Looking for the ultimate gaming screen

I use a Diamondtron (Trinitron licenced to Mistubishi) 22" PC monitor. 20.5" of visible picture (52 cm). An UNMATCHED quality, no other screen can display this resolution with such a precise and pleasant to the eye pixel, no other screen can produce this "scanline feeling", so "video games" like.
There's no way I would play 480p on fixed res flat screen (no matter LCD, plasma, DLP...). Even If I find one of those 4/3 40" 640x480 plasma (to avoid any loss of picture quality and lag due to scaling), I would not trade my little PC monitor. Even when you consider CRTs (the best technology ever for gaming :P ), I wouldn't buy a large 29" tri-sync monitor (from any type), because I know I wouldn't get such an amazing picture (because of the large pitch, and quite unprecise cathodes, focus system and yoke winding). Sure, I would still get a very nice picture (much better than any crap flat screen), but "plain" (= no "scanlines", no little black space between lines) and rather soft, with some moiré and convergence issues (which can be slightly reduced for the few tubes with a slightly smaller picth, and with a precise yoke that you will need to adjust anyway for convergence issues, because they become very annoying when you go to the limits of the tube).

So, for me, the ultimate gaming screen (only one, for every use, meaning every resolutions) doesn't exist.
You need CRT technology of course :D , but you definitely need at least two kinds of CRT:

- one for 15 Khz (and the few 24 Khz stuffs).
Easy, it exists since forever, it's the "standard resolution" tube, that can display the best 240p output in large format, direct view (29" to 40"). No other tubes can display such a large beam, with all the quality we like from the behavior of the beam (visible variations of scanlines size).
The curved Trinitron is your best friend, especially in tate, because it gives you not only the sharpest beam and precise scanlines (with nice variations of size according to colors, and still precise for the smallest spot size), but the cylindrical shape gives you an "Axelay effect" to all your vertical shooters, much more than a spherical tube (and of course a flat CRT ^^').
Playing some masterpiece like Layer Section (with lots of "3D" effects due to paralaxes and multiples sprites with their own speed for big enemies) on a finely tweaked curved Trinitron is really amazing, a quality you had never find in any arcade cab'. It's like you rediscover the game ! ^^

The old analog chassis (before 1994) are the best to provide you accurate and well balanced colors, with the least modifications of video signal, and easy geometric corrections. Digital chassis tend to have too much "enhancement" features (denaturation of the signal), and on flat CRT, it's a pain in the ass to get a good linearity (when you want perfect scrollings, something you especially want in shoot'em ups), and even difficult to adjust colors (because of design choice, every manufacturers wanted to show a model with the blues more blue than blue and reds more red than red, because the digital ships allow it easily).
But you can only find "raw deinterlacing" (as a feature in the TDA-8366 for example)  in digital chassis, and until I managed to achieve a separate circuit to do it properly (or someone else do it ^^), it's the only way to do it with genuine hardware and games.

- then, if you want the best 31 kHz picture, you need CRTs that can go higher than 31 kHz. But because they can go higher, it means they can't go lower than 31 Khz (when they accept 15 kHz input, they upscal it to 31 Khz).

The easiest and cheapest way is to buy a high-end PC monitor, you can buy some for a few peanuts (<- we use this expression a lot in french, for saying "ridiculously inexpensive" ^^' ).
I have 5 big 21-22" monitors, from 1995 (curved Trinitron) to 2002 (flat Diamondtron). They all produce nice pictures, but the last one delivers an amazing display. Each lines have the same characteristics as the ones you see from a regular 29" Trinitron at 240p. It's your 31 kHz stuff with a 240p look, Trinitron quality. Something that I personnaly highly appreciate. :P But OK, it's small...

To find the same quality on a bigger display, you don't have to look over regular tri-sync monitors who are basically "simple TV tubes" (large pitch) with electronics that allow 31 Khz (and think that many large "XGA" CRTs (that are supposed to handle 1024x768) have a large picth too, meaning you can't achieve the same quality than on a smaller PC monitor (fine pitch). No, you need to find one of those early HD TV in USA (around 1999, fine pitch and 4/3 format) or expensive (even in the second-hand market) broadcast/graphist monitors. Almost none of them support 15 kHz. Because they are basically PC monitors of bigger size (and they were damn expensive when they where out, and non available to home market).

