Product Review - Faroudja VS50 Chroma Decoder - May, 1999
Stacey L. Spears
Inputs: One Composite Video, One S-Video
Outputs: 2 RGB + H/V Sync/YUV (1 BNC, 1 15-pin VGA)
Bandwidth: Composite NTSC Input: -2dB @ 5 MHz
S/N Ratio: 61 dB (NTC-7 Weighted)
Size: 2 6/16" H x 19" W x 12.5" D
Weight: 10 pounds
Price: $3,595 USA
Faroudja Laboratories, Inc., 750 Palomar Avenue, Sunnyvale, California 94806; Telephone (408) 735-1492; Fax (408) 735-8571; Web http://www.faroudja.com; E-Mail email@example.com.
Faroudja, world renowned for their video products, have taken the front end from their video scaler line and packaged it into a separate, affordable product. Actually it is an improved version of their broadcast quality chroma decoder, only the VS50 is about $5,000 cheaper and does a much better job!
The VS50 is actually designed for the professional market, but it just so happens that it is a great home theater add-on.
As I have said in the past, TV manufacturers do a cost-concious job of converting composite and S-Video to component and RGB. Most manufacturers will have a red, and sometimes, green push (emphasis). This is to compensate for the outrageously high gray scales (the blue discoloring of the picture) they ship with.
The naive consumer tends to look for the brightest picture on the showroom floor, and manufacturers know this. To win the sales battle, they crank up the gray scale so that the picture appears to be brighter. This is just an illusion, much like putting blue dye in bleach to give you whiter whites.
In the last couple of years, the ISF (Image Science Foundation) has educated many dealers on how to properly set up TVs. The problem is still evident today, even when using the component inputs. The TVs are not properly converting component to RGB. Toshiba and Pioneer are guilty of this as well as many others. In fact, the latest HDTV sets from Toshiba and Pioneer still seem to have the same decoder problems as their NTSC sets. As consumers we must demand more from our manufacturers. They are capable of delivering sets that image properly, so perhaps if we just educate ourselves and expect proper images when we shop, they will manufacture them that way.
Getting back on track, without a doubt, in my opinion, the VS50 is one fantastic chroma decoder! Let me let you in on a little secret. It's even better than what is inside their LD100 line doubler. Shhh, dont mention to anyone I told you this.
Picture Plus Technology
The comb filter in the VS50 performs just like their VP-100, which was previously reviewed here in Secrets. I still consider the Crystal Vision VPS-1 comb filter to be better than the VP-100 and the one inside the VS50. To be fair, I turned off the edge enhancement in the VPS-1, as well as the detail and noise reduction in the VS50. I used the same test patterns as in the Crystal Review. I found the Faroudja to exhibit slightly more dot crawl on the higher saturated color bars. The Faroudja is far better than any LD player out there, but it is just not as good as the VPS-1.
The Chroma decoder in the VS50 cant be touched by its competitors, in my opinion. I remember when I first heard that the VS50 was on the way. It was a couple of years ago at the AES convention in LA. Back then, they had a mock-up case with several knobs on the front. But, he final product looks nothing like it. I have been waiting anxiously for the VS50 to actually hit the market.
I thought that bypassing the internal NTSC-to-Component decoder in the Toshiba TV would bring the TV to life. Using the VS50 is an improvement over their decoder, but the final image is limited by Toshiba's inability to accurately convert component to RGB.
I was able to reap the full benefits from the VS50 when pairing it with the Dwin TranScanner. If you remember my review of the Dwin, they offer a really good NTSC-to-component decoder. Well, its just not as good as the Faroudja. The only thing better than the VS50 is the component outputs on your DVD player.
The VS50 offers two types of bandwidth expansion. First is the Chroma bandwidth expansion, which has been around since the LD100 time frame. Secondly, it also offers the new Luminance bandwidth expansion, which was introduced with the VP400a line quadrupler.
The bandwidth of laser discs goes out to about 5.5 MHz. For each MHz, you get 80 lines of horizontal resolution (meaning vertical lines on the TV screen). Its not flat to 5.5 MHz, but some players, like my CLD-97 do go out there. DVD has a bandwidth of 6 MHz, which can be pretty close to flat. The bandwidth expansion technology can actually give LD the appearance of a much higher bandwidth by using a few tricks that Faroudja pioneered and patented.
A simple explanation is that they tie the Chrominance (C) signal to the Luminance (Y) signal.
This is based on the Y rise time, which is faster than the C rise time. The VS50 monitors the Y transitions and then synthesizes a new C transition so that it matches the Y transition.
Rise time is the amount of time it takes the video signal to change from one color to the next. The shorter the rise time, the sharper the edges appear to be (NS on the diagram means nanoseconds, or 10-9 seconds, or billionths of a second).
To see this effect, you can look at the NTSC color bars on VE ("Video Essentials" DVD) or "A Video Standard" for LD. You can see the effect between the Green and Magenta color bars.
The VS50 takes the same technology and now shortens the rise time of the Y signal. Our eye is more sensitive to black and white (Y), so this makes an even greater impact.
The visual effect is that laserdisc movie looks better. It is still not as sharp as DVD, but it is much closer. VHS is also improved, so it is now almost tolerable to watch Disney animations that are not available on LD yet.
Noise Reduction (NR)
This works in conjunction with the detail control. It is said to remove background noise including film grain and dust. I found that with just the right settings, overly enhanced DVDs could look better when using this feature.
Time Base Correction (TBC)
The VS50 includes a two-line TBC. Most LD players have this built-in. VHS can sometimes appear to be a little jumpy; and the TBC feature is supposed to help stabilize it. Pro TBCs can actually eliminate Macrovision artifacts. I did not test to see if the TBC in the VS50 did this type of work because I could not disable it, but VHS through the VS50 does look very good.
