TV calibration via Spyder2 and that old nemesis: cables

[sanlyn]

Something very helpful that I realized while trying to make my PC and TV calibrations match each other -- at least, as far as technology and budget permit:

I had good results recently using Colorvision's Spyder2 on my 3 PC monitors, so I recently bought their SpyderTV product to calibrate my two TV monitors -- and monitors belonging to relatives and friends, just to cross-check the results.

Note: both my TV's were professionally calibrated some time back, for much $$$. But tv's change with time, so I figured my sets were due for a checkup that wouldn't cost $800 and up.

I bought my SpyderTV at newegg.com. The price was right, even if it makes you wince over the price of popular tv calibration DVD's like AVIA (which, I found thru research, has many color errors). Keep in mind that SpyderTV and all DVD-disc based calibration devices will calibrate your tv to your DVD player. It can make DVD movies look pretty good. But you'll have to check other tv inputs by eyeball, such as cable box or VCR, which might not look as perfect after calibration.

I haven't used Monster Cable wire on my tv's for some time now, but I decided to try them with SpyderTV. I spent an entire weekend, much to wife's dismay and annoyance, using the Spyder with different cables and DVD players. I used cable brands not mentioned here, including Mogami, Sony, and some borrowed Monster "THX Certified" (I'm surprised Monster is allowed to use that term. THX has nothing to do with the IEEE's broadcast cable standards and nothing to do with cable, period. THX isn't even an "official" DVD spec anyway, but is LucasFilm's effort at standardizing commercial DVD video production. But consumers don't know that, especially consumers paying hyped prices for the same repackaged non-THX cable Monster has been selling for 20 years. THX "certified" surge protectors and cans of compressed "digital" air are next).

To make a long story short(er): different DVD players and different wire gave wildly different tv picture control settings to get the same calibration results. Spyder's software gives you before/after comparisons; you keep a record of your own TV settings which can also be saved in Spyder's software. Just to make the comparison interesting, I kept my cable box and VCR, etc., usually unchanged -- just to compare how DVD-to-TV calibration might affect other connections. The video wire that I normally use on my cable box, VCR, DVD's, and other inputs are:

Composite and Component: budget blue-jacket AR Performance series, RCA plugs.
S-video: cheap RCA-branded cable from CircuitCity or Amazon.

The first series of SpyderTV calibrations was run from my DVD player with my "usual" wire, which I've used for normal viewing and all previous calibration schemes:

Results through DVD player #1 (Toshiba SD-4800 player w/picture controls at default):
a) Composite correction seemed to involve elevated white-level and sligtly lowered red, but similar to my earlier eyeballed corrections.
b) S-video: tv settings are almost (80%) the same as my old corrections, but visibly better.
c) Component: SpyderTV made major blue and green + contrast corrections. By eyeball, I never could get that one right.

Compared with other inputs such as cable box, VCR's, etc., that use these same wires, all TV inputs looked pretty much the same, to the point where I felt no need to change my tv controls. All connections looked okay, but my VCR required lower contrast and was a tad red, and the cable box was often a bit dim (but no two channels look alike thru cable anyway. Fox Movie Channel looked splendid). Comparing calibrations using the DVD component output correction: every other input looked totally different. I was resetting picture controls constantly and pretty soon got tired of it. Went back to S-video all the time.

SD-4800 DVD player with Monster Cable on all outputs:
All Monster Cable corrections from the DVD required rather extreme red correction adding a lot of my tv controls' green to the image. SpyderTV also removed a lot, but not all, of Monster Cable's blue tint from DVD shadows and whites. Because I left the wire unchanged from my other tv inputs, all other inputs compared to DVD were far too green and the whites looked overblown. Very unpleasant. I then changed the default wire on all my other connections and replaced them with Monster Cable; now they were all Easter-egg green, but DVD's looked okay. Result: all the old Monster Cable wire was returned to my closet.

Results through DVD player #2 (Toshiba RD-XS34 recorder):
Results with all cables above were nearly exactly the same as with the SD-4800 player, except the RD-XS34 didn't require as strong a contrast (white level) correction. This confirmed my impression that the recorder and player look alike because they use the same Zoran chips and are of the same vintage, tho the recorder always struck me as having more "natural" contrast.