An other way is to use a tri-tube projector. You need a dedicate room to operate it if you want a decent picture, and of course you need to know how to set-up the projector. You can also make a rear-projection system with tri-tubes projector (the basic 7" ones can produce a nice 800x600 easily and are cheap nowaday), so you can use it in a daily room, but you have the typical issues of rear-projection: narrow view angles, low contrast. Never as good as a direct view tube.

So, for me, in tri-sync monitors, only the chassis are interesting. Just buy the electronics and adapt it to a good TV tube (you find it for free on the streets, or buy it in repair shops for 10-15 €). But, in arcades, there aren't any Trinitron tubes, so all the chassis are designed to run on the classic shadow mask tubes, either spherical or flat. And the difference of quality between a 240p picture on a Trinitron and on a shadow mask tube will be even stronger for 480p stuff, because a Trinitron is better to display thin spot (but you always have the large pitch issue, a 29" large pitch Trinitron can't produce the same précision as a 22" low pitch). But, hey, it's a decent quality anyway, but from everything I saw until now (in arcades and home cab' of friends), the 480p result is far from my little 22" monitor. Even worse, a 480i non filtred picture on a classic Trinitron is more precise (because the shadow mask dont' have enough space to let the beam strike the phosphore in every situations). That's why I don't want to spend several hundred € (monitor and shipping) to buy a thing that my little 30€ PC monitor will put to shame (and even the old 1995 one, found for free in the street, will produce a better 480p picture :P).

Yeah, it's not easy, you need to know exactly what you want, what is available, and your degree of exigency.

This is the last reply of Pegote, but when I moved the messages here, I forgot that he doesn't  have access to this place. If he shows his email adress in his profil (after reading my last reply on the other topic), I will send him the explanation :

No, on direct view tubes, you always have parallel lines. The only tubes that can display a trapezoid image (with on side bigger than the other) are those in tri-tubes projector /rear projection sets (because it is requiered to converge the red and blue picture to the green one. But after a good set-up, from your point of view, you should see horizontal, parallel lines on the final picture).

The geometric corrections on direct view tube allow you to change the shape of the picture, but you always have parallel lines (you can have a trapezoïd picture, but with the top lines having a different size of the bottom ones, and still always parallel).

The linearity (in this case: the horizontal one) concern the variation of the pixels size from left to center, and center to right. To display a regular picture on any tube, you need to add some variations to the signal (wave forms), because the course of the beam, which should describe a perfect circle, never matches the shape of the tube. When you have a spherical (or cylindrical) tube, it's a different radius, but it's relatively easy to adapt the radius of the beam closely to the radius of the tube. When you have a flat tube, you need to change a radius into a straight line. And it's never perfect. It involves not only wave forms but also a really precise driving of the high voltages in the THT, something you can't find in large TV set for home market (because accurate electronic for such high voltages cost lots of money, and home TVs are not supposed to display graphics with straight stuffs, it's movies, broadcast shows etc.).
The linearity issue is really annoying for 2D stuffs, especially when you are a shmup addict like me, because the slow,regular, continuous scrolling always shows the defect. That's why I prefer spherical tubes over flat ones.
On spherical tubes it's not perfect too, but is much less visible, and easy to correct to a decent level.

A picture tube displays whatever you send to it. But if you want a good picture, with good geometry, you need electronic circuits that allows you to finely tune the most parameters possible, you need something well designed. And on cheap chinese TV sets, you can barely find something good enough to correct your signal. But on those TVs, you can find good picture tubes, because only big and longtime manufacturers make tubes (RCA, Thomson, Philips, Sony, Panasonic, Samsung, Nec...in fact, they are very few). Most time, a small compagny buy tubes to big manufacturers, then they design their own eletcronics to drive the tube or simply buy
cheap chassis made by brands that don't make their own CRT too, they put all together in a plastic case, they put a sticker in the front, and here you go !

