tomlang Posted November 5, 2011 Share Posted November 5, 2011 If you got the space (sounds like you will when the shop is done) I may be able to bring the University Deans I am finishing up to compare. I'm about 3 hours from you so not too bad. What are you using for HF units? I cannot recommend highly enough the midrange and HF unit combo from QSC as used on the SC-2150 http://www.qscaudio.com/products/speakers/dcs/dcs_sc2150.htm. The crossover is dead simple also. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 5, 2011 Share Posted November 5, 2011 WC, This is looking great. A few comments: 1) I don't understand the struts shown in the photo time-stamped "3:46 PM". When attached to that wall, they will not be the ones visible from the front (what you have shown is too long). One of us is confused here. 2) regarding the T-nuts and inadvertantly hiding them under a ramp: Yes, you are not the only one who almost did that. In my case it was dumb luck rather then planning that I got it right. 3) No, I would not put the drivers in yet. There will be room to install them later. Not much room but ... 4) Some of us used caulking to seal the seams and joints inside the doghouse to keep it airtight. It is easier to this now rather than later. 5) It looks like you had an easier time of gluing the back of the doghouse together. I did not have an easy time at that point. I had to use various jigs to keep things lined up for the assembly and gluing. Keep up the good work, but please check on point #1 (above). -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 5, 2011 Share Posted November 5, 2011 Very cool build. Looking forward to the results. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted November 5, 2011 Author Share Posted November 5, 2011 Mike, When it comes to testing I am going to have to rely on you guys expertise. I have all of the equipment but deciphering the results is a bit beyond my expertise. When someone ask me about DB I'm thinking of jumping out the stairwell of a jet. Ask me about Watts, Ohms, Farrads, Henry's or anything to do with Flying, Power Generation or Fluid Dynamics and I am cool. My technical expertise in Acoustics is sorely lacking. The closest I got to technical Acoustics was when I dated the head Acoustical Engineer (yes it was a she and a Doctor of something) at NASA Langly. I spent some quality time in the Anachoic Chamber there but it wasn't listening to music.....! That's a whole NOTHER story .....................[6] Quote Link to comment Share on other sites More sharing options...
Guest " " Posted November 5, 2011 Share Posted November 5, 2011 I like this approach. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted November 5, 2011 Share Posted November 5, 2011 My opinion .....others might disagree.....if you were to extend this by adding a small section to fill in the gap to the front motorboard, you would basically have the extended ramp assembly I disucssed earlier, which I believe will reduce cancellation. Give this some thought and certainly get the input of others. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted November 5, 2011 Share Posted November 5, 2011 This is how it's normally done....I like your approach better Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 5, 2011 Share Posted November 5, 2011 Okay, Okay. SF has cleared up the confusion. Your approach is different. The confusion was on my part. So ignore what I said about the ramps being too long etc. Quote Link to comment Share on other sites More sharing options...
jorjen Posted November 5, 2011 Share Posted November 5, 2011 Another shot of the final brackets that are the ones that you will see from the front on the finished cabinet. Again, the Kreg Jig is an absolute life saver for this type of installation...... heli001, Not trying to be negative or critical, very nice job on a great project(I know, I built a pair), hat is off to you. But, those three braces do not mount to the doghouse panel. They mount to the panel on the next fold. Just tryin' to help. EDIT: OK, what am I missing here? Am I not seeing something correctly? Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 5, 2011 Share Posted November 5, 2011 Jordan, You are having the same confusion I had. Mentally, flip the top section over. Now the angles on the struts will flare outward and not inward. He has laid it on top for the picture and not assembled / glued it up yet. I had the same thought as you: "uh oh, something is wrong here". Quote Link to comment Share on other sites More sharing options...
Coytee Posted November 5, 2011 Share Posted November 5, 2011 Hell take some time off, drive up to Charlotte and help me drink some beer.....! We can make TWO toasters or TOAST something with adult beverages. I don't need much of an excuse to stop work and drink.....I have officially joined the ranks of the retired as of last Monday! Maybe wait til your done and I'll "toss" a 402 in the back seat. (can one merely "toss" a 402 into the back seat of a Camry?) [Y] Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted November 5, 2011 Author Share Posted November 5, 2011 Tom, Fritz and all, Sorry, I have been away for a while........ I am glad of one thing, you guys will not let me make a mistake and get by with it. In my ZEAL of using the Kreg Jig I attached the wrong struts to part E at the first turn. The bad thing is, I seriously didn't notice this until I went to dry fit the outside panels part B and of course it became very obvious. Good thing is I am dry fitting everything before I glue. This is one of the main reasons that I am doing one cabinet at a time and I am writing a sequence of assembly, also. Sorry for any confusion but I truly appreciate everyone being so observent. I will report the build accurately even with all of the mistakes I make......more pictures to follow in the morning. Please continue to keep me on my toes...........W. C. Quote Link to comment Share on other sites More sharing options...
