thanks for you suggestions. At this point, I think I will just go with the DNA-350. It is not like I have great ears to detect the small differences between the two compression drivers. Unless someone could really make a hard case for the advantages for the extended roll off frequency of the DNA-360.
The $17 difference between the drivers is a small price to pay to not have to wonder if you should have spent the extra $17.