Acoustic Transparency of Spandex - The Truth - Page 13 - AVS Forum | Home Theater Discussions And Reviews

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post #361 of 382 Old 11-26-2015, 08:43 AM
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MississippiMan
I'm almost done redoing the front wall of my 15'w by 24'l room. The wall where I can put a screen is 152" wide.
I'm currently using a Benq w1070 (will upgrade to a Sony or JVC when funds allow)
What is the largest size screen you would recommend for my setup? And what distance to mount the projector?
Thx

Sent from my HTC6525LVW using Tapatalk

________
Ltek

setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES
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post #362 of 382 Old 11-26-2015, 11:43 AM
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Originally Posted by bud16415 View Post
If I can ask a question about your setup?

How will you get your projector to focus on a curved screen? I also have been thinking about curved screens and the focus problem is my biggest issue in trying.
Bud,

The screen is 115.75" wide (ID) of a 2x8 support frame and 118.75" (OD). This is .5" over the calculated 115.25" width needed for a 125" diagonal 2.37:1 aspect ratio needed so the picture frame (wrapped in black velvet) will overlay the support frame on the inside by .25" on all sides. The depth of the curve at the center of the screen is only 3.5" in my case. I will check the focus when completed and if it is unacceptable I will go back to an anamorphic lens.

I am taking pictures and hope to share the tweaks I have made to other designs that have inspired and given me the opportunity to learn from the experiences of others on this great forum. I have attached a pdf file that I found helpful in creating a smooth curve.

I am not sure when I will be able to post my screen build as last week the northwest suffered a severe wind storm with a loss of power to approximately 175,000 people in the Spokane, WA area. Our power was restored after 3 days but many trees were also knocked down including a 70+' ponderosa pine on my house causing extensive damage. On top of that we received our first snowfall Tuesday.

I hope this helps and let me know if you have any other questions.

Jack
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File Type: pdf Chords and arc heights - Math Central.pdf (358.9 KB, 17 views)
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post #363 of 382 Old 11-26-2015, 03:02 PM
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Quote:
Originally Posted by MississippiMan View Post
Thank you, your welcome....And I'll do my best.


With such a slight radius, if the Spandex is stretched equally across the Frame, with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension.

Since I do not know what materials or method you are using / have used to construct the frame, I'm limited in what suggestions I can provide. I can relate that if a Flexible Frame is used, and the material is stretched across it first, when it is bent into the Curve desired, the Spandex easily conforms equally to said curvature.

A great PJ, that. More on that below....

No.....White over White. You need none of the additional Contrast enhancement Black would provide, and two layers of White will effectively mask any surfaces behind the first initial layer.

Also, White on White will maintain the maximum allowable Gain that Spandex can provide.

And you should. By availing yourself of the Lens Shift, you should mount the PJ as far forward as you possibly can tolerate. Again, this is to preserve your available Lumen output, and therein the gain off screen.

Looking at all the above suggestions, if you place the PJ forward to 14'-3" to achieve 20 fl (18' would garner only 16 fl ) your results watching 3D in a totally darkened room would be very acceptable.

Following just behind it's fantastic Audio properties, the one other thing that helps justify Spandex above all else it it's smoothness. Using DLA optics, the last thing anyone would want is seeing any vestige of surface-induced texture. XD material just isn't in the same league in that respect. Virtually nothing "AT" is for that matter.

Hey...I got'cher back, Jack.

(...I couldn't resist.... )
MM,

Thanks for the quick reply and I hope you are having great Thanksgiving!

