shmups.system11.org

About the appearance of the shadow mask or aperature grill on the BVM.

In those photos I see an image that is very similar to what I've seen from Sony Trinitron PC monitors in 120hz modes, or the various PVM models I've owned. A razor sharp, thickly scanlined image. Not that this is a bad thing but...

IMO I've always preferred the smoother, slightly blurrier graphics that come from older CRT tech, such as those that used dot triads or chromaclear rather than stripes. On those it seemed like the scanlines were not nearly as delineated. It's not as if you're actually losing detail at 240p. All the pixels are there and easily counted, it's just that the black scanlines between them are not as apparent.

However, from what I gather you're saying that the overly scanlined effect you would get from a Sony PC CRT monitor is not there? How can that be when this monitor has such an extremely fine pitch?

Note: all the references to PC monitors assume running in true 240p modes at double the vertical scan rate.

Here's an example from a thread at BYOAC on the subject

old hantarex 9110

old Mitsubishi AM-3501R

newer m2c

modern 21" CRT PC monitor


Is it possible you could post up a pic of this R from R-type Leo for comparision?

because it's a native 15khz monitor and not a 31khz one. Your Sony VGA CRT is able to display another full line of pixels between every visible line from the picture (with a real 480p source). That's why the "scanlines" (the dark lines between the pixels) appear much thicker than on a 15khz CRT. The display has to keep a certain distance, so the lines don't overlap.

The PVM/BVM monitors are only capable of displaying 240 lines per frame/field and even in 480i mode the lines are only alternated. On the extreme close up I posted (Fio's head from MS2) you can see that the height of the visible pixels changes with the luminance level. On the white "pixels" the height is maxed out and leaves only a thinner scanline visible.

I don't have R-Type LEO, but I can take a picture of the first R-Type. The R's quite similar. I'll take a few photos with different contrast settings. Your monitors's contrast is set quite high - I see serious blooming. My displays' contrast is usually set very low.

Some Rs in various contrast settings:



I usually play on low contrast (middle row), but as you can see in the lower right, even with a little increased white level, the scanline thickness is already reduced. Overall a much smoother picture than on a VGA CRT. But you might of course prefer the lower resolution shadow masks of the older arcade monitors.

Overall I would say that the scanlines appearence is close to your Mitshubishi pic above - minus the low res mask effect though.

Fudoh,
You've spent way too much time in front of an emulated scanline set-up...... the middle row looks awful imo.

not really, that's why I don't like 100% on the XRGB neither, but what I dislike more is any kind of blooming and that's obvious on the lower ones. Only because 99,9% of all arcade cabs and most CRTs in consumer households are set at way too high contrast levels, doesn't make it better

The only photo of the group which was taken by me is of the Mitsubishi monitor. So I can't speak to the contrast settings of the other monitors.

I would agree that the Hantarex is definitely set to a too high contrast level, however that won't hide the nature of its display technology. It has a sort of honey-comb structure when looked at in close up. Of course, that honey-comb is the shadow mask.

As far as being a 15khz display vs a 31khz one, there shouldn't be any issues differences between the two display types given the same luminosity and screen type. Both monitors will automatically adjust the size of each line of pixels to fill the screen, and the scanlines are just the leftover effect of the guns moving back into place to do each row of pixels.

However, most of the time 15khz and 31khz+ displays are made for quite different purposes. The PVM and BVM are meant to be used in the place where you would need a high quality display with similar qualities to a television. This means they usually put off a ton of light, and they aren't designed for 31khz. This also means they can produce thick, powerful lines of pixels with a reduced appearance of scanlines. Very good for us.

31khz and higher PC monitors are designed to be used for long periods of time from a close distance. So they don't put out nearly as much light. This accounts for the "flat" or dim image people often accuse them of having when they try to play games or watch movies on them. Additionally, and this pure speculation on my part, I believe that even when they are set to display in 240p mode the electron guns still have an overriding setting to draw thinner lines of pixels compared to something like a PVM. That results in the overly scanlined appearance. The 240p modes are sort of a bonus, unused feature that they were never really designed for. So while they are useful in a pinch, they are probably the lowest ranked choice when it comes to RGB 240p gaming.