Results thru DVD player #3 (Panasonic DMR-ES20 recorder):
Apparently SpyderTV had to raise the black level and make rather strong corrections for too much red and too little blue from the ES20, on all cables used. The correction for red using Monster Cable wasn't as strong, but a strong correction for cyan tint in shadows was still required with Monster. Comparing the ES20 correction with all other inputs, other inputs were a tad green but not by much, and contrast for others looked washed out. As for all component i/o: DVD's looked fine, but all other inputs were really off. Again, I stayed with S-video.

Results thru DVD player #4 (borrowed Sony DVDP-NS700H player):
In all cases and with all cables, Spyder kept asking for strong corrections for too much green, especially in the blacks. The software kept asking for repeated readings in the black-level area and couldn't seem to make up its mind about red/green color content. The software repeatedly asks for re-sampling in areas where it's having a problem determining min and max ideals within the player's capabilities. With this player, SpyderTV took over an hour to make its conclusions. In the end, skin tones and shadows improved markedly, but they never really looked as clean or clear as they did with the older Toshiba and Panny players. All other inputs looked really strange at times (all too red). Result: the recent generation of Sony upsampling players will never find a place in my a/v setup.

Results thru DVD player #5 (borrowed OPPO 980H player):
I was struck by the fact that in all cases SpyderTV was asking me for picture control corrections that were almost the same as required by the Sony player. These two players use similar MediaTek decoder chips. In all cases, the results were the same with this player as with the Sony, though OPPO's image seemed sharper and had fewer motion artifacts. Results: No more OPPO players in this house.

Spyder saves a stats report after each run. According to Spyder's report, a target color temperature of 6500K couldn't be attained with the Oppo or Sony player. With both players the final compromise after a couple of runs on each was either too warm (around 5800K) or too cool (approx 7200K). That could account for the fact that flesh tones thru these players never looked quite right. The panny and Toshiba's allowed Spyder to hit 6500K almost right-on. Spyder2 on my PC monitors achieved the same result there.

RUNNING THE WHOLE RIGAMAROLE ALL OVER AGAIN:
This took an extra 9 hours on a 3rd day of testing. This time I used old Belden cable from various websites. I gave up on Belden cable a while back, but I thought I'd give them another try. The cables were:
Composite: Belden 1505A, Canare RCA plugs
S-video: Belden 1808A standard s-video cable.
Component: Belden 1694A w/Canare RCA connectors
I was flabbergasted to find that SpyderTV required corrections almost identical to those for all Monster Cables, except Belden didn't seem to have as much trouble with reds that Monster did, though Belden had Monster-like noise in the deep reds. All Beldens also had a problem with burned-out highlights, something I'd noticed on my own some time ago. SpyderTV made good color corrections, but highlights seem overly tamed so I repeated the calibation 3 times. Got the same effect each time. Result: back into the closet with the Belden stuff. $275 down the drain.

Conclusion 1: tv monitor cailbration is influenced by cables the tv and DVD players use. You can avoid many PC-to-DVD conversion variations by using the same cables everywhere and by making your PC monitor and TV look as similar as possible

Conclusion 2: I'm staying with my original budget cables, for both tv viewing and capturing VHS tapes to PC. Using Spyder2 on my PC monitors and SpyderTV on my two TV's, PC and TV look pretty much the same, at least as far as overall color balance are concerned. My cheapo default cables also have a sharper image (cleaner detail) than the others. Only major problem with AR blue-jacket cable: their RCA-plug cables have a bit too much contrast in the blacks. All of AR's S-video cables are crap; the cheapo "RCA" house brand S-videos are still the best I've found within monetary reason, even if they're a tad bright. Midtones and skin colors are gorgeous.

HDMI: No HDMI i/o tests here. I don't use HDMI and never will. The prices are too high, quality is too low, and I have too much good equipment anyway that never heard of HDMI.

[edDV]

I think all you are measuring from the DVD players is that "default" settings are usually way off. I calibrate* the TV usually to best match the TV tuner/cable box which has no adjustment and then adjust the players with user settings to match the tuner. Cables should have very little impact especially for short lengths.

There are two ways to think about TV calibration. One is system level with simple device levels matching as described above matching black level, white level, saturation, hue and gamma at the TV.