To answer your question about what materials or methods I have or am using I hope the following makes sense:

The material I am using for the support frame is almost clear, hand selected 2x8 fir/larch (nominal width is 7.25") with the 3.5" depth of the curve cut out over an arc of 118.75" leaving a 3.75" width at the center. I was going to route a key track approximately 2" back from the front edge to slide black .25"x.75" hex head bolts to line up with the black .25" (ID) grommets I was going to put in folded over and glued XD material to be tensioned with .125" 325 paracord. The .25" hex head bolts would be topped with black washers and locked in place with a black .25-20 x .375" Knurled Thumb Nut. Below the knurled top is a nice rounded groove to rap the paracord. Each side would have two paracord locks to adjust the tension independently. Two 1x3 clear hemlock supports placed 1/3 from the sides to provide horizontal support. Route a 45 degree angle on the back inside edge of the top and bottom support frame for long french cleats with an allowance to adjust laterally to center. Black felt on the wall facing edge. The outer picture frame wrapped with black velvet will overlap the inside edge of the support frame by 1/4" and will be built flat with 3 flush bolts on the top and bottom (1 in the center and the other two 1/3 from the sides to pull the frame to the curvature of the screen). The velvet frame is 3.5" wide and will extend 1.75" beyond the support frame. I was planning on putting 2 90 degree angle brackets in each corner to align the velvet frame on the support frame. If I put LED rope lights around back of the velvet frame there will be no light leakage to the inside. Additionally, if I put some LED lights behind the screen to light up the inside to see the speakers it will not leak out around the edges.

Now that you have saved me from the brink of ordering the XD material and I am sold on the white Milliskin I would still like to be able to adjust the tension on the Milliskin, if possible, instead of stapling?

Do you know if it is possible to fold over Milliskin 2 or more times and/or either glue or sew clear elastic to reinforce a seam to put grommets in? Or if the Milliskin can be folded over on itself to allow a a stiff wire to be inserted to provide tension in both directions? The more I think about it the more it seems like a lot of work since the stretchiness of the Milliskin is the tension that the XD doesn't have.

I am assuming that once the Milliskin is laid out the order of tensioning/stapling would be starting with the center top and bottom then the center sides and gradually work your way around in a circle until the corners are reached? How do you tell what is enough or too much tension for the Milliskin? Is the tension the same for both layers? I would think that once the initial tension is set that it would be fairly easy to duplicate by just watching the material as you pull and staple. Can a coin drop determine if the tension is correct? Or a spring scale for the opposite side of the first staple? Another thought I just had is probably the simplest - if the Milliskin should be stretched say 15% for every foot that would translate to 1.8" for every foot which can be easily measured!

What is the gain of 2 layers of Milliskin matte white you used in your screen calculations?

I am also considering implanting round coin sized neodymium magnets under the velvet to add 1.78/1.86 and/or 1.33 masking panels at a later date. Do you have any suggestions? Would the Milliskin matte black make a good AT mask?

I have 3 Sunfire CRS-3C speakers that will all be mounted vertically behind the Milliskin. Should the speaker grills be removed? What is the closest the speakers should be to the Milliskin?

Is there anything that an Audyssey XT32 calibration does not correct on an AT screen?

Wow, I hope this isn't too much information. Any suggestions greatly appreciated!

Jack
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post #364 of 382 Old 11-26-2015, 08:07 PM
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Quote:
Originally Posted by Livin View Post
MississippiMan
I'm almost done redoing the front wall of my 15'w by 24'l room. The wall where I can put a screen is 152" wide.
I'm currently using a Benq w1070 (will upgrade to a Sony or JVC when funds allow)
What is the largest size screen you would recommend for my setup? And what distance to mount the projector?
Thx

Sent from my HTC6525LVW using Tapatalk
Suggested Throw Distance: 11'

Foot Lambert for both the following size is 18 fl @ 0.9 gain (White on White Milliskin)

Largest Suggested Screen Size:

16:9 @ 126" Diagonal = 62" x 110" (view-able)

Mount Speakers within 6" of Spandex. You can remove the Grills...it cannot hurt

"They said it couldn't be done. Well, we sure showed 'em otherwise!"
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post #365 of 382 Old 11-26-2015, 08:11 PM
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Jack...lots to digest while digesting.

I'll attempt to answer you coherently tomorrow.

"They said it couldn't be done. Well, we sure showed 'em otherwise!"
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post #366 of 382 Old 11-26-2015, 08:24 PM
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Quote:
Originally Posted by MississippiMan View Post
Suggested Throw Distance: 11'

Foot Lambert for both the following size is 18 fl @ 0.9 gain (White on White Milliskin)

Largest Suggested Screen Size:

16:9 @ 126" Diagonal = 62" x 110" (view-able)

Mount Speakers within 6" of Spandex. You can remove the Grills...it cannot hurt
Would white on silver or black increase contrast noticeably?