jorjen Posted November 5, 2011 Share Posted November 5, 2011 Tom, Fritz and all, Sorry, I have been away for a while........ I am glad of one thing, you guys will not let me make a mistake and get by with it. In my ZEAL of using the Kreg Jig I attached the wrong struts to part E at the first turn. The bad thing is, I seriously didn't notice this until I went to dry fit the outside panels part B and of course it became very obvious. Good thing is I am dry fitting everything before I glue. This is one of the main reasons that I am doing one cabinet at a time and I am writing a sequence of assembly, also. Sorry for any confusion but I truly appreciate everyone being so observent. I will report the build accurately even with all of the mistakes I make......more pictures to follow in the morning. Please continue to keep me on my toes...........W. C. Sorry you had a glitch there heli. But at the same time I am extremely relieved I am not crazy[] . Even after reading the posts by Fritz and Tom, I still could not see it. I spent three years on mine(on and off)and know their guts like the back of my hand. Great looking build, keep up the good work. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted November 5, 2011 Author Share Posted November 5, 2011 Jordan, Funy thing is, I have been studying these for the past three years, drew a complete set of detailed drawings and still put the braces on the wrong piece. I don't know if I have been looking at them so much for the past week that things are running together or it is just "sh!t happens"......also, working by myself an getting pulled off to go out to the construction site is a bit distracting. Anyway, I doubt that it will be the last mistake and it IS a learning process. Gives new meaning to what the guys go through at the factory and I can tell you it is NOT an easy build...of course you already know that. The vaneer on yours is absolutely beautiful....! If mine look half that good, I will be very pleased. W. C. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted November 5, 2011 Share Posted November 5, 2011 In my ZEAL of using the Kreg Jig I attached the wrong struts to part E at the first turn And here I thought you were preparing to extend the ramps around the first turn to minimize cancellation between the drone and actives in the same space. . Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted November 6, 2011 Author Share Posted November 6, 2011 Questions for the Experts How smoothe does the signal path through the flair need to be? Does the bracing need to be rounded over or would it be a good idea? Would the end of the board at the second turn need to be rounded over or would it make a bit of difference? Same thing with the backside of the braces at the mouth, would rounding over the end facing the signal make any difference? I'm thinking of eliminating any turbelence caused by the bracing in the signal path kind of like wing vortices. Now is the time to do this before glueing of the parts. May sound silly but i am thinking in Fluid Dynamics or Air flow...seems like anything to eliminate any turbelence would be an improvement. W. C. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 6, 2011 Share Posted November 6, 2011 I am certainly not an expert, but I can tell you what I did on my build. I was also concerned about turbulence so I did a slight round over on the throat with a router (mostly on the far side, opposite the driver). On the struts/braces, I eased the edges with some light sanding. I will confess that I caulked/ primed the insides and did a quick coat of black paint. In my case I used MDF and was worried about moisture. Also the black paint is good since the grill cloth (also black) is not opaque. Regarding sanding the insides to make it smooth: I would not worry about it since the wavelengths are huge in comparison to the imperfections. We all become a bit obsessed during the construction. Do I think that easing the edges a little bit helps? Well, I don't think it hurts .... Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 7, 2011 Share Posted November 7, 2011 The production braces actually come to a point...the angle brings the cut back ~2" to 3" if I'm recalling correctly. Depending on how high you intend to xover, the 3/4" cross-section starts getting big enough to have a minor effect (I try to stick to a 20:1 ratio, and that happens at 900Hz). Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 7, 2011 Share Posted November 7, 2011 Mike: That is news to me. You are saying there is a sharp face on the "throat side" (and not the "mouth side")? I agree that a flat 3/4 inch cross section is small relative to the waveform, even at 900Hz (close to a 15 inch wavelength or so) is small. To my knowledge, most of the DIY builds have not incorporated this detail. Geez, my belt sander will not fit in there. I might have to taper those struts the old fashioned way. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted November 7, 2011 Share Posted November 7, 2011 Hey Tom you can rest easy......mine have no rounding or tapering on the braces. I had seen the tapering on an early prototype though. Like you have mentioned the wavelengths involved should make any rounding or tapering unnecessary IMHO. I'm enjoying this thread W. C. Keep the pictures coming....! mike tn Quote Link to comment Share on other sites More sharing options...
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