[Hank Perkins]

I am an LT150 owner who is considering joining the ISCO II powerbuy. I would like to hear why is is good for a LT150.


How hard it is to install on the ceiling, rough adjust and fine tune.


Is masking a requirement?


the best way to install on the ceiling.


Any changes in the throw ratios.


How bad will the pincushion be on a 16:9 screen 104 inches wide?


Thanks in advance.


Hank

 

[Greg Risley]

I'm in the same boat as Hank. Just got my lt150 and haven't mounted it yet because I am thinking of going with this but need some specs. I have an 80" x 45" screen.


Greg

 

[Wireless]

I have that exact combination and there are tradeoffs.


Mounting on the ceiling, I had to build a two shelf system, which can be seen in the picts under my signature.


I do think masking is necessary for 2.35:1 movies. I overscan for 1.85 on my 16:9 screen.


My throw ratio was shortened, by about 6" based on my 92" wide screen.


I have no idea how a longer throw and wider screen will affect your potential pincushion. Maybe someone with a similar configuration can chime in.


For me the increased resolution and brightness is worth the increased distortion. The picture is more 3d and film-like than without the ISCO.

 

[Hank Perkins]

John,


What are the dimensions on your ceiling mount?



How do you handle Masking?


Hank

 

[jkaiser]

Is the ISCO II that huge? I can't see the LT150!

 

[MrWigggles]

Wireless,


Forget the ISCO...


That is nice set-up of Waveform audio speakers. I was just about to get some before the company went under.


I never got to hear them but I hear they were/are fantastic.


Good find.


-Mr. Wigggles

 

[Wireless]

Hank all Home Depot supplies. The shelf for the LT150 is 12x36 and the ISCO II shelf is 8x36. I should have gone 10x36 for the bottom. 1/4"threaded rods, nuts, chain, some 1/4" eyebolts, and ceiling picture hooks. I didn't really need 36" wide boars either but I wanted to make sure I had room to move it around for centering.


jkaiser, yep it's that big!


Wiggles, I love my Waveforms! These are the floor pair from the 1997 Stereophile show in San Fran. Bought them on the spot. Incredible smoothness, flat frequency response, and rock solid imaging. I may never own a different speaker. I bought the surrounds during the fire sale.

 

[Hank Perkins]

John,


Thanks for the reply. on the mount. What about the masking?


Hank

 

[Jeffrey]

Quote:

Originally posted by jkaiser Is the ISCO II that huge? I can't see the LT150!

No, the LT150 is that small

 

[Wireless]

I overscan for 1.85 movies so I don't use masking. For 2.35 I made a frame of 1x2s 96" long, and stapled black velvet to the frame, the distance between the top and bottom of the frame for me was about 6.5". I hang the frame from the hooks supporting the screen using springs. For bottom masking, that's just raising the screen to the proper height from the floor. When I'm not using the top masking, I move it around to the back of the Dalite manual pull down.

 

[dfriend]

I just signed up for the ISCO II powerbuy, so I thought I'd pick your brain some more on the LT150+ISCO II combo. Fortunately my HT is as yet unfinished so I can plan accordingly. But a man needs to be prepared, and I want to have everything planned out beforehand:

Quote:

Originally posted by Wireless I have that exact combination and there are tradeoffs. Mounting on the ceiling, I had to build a two shelf system, which can be seen in the picts under my signature.

About how tall is the ISCO II mount? I plan on having an enclosed ceiling mount and from the looks of it the height is going to be determined by the height of that monster.

Quote:

I do think masking is necessary for 2.35:1 movies. I overscan for 1.85 on my 16:9 screen.

I'm of the opinion that masking is required regardless of aspect ratio, what with all the light spill from these projectors, but your suggestion is duly noted.

Quote:

My throw ratio was shortened, by about 6" based on my 92" wide screen.

I'm a bit confused my this statement. By my calculations (and as others have pointed out), the throw of the projector is shorted by about 1/3 with the addition of the lens, keeping the screen width the same. What exactly are you referring to here? Are you saying that the throw was reduced an addition 6" due to the lens?

Quote:

I have no idea how a longer throw and wider screen will affect your potential pincushion. Maybe someone with a similar configuration can chime in. For me the increased resolution and brightness is worth the increased distortion. The picture is more 3d and film-like than without the ISCO.

I can't remember if I asked elsewhere, but I'm also wondering how the lens affects the LT150's image offset from the center of the lens. For example, at a throw distance of about 8.75', the top of the 150's 4x3 image is a little more than 8" down from the center of the lens. Any idea what happens with the ISCO II? Even an indication as simple as whether it moves up/down/not at all would be helpful.


Also, I can't tell from your pictures if the ISCO is mounted so its center coincides with the center of the LT150's lens, or if there's some angling there. Can you describe the relationship between the LT150's lens and the ISCO II's lens?