I'm using BOM from Joanne fabrics with a 11' throw and the w1070 is super bright even in Ecosmart and Eco modes

Sent from my HTC6525LVW using Tapatalk

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Ltek

setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES

Last edited by Livin; 11-26-2015 at 08:28 PM.
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post #367 of 382 Old 11-27-2015, 03:42 AM
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Would white on silver or black increase contrast noticeably?

I'm using BOM from Joanne fabrics with a 11' throw and the w1070 is super bright even in Ecosmart and Eco modes

Sent from my HTC6525LVW using Tapatalk
Silver underlay would give the most "controlled" increase....Black the most dramatic. But the subsequent loss of gain ( 0.8/ Grey - 0.7/ Black ) might overwhelm even the 1070's brightness at sizes larger than 120" diagonal....especially if any 3D viewing comes into play.

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post #368 of 382 Old 11-27-2015, 08:53 AM
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Quote:
Originally Posted by MississippiMan View Post
Silver underlay would give the most "controlled" increase....Black the most dramatic. But the subsequent loss of gain ( 0.8/ Grey - 0.7/ Black ) might overwhelm even the 1070's brightness at sizes larger than 120" diagonal....especially if any 3D viewing comes into play.
I guess I could do WoW and buy some Black and/or Silver for when I get a projector upgrade to an Epson 5025/30 or Sony? But even right now, Contrast & PQ is more important than brightness to me - trying to squeeze as much out of my W1070 until I can afford an upgrade.

How much difference is 15 or 16 vs 18 FL? If I want a 139-140" diag the calculator shows 15-16FL (looks like 140 is on the bubble) - placing the proj at 13' throw (which would be nicer since it would be behind the first row of seating (less noise).

thx for the help!

________
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setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES
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post #369 of 382 Old 12-06-2015, 08:39 AM
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Quote:
Originally Posted by MississippiMan View Post
Silver underlay would give the most "controlled" increase....Black the most dramatic. But the subsequent loss of gain ( 0.8/ Grey - 0.7/ Black ) might overwhelm even the 1070's brightness at sizes larger than 120" diagonal....especially if any 3D viewing comes into play.
I concur. A couple years ago I resurfaced my 114" wide screen (130" diagonal) four times while experimenting with various combinations; WoW, SoW, WoS & WoB.(The poor frame looks like a pincushion from all the staples). I settled on WoB in an effort to optimize the balance between brightness and black level. Now 4000 hours later the image from my W1070 mounted 11' feet away is still very watchable however I am aware that it is tad dim. A bulb replacement will bring back the "pop", but White over Silver would likely have been a better compromise.
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post #370 of 382 Old 12-12-2015, 08:26 PM
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Since I am planning only a 100" diagonal, WoB (or just W -- I have a black background) seems the best.
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post #371 of 382 Old 01-04-2016, 11:48 PM
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Originally Posted by jkosanke View Post
MM,

Thanks for the quick reply and I hope you are having great Thanksgiving!

To answer your question about what materials or methods I have or am using I hope the following makes sense:

The material I am using for the support frame is almost clear, hand selected 2x8 fir/larch (nominal width is 7.25") with the 3.5" depth of the curve cut out over an arc of 118.75" leaving a 3.75" width at the center. I was going to route a key track approximately 2" back from the front edge to slide black .25"x.75" hex head bolts to line up with the black .25" (ID) grommets I was going to put in folded over and glued XD material to be tensioned with .125" 325 paracord. The .25" hex head bolts would be topped with black washers and locked in place with a black .25-20 x .375" Knurled Thumb Nut. Below the knurled top is a nice rounded groove to rap the paracord. Each side would have two paracord locks to adjust the tension independently. Two 1x3 clear hemlock supports placed 1/3 from the sides to provide horizontal support. Route a 45 degree angle on the back inside edge of the top and bottom support frame for long french cleats with an allowance to adjust laterally to center. Black felt on the wall facing edge. The outer picture frame wrapped with black velvet will overlap the inside edge of the support frame by 1/4" and will be built flat with 3 flush bolts on the top and bottom (1 in the center and the other two 1/3 from the sides to pull the frame to the curvature of the screen). The velvet frame is 3.5" wide and will extend 1.75" beyond the support frame. I was planning on putting 2 90 degree angle brackets in each corner to align the velvet frame on the support frame. If I put LED rope lights around back of the velvet frame there will be no light leakage to the inside. Additionally, if I put some LED lights behind the screen to light up the inside to see the speakers it will not leak out around the edges.

