In the case of Pensils, another design in which removable back panel is recommended, I built mine with a continuous ledger of 3/4" x 3/4" plywood, which makes for very easy re & re of panel, and air seal with foam tape. Dave could opine whether the loss in total CSA/volume of this approach would diminish performance on the Microtowers, but my intuition is - probably not.
Of course it's a bit late to advise, but I'd always be inclined to fabricate with either the rear or bottom panel removable. In the case of this design, particularly when as well braced as your build, the latter option would only work for very skinny arms.
That's ok, don't sweat it. I'd like to see how some of these projects measure. I guess I'll just have to build a full range and find out
I'd like to build a small and sealed upper section with a large woofer ported woofer bottom section, actively crossed around 2 to 300hz. So a lot different. But I think I'll just build a small sealed full range with the plan to add the bass as fund become available. I don't have any active equipment right now. So if I did that I could measure it full range and put an end to my curiosity.
That is using bats of polyfluff... for pensil or microTower i would be "shredding/fluffing" that into a more or less homogenous volume fill.
dave
That would be my call. Even with holey braces, between the bottom & the 2 driver holes, hands, arms amd maybe a stick would be all that is needed.
dave
Sigh... already fixed the bottom at the insistence of the carpenter.
What says you to a removable top? since I already fixed the bottom, that is the last resort available to me. Sorry, maybe I forgot to indicate that top is still open.
-Zia
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Thanks Dave,
That was exactly my point of cocern (and confusion) - would I need 2 ohms or 8 ohms in parallel
... Now I am clear.-Zia
Stuffing
Dave,
Here you go with a pic of polyester fluff I took out of a cushion. Fluffier but denser material vs the poly batting... feels like a fluffy springy synthetic cotton - is this the Dacron polyfill people talk about?
Have I over-stuffed by any chance?
Also attached a pic of a "grabber" tool used for picking up things and litter. Even if I seal the cab completely, I can use this to pinch poly fluff in an out - just need to careful I don't nudge the drivers.
-Zia
Dave,
Here you go with a pic of polyester fluff I took out of a cushion. Fluffier but denser material vs the poly batting... feels like a fluffy springy synthetic cotton - is this the Dacron polyfill people talk about?
Have I over-stuffed by any chance?
Also attached a pic of a "grabber" tool used for picking up things and litter. Even if I seal the cab completely, I can use this to pinch poly fluff in an out - just need to careful I don't nudge the drivers.
-Zia
Attachments
Hope you're not making fun
. The grabber thing belongs to a friend of mine, and I've ribbed him a lot over the past few months on what a useless thing it is (he claims it's useful for picking up things scattered on the floor and reaching to get items on high shelves)... now the joke is on me
. Now I need to borrow his one for the time being and get one in the future.-Zia
Sorry to ressurect this thread, but I am wondering if you (zman01) have any feedback on the amount of stuffing that ultimately ended up working best in these Castle microtowers. I am building mine with a removable bottom, but I would like to get things as close as possible to "ideal" before installing the front panel. I am interested in drawing as much bass from the cabinet as possible...
With any enclosure design there's a balancing act between maximizing amount of bass attainable with given driver(s) and control of ripple and other artifacts from under-damping. I remember the old Bazooka brand car woofer enclosures - it's amazing the volume of bass you can get from a small diameter driver in a tube, as long as you don't mind it's only one or two notes.
Thanks Chris. I was afraid that might be the case. In my searching I found this other thread by Zman01 http://www.diyaudio.com/forums/full...material-big-differences-poly-fill-types.html so I am getting a bit closer.
Cogitech,
The Ultratouch recycled denim is really good for lining on the inner walls near the driver - very effective in absorbing the early reflections.
For Microtowers, you need to line the inner side of the top and 3 walls (inside of back panel, inner sidewalls - from top to just beneath the driver) with .75"-1" thick recycled denim. After that, it is also advised to put in a wad of fluffed up 3"-4" thick recycled denim diagonally from under the drivers to the port.