Thanks a bunch for any info you might have. I'll no doubt dummy up the positions of everything before I finish the room but I'm itching to get started with some planning. Thanks!

 

[Morbius]

dfriend,


With an ISCO the throw will be 75% of what it used to be if you keep the same zoom setting.


The expansion factor is 1.33 = 4/3 so the throw is

changed by the inverse of 4/3 or 3/4 = 0.75 or 75%

if you don't change zoom setting.


I'll bet that after the addition of the ISCO, the change in zoom setting was not sufficient to compensate for the change in throw - so he ended up moving the PJ 6" until he was in range of what

the zoom could do.


Greg

 

[Wireless]

"About how tall is the ISCO II mount? I plan on having an enclosed ceiling mount and from the looks of it the height is going to be determined by the height of that monster"


I don't remember exactly but it's between 9-9.5" tall.


"I'm a bit confused my this statement. By my calculations (and as others have pointed out), the throw of the projector is shorted by about 1/3 with the addition of the lens, keeping the screen width the same. What exactly are you referring to here? Are you saying that the throw was reduced an addition 6" due to the lens? "


Sorry about the confusion, between moving the projector forward and moving the screen, I had to move about about 6-8" forward from where I had installed the mount. I'm more of a trial and error guy and with a curved ceiling it was difficult to measure exactly.


"I can't remember if I asked elsewhere, but I'm also wondering how the lens affects the LT150's image offset from the center of the lens. For example, at a throw distance of about 8.75', the top of the 150's 4x3 image is a little more than 8" down from the center of the lens. Any idea what happens with the ISCO II? Even an indication as simple as whether it moves up/down/not at all would be helpful."


Since the offset is different for different throw ratios, the addition of the lens will change the drop from lens center to the bottom of the screen. I calculated that I was using the chart for a 69" wide screen for my 92" wide (69*1.33=91.77). Also the image height can be changed by increasing or decreasing the angle of the ISCO on its rails, although the distortion changes as well.


The ISCO is angled down because of the LT150s offset, on the inside of the lens the LT150s image is toward the top. That actually makes it more centered on the outside glass of the lens. It sounds confusing but once you play around with it you will see what I mean.

 

[dfriend]

Quote:

Originally posted by Wireless I don't remember exactly but it's between 9-9.5" tall.

Damn that's big.

Quote:

Sorry about the confusion, between moving the projector forward and moving the screen, I had to move about about 6-8" forward from where I had installed the mount. I'm more of a trial and error guy and with a curved ceiling it was difficult to measure exactly.

I see... my room is completely unfinished at the moment so I have a lot of freedom, but I just wanted to make sure I wasn't making a gross error. Morbius's calculations is what I was referring to, although my number was wrong.

Quote:

Since the offset is different for different throw ratios, the addition of the lens will change the drop from lens center to the bottom of the screen. I calculated that I was using the chart for a 69" wide screen for my 92" wide (69*1.33=91.77). Also the image height can be changed by increasing or decreasing the angle of the ISCO on its rails, although the distortion changes as well.

I know the drop changes with throw, I was wondering though if I had the projector sitting at a fixed throw projecting a full 4x3 image, when I put the lens in front of it to stretch it to 16x9, does the image also shift slightly up or down? Your point about angling the lens and distortion is well taken as well. Since I have so much freedom with regards to placement, I'll do whatever I can to minimize distortion and if that means awkward placement or angling of the lens, so be it.

Quote:

The ISCO is angled down because of the LT150s offset, on the inside of the lens the LT150s image is toward the top. That actually makes it more centered on the outside glass of the lens. It sounds confusing but once you play around with it you will see what I mean.

It does sound confusing, to the point that it sounds incorrect. It seems to me for the LT150 to produce the offset that it *cannot* project through the center of the lens. But perhaps I'm misunderstanding. No matter... perhaps a more general question would shed some light:


How should the lens be configured with respect to the light path of the (*any*) projector? Seems to me that the best way to align it so as to minimize or at least equalize distortion would be so the center of the "cone" of light emanating from the projector passes through the center of the ISCO II, as well as being coincident with the "optical axis".


I know this is getting kind of silly, but I'm anxious to start playing around with my setup. Thanks for your help, you've been very helpful!

 

[Wireless]

The height shouldn't change. You can fit the 4:3 image in the center portion of your 16:9 screen, assuming of course your screen is 16:9.


I'll try this one again. The inner lens of the ISCO is egg shaped. The image is centered in the ISCO lens, however to acheive the centering I had to raise the ISCO so that the LT150s lens is a little above the center of the ISCOs lens. Otherwise shadows were created.


Good luck in your setup and have fun!