Internal TV calibration requires a standardized set of test signals from a hardware TV signal generator to adjust internal component RGB black/white/gamma, overall white/grayscale balance, linearity, RGB gun convergence, pincushion, trapezoid and on and on. Get the TV service manual for proper procedure.


* TV calibration is often confused with desktop publishing color match which has very different goals. In publishing or photo editing the goal is to adjust the monitor to match the target printer. That monitor setting is normally useless for video which targets standardized ITU/SMPTE reference test signals that are used for TV broadcasting.

[sanlyn]

I think all you are measuring from the DVD players is that "default" settings are usually way off. I calibrate* the TV usually to best match the TV tuner/cable box which has no adjustment and then adjust the players with user settings to match the tuner.

edDV, that's how I originally calibrated my tv for usual viewing -- preceded, of course, by the "internal" calibration by a video engineer, as you mention. This internal setup and my eyeballs told me that all inputs looked looked pretty much the same (with the exception of many cable channels, some of whom just send a pathetic signal, period). But I was using some old Monster cable at the time and I kept readjusting the pic controls; things just never seemed "correct", even tho I'd spent plenty on a professional calibration for both tv's. I even had the engineer pay a house call (and paid $150) to have him re-check his work. He couldn't find anything wrong. However, as soon as he saw the Monster cable he smirked a bit and said, "You might try some Audioquest wire, I hear its has cleaner color").

Well, I did try some Audioquest -- I was a working programmer in those days, so the price didn't hurt, not too much. But I returned all the Audioquest wire after a big hassle. Too blue -- and I mean, BLUE! -- on every input.

One day I got a Toshiba SD-4800 player, my first DVD player. It came with a 50-cent OEM composite wire. Plugged it in, and, wow, what a picture! Everything I threw into this player looked gorgeous. So I got the brilliant idea of "improving" the picture by replacing the 50-cent wonder with my $60 Monster S-video. Surprise: it looked like crap, and reds were bristling with noise. Back to the 50-cent wonder. I tried it on my cable box and two vcr's. Had beautiful color and contrast from all inputs. But its image seemed a bit soft.

For 6 months I went thru Monster, Belden, Belkin, Mogami, various house brands, Cables2Go, Cardas (VERY sharp, VERY pricey, LOUSY color), BetterCable, Sony OEM, JVC, and lord knows how many more. One day in desperation I picked up a 6-foot $12 "RCA"-branded s-video. Wow! I ran back to Cuircuit City and bought 5 more, which was all they had. Everything with an S-video connection looked, as Goldilocks would say, just-right. -- including the Toshiba. I didn't have to make a single adjustment of my own, except the Toshiba needed a tiny nudge for slightly more green; the ES20's contrast wasn't so bad that I found it objectionable. Everything was looking pretty even across all inputs. But for composite connections (VCR's and playback for capture), all I had was one piece of 50-cent Toshiba wire, and Toshiba's website didn't sell extra copies.

Next, a local Wiz shut down and put all its AR cable on sale. I bought several pieces, even some RF cable. Except for AR's slightly high contrast (only 5 points down on my tv's, from 50% to 45%), and their really cruddy s-video wire and "Pro II" line, these budget AR's had nearly perfect color, almost film-like. I was amazed: after all this time and effort, it was the "cheap stuff" that was looking good. Those AR's threw out some pretty good detail, too.

So I have to strongly disagree with your statement:

Cables should have very little impact especially for short lengths.

I don't think it's true of video cable, nor of audio cable. It has more to do with overall wire impedance at required frequencies. I've seen old reports on the 'net saying Monster products are made from plain 30-ohm hookup wire using cheap connectors with high inductance and bad ground-loop noise. Belden wire sold on "home-made" websites were deigned for 400-foot runs, not 6-foot runs that make highlights appear to burn out. However true those reports might be, I have to trust my eyeballs and these recent Spyder runs. While I do see a slight difference between different inputs, they all look pretty well balanced without my having to fiddle every time I switch signal sources.

If I can say that my tv's have internal pro calibration, and my wire seems to have fairly neutral characteristics for all inputs, and all of my inputs look satisfactory and appear to have well-adjusted default settings, then I think I'd have to conclude that I must have made some correct choices -- or, just by chance I happened to pick various components that have good synergy together but separately might look like garbage in someone else's setup.

