Da-Lite HC Cinema Vision vs. Firehawk - AVS Forum
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post #1 of 12 Old 01-30-2002, 08:59 AM - Thread Starter
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Please help me...

I have read in this forum, that the new Da-Lite material (I think HC Cinema Vision)with 1.1 gain is identical to the Firehwak with 1.35 gain ?????
I'm a little surprised! How can a 1.1 gain screen be identical to a 1.35 gain screen ??

Thanks

Anthony
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post #2 of 12 Old 01-30-2002, 09:56 AM
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The Da-Lite High Contrast Cinema Vision is not the same material as the Stewart FireHawk. The FireHawk has higher gain and a smaller viewing angle. The HC Cinema Vision is a grey version of their ISF certified Cinema Vision. I have not seen the FireHawk material but I can tell you that the HC Cinema Vision material is darker than the GreyHawk material.
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post #3 of 12 Old 01-30-2002, 10:18 AM
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Anybody seen this material (HC) in action?
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post #4 of 12 Old 01-30-2002, 10:30 AM
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I received a sample of HC Cinema Vision, however, the sample is so small at approximately 6" square as to make meaningful observations very difficult.
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post #5 of 12 Old 01-30-2002, 02:38 PM
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Tony - Scott & John,

I have seen this material very recently when the Da-Lite factory person and our local representative was in our office. The material is basically their other gray material with a reflective coating. The gain as they have advertised is indeed 1.1. However, they also stated that they way Stewart measures their gain and the way that Da-Lite measures their gain is different. Apparently Da-Lite uses some type of Magnesium Carbonate product to measure gain and Stewart uses some type of white plastic. Hence you get the two different gain measurements.

They continued to say that if you measure them the same way, with the Mag or the Plastic that the gain will be equal on the two surfaces.

I do have to say that even with the 6"x6" sample that they had the colors and black level of the High Contrast Cinema Vision was far superior to the Stewart Studio Tek 1.3 gain that we have in our showroom. The whites were even very bright and the fabric had little affect on them.

Based on my personal experience and opinion the Da-Lite High Contrast Cinema Vision is far and away the better fabric. You will be better off spending less money on the Da-Lite and putting the extra $ into your sound system or a video processor.

Good luck,

BrewsterMan
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post #6 of 12 Old 01-30-2002, 07:51 PM
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Brewsterman,

Your post confirms my suspicion that the 0.25 difference between the FH and the HC CV is the result of a difference in measurement method.

LoFi
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post #7 of 12 Old 01-31-2002, 02:16 AM - Thread Starter
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@Scott
I received the sample too :) Da-Lite thanks for the quick response!!
As you mentioned, the sample will give an idea,what there is to expect but much to small to make a decision based on the sample.
I'll have to wait until a screen with the new material is available.
My dealer in Switzerland has Stewart and Da-Lite so maybe in a few months I can make the comparison Firehawk vs. HC Cinema Vision.
What is tempting about the Firehawk are the Velux boarders and a slightly larger image:
Da-Lite = 106'' diag.
Stewart= 110'' diag.
Can't go any larger because of my speakers :(

As for now I'm enjoying my Da-Lite 106'' Cosmopolitan Electrol Da-Mat 1.1 screen :)


Anthony
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post #8 of 12 Old 01-31-2002, 03:40 AM
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Tony,
Da-Lite also offers a light absorbent black border on most of their frames called Pro-Trim. I am not sure what you mean by the Stewart screen is larger than the Da-Lite. All Stewart screens are custom made, so they will build whatever size of screen you need. Da-Lite will also custom build to any size, however, this is at an extra cost.

BrewsterMan,
I have samples of both the HC Da-Matt and the HC Cinema Vision and the HC Da-Matt is darker than HC Cinema Vision. The FireHawk has a much smaller viewing angle than the HC Cinema Vision, so the two materials are certainly different. I personally am interested in the HC Cinema Vision because it offers a wider viewing angle than the FireHawk. I only wish I had a larger sample to experiment with.
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post #9 of 12 Old 01-31-2002, 08:26 AM
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That's interesting, about Stewart measuring gain by comparing to white plastic... If that's true it could be considered somewhat misleading, because as Robert Harley (the editor of The Perfect Vision ) states in his book, Home Theater for Everyone ,"Screen gain is a measure of reflectivity relative to an industry-standard reference: magnesium carbonate applied to a flat surface."

BTW its an excellent book.
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post #10 of 12 Old 01-31-2002, 11:43 AM
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To all concerned:

I want to take a minute to clarify some things that are being said here on this thread.

There seems to be a concern over the way that different manufacturers of projection screens are measuring their gain properties. For those who may not know, a block of Magnesium Carbonate is used as the base white material for all gain measurements in the screen industry. To my knowledge, our friends at Stewart are using the same type of measuring devices and base material that we use at Da-Lite. Therefore, the claim that was listed above, to my knowledge is not true and as many statements on this forum, should be taken with a grain of "salt". Perhaps the reason for the statement is the fact that as stated in their literature, Stewart uses a material by the name of PTFE as a reference material for color reflectivity. However, I am doubtful that that is the material used for gain measurements. Perhaps that is a question to ask them directly.

If you want to verify what a particular screen manufacturer is using to determine the gain of their screens, simply ask them. Either through the forum (which I now Don Stewart is a member) or by calling them directly.

I felt obligated to address this situation, since Da-Lite was mentioned in the above posts.

Thank you,

Blake

Blake Brubaker, CTS
Vice President of Sales
Da-Lite Screen Company, Inc.
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post #11 of 12 Old 01-31-2002, 12:17 PM
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Thanks for the explanation Blake. It should be clear now that the FireHawk and the HC Cinema Vision are NOT the same material. Which is better would depend on the size of screen, projector, width of seating area, and personal preference.
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post #12 of 12 Old 01-31-2002, 11:23 PM
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Thanks for the clarification Blake! Let me add some more info on the type of reflectance standard Blake was talking about (thanks to Google's fast and relevant searches! :D ):

- PTFE is the abreviated name for the plastic resin that we all know and love as Telflon.

- I don't have access to CIE or ASTM standards, but this website: http://www.aviantechnologies.com/reflect.html states that packed PTFE powder is one of the specified standard for measuring diffuse reflectance. (check under reflectance standards kit)

- I believe the relevant ASTM standard is E259-98 Standard Practice for Preparation of Pressed Powder White Reflectance Factor Transfer Standards for Hemispherical Geometry and Bi-Directional Geometries, available for purchase at www.astm.org. I don't know what the relevant CIE standard is.

- also check out http://www.oceanoptics.com/products/ws1.asp

- As Blake mentioned, Stewart's literature specifically refers to their use of this standard.

I can see how there would be some confusion as Magnesium Carbonate is the original reflectance standard, although I believe that was from the days before Teflon even existed. Anyways, if you read the specs on those sites the PTFE standard is highly reflective at a wide range of wavelengths and a good enough lambertian/diffusive surface to be used as a reference standard. (i.e. it's very good :D )

Regards,

Kam Fung
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