It's likely you'll have to experiment a bit.
Are you building the top firing "Castle" version?
-Zia
The Ultratouch recycled denim is really good for lining on the inner walls near the driver - very effective in absorbing the early reflections.
For Microtowers, you need to line the inner side of the top and 3 walls (inside of back panel, inner sidewalls - from top to just beneath the driver) with .75"-1" thick recycled denim. After that, it is also advised to put in a wad of fluffed up 3"-4" thick recycled denim diagonally from under the drivers to the port.
It's likely you'll have to experiment a bit.
Are you building the top firing "Castle" version?
-Zia
Thanks for the response, Zia! Yes, I am building the Castle version.
I did not check the forums at all yesterday because I woke up and immediately started working on this project, so I was acting without this advice as I completed the assembly yesterday.
Hence, I ended up using the following method:
1) 2" fibre glass insulation on back wall and one side wall
2) 100% Polyester "Supreme" Polyfil stuffed fairly consistently from just beneath/behind the two drivers all the way to the bottom of the second holey brace. The bottom section of the tower, where the port is, is empty except for the fibre glass on the back and one side.
So far, so good. I have made the base plate removable (I came up with a rather unique and very effective way to do this) , so I might add/remove some polyfil once the drivers are burned in a few hundred hours.
I did not check the forums at all yesterday because I woke up and immediately started working on this project, so I was acting without this advice as I completed the assembly yesterday.
Hence, I ended up using the following method:
1) 2" fibre glass insulation on back wall and one side wall
2) 100% Polyester "Supreme" Polyfil stuffed fairly consistently from just beneath/behind the two drivers all the way to the bottom of the second holey brace. The bottom section of the tower, where the port is, is empty except for the fibre glass on the back and one side.
So far, so good. I have made the base plate removable (I came up with a rather unique and very effective way to do this) , so I might add/remove some polyfil once the drivers are burned in a few hundred hours.
EL-70s or Pluvia 7's?
Hey Folks,
I hope you're all hanging in there as best as possible during this difficult time.
I've had my 45degree castle microtower panels milled for some time now. All that remains is routing driver holes, gluing/clamping and veneering.
Question: I have two sets of EL-70's and two sets of Pluvia 7 (the older ones, not the newer HDs).
Any recommendations? I've found the high end of the EL-70s a bit soft but to me they have killer bass...so I may add a tweeter/cap if I go with them. I've never heard the Pluvia 7's.
Thanks,
Mario
Hey Folks,
I hope you're all hanging in there as best as possible during this difficult time.
I've had my 45degree castle microtower panels milled for some time now. All that remains is routing driver holes, gluing/clamping and veneering.
Question: I have two sets of EL-70's and two sets of Pluvia 7 (the older ones, not the newer HDs).
Any recommendations? I've found the high end of the EL-70s a bit soft but to me they have killer bass...so I may add a tweeter/cap if I go with them. I've never heard the Pluvia 7's.
Thanks,
Mario
Bass on the P7 is pretty much the same as EL70, they are voiced like the Alpair 7.3
After thinkin gabout it for some time, and taking in what people say, and the 3 boxes with EL70eN i still have (2 up for grabs), i strongly susect as Mark Audio’s 1st significant build that the top ends of the drivers shipped was somewhat variable, with both some suggesting to hard on the top or too relaxed. You might have a pair of each, fire the ones with better top forward.
45° forward, or backward (like the BD-Pipe)?
dave
After thinkin gabout it for some time, and taking in what people say, and the 3 boxes with EL70eN i still have (2 up for grabs), i strongly susect as Mark Audio’s 1st significant build that the top ends of the drivers shipped was somewhat variable, with both some suggesting to hard on the top or too relaxed. You might have a pair of each, fire the ones with better top forward.
45° forward, or backward (like the BD-Pipe)?
dave
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