As for player default settings: the Sony and Oppo players I mentioned were borrowed for the Spyder tests, but last year I owned copies of those players. Despite every adjustment I could make, I was terrifically disappointed with their performance and returned both to the sellers. Others who came over to see those players didn't like them either. I immediately went shopping for spare Toshibas, and found the player, the recorder, and the Panasonic ES20 available as half-price refurbs (Today a -used- Toshiba RD-XS34 recorder is selling on Amazon for nearly $900 !! They were $499 brand-new in 2004). I've had many people call me to ask if we could have another movie party so they could play some of their DVD's and tapes on my setup "just to see what they really look like".

But no disputing your observation about starting with professional calibration. Whether you want to play with default input settings or test further calibration devices, you're better off beginning with a pro setup if you can afford it. No calibration device works well if you can't start from neutral territory.

Finally, my PC and tv calibrations, captures, and playback all look "alike" between systems. edDv, I don't agree with all your observations, but in this respect you're absolutely correct: you need pro work to start with; you can't work on eyeball power alone, any more than you can design a good speaker system from scratch on ear power. You need solid numbers and firm standards, or you'll drive yourself crazy. And anyone who gets into a hobby like this is probably crazy to start with, so why make it worse.

[edDV]

So I have to strongly disagree with your statement:

Cables should have very little impact especially for short lengths.

I don't think it's true of video cable, nor of audio cable. It has more to do with overall wire impedance at required frequencies.

Please explain your impedance issues with specific types of cable.

Well we need to agree to disagree in general. There may be some special cable issues. Yours sound like corroded connectors.

I'm a degreed electronics engineer and have worked in the broadcast systems industry for over 25 years at the broadcast network/production house level. Even so, I don't claim to be an expert in all the home theater claims. I just do my own tests and see no significant difference from expensive hookup cable vs good grade coax or optical fiber. Audio cables differ by high impedance consumer vs. low impedance professional. There are issues by type of connection and cable lengths. By good cable I don't mean the cheapest shipped with Asian DVD players.

One of the most honest retail sources on the state of consumer cable art is Blue Jeans Cable. I have yet to find serious errors in his technology or performance analysis. Read his FAQs. The issues are well explained by type of application.
http://www.bluejeanscable.com/
http://www.tartancable.com/aboutus.htm (consumer division)

Other good suppliers of less extravagant consumer cables are
Ram Electronics http://www.ramelectronics.net/
Cables To Go http://www.cablestogo.com/product_list.asp?cat_id=2014&sortType=price&sortDir=ASC

I'd be happy to go into technical depth if you have a specific issue.

[sanlyn]

edDV, your posts are always so well-informed that they've helped me solve countless problems caused by my own inexperience, so I'm always on the lookout for your posts. I do disagree with the effects of certain cable products; I've known a couple of engineers who say most wires don't make a difference as long as they're properly designed and constructed, but I've known a few who can see and hear differences that don't seem to impress others. As for Belden: all my Belden wire was made by Bluejeanscable. I've never disputed their design or construction, which always appears to be first rate. I do have disputes with Monster, which always struck me as cheaply made and carelessly designed, right down to their overpriced and ineffective "power conditioners". I also have disputes with BetterCables penchant for expensive silver-plated wire, which adds nothing to performance and, as one engineer told me, the silver plating creates echos that can be seen in video (exploding highlights, which I've clearly seen) and heard on audio (grungy fuzziness across all frequencies and muddied detail, which I've clearly heard as well, not only with BetterCables but with other pricey, high-end silver plated stuff). Monster's low impendance generates streaky, orangey reds, and skin tones that never look correct.

As I understand it, video and audio connects require a nominal 75-ohm impedance at critical sampling frequencies. I don't recall the frequencies, I do recall they are different for audio, video, VHS, etc., but they are specified, as you know, by various standards. Wire that doesn't meet those specs obviously can't offer optimal performance. I also understand that some hardware makers observe those i/o impendance specs more closely than some others.

So, by chance, you might get some good wire plugged into some off-spec hardware, or vice versa; something won't look or sound right somewhere, but who can say where the mismatch exists? You can always measure it, but for most users this isn't possible. Most people, if they don't know exactly where the problem exists, can either replace the wire or replace the input. I couldn't afford to replace every tv or recorder, but for a while I could afford to keep trying out one wire after another. I strongly suspect that the satisfactory result I achieved (finally) was ultimately finding a few stetches of wire whose electrical characteristics were well-matched to my hardware's inputs.