Chroma Automatic Gain Control (AGC)
I have never been a fan of AGC circuits. The first sample of the Audio Alchemy (AA) comb filter had an AGC circuit that was quite severe. With that said, I did not notice any problems with the AGC circuit in the VS50. On the AA, the AGC affected the Luminance signal, while the VS50 works on the color signal to deal with abnormal chroma levels.
Front Panel Controls
The front of the VS50 is very clean. It contains an LCD panel (a nice blue color) to tell you what you are adjusting. There are five buttons on the front consisting of two function buttons (forward and backward), two value buttons (+ and -), and a factory reset/recall button.
Through the front panel, you specify whether you want RGB or YUV to be output through the BNC and VGA connectors (use some of these abbreviations at the video store to see if the salesman knows his stuff).
The front panel buttons push in deeply with a little click. The unit is slim and has a solid feel to it, and it was easy to set up.
The function control lets you access the Brightness, Contrast, Color, Tint, Detail, and Noise Reduction. Each control has a different range, but they all are quite flexible and allow you to fine tune each one.
Of all the above, detail and noise require some caution. These two controls are quite powerful and can not only improve a picture but also degrade it if you set it incorrectly. These two controls interact with each other. The detail control is a super sharpness control that, if you are not careful, can give the picture an etched look. When used properly though, it can sharpen or remove ringing found in some of the video software out there.
The back of the VS50 has a power switch, RS232 port, one composite video and one S-Video input. There is also an S-Video output, and the RGB/YUB outputs. The composite and RGB all use BNC connectors. A 15-pin VGA style output is there for connection to a computer monitor. You can use all of the three video outputs at the same time.
The RS232 port is a feature found only on high-performance products. It allows you to connect to a PC or home automation system. You can then adjust the controls without actually handling the VS50.
I wish they had added a component input so that I could use the bandwidth expansion and detail/noise reduction with DVD. However, you can use these features with the S-Video output from DVD, which is what most people have.
Since the VS50 only has one composite and one S-Video input, I used the Entech video switcher in front of the VS50 to accommodate my various sources. I had a few problems with this,. When I switched sources, the VS50 would loose sync (synchronization lock). I had to actually reset the power on my LD player and VHS to regain the sync.
Let me explain that in another way. I had my LD plugged into V1 of the Entech and the output of the Entech into the VS50. I would then switch the Entech to use a different source and then switch back to the LD, but the VS50 would not lock in to the signal (that is a function of the sync). If I powered the LD off, then on again, it would re-establish sync.
Setting the Color, Tint, Brightness, and Contrast is pretty straightforward and is explained in detail on the VE LD and DVD, so I won't cover how to set them here. These should all be set first, and their settings will actually vary from source to source. If you configure the VS50 based on your LD preferences, the settings will also work nicely for both DSS and VHS. A DVD player may actually require different settings though.
Setting the Detail is much more critical. I used the Sharpness pattern [Click here to see pattern] on VE [Frame: 27960] to set the detail. Other sources that are also helpful include the multiburst [Click here to see pattern] on VE [Frame: 46619] or A Video Standard (AVS) [Frame: 5060, 14384, 50790, and 50816], and the sweep pattern [Click here to see pattern] from VE [Frame: 46622].
When looking at the burst, you want to start with a setting that gives you a background that is equal in intensity across the entire pattern. Then increase the detail control slightly above that to increase the detail in the picture. Be very careful no to add too much or you may actually add a lot of video noise. To see what I am talking about, start with the detail in the default position then increase to +011. You should see a HUGE difference, lots of noise, which you do not want (at least, I don't).
I have found that cartoons, such as those from Disney, reveal the most improvements provided by the VS50. Cartoons tend to have edges that get smeared, and the bandwidth expansion circuit really helps to sharpen these edges.
I also found the detail/noise reduction to help out with some of those overly enhanced DVDs. A good example of this is with "Rob Roy". The DVD has a lot of noticeable noise. You can see ringing throughout the picture. By "ringing", I am referring to an outline that surrounds each object, kind of like a halo.
To check the quality of the chroma decoder, you simply calibrate the projector using the NTSC color bars and a blue filter (or cap off the green and red guns). Once this is done, you uncap the red and cap the blue guns. The two sets of red bars should be identical, and the same holds true for the green decoding.
Red is the one color that will quickly identify the quality of the chroma decoding. All too often, TV manufactures will push the red (i.e., too much red). When proper decoding is being done, various shades of red will stand out that you did not know were there before, such as brick red, beet red, dark red, light red, etc.
The best results that I obtained with the VS50 were when it was paired with the Dwin TranScanner (TS). The TS has a nice NTSC-to-Component decoder, but the Faroudja is better. The TS does not offer any of the bandwidth expansion or detail/noise features that the Faroudja VS50 has. I also obtained a better picture when I placed the Crystal VPS-1 comb filter in front of the VS50.
The only thing that the VS50/Crystal/Dwin combo could not do is eliminate cross color. This is one feature that Faroudja did not pack into the VS50, but it is in their other (more $$$) video processor products.
The VS50 is expensive at $3,595, but when compared to its broadcast big brother which sold for $8,000, it is pretty close to being a bargain. The inclusion of the bandwidth expansion technology really tightens up those edges.
The VS50 can improve any video source and projector that will accept an RGB or YUV input. The chroma decoding is really superb. If your only video source is DVD, you might not have a reason for purchasing the VS50, but if you are like me and have a nice LD library, it really can bring you closer to the film experience.
Stacey L. Spears
© Copyright 1999 Secrets of Home Theater & High Fidelity
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