The quality of a monitor relies heavily on the chassis (the electronics) that drive the tube, and on the proper set-up that needs to be done by trained technicians (or crazy old-school video game addicts :P ), because it's very difficult and involves lots of constraints and compromises. And much more, it requiered time to do it. Time is money, so if you want to sell cheap monitors/TVs, you choose an easy tube to drive (a spherical one), you put a cheap chassis, and you don't spend any time to properly tune the picture at the end of the assembly line.

For you your picture problem (with a  ))|((  shape), it's a typical pin-cushion issue (it's different from linearity). Normaly, even on flat CRT, you should be able to correct it easily, via the "service menu", in which you can enter by taping a special code on your remote (you need to know the reference of the chassis and find it on the web, on http://www.eserviceinfo.com/ for example).

Calamity, that's good you are here, I just would like to ask you few questions about drivers.

So, you made a hack to allow more different resolutions at a time. But do you know why all different resolutions can produce different voltage levels at the VGA output ? It's not a hardware question (few resistor or amps) , because values change according to different drivers and safe mode... For now, I'm quite clueless because I just noticed it recently, in the past few years I would never had the idea of mesuring the voltage out of the VGA port.
Because you know, wide range of resolutions is good, but signal accuracy is really crucial to get the best result possible on CRT. You will say that most video games have a very limited on-screen color palette (and that's true), but to properly calibrate a CRT, you need to have a signal between 0.3 and 1.0 V .
When you display 15 kHz picture at 321x240 for example, you can't change the values of gamma/brightness/contrast for each channel (red green and blue). You can do it at 480i, but anyway, you can get slighty variations between 480i and 240p ...

The ultimate driver would be the one that allows many different resolutions and a constant voltage signal (video part always between 0.3 and 1.0 V), or at least, a possibility to quickly adjust parameters in any resolution (like the gui of Zsnes, which suits every resolution, unlike many other emulators designed for 640x480).

Since PC users had never ever complain about voltage levels (who the fuck cares ? Even those who wanted accurate colors just tweaked the drivers options, whitout mesuring the voltages), I think this issue had been there for almost the beginning. I need to check other graphic cards, and different motherboards to confirm if there are some set-up that delivers more variations or more regular level among resolutions. (if you guys could do it with your graphic card, even with a basic 10€ multimeters, that would help !^^' )

Bluesky is a brand of cheap TVs. While they have some good Philips/Thomson tubes in it, they got some crappy Vestel chassis ("11AKxxx") that break easily and are not well designed. And of course they come with a poor set-up.

In general way, digital electronics tend to be much simpler to design, they have a more regular behavior than analog one. So, on older analog chassis, you often find very wide tolerances on timings, porshs, frequencies. In digital ones, especially because they are designed according to very few broadcast signals (and not video games :P ), you tend to have very few room for your non-standard signals.

If you have troubles, it's better to display a non standard picture in a standard frame ( for example, a 304x224 picture in a 320x240 frame), and choose refresh rates close to 50hz and 60hz (meaning that you won't be able to have perfect emulation for 53hz and 57hz games, because they are too much out of range, generaly a 2 Hz only one).

In other way, you need to try several pixel clocks and porchs to avoid picture deformations. Some chassis won't show you any picture at all if the signal is too much "way off" (but the same signal can be send into a much "friendly" analog chassis...).

So, as usual, older means better, you will enjoy the wide variety of the 15 kHz picture on spherical analog TV sets. If you choose a TV from 1994 to 1996, you can still find "hybrid" chassis that have both digital (geometry correction) and analog parts (especially for the video amplifier on the neck-board).

Recap's Trinitron may be the ultimate TV, because it's a cylindrical tube with an early digital chassis that allows you to easily deinterlace 480i and still has lots of analog components, and it takes lot of resolutions around 15 kHz. Ok, it's a pain in the ass to properly converge it ^^, but I got many skills by working on it (in fact, this TV set had been my "conejillo de india" :P to test everything about CRT convergence and geometry).

And you forgot the best feature of they all -- it's incredibly easy to rotate for a vertical-orientation display. Not only the sides are flat and speaker-free, the corners are perfectly rounded to serve as the pivot, hence saving you from low back pain and whatnot.