A few years ago during the wild and wooly days of my reckless search for great cheeseburgers and the perfect audio wire, I ran into a test site that published impedance tests on Monster Cable at specified a/v frequencies. At certain sampling frequency bands that require a 75-ohm wire impedance, Monster measured a low 30 ohms in the red spectrum and a "high" of 45 ohms in the higher blue spectrum -- still below the 75-ohm spec. The test concluded that this is why Monster so often displayed noisy, streaky, off-color reds and cyan-tinted highlights. What this tester was seeing in his numbers corresponded exactly with my own visual experience in my living room and in showrooms. The tester also compared this with earlier tests of generic electronic audio hookup wire; he concluded that ordinary hookup wire and many Monster Cables produced very similar impedance curves across critical frequency bands. I guess I had to trust this tester's judgements, since he wasn't selling anything on his site and had links only to reputable and scholarly engineering sites and papers.

Another example is from my cheapo Sony 5.1-channel audio setup that I often use on my DVD players. No way this gear is high-end, but it did have choppy base and really harsh treble. I read in an upscale audio mag that one reviewer thought Radio Shack 18-g. hookup wire made decent speaker cable. So I replaced Sony's OEM speaker wire with this specified RS wire, and the audio took on greater depth, deeper bass, and smoother treble. Far from perfect, but a vast improvement. The RS wire set me back $22 and two hours' work. No one has any explanation for this improvement, except that 18-g solid-core wire replaced 26-g stranded hookup junk and sounded clearly better. Obviously thicker wire usually gives better bass, but I didn't expect the treble would improve as much it did.

I do have some $300/ft audio connects to my preamp and a $175 cable on my main PC monitor. Why the $300/ft audio sounded better than the previous $450 connect that I auditioned and returned is anyone's guess. I wouldn't start blaming my $1800 Adcom preamp or my Dynaco power amp with $200 gold teflon-insulated input jacks, but I plan in the future to avoid $450/ft silver-plated audio wire. I can't offer any numbers to prove why or how the two wires sound different; one would think at those prices there should be little or no difference. But I certainly heard a difference, and later found published reports from other buyers in the USA and Britain who heard the same thing I heard.

Thanx also for the two supplier links. I've been using Cablestogo XVGA cables on my PC monitors for some time now.

[edDV]

...
As I understand it, video and audio connects require a nominal 75-ohm impedance at critical sampling frequencies. I don't recall the frequencies, I do recall they are different for audio, video, VHS, etc., but they are specified, as you know, by various standards. Wire that doesn't meet those specs obviously can't offer optimal performance. I also understand that some hardware makers observe those i/o impendance specs more closely than some others.

Each cable application varies for sensitivity to frequency response (attenuation vs. frequency) and group delay (delay vs. frequency). In most SD video applications, standard 75 ohm coax has ample frequency response and group delay specs out to hundreds of feet. In broadcast facilities only extremely long cable runs need equalization.

Frequency response primarily affects luminance detail. Composite and S-video "color" (quadrature modulated subcarrier) is carried around 3.58MHz +/- 1MHz (4.43MHz +/-1MHz PAL) which is mid frequency. Analog component video requires three similar coax cables of equal length. The signal is sent as YPbPr which reduces "color shifts" resulting from minor cable variation. PbPr are lower bandwidth than luminance. Attenuation or delay issues are encountered only in long cable lengths.

Progressive video and high definition require much wider bandwidth per component (20-60MHz vs 5-10MHz for SD) but are still within acceptable specs for coax cable. The higher frequencies are more susceptible to external interference so most of the attention for HD cable is for additional shielding. At 60 MHz, attenuation and group delay issues become a problem with analog component cable lengths in the 20-75 foot range rather than hundreds of feet for SD, so broadcast facilities have converted to SDI (serial digital interface) for long component cable runs. For SDI, Belden 1694A coax can be used for hundreds of feet. Below 20 feet, double shielded coax is adequate for analog component.