Now that you have saved me from the brink of ordering the XD material and I am sold on the white Milliskin I would still like to be able to adjust the tension on the Milliskin, if possible, instead of stapling?

Do you know if it is possible to fold over Milliskin 2 or more times and/or either glue or sew clear elastic to reinforce a seam to put grommets in? Or if the Milliskin can be folded over on itself to allow a a stiff wire to be inserted to provide tension in both directions? The more I think about it the more it seems like a lot of work since the stretchiness of the Milliskin is the tension that the XD doesn't have.

I am assuming that once the Milliskin is laid out the order of tensioning/stapling would be starting with the center top and bottom then the center sides and gradually work your way around in a circle until the corners are reached? How do you tell what is enough or too much tension for the Milliskin? Is the tension the same for both layers? I would think that once the initial tension is set that it would be fairly easy to duplicate by just watching the material as you pull and staple. Can a coin drop determine if the tension is correct? Or a spring scale for the opposite side of the first staple? Another thought I just had is probably the simplest - if the Milliskin should be stretched say 15% for every foot that would translate to 1.8" for every foot which can be easily measured!

What is the gain of 2 layers of Milliskin matte white you used in your screen calculations?

I am also considering implanting round coin sized neodymium magnets under the velvet to add 1.78/1.86 and/or 1.33 masking panels at a later date. Do you have any suggestions? Would the Milliskin matte black make a good AT mask?

I have 3 Sunfire CRS-3C speakers that will all be mounted vertically behind the Milliskin. Should the speaker grills be removed? What is the closest the speakers should be to the Milliskin?

Is there anything that an Audyssey XT32 calibration does not correct on an AT screen?

Wow, I hope this isn't too much information. Any suggestions greatly appreciated!

Jack
MM,

Your quote:

Since I do not know what materials or method you are using / have used to construct the frame, I'm limited in what suggestions I can provide. I can relate that if a Flexible Frame is used, and the material is stretched across it first, when it is bent into the Curve desired, the Spandex easily conforms equally to said curvature.

Pictures attached,

The outside dimensions of my frame is 118.75" wide and 52" high. If I allow for a 50% stretch in both directions I would be cutting the spandex to 79.2" (W) x 36.6" (H). Stretching another 2" in each direction (1" around the corner of the frame and 1" to fold back over the elastic hem) would result in 54% stretch horizontally and a 59% stretch vertically. I have attached pictures of my frame with a 1/4" T-Slot routed around the entire frame 1-7/8" back from the leading edge. The 1/4" hex bolt will slide in the T-Slot with a washer and knurled knob to line up grommets attached every 2.5" (unstretched) and every 3.75" after stretching. The 1/8" paracord will be laced through the grommets and around the groove in the knurled knob.

Your quote:

With such a slight radius, if the Spandex is stretched equally across the Frame, with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension.

I am not sure what you mean about "...with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension

I mocked up a table with dimensions of 118.75" x 52" and covered it with a tarp to keep from snagging the spandex when I work on it. Is a sharp razor the best way to cut spandex? Scissors don't seem to cut very straight.

I am ready to prepare the spandex to attach to the frame when I return from CES and was wondering if you have a final suggestions?

Thanks again for your help and Happy New Year!

Jack
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post #372 of 382 Old 01-04-2016, 11:49 PM
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Originally Posted by jkosanke View Post
MM,

Thanks for the quick reply and I hope you are having great Thanksgiving!