So yeah, even with the same finely pitched screens, I can see how there would be a difference in the two. Forgive me for possibly restating what you've already said, but I like to try to summarize these things or discuss them so that I can get a better understanding of the technology overall.

RE: the R

Fudoh is definitely right about most displays being set to too high contrast levels. The middle row is the correct setting, and the same one that I use. If you look closely at the left side of the letter you can see that a ton of detail is being lost because the white is blooming. The top and bottom images could be considered to be more "arcade" or period looking, but I think in this thread we're talking about superior technical abilities.

I think that R looks a lot better than the m2c and PC monitor shots, but worse than the Hantarex or Mitsu. I also think the PC monitor shot is quite a crappy one. I'll see if I can get a better one to replace it tonight.

on arcade cabs I think it's actually a chassis issue. You can drive the same tri-sync tube with different chassis types and get wonderful "15khz" scanlines with the one and get ultra-thick ones with another chassis. But I'm not a regular cab user, so guarantee on that.


I would probably prefer the low-key scanlines on those as well, but the strong mask/grill effects are quite distracting (to me). But wouldn't it be boring anyway, if there weren't different tastes and preferences....

Rereading some of your comments Fudoh. Just understood what you were saying about the BVM and the white pixels maxing out in size vs the black sections of the image showing only the faintest amount of energy being applied to the screen. I assume the extremely faint red bits in the black sections are sort of "splash" energy coming from the surrounding pixels, or carryover from drawing the before and after pixels around it.

But anyway, this is a good measurement of the overall performance of a display in having a great low-res image. In your R-type photo the brightest whites of the image nearly come together, leaving only a very thin black space between. It's maybe half as thick as a pixel line. Where on the 21" pc monitor image you can see that even with all three guns maxed out there's still a pretty noticeable void between them. It's about the same thickness as a pixel line.

I agree that it is probably the chassis that is making the difference in that respect. The actual tube and guns just do whatever the chassis tells them to do. Which leads to some promising potential in future (like 30 years from now) when arcade and pro CRT tubes get scarce and the millions of TV and PC CRT's have to come into service for those that desire a classic image.

For comparision, here's a close up of Ryu. View the image in a tab by itself to see full quality.



You're right, at this distance the shadow mask is wayyyyy more apparent.

If anything this conversation shows how subjective that the term "better" is.

The chassis of any CRT can have a massive effect on the image given, but the quality of the tube itself also plays a key part as well. The end result in CRT's is the sum off all the parts.

I totally agree with you with regard to contrast ratio's, but I find there is a fine line between achieving an image that "pops" out at you and one that looks flat. In many ways you can cheat the effect of a, shall we say, poorer 15khz image (scanline wise) by using slightly more contrast than "perfect".

Alot of this is personal taste, but I would wholeheartedly agree that what most enthusiasts expect is a far cry to what is technically good. But then most of us just want an experience that is what we grew up with, rather than looking at it from a pure perfection stance. I'm a fine one to talk as I've certainly become more anal about this stuff the older I've got.... perhaps it's an old age thing. You must be at least 150 then Fudoh!

I do like this kind of discussion..... in a nerdy kind of way.

I mostly consider the time I spend tuning compared to the time I spend playing. In the recent years that's certainly a 10:1 ratio.

I can relate to that one!!!

Ha!

In recent years I've realized I spend more time reading about, collecting, and fine tuning hardware and software than I do actually playing games. For a little while I felt sort of bad about this, but f**k it. Do what makes you happy.

Haha, same here...gear heads.

BTW, the electron guns don't actually move, of course. It would be more correct to say the beams move back and forth (as deflected by the yoke).

You guys are crazy, but then again I've always had a natural loathing for things that are not near perfect out of the box because I hate fiddling with things too much.

I got my CRT's about two years back and before they arrived I made sure to secure and research all the required cables and equipment. Took me a few days to set everything just right to satisfy the videophile in me, and after that all I did was just play games.

That is why I do not view the Framemeister as a proper alternative to CRT's for me in the long run. I can never quite get that sufficiently satisfying feeling from it no matter how much I fiddle.

