Are 9" crts that much better visually than 7"

You're opening up a can-a-worms.


Overall, generally, and non-specifically speaking, a 9" CRT will output a brighter and thusly larger image. That would probably be the first obvious difference. Next would probably be the differentiation between an electro-magnetically focused beam (most 9") vs an eletrostatically focused beam (most 7"). The end result is a tighter more highly focused beam.


You can do a lot to improve on the electrostatically focused projectors, and probably get darn close to the spot beam size. The real issue is about the resolution you would like to run. If you're going to run a 480P signal, a 7" CRT will resolve all of the information just fine, and the only benefit a 9" CRT would be brightness (size of screen). Move up to 1080i and the general consensus is that most 7" CRT's will fully resolve the image... the final would be 720P and this is the hot debate. If you do a lot of electronic mods to your 7" CRT, you will be able to do 720P. 1080P (doubled 1080i) is probably not a goal the average 7" owner should think about. Yes, many of the projectors will to 1280x1024, but there is going to be a lot of line overlap, ie. not fully resolving the image. If you're not the average 7" owner, an fine role model would be KBK when he was tinkering with a 7" CRT that he had HEAVILY modified. He had touched nearly every aspect of that projector. As I recall, he said that he had achieved some sick and wrong numbers and was STILL able to discern line structure... I don't recall the number, but he was well over 1280P!

I relate sharpness to the projectors ability to resolve the data. When we start talking about 480i DVD's scaled up to 720P, you not gaining any extra resolution or information. In theory, a good scaler will allow that interpolated data to reduce some stair stepping... but a DVD at 480P should have just as much detail as a DVD at 720P. The reason for going to 720P is to elimate the ability to see line structure.


With this in mind, a 7" CRT will be able to display just as much detail as a 9" CRT with DVD source. When you start talking about HD sources things change. 1080i is still a low bandwidth resolution. Heck, the ECP usually sees that resolution in the low pass band of it's frequency range. A native 720P HD source is where a stock 7" projector is going to be left in the dust by a 9" on the detail. Start modding the projector so that it can fully resolve all of that detail, and I think a lot of 9" owners would be surprised with the level of detail that can be resolved by 7" guns. Again, the brightness and therefore the screen size will always suffer. No mod will increase that.

Guys!


There are more factors at work here than might seem apparent; seven inch systems, and some eight inch systems, are built to meet certain price points. Designers are faced with having to choose what sophistication can be incorporated in a system and still have something that the marketplace accepts. Few if any seven inch systems have magnetic focus, zone stig correction, glass lenses, or liquid-coupled optics. They do not often boast 100+ mhz video bandwidth or 24/7 durability. Most 9" systems will outperform most any other CRTs because they can build 'em with the above-mentioned features and still make money. I built myself a 9" Marquee system over two years ago to replace a Marquee 8000 and I was thinking "Dang, this will blow the 8000 clear away". Well, it wasn't a day and night difference, noooo. The 9"er was a tad brighter and somewhat sharper, but I didn't appreciate it until I used it awhile; the superior lenses and LC optics are key; light bounce is almost non-existent and it is the contrast ratio versus air-coupled lenses that is to die for.

I was up at a showroom in MA (Hi-Rez?) and saw an ECP, a marque, and a 1292 on the same screen with the same source material (I think they were using a DTC-100. The three projectors were on a rail system so switching was about 3-5 seconds away...


I liked the ECP the best as it seemed to give the smoothest image of the three. Scan lines were very apparent on the 1292! I'm sure the 1292 and marque can look much better with scalers and video processors that show off their high performance, but for me, I just want a good image with a minimum of fuss. I consider it a benefit that it is unnecessary to purchase additional components to bring the signal up to a level where it looks good on the higher end projectors...


Of the three projectors, the brightness was somewhat similar but not identical. The bigger projectors were in fact brighter in order of tube size, but I had to really look to notice it on source material.


So, that left me with a decision on what to get... And I got an ECP4501. Not the best out there by any means, but good enough for me and my wallet.

Sean

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If this is true, then you're saying that a 7" CRT isn't capable of fully resolving 480i material. I feel 100% confident that a high quality 7" CRT will indeed fully resolve 480i DVD content. So if properly set up, there would be no less detail on a 7" CRT.


I'm not going to argue about 720p HD content however, because an average 7" CRT certainly won't have as much detail. With a highly modded 7" projector, 1080i is questionable in my mind, but stock, a 7" won't have the same detail at the 9".


I argue this from my experience viewing HD and DVD content on a G90, a Madrigal MP9 and an ECP 4501. On the highly modded 7" CRT, a friend of mine believed that the 4501 looked better (as was Jeep Lover 2's Experience) with the 1080i content than the G90 (probably because the G90 is shooting on a screen twice the size I'm guessing).


Tim also brings up some excellent points too. The liquid coupled lenses and superior optics usually supplied with the 9" CRT's offers a significant heads up on most 7" CRT's too.


romy101, there's tons of reading on hot rodding the ECP series projectors. About a year back (before KBK got his Marquee) there was great reading on the jaw dropping results that KBK achieved with a 7" CRT. The first mod that will achieve some of the best results for the investment is the input card. I personally saw night & day differences with this mod alone. Jay Wilson was offering this as a service not too long ago actually.