To answer your question about what materials or methods I have or am using I hope the following makes sense:

The material I am using for the support frame is almost clear, hand selected 2x8 fir/larch (nominal width is 7.25") with the 3.5" depth of the curve cut out over an arc of 118.75" leaving a 3.75" width at the center. I was going to route a key track approximately 2" back from the front edge to slide black .25"x.75" hex head bolts to line up with the black .25" (ID) grommets I was going to put in folded over and glued XD material to be tensioned with .125" 325 paracord. The .25" hex head bolts would be topped with black washers and locked in place with a black .25-20 x .375" Knurled Thumb Nut. Below the knurled top is a nice rounded groove to rap the paracord. Each side would have two paracord locks to adjust the tension independently. Two 1x3 clear hemlock supports placed 1/3 from the sides to provide horizontal support. Route a 45 degree angle on the back inside edge of the top and bottom support frame for long french cleats with an allowance to adjust laterally to center. Black felt on the wall facing edge. The outer picture frame wrapped with black velvet will overlap the inside edge of the support frame by 1/4" and will be built flat with 3 flush bolts on the top and bottom (1 in the center and the other two 1/3 from the sides to pull the frame to the curvature of the screen). The velvet frame is 3.5" wide and will extend 1.75" beyond the support frame. I was planning on putting 2 90 degree angle brackets in each corner to align the velvet frame on the support frame. If I put LED rope lights around back of the velvet frame there will be no light leakage to the inside. Additionally, if I put some LED lights behind the screen to light up the inside to see the speakers it will not leak out around the edges.

Now that you have saved me from the brink of ordering the XD material and I am sold on the white Milliskin I would still like to be able to adjust the tension on the Milliskin, if possible, instead of stapling?

Do you know if it is possible to fold over Milliskin 2 or more times and/or either glue or sew clear elastic to reinforce a seam to put grommets in? Or if the Milliskin can be folded over on itself to allow a a stiff wire to be inserted to provide tension in both directions? The more I think about it the more it seems like a lot of work since the stretchiness of the Milliskin is the tension that the XD doesn't have.

I am assuming that once the Milliskin is laid out the order of tensioning/stapling would be starting with the center top and bottom then the center sides and gradually work your way around in a circle until the corners are reached? How do you tell what is enough or too much tension for the Milliskin? Is the tension the same for both layers? I would think that once the initial tension is set that it would be fairly easy to duplicate by just watching the material as you pull and staple. Can a coin drop determine if the tension is correct? Or a spring scale for the opposite side of the first staple? Another thought I just had is probably the simplest - if the Milliskin should be stretched say 15% for every foot that would translate to 1.8" for every foot which can be easily measured!

What is the gain of 2 layers of Milliskin matte white you used in your screen calculations?

I am also considering implanting round coin sized neodymium magnets under the velvet to add 1.78/1.86 and/or 1.33 masking panels at a later date. Do you have any suggestions? Would the Milliskin matte black make a good AT mask?

I have 3 Sunfire CRS-3C speakers that will all be mounted vertically behind the Milliskin. Should the speaker grills be removed? What is the closest the speakers should be to the Milliskin?

Is there anything that an Audyssey XT32 calibration does not correct on an AT screen?

Wow, I hope this isn't too much information. Any suggestions greatly appreciated!

Jack
MM,

Your quote:

Since I do not know what materials or method you are using / have used to construct the frame, I'm limited in what suggestions I can provide. I can relate that if a Flexible Frame is used, and the material is stretched across it first, when it is bent into the Curve desired, the Spandex easily conforms equally to said curvature.

Pictures attached,

The outside dimensions of my frame is 118.75" wide and 52" high. If I allow for a 50% stretch in both directions I would be cutting the spandex to 79.2" (W) x 36.6" (H). Stretching another 2" in each direction (1" around the corner of the frame and 1" to fold back over the elastic hem) would result in 54% stretch horizontally and a 59% stretch vertically. I have attached pictures of my frame with a 1/4" T-Slot routed around the entire frame 1-7/8" back from the leading edge. The 1/4" hex bolt will slide in the T-Slot with a washer and knurled knob to line up grommets attached every 2.5" (unstretched) and every 3.75" after stretching. The 1/8" paracord will be laced through the grommets and around the groove in the knurled knob.