There's a new Dell 24" screen with only 5ms delay. Would love to try it with a XRGB-Mini. I'm just waiting for the 27" version to see if it's as fast and I'll then give it a try with the Mini. I never actually had the Mini on a small display yet.

Just picked up one of the Sony BVMs after reading this thread. I'm currently using an NEC XP29 Plus for all my tate gaming. I wanted to pick something up for my fighting games and yoko shooters (sega saturn mainly). Anything I should know or prepare for? I know it comes with the control unit. Not much else. Hope it turns out ok.

To connect your Saturn using RGB you need either a cable which uses the sync output pin on the Saturn or a sync stripper

Is it possible to use the slg3000/cga2vga/sync strike on it? Thanks Fudoh

You can use a sync strike. Saturn with Scart into the Sync Strike, then VGA to 4x BNC to the BVM. You can't use the SLG3000 or the GBS8220 with the BVM. Those are for 31khz displays.

This cable look alright?

http://www.monoprice.com/products/produ ... largeimage

Or do you have any specific ones you use. Thanks again

sorry, missed that question on the last page. Aperture control on the BVM is sharpness control. It's usually disabled, but can still be set. With a single button you can then switch between the unaltered and the sharpened picture.


that's right. I usually prefer to keep them shorter, but 10ft is still ok for 15khz signals.

I have no real expertise in this matter (all I know is that Sony TVs are damn good ones), but I assume the KVM model is by-and-large related to the BVM? I saw a Sony KVM in my university's language lab and it looked exactly like the CRT posted in your first post, except it was a different color and had a slightly different control panel.

I really wanted to snag it, too, after reading all the posts in this topic. It would be so perfect for TATE and it was covered in cobwebs...

sure about the model ? KVM are usually the product codes for Sony's remote control units. The differently colored PVM/BVM sets are often medical units, which are technically the same, but have higher quality control standards.

Well I took a punt on a eBay PVM and just picked it up.

Whilst I know it is a 14" piddler it is one of the HR range giving 800 lines, a PVM-14M4E.

The quality is totally mind blowing and much better than any other PVM 500 or 600 line set I have seen before. I'm not sure how close it is to a BVM, but it looks bloody fantastic!



It makes my consumer Sony Trinitron CRT's look positively retarded!!!!

And that looks so much different compared to what you called "awful" a few postings above ?

From a normal distance and on 14" display it shouldn't make a difference. Yours has 800 lines, the F1 has 900 lines and the E1 has 1000 lines. How far are you sitting from the 14" PVM ? 2-3 ft' I would guess. I doubt that you can actually see the grill.

Yeah.... I'm a cock I admit and a converted one at that!

Yes 2-3ft away.

It just looks so clean, but so pretty and nice.

small update to the BVM test: I don't know what I did wrong before, but composite video for RGB sync seems to be supported after all. I tried a bunch of SNES units today and the cables just use composite video. Worked flawlessly.... So it was either an issue with the Saturn composite video signal before or I just did something wrong with the cabling. Another possibility is that this depends on the installed decoder boards: the SDI/YUV board I have installed as an extra has a composite video decoder on it and maybe that's used with the sync input to clean it up......

In my defence (and I need some! lol) still images don't do this thing justice. The images posted do look overly sharp and very PC with scanlines type (to me anyhow - even mine). Until you see these things in operation with your games, the clarity and almost HD-like egde it gives to these 240p games, is really breath taking. I've been using mine solid for the past few hours and it really does blow your brains at how "new" the images look. Quite remarkable really. The preciseness of the colours as well are just giving me a blood rush.

It is, isn't it ?

I'm very tempted to pick the new lag-free 24" Dell IPS monitor to have a comparable size to the BVM and then compare the two setups (BVM vs. Dell+Mini). Will be a fairer match than using a 50+ inch display with lots of lag. Just waiting for the 27" review to see if it's basically lag-free as well.

Thanks for the article Fudoh, I ended up buying a BVM I came across on eBay! Really looking forward to getting it even if I wonder how im going to get my consoles to work through it lol!

Thanks again!