DVI-D and HDMI were designed for shorter cable lengths (under 20 feet). Extending these to long lengths takes expensive shielding and larger gauge wire. Similar to high impedance unbalanced audio, HDMI is a home standard and isn't used for professional work. Pros use low impedance balanced analog audio or AES digital audio + SDI for digital video.

S/PDIF audio is based on AES pro audio which also uses standard 75 ohm coax. AES digital audio can easily go out hundreds of feet depending on sampling frequencies and coax quality used. There is nothing special about S/PDIF coax for short lengths.

All these cable issues are minor compared to what goes on inside the home theater device. Most cable problems are caused by the connector attenuation or damaged coax.

Consumer cable marketing is similar to that used historically for snake oil health remedies or gasoline additives. These companies rely on psychology and legal language to prey on the ignorant.

[edDV]

...
I ran into a test site that published impedance tests on Monster Cable at specified a/v frequencies. At certain sampling frequency bands that require a 75-ohm wire impedance, Monster measured a low 30 ohms in the red spectrum and a "high" of 45 ohms in the higher blue spectrum -- still below the 75-ohm spec. The test concluded that this is why Monster so often displayed noisy, streaky, off-color reds and cyan-tinted highlights.

What type of cable are you talking about here?

For composite or S-Video, nothing in the cable spec is going to affect red or blue shifts. Color is contained in a modulated subcarrier at 3.58MHz. Attenuation would affect saturation but by the time 3.58MHz is affected, most of the upper luminance detail would be long gone.

For component cable, color is carried as PbPr which uses the color subtraction B-Y and R-Y. Green is derived from a formula using the luminance component Y. Attenuation of Pb causes a pink-purple shift*, attenuation of Pr causes a yellowish green shift*. Group Delay causes color smear to the right vs. luminance. I fail to see how a faulty cable will cause a red or blue shift.

Mismatched impedance causes return reflections seen as ghosting or edge ripple on the screen. Luminance is affected most because it contains more high frequency than PbPr.

* pull your Pb and Pr cables one at a time to see for yourself.

[edDV]

...
Another example is from my cheapo Sony 5.1-channel audio setup that I often use on my DVD players. No way this gear is high-end, but it did have choppy base and really harsh treble. I read in an upscale audio mag that one reviewer thought Radio Shack 18-g. hookup wire made decent speaker cable. So I replaced Sony's OEM speaker wire with this specified RS wire, and the audio took on greater depth, deeper bass, and smoother treble. Far from perfect, but a vast improvement. The RS wire set me back $22 and two hours' work. No one has any explanation for this improvement, except that 18-g solid-core wire replaced 26-g stranded hookup junk and sounded clearly better. Obviously thicker wire usually gives better bass, but I didn't expect the treble would improve as much it did.

Speaker wire is a different subject. 2-4 ohm speakers need thicker wire and more amp power to get flat response compared to 8 ohm. 8 ohm impedance needs thicker wire as cable length increases. Receiver manufacturers package cheap thin speaker wire to keep costs and shipping weight down especially for six to eight speaker systems. "26-g stranded hookup junk" is clearly inadequate even for short lengths.

[edDV]

...
I do have some $300/ft audio connects to my preamp and a $175 cable on my main PC monitor. Why the $300/ft audio sounded better than the previous $450 connect that I auditioned and returned is anyone's guess. I wouldn't start blaming my $1800 Adcom preamp or my Dynaco power amp with $200 gold teflon-insulated input jacks, but I plan in the future to avoid $450/ft silver-plated audio wire. I can't offer any numbers to prove why or how the two wires sound different; one would think at those prices there should be little or no difference. But I certainly heard a difference, and later found published reports from other buyers in the USA and Britain who heard the same thing I heard.

I'm one of those that can't hear the difference for line level audio interconnects. The job of a pre-amp is to lift turntable or mic levels to line level. Audio is fragile and subject to interference at low level (unless balanced), but at line level S/N is adequate. I really don't see the point of expensive line level audio wire except for long lengths. If I wanted long distance line level, I'd use pro 600 ohm balanced cable and a matching transformer at each end.

[sanlyn]

I'm one of those that can't hear the difference for line level audio interconnects.

I know many in the audio and video worlds who express the same sentiment, edDV, and I confess: I'm envious. There are times I wish I didn't have a tweaked eye or ear from my years in theater and film work. Life would be simpler and far less expensive.