Your quote:

With such a slight radius, if the Spandex is stretched equally across the Frame, with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension.

I am not sure what you mean about "...with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension

I mocked up a table with dimensions of 118.75" x 52" and covered it with a tarp to keep from snagging the spandex when I work on it. Is a sharp razor the best way to cut spandex? Scissors don't seem to cut very straight.

I am ready to prepare the spandex to attach to the frame when I return from CES and was wondering if you have a final suggestions?

Thanks again for your help and Happy New Year!

Jack
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post #373 of 382 Old 01-05-2016, 06:53 AM
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Quote:
Originally Posted by jkosanke View Post
MM,

Your quote:

Since I do not know what materials or method you are using / have used to construct the frame, I'm limited in what suggestions I can provide. I can relate that if a Flexible Frame is used, and the material is stretched across it first, when it is bent into the Curve desired, the Spandex easily conforms equally to said curvature.

Pictures attached,

The outside dimensions of my frame is 118.75" wide and 52" high. If I allow for a 50% stretch in both directions I would be cutting the spandex to 79.2" (W) x 36.6" (H). Stretching another 2" in each direction (1" around the corner of the frame and 1" to fold back over the elastic hem) would result in 54% stretch horizontally and a 59% stretch vertically. I have attached pictures of my frame with a 1/4" T-Slot routed around the entire frame 1-7/8" back from the leading edge. The 1/4" hex bolt will slide in the T-Slot with a washer and knurled knob to line up grommets attached every 2.5" (unstretched) and every 3.75" after stretching. The 1/8" paracord will be laced through the grommets and around the groove in the knurled knob.
Oh Jack.

The Spandex will never stretch to 50%. Not even close. 20% would be...well a stretch.

For your "Length" of 118.75" you'll need a minimum of 4 yards because stretching 3 yards (108") just won't happen without opening up the weave and also creating a "bridge" between the two higher end-points.

Quote:
Your quote:

With such a slight radius, if the Spandex is stretched equally across the Frame, with just a slight adjustment "directional-wise", it will conform to the curvature even better than a material without such 4-way stretch potential. In any case, it's easily adjustable. It won't take much effort, or a really significant difference in tension.

I am not sure what you mean......
As in most such use of Spandex you will be starting at the center of the long edges with your first attachment. Then the center of each end. Because of the Curve you will want to minimize the pull length-wise, and equalize any "bridging" through the "directional-wise" adjustment across the short axis.

Quote:
I mocked up a table with dimensions of 118.75" x 52" and covered it with a tarp to keep from snagging the spandex when I work on it. Is a sharp razor the best way to cut spandex? Scissors don't seem to cut very straight.
Do not attempt to cut the Spandex on the Width side (58"-60") until your certain of the degree of stretch you'll use. I'm more than a bit concerned about your attachment method since this is not a non-stretch, dense cloth. I do suppose that if you cut the material to a dimension that includes folding and Hemming the edges for additional strength at the tension points, that would make a lot of difference.

That would mean cutting (with SHARP scissors) the material to 124" long and leaving the Width as is, and folding / sewing the perimeter edges to the actual screen dimensions. Then you'd stretch out to the amount needed to effect a smooth layout.

Quote:
I am ready to prepare the spandex to attach to the frame when I return from CES and was wondering if you have a final suggestions?

Thanks again for your help and Happy New Year!

Jack
I hope I did in fact "help".

MMan

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post #374 of 382 Old 01-05-2016, 02:28 PM
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Oh Jack.

The Spandex will never stretch to 50%. Not even close. 20% would be...well a stretch.

For your "Length" of 118.75" you'll need a minimum of 4 yards because stretching 3 yards (108") just won't happen without opening up the weave and also creating a "bridge" between the two higher end-points.



As in most such use of Spandex you will be starting at the center of the long edges with your first attachment. Then the center of each end. Because of the Curve you will want to minimize the pull length-wise, and equalize any "bridging" through the "directional-wise" adjustment across the short axis.



