Hey folks. Hope everyone is doing well.
Few things i want to clarify
In the original plan of pensil 11 i don't see any damping for lining the internal walls. Is it required or only polyfill is enough.
About polyfil. Is the fillng inside pillows suitable because as far as i know they are 100% polyester fibers.
Amount of Polyfill. Is the 648 grams given in the original plan is per box..?
I do not see bevelling edges of baffle to avoid diffraction. Is it important or not really required?
regards
Berly
Few things i want to clarify
In the original plan of pensil 11 i don't see any damping for lining the internal walls. Is it required or only polyfill is enough.
About polyfil. Is the fillng inside pillows suitable because as far as i know they are 100% polyester fibers.
Amount of Polyfill. Is the 648 grams given in the original plan is per box..?
I do not see bevelling edges of baffle to avoid diffraction. Is it important or not really required?
regards
Berly
berylassocial,
My understanding is that for the Pensil design, the lining near the inside walls close to the driver helps absorb some of the early reflections. But you still have to use the required amount of poly fill.
Some pillows have good quality poly-fill inside of them - they should work fine. Look for dacron type hollow fiber fill material.
A small round-over does not do much in terms of diffraction, but still probably better than nothing. I usually do a 45 degree chamfer. If you can do round bevels that's fine too.
My understanding is that for the Pensil design, the lining near the inside walls close to the driver helps absorb some of the early reflections. But you still have to use the required amount of poly fill.
Some pillows have good quality poly-fill inside of them - they should work fine. Look for dacron type hollow fiber fill material.
A small round-over does not do much in terms of diffraction, but still probably better than nothing. I usually do a 45 degree chamfer. If you can do round bevels that's fine too.
Berly,
You are most welcome.
Looks like there are poly-fill products from from India based manufacturers:
http://www.recron.com/polyester_fibre_fill.html
I prefer the standard hollow type poly-fill vs the "Hollow Conjugate" type; I found the hollow conjugate fibers too springy.
Noticed that your location is in Dubai - so you are likely to get other brands / options too.
For lining, some wool felt / wool felt carpet underlay / jute felt carpet underlay or recycled denim felt, all should work nicely.
The lining is usually applied on inside of top, inside both sides from the top to a few inches below the driver, and similar for the inside of the back and inside of front baffle. For inside of the front baffle keep the lining away from the speaker mounting hole.
You are most welcome.
Looks like there are poly-fill products from from India based manufacturers:
http://www.recron.com/polyester_fibre_fill.html
I prefer the standard hollow type poly-fill vs the "Hollow Conjugate" type; I found the hollow conjugate fibers too springy.
Noticed that your location is in Dubai - so you are likely to get other brands / options too.
For lining, some wool felt / wool felt carpet underlay / jute felt carpet underlay or recycled denim felt, all should work nicely.
The lining is usually applied on inside of top, inside both sides from the top to a few inches below the driver, and similar for the inside of the back and inside of front baffle. For inside of the front baffle keep the lining away from the speaker mounting hole.
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Adding some absorbent felt on the walls near the driver may decrease some internal reflections back thru the cone, Sort of bealt & suspenders.
About polyfil. Is the fillng inside pillows suitable because as far as i know they are 100% polyester fibers.
Tease very thoroughly. It seems that most people who build Pensils use less damping than specified.
Room placement, taste, amplifier all play into what works best.
A chamfer or roundove ris alwats recommended, but for a real practical effect it has to be very large, which to do would require a bit of trickery with the box and the joinery.
dave
Berly,
Definitely worth trying out poly-fill from pillows. Quite a few ones in good department stores usually mention "Dacron" or use terms like "hollow fiber fill". Get the ones that feel a little dense.
Avoid the ones that feel too springy.
And Dave makes a very good point in getting the fill properly teased out.
Good luck and let us know how it goes.
- Zia
Definitely worth trying out poly-fill from pillows. Quite a few ones in good department stores usually mention "Dacron" or use terms like "hollow fiber fill". Get the ones that feel a little dense.
Avoid the ones that feel too springy.And Dave makes a very good point in getting the fill properly teased out.
Good luck and let us know how it goes.
- Zia
For my Pensils in this build I definitely used a lot less. Part of why I made the back easily removable using threaded inserts. I opened and closed it a bunch of times deciding on the fill. Scavenging from pillows is probably the way to go. But odd that it’s so expensive. In the US I found it was expensive some places and cheap others. Ended up getting it at a local upholstery store for hobbyists
Berly,
From your description I am understanding that the side pieces are 965 mm tall. So if you consider the bottom and top, they will make the inside height smaller: Total 965 mm - 18 mm (for top) -18 mm for (bottom) = 929 mm.
I would suggest make your cabinet like the attached image - the top piece and bottom piece will be on top and the bottom respectively of the two side pieces.
Previously they were placed in between the side pieces, and both had a width of 203 mm. Assuming 18 mm sides, your top and bottom pieces need to be 239 mm at least. Making them 2-3 mm extra wide and then finishing to make flush later also works.
You will be able to maintain the 965 mm internal height as outline in the plans if you build the cabinet with this small adjustment. If the top and bottom pieces have been already cut then those pieces will not come to immediate use (unless for bracing).
If the back and the baffle has been cut also, it is also salvageable with a few tricks.
Hope this makes sense.
From your description I am understanding that the side pieces are 965 mm tall. So if you consider the bottom and top, they will make the inside height smaller: Total 965 mm - 18 mm (for top) -18 mm for (bottom) = 929 mm.
I would suggest make your cabinet like the attached image - the top piece and bottom piece will be on top and the bottom respectively of the two side pieces.
Previously they were placed in between the side pieces, and both had a width of 203 mm. Assuming 18 mm sides, your top and bottom pieces need to be 239 mm at least. Making them 2-3 mm extra wide and then finishing to make flush later also works.
You will be able to maintain the 965 mm internal height as outline in the plans if you build the cabinet with this small adjustment. If the top and bottom pieces have been already cut then those pieces will not come to immediate use (unless for bracing).
If the back and the baffle has been cut also, it is also salvageable with a few tricks.
Hope this makes sense.
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