I've got a series network question - all I could find to hear a D216 with the Goldwood was an 8mH choke and 47uF electrolytic cap -- - does this let the fullrange interact with the Z as with odd order parallel passive networks with subsequent peak and flopping of the fullrange cone? besides sounding rather horrible theres too much cone movement on the fullrange with lots of "gargle" (the FR does move less than the woofer) - it seems to me if a FR can be even felt to move it will gargle - - I'm hoping a better level match plus 2nd order parallel highpass will make it near listenable but don't have the parts yet to find out what might be done with a better kludge. (D216 could use a helper tweeter too - its going to be a challenge to get near a K with HF tube) . -- - btw - put a L-Pad on D216 - got levels better but this D216 makes oem sort of rattling noise when moving ~1/8" p-p on Chinese drums - loose screws
Hi Brad
OK, so now I have to embarrrassedly admit that I was wasting Martin's time with what might turn out to be a hypothetical question, since this is quite a ways down on my project list.
The illustration shows my (not very carefully thought out) idea so far. A sonotube of a little over 22 1/2" inside diameter would meet Martin's requirement of same area, and that's the way I've drawn it - this is an unlikely size for sonotube, so I also didn't worry too much about drawing it with a 3/4" thick wall.
If I actually got around to doing it, I'd likely buy 24" sonotube and fill the inside wall with something (felt to damp ringing? bendy plywood covered with veneer?) and veneer the outside.
I've drawn the baffle for the Jordan as a simple vertical 3/4" piece of ply with a hole for the sonotube. Again, if I were to actually implement this, I think I'd try to make a baffle where the front face curved towards the front as it went to the bottom, so the top edge would be 3/4" thick (or thereabouts) and the bottom maybe 4" thick. The easiest way to do this would be to build ribs and panel them with thin plywood front and rear - then fill in the voids with sand, kitty litter, or expanding foam, depending on weight and convenience requirements.
Probably you'd want to make the simple baffle first to find the correct fore-and-aft alignment for the drivers.
Anyway, that's as far as I had got. Do show us if you implement something with your sonotube.
Regards.
Aengus
Attachments
hey Zilla - if "full-out" applied to me = probably so - "1st order" highpass can push excursion beyond no highpass at all at resonance. - - I dug out an old 10 gauge 3.3mH aircore to put across D216 plus 47uF cap - excursion is bearable but theres what might be dustcap rattle. re:High Q OB FR - lest see if Nelson will give some opinion at a certain price point such as Fe206E vs L. Cao ferrite - - at the place they're crossing over with woofer on baffle lower Qts might not matter too much
got a pad question - with 2nd order passive highpass is it good to put a simple series R "berfore" the cap? - does this retain the good damping of the network and lallow some possible HF tailoring via cap across the pad R?
got a pad question - with 2nd order passive highpass is it good to put a simple series R "berfore" the cap? - does this retain the good damping of the network and lallow some possible HF tailoring via cap across the pad R?
Aengus,
Thanks for your input. your idea looks great. As you this is just a thought since I have quite a few projects on the table.
I was envisioning something differant than you. Thinking of making the sono look like it is floating with one spike in the front and two in the rear. Then make the baffle for the Jordan the same width as Martin's but have the top and the bottom of that baffle matching the radius of the sono.
At our next club meeting I am going to offer my services to build one as per Martin's spec to one of our members and hoping someone will bite just to have the first listen. Figure I could knock one of them out in a weeknd with all of the parts on hand and if I like it go for something maybe as I described above.
Just thought of something. With the top of the sono being a radius, will this have any effect on the performance of top baffle?
Brad
Thanks for your input. your idea looks great. As you this is just a thought since I have quite a few projects on the table.
I was envisioning something differant than you. Thinking of making the sono look like it is floating with one spike in the front and two in the rear. Then make the baffle for the Jordan the same width as Martin's but have the top and the bottom of that baffle matching the radius of the sono.