Do not attempt to cut the Spandex on the Width side (58"-60") until your certain of the degree of stretch you'll use. I'm more than a bit concerned about your attachment method since this is not a non-stretch, dense cloth. I do suppose that if you cut the material to a dimension that includes folding and Hemming the edges for additional strength at the tension points, that would make a lot of difference.

That would mean cutting (with SHARP scissors) the material to 124" long and leaving the Width as is, and folding / sewing the perimeter edges to the actual screen dimensions. Then you'd stretch out to the amount needed to effect a smooth layout.



I hope I did in fact "help".

MMan
MM,

Thanks for letting me know that 20% is the max I should stretch the spandex. I have seen posts where it was stretched up to 100% and that sounded well like a stretch. I want to be in the Goldie Locks range and your 20% number is the first I've seen.

My intent is to seam two adjacent sides first and clamp the corner where the seams meet and then mark the other end of the two seams before having two people pull each of the unfastened ends to measure a 20% stretch on the flat table. It would also enable me to see if say 15% or 10% would work fine?

Is the intent of the stretching just to make the screen material flat without an ripples or wrinkles? Is there a point where it is not stretched enough and it affects the AT? I purchased 7 yards and had it shipped wrapped around a tube so there are no folds. It also appears like they sent an extra couple of feet.

If 20% is the max, what is the minimum that I should not go below?

If I have problems with trying to use my approach to fastening the screen material I can always fall back on stapling.

I appreciate your quick response before I attempted to stretch the spandex to 50%!

Jack
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post #375 of 382 Old 01-08-2016, 02:25 PM
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I have been excited about Milliskin until I found out that the rolls are only available in 60" width. Does anybody know if this can be purchased wider?

I want to build a screen that is 72-75" tall and will need at least an extra inch for attaching to the frame...

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post #376 of 382 Old 01-08-2016, 03:53 PM
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Originally Posted by Pultzar View Post
I have been excited about Milliskin until I found out that the rolls are only available in 60" width. Does anybody know if this can be purchased wider?

I want to build a screen that is 72-75" tall and will need at least an extra inch for attaching to the frame...
Here is a 120" wide spandex. It's only 2-way stretch though; not sure how much difference that makes...
http://www.spandexhouse.com/products...id%20Colors%29
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post #377 of 382 Old 01-08-2016, 04:05 PM
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Originally Posted by techtre2003 View Post
Here is a 120" wide spandex. It's only 2-way stretch though; not sure how much difference that makes...
http://www.spandexhouse.com/products...id%20Colors%29
Cool thanks. I ordered a few yards of the 60" to see how well it stretches up but may get some of this to compare as well.
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post #378 of 382 Old 01-08-2016, 04:22 PM
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Quote:
Originally Posted by Pultzar View Post
I have been excited about Milliskin until I found out that the rolls are only available in 60" width. Does anybody know if this can be purchased wider?

I want to build a screen that is 72-75" tall and will need at least an extra inch for attaching to the frame...
72 inches is doable...and approaching the maximum. Settle for 70"s and your in there.

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post #379 of 382 Old 01-08-2016, 05:21 PM
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72 inches is doable...and approaching the maximum. Settle for 70"s and your in there.
But my current screen is 72". How can one possibly go with a smaller screen? Not possible! hehe

I am interested in the AVS screen material but that isn't currently available.
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post #380 of 382 Old 01-09-2016, 06:21 AM
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But my current screen is 72". How can one possibly go with a smaller screen? Not possible! hehe

I am interested in the AVS screen material but that isn't currently available.

Well I did say 72" was possible.Just that 70" was all the more so.

Stretching the 60" Spandex 8 " in each direction (16" total) is within reason. You'll just have to be certain you stretch it equally in all directions.

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post #381 of 382 Old 03-07-2016, 11:13 AM
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Any discussion in this thread of spandex' rear projection qualities?
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post #382 of 382 Old 03-07-2016, 11:35 AM
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Nope...but it does work, albeit with significant attenuation.

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