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Old 29th January 2013, 03:44 AM   #1131
xrk971 is offline xrk971  United States
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Quote:
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IG,
Drilling small de'Q'ing holes would indeed reduce the other modes but at the expense of collapsing the strength of the fundamental mode - as anyone who has played a flute knows how the smallest leak in one of the pads or finger holes will make the low note disappear. I discovered this first hand in my recent BIB (FIB) build when I did not seal the bottom on well because I was adjusting stuffing. There was no deep bass at all. Once it was sealed properly the low note came in strong.
On my second FIB build I found that the "Contact Paper" (used to line drawers) works as an excellent temporary seal tape for foam core boards. It provides an airtight seal to adjust stuffing while being easy to peel off without damaging the facer paper of the foam core boards.
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Old 29th January 2013, 04:54 AM   #1132
solhaga is offline solhaga  Sweden
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What about simple camping mattresses?

Click the image to open in full size.

Or are they not air tight enough??
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Old 29th January 2013, 11:16 AM   #1133
KLBIrd is offline KLBIrd  United States
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That sounds like it would work. I will check it out at Lowes the next time I am in town.
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Old 29th January 2013, 11:50 AM   #1134
solhaga is offline solhaga  Sweden
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If those can be used one can have really long strips and they are really flexible too.
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Old 29th January 2013, 03:52 PM   #1135
xrk971 is offline xrk971  United States
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The neoprene foam camping mattress should be a great gasket material (cheap and you can get long strips). For wood enclosures with screws or other means to clamp and apply pressure to make a seal in the neoprene this is fine. For foam core enclosures with no clamping screws (perhaps books applied on the face or cap to be sealed with gasket) it is more difficult. The removable tape using the Contact Paper (TM) brand covering is great because of its special adhesive which allows easy removal from the foam core without damaging the paper whatsoever. I am using it to seal the bottom cap on my Flatter (Bigger) Is Better or FIB design (Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?) and it makes a perfect seal that I can measure.
The camping mattress may also be useful for a sound absorber/damping material for lining the wall directly behind driver?

Below is a picture of the bottom cap on the FIB that I ended up taping with the Contact Paper.

Click the image to open in full size.
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Old 29th January 2013, 10:37 PM   #1136
xrk971 is offline xrk971  United States
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Default Completed Flatter is Better (FIB)

Here is a photo of my completed FIB next to the FH3-inspired speaker so you can get a sense of scale. It is 27 in tall x 16 in wide x 3 in deep and is a good size for wall mounting or covering with a painting or poster. I need to start decorating my speakers one of these days instead of leaving them in their all white glory. If you are interested in the FIB, the discussion is in the Terry Cain BIB thread. These sound very nice and they can get quite loud for how small the driver is. If you are looking for another wall mount speaker, this is an option.
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Old 29th January 2013, 10:46 PM   #1137
IG81 is offline IG81  Canada
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Quote:
Originally Posted by xrk971 View Post
Here is a photo of my completed FIB next to the FH3-inspired speaker so you can get a sense of scale. It is 27 in tall x 16 in wide x 3 in deep and is a good size for wall mounting or covering with a painting or poster. I need to start decorating my speakers one of these days instead of leaving them in their all white glory. If you are interested in the FIB, the discussion is in the Terry Cain BIB thread. These sound very nice and they can get quite loud for how small the driver is. If you are looking for another wall mount speaker, this is an option.
Looks good! Bye-bye baffle-step!

I might have a foam-core monstrosity to post later on...

IG
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Old 30th January 2013, 12:04 AM   #1138
xrk971 is offline xrk971  United States
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IG,
Yes, one of my favorite reasons for wall mount speakers is no need for baffle step comp.
Looking forward to seeing your creation, and I am sure it's not a monstrosity. I might take a razor to the side of the FIB and cut a Karlson aperture in it. Start small and cut more as needed. Good test bed for experiments like this.
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Old 30th January 2013, 01:17 AM   #1139
IG81 is offline IG81  Canada
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Here is my build. Inspired by the Nagaoka F-81, I wanted to provide more of a load to the driver than the F-81 at 12ft long (!) so made the pipe 224cm long, in order to tune it at 1/3 the driver's Fs and provide some acoustical impedance at Fs via the ¾-wave mode. Tuning ended-up at 36Hz compared to the 38Hz aim - not bad at the first try. I also wanted the terminus to be on the floor, at the side of the enclosure in order to load it with the floor, back-wall and enclosure side up to a certain point. No need for BSC here too. Some stuffing to eliminate the 7/4 and 9/4 modes above 200Hz would be necessary in a serious effort.

Here is the F-81 to have some background, just scroll down a bit:

SPI sound plaza Ida / handmade speaker basic lecture (3)/8.10cm speaker.page

Three internal segments with two folds, 30" high, 10.5" deep, 4.5" wide, with doubled-up 3/16" foam-core, here it is:

Click the image to open in full size.

Click the image to open in full size.

It's quite rough, with tons of hot-melt glue, but works. It's meant to be a very quick build for proof-of-concept after all.

There is bass down to 70Hz and good sound overall. Has the typical foam-core coloration, or so I find. Limited in SPL - yes - but good for small rooms.

IG

Last edited by IG81; 30th January 2013 at 01:19 AM.
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Old 30th January 2013, 01:34 AM   #1140
xrk971 is offline xrk971  United States
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IG,
Nice work there! Very cool to see someone taking on an old design and modding it quickly and cheaply. Thanks for the link to the Nagaoka speaker lecture - very interesting stuff there, lots of potential ideas for trying in foam core. The Flamingo and cobra are just plain crazy looking but interesting. What are the internal dimensions of your flow paths because it looks like it is expanding? Also, is that an FF85k driver?
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