Ed -are we talking about the Dayton RS180 or RS180S here?
Assuming the former, then with the drivers paralleled, so Sd & Vas double, and impedence (Re & Le) halves then I get this, from an MLTL: 48in x 7.5in x 12in (Internal HxWxD), Zdriver between the two units 10.25in, 3in diameter, 6in long vent, 0.25lbs ft^3 stuffing in the first 28in of the line. Admittedly this doesn't take what occurs with the XO into account, but from a mechanical standpoint it should still be happy enough. In-room, it'll be a bit over-powerful in the LF to be honest -could do with rolling off some more as room-gain is going to boost it a fair bit. Damping the bottom of the cabinet should sort that as we'll get closer to an aperiodic alignment. Either that or shifting to a classic negative taper TL alignment.
Best
Scott
Assuming the former, then with the drivers paralleled, so Sd & Vas double, and impedence (Re & Le) halves then I get this, from an MLTL: 48in x 7.5in x 12in (Internal HxWxD), Zdriver between the two units 10.25in, 3in diameter, 6in long vent, 0.25lbs ft^3 stuffing in the first 28in of the line. Admittedly this doesn't take what occurs with the XO into account, but from a mechanical standpoint it should still be happy enough. In-room, it'll be a bit over-powerful in the LF to be honest -could do with rolling off some more as room-gain is going to boost it a fair bit. Damping the bottom of the cabinet should sort that as we'll get closer to an aperiodic alignment. Either that or shifting to a classic negative taper TL alignment.
Best
Scott
Attachments
Scott,
Yes, the Dayton RS180. I plan to use Jon Marsh's Modula x-over and baffle lay-out. My response is in anticipation of room gain. I've fiddled at length with the parameters and found what I think to be a "sweet spot". It yields a response above ~150 Hz that is +/- 1 dB of the infinite baffle response. Using only 0.15 lb/cf in the upper ~third. Glad to share if you wish....though mostly concerned with energy storage issues here...and recognize I may have some with panels 14" wide.
Yes, the Dayton RS180. I plan to use Jon Marsh's Modula x-over and baffle lay-out. My response is in anticipation of room gain. I've fiddled at length with the parameters and found what I think to be a "sweet spot". It yields a response above ~150 Hz that is +/- 1 dB of the infinite baffle response. Using only 0.15 lb/cf in the upper ~third. Glad to share if you wish....though mostly concerned with energy storage issues here...and recognize I may have some with panels 14" wide.
Ed Lafontaine said:
I'd run a single holey brace most the length of the box with attachment just off-centre of the largest panels. Maybe a bit more then just off centre, since that take you uncomforatbly close to having 6 panels the same width... maybe move it to a 4th root of 2 ration?
Then i'd add at least a vestigial holey brace from the driver cutout to the cross-brace.
As an ML-TL it shouuld be fairly tolerant of a little volume loss (you dsaid you had the pieces cut.
An unbraced 14" panel is pretty significant size, i don't think dowls are going to do much.
dave
Hi Dave,
I'll look at that. I'm not stuck on the volume. The panels are still 49" long so that option is open. I've got some BB large enough for the holey braces as well.
I'm less concerned for the baffle. Home builders use a material called "LVL". The pieces for my baffles are made of this. They are 1-5/8" thick poplar plywood. There will be ~1/4" hardwood applied to them.
I'll look at that. I'm not stuck on the volume. The panels are still 49" long so that option is open. I've got some BB large enough for the holey braces as well.
I'm less concerned for the baffle. Home builders use a material called "LVL". The pieces for my baffles are made of this. They are 1-5/8" thick poplar plywood. There will be ~1/4" hardwood applied to them.
Ed Lafontaine said:
BB will make a better brace than MDF. The point with the vestigial brace for the driver, isn't with bracing the baffle, but creating a situation where the only thing attaching the driver to the structure is not the bezel. ie it is a brace -- support for the back of the driver.
dave
Ed Lafontaine said:
If I read you right, that's a total baffle thickness of approx 2/3 the mounting depth of the driver. I'm not familiar with the driver, and the pictures show a small magnet profile, with super-sized terminals.
Even fully rebated to flush with the front out the panel, you'll have a narrow constriction unless you chamfer or countersink the rear of the driver opening.
Dave,
The thought I've put into the vestigial brace leaves me challenged:
Fewer pieces would be ideal...as in just one. I think the time spent in fit-up for just one piece gets into trying even my patience...so I think I'll do it in 2: one that is fit to the drivers mounted in the baffle and one that extends from the back of the case. I'll overlap them, glue and screw them together.
The thought I've put into the vestigial brace leaves me challenged:
Fewer pieces would be ideal...as in just one. I think the time spent in fit-up for just one piece gets into trying even my patience...so I think I'll do it in 2: one that is fit to the drivers mounted in the baffle and one that extends from the back of the case. I'll overlap them, glue and screw them together.
chrisb said:
My experiment is panel resonance only, not listening. It will be a MLS signal. Listening is a subjective thing. I just want to see the differences between materials.
Exact same set-up, same driver. Small sealed box with small sized panels(don't want to waste too much of my precious MDF
)If someone has already done this, point the way to the data please.
I have the MDF, I have the spruce plywood, I just need the baltic birch - it's not available at Home Depot or Rona or any other local building supplies. Will have to go to Toronto to get it.
Ed Lafontaine said:
Both are referenced... if i use too fat a gasket on the front back of the front bezel when i mount the driver, a "spacer" needs to be added to make sure that the magnet firmly butts up againt the brace... usually it is within a couple paper thicknesses.
dave
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planet10 said:
Dave, you are the MAN! I'm thinking I'll use my Vifa PL18 and have the box~ 15 litres. Sides, front/back 10 x 12 inches; top/bottom 10 x 10.
Email cost of postage and how I will pay you.
I will be away for a week starting next week, so I'm looking forward to doing this when I return. Should be enlightening.
Hi Dave,
I'm not sure how it relates to your particular bracing, but I tried to use a support bracket with Fertins and it didn't work well.
I was a bit dissapointed as I thought that would be an improvement, but it wasn't; it sounds better without magnet supported in a back. The baffle is made out of 3" acrylic and mounted inside a stud wall with cavities filled with sand.
I'm not sure how it relates to your particular bracing, but I tried to use a support bracket with Fertins and it didn't work well.
I was a bit dissapointed as I thought that would be an improvement, but it wasn't; it sounds better without magnet supported in a back. The baffle is made out of 3" acrylic and mounted inside a stud wall with cavities filled with sand.
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Peter Daniel said:
Thanks Peter. 8-90 Venture Drive in Scarborough. Thier website says they have a Brampton location, would be better for me as I hardly ever get to the east end.
I'd like to get a couple pieces for an OB I'll be doing soon, using the Criterion woofers mentioned earier in this thread. Of course it would not have to be 3 inches thick. 3/4 or 1" would do.
Any experience bending it? Possible with a heat gun?
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