At our next club meeting I am going to offer my services to build one as per Martin's spec to one of our members and hoping someone will bite just to have the first listen. Figure I could knock one of them out in a weeknd with all of the parts on hand and if I like it go for something maybe as I described above.
Just thought of something. With the top of the sono being a radius, will this have any effect on the performance of top baffle?
Brad
Hi Brad
Your suggestion should look pretty good as well. Both your and my ideas have (if I'm understanding your description) the drawback of having to make a large precise hole in the baffle, so it fits around the sonotube, but at least with your design you're not trying to make the hole through a thick, curved-front one!
You still have the problem of connecting the two rear spikes to the sonotube in an aesthetically pleasing fashion - I'm not sure how I'd tackle it.
I attach a sketch showing what I think you described, and showing one possible way of attaching the rear spikes - don't know that I'm all that keen on the leg shape, though. What did you have in mind?
Regards.
Aengus
Your suggestion should look pretty good as well. Both your and my ideas have (if I'm understanding your description) the drawback of having to make a large precise hole in the baffle, so it fits around the sonotube, but at least with your design you're not trying to make the hole through a thick, curved-front one!
You still have the problem of connecting the two rear spikes to the sonotube in an aesthetically pleasing fashion - I'm not sure how I'd tackle it.
I attach a sketch showing what I think you described, and showing one possible way of attaching the rear spikes - don't know that I'm all that keen on the leg shape, though. What did you have in mind?
Regards.
Aengus
Attachments
Hey Aengus,
You are pretty good with that sketching. Note that the baffle for the Jordan is 20" square. I was thinking since the sono will probably be wider than the upper baffle the sides would be stratight and not extend as far down Now seeing your sketch I probably wouldn't have as large of a radius at the top.
Other words more like this but the bottom fitting the sono.
http://www.audiocircle.com/circles/index.php?topic=59619.msg543404#msg543404
The rear feet is what I was thinking but not as wide.
Thanks for posting the sketch.
Brad
You are pretty good with that sketching. Note that the baffle for the Jordan is 20" square. I was thinking since the sono will probably be wider than the upper baffle the sides would be stratight and not extend as far down Now seeing your sketch I probably wouldn't have as large of a radius at the top.
Other words more like this but the bottom fitting the sono.
http://www.audiocircle.com/circles/index.php?topic=59619.msg543404#msg543404
The rear feet is what I was thinking but not as wide.
Thanks for posting the sketch.
Brad
Brad, those look pretty good. The trick in the sonotube design will be finding an upper curve that harmonizes with the sonotube's curve. What about tapering, so that the baffle is 20" across where the Jordan is but widens to fit the sonotube?
Damn, I'm starting to want to build this thing.
Regards.
Aengus
[edit]I used to be able to punctuate...
Attachments
Visio. I use it often and find it pretty fast and intuitive by now. Sketchup would obviously be better for 3d views but I struggle every time I use it. I should get Dave (Planet10) to give me a lesson - he does great stuff with it.
Details of attaching the upper baffle to the sonotube need to be worked out - the problem being that I don't think the sonotube walls are all that good for fastening to. I expect you'd have to glue some longitudinal braces to the tube and fasten to that.
Regards.
Aengus
That should work and look good. I think I'd glue that rear brace to the sonotube though, not just rely on screws. There'll be a lot of leverage against it if someone pushes on the top of the baffle.
You must have a bigger listening room than mine.
I'm still dithering over whether I could get away with the 18" in my living room or should try it (assuming I do this at all) with the Alpha 15.
Regards.
Aengus
Hi Brad
I was referring to freddi's suggestion of two of the 18" drivers per channel - that would make a pretty imposing speaker!
Have you tried the Alpha with any other FR besides the FE87E? I have a pair of Jordans and a pair of FE108EZ waiting for me to do something other than work and/or furniture projects. Wouldn't mind trying these combos...
Regards.
Aengus
Sorry missed that.Aengus said:
I have only used the 87E in this project.
http://www.quarter-wave.com/OBs/OB_Design.pdf
Others have used the 108EZ but said it needed to be padded, The 87E to me was a perfect match.
Brad
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.