I'm now thinking the straight line without any folds, and with the driver in the middle is prob going to be:
-easy to make
-most likely to match calcs.
-Perfect to lay on its side as a center channel
-Still could be extended with a false stand to raise the driver if a
tower format is desired.
-Easy to bolt back to back to create a BI pole
- All in all, a very nice modular unit!
Also, if the line terminates on the bottom, then the false stand requires it to be changed. I feel that the front port adds some interest to a very plain front
-easy to make
-most likely to match calcs.
-Perfect to lay on its side as a center channel
-Still could be extended with a false stand to raise the driver if a
tower format is desired.
-Easy to bolt back to back to create a BI pole
- All in all, a very nice modular unit!
Also, if the line terminates on the bottom, then the false stand requires it to be changed. I feel that the front port adds some interest to a very plain front
Variac said:
And make a real tall, slim, elegant speaker... i was going to do a 3D model of this one last night, but instead got really frustrated trying to get martin's worksheets to generate anything useful for an Apexjr Super 8
I've built a couple bi-pole 1197 centres along this theme that work really well (systems both use 4 1197 BD-pipes for mains & reares & a single push-push sub (one with Philips 12s, the other with Foster 12s -- the extended range bass drivers really do much better than "official" subwoofers in these aps)
dave
Oh no! Got the drivers this evening, immediately hooked a few up to break them in a little, started ripping up some MDF, and I take a little break, come here to find you're completely changing the project?
Oh well, "spin me around and smack me upside the head" as one of our more eloquent fellow posters once said. Serves me right to be in such a hurry.
VO.1 (plus 2") is what I've got going. No prob. I'll work on something that'll be appropriate. Anyone got the dims for Spires baffles? Thanks to Tim, those drivers will be here tomorrow. How long before Xmas?
And a real question: The threads dealing with break-in didn't help much. Any recommended procedure? And how long should we expect before we appreciate what these lovely little beauties will do? 300 hrs or so?
Oh well, "spin me around and smack me upside the head" as one of our more eloquent fellow posters once said. Serves me right to be in such a hurry.
VO.1 (plus 2") is what I've got going. No prob. I'll work on something that'll be appropriate. Anyone got the dims for Spires baffles? Thanks to Tim, those drivers will be here tomorrow. How long before Xmas?
And a real question: The threads dealing with break-in didn't help much. Any recommended procedure? And how long should we expect before we appreciate what these lovely little beauties will do? 300 hrs or so?
There's nothing wrong with that, in fact, I was going to suggest that the CSA be reduced to 48" but a couple of inches of CSA doesn't seem to change the modeling. What it does do is invoke the mystical powers ala the "golden ratio".
Great! Even on a broken blade?
V0.1 plus 2" courtesy of Martin King's MathCAD worksheet
Attachments
Thank you for putting my mind at ease, Tim. This Santa's Helper will sleep better now.
Broken blade, huh? You'll laugh at this, but a tool I've had on my bench for decades is a broken sabre saw blade, fastened by a(tiny) screw and wire wrapped to a whittled, pencil-sized stick of hickory. It's a homemade x-acto knife, only longer, stronger, and sharper. That blade takes and holds a polished edge as well as my Marples chisels.
Broken blade, huh? You'll laugh at this, but a tool I've had on my bench for decades is a broken sabre saw blade, fastened by a(tiny) screw and wire wrapped to a whittled, pencil-sized stick of hickory. It's a homemade x-acto knife, only longer, stronger, and sharper. That blade takes and holds a polished edge as well as my Marples chisels.
stands and other thoughts
Stands:
I am not a big fan of stands they are an additional project that often does not get done. If possible try to not require a stand. Most speakers that requie stands end up as bookshelf speakers that look to big. I think it is reasonably easy to integrate a stand into any design. The easiest way is to extend the sides, this allows for down firing ports. A good example is the design that GM did for Pea and his JS92 project.
To help off set the tippy look it is nice to oversize and bulk up the base. The material of choice for me is polished granite, but any othe material will also work. A doulbe layer of MDF or a MDF/sand/MDF sandwinch also works.
Sharp cutting blades:
I have carefully taken appart a new Bic razor and attached the blade to a thin piece of wood. This is real sharp. A spot of epoxy glue and a wrap of hockey tape did the job for me. I think it is sharper than a regular hobby knife. You may have to use a strip or belt sander to sharpen to a point.
Be real careful these blades are sharper than you think. Of interest if you can see the blade when looked straight down at it is dull.
Another design concept for the bipole:
Rather than folding the TQWP, it would be nice to mount one driver on the slant face @ 50% and on on the back face right behind it. This would reduce the off set issue and eliminate the need for a stand. A nice slot port in the front and a granite base would be my choice. Thoughts?
Stands:
I am not a big fan of stands they are an additional project that often does not get done. If possible try to not require a stand. Most speakers that requie stands end up as bookshelf speakers that look to big. I think it is reasonably easy to integrate a stand into any design. The easiest way is to extend the sides, this allows for down firing ports. A good example is the design that GM did for Pea and his JS92 project.
To help off set the tippy look it is nice to oversize and bulk up the base. The material of choice for me is polished granite, but any othe material will also work. A doulbe layer of MDF or a MDF/sand/MDF sandwinch also works.
Sharp cutting blades:
I have carefully taken appart a new Bic razor and attached the blade to a thin piece of wood. This is real sharp. A spot of epoxy glue and a wrap of hockey tape did the job for me. I think it is sharper than a regular hobby knife. You may have to use a strip or belt sander to sharpen to a point.
Be real careful these blades are sharper than you think. Of interest if you can see the blade when looked straight down at it is dull.
Another design concept for the bipole:
Rather than folding the TQWP, it would be nice to mount one driver on the slant face @ 50% and on on the back face right behind it. This would reduce the off set issue and eliminate the need for a stand. A nice slot port in the front and a granite base would be my choice. Thoughts?
Interior dims:
L = 44.75"
So = 6.5"
SL = 71.5"
port = 2" dia x 2" L
Courtesy Martin King's MathCAD worksheet.
L = 44.75"
So = 6.5"
SL = 71.5"
port = 2" dia x 2" L
Courtesy Martin King's MathCAD worksheet.
