Industry Professionals?

[Bobbsy]

The maximum distance you can run VGA is dependent on a number of factors and a flat "X is the longest you can use" is too simplistic. Some of the factors would be:

 

-quality of the video adaptor output

 

-quality of the cable being used

 

-resolution settings on the video adaptor.

 

This last item is quite important. The losses that the cable run cause are worst at higher frequencies so, the higher the resolution, the worse the effects of longer runs.

 

Having said that, with ordinary domestic cables at a reasonable resolution, 5 metres IS probably getting near the limit that you can feed a signal and remain within spec. The thing is, once you exceed the distance the picture doesn't just disappear; rather it drifts out of spec (losing high frequencies first) and gradually degrades. How visible this is will depend on the quality of display at the far end...and the quality of "eye" the technician has to start to see faults.

 

I must say this is an area where I have sympathy with the original poster. All too often I find that posters here will provide an answer based on doing things "properly" only to have three other people pop up giving details of a "bodge" solution they've used and made to "work". Well, feeding video down a mic cable may "work" but I guarantee that it is at the expense of losing most of the high frequency information--with the resultant loss of resolution. I suppose there may be emergencies where you have to put up with this, but should anybody on this board actually be advocating solutions like this by choice? Certainly, they should at least understand the issues involved and, in some cases, train themselves to recognise the early onset of problems. Be honest...how often have you seen rubbish video image or heard major intermod products on radio mics while the operator claimed everything was fine?

 

Yeah...sometimes there's a place for shortcuts, but I don't like seeing them advocated as normally acceptable practice.

 

Bob

[AndrewR]

I'm not going to stir the professionalism argument as people are already saying what I would.

 

But:

 

Terminating Video/VGA/XGA (sorry if I dont meet you standards, but XGA is just a form of VGA output is it not? if fact describing a higher resolution but essentially the same type of signal (at a higher frequency though))

I'm confused by this statement. I understand you think that I should be terminating my Video and VGA cables, but I dont understand how I am supposed to do this. Where can I buy said terminators? and more importantly how do I connect them? I seem to have the slight obstacle of a piece of equpment attached to the end of the cable...... :** laughs out loud **:

/pedant

 

And now I am going to stick my oar in....

 

People need to learn and so long as they know what they are doing is not best practice (but still safe) what is the problem? You are obviously not doing these things, so just ignore these people and don't employ them. People need to ask questions to learn, even if they are stupid questions. In fact the first question I asked on this forum got me near abuse for being an idiot, till someone came along and actually gave me a helpfull answer. A year later, a little wiser I have discovered that there is yet another answer to my question (and that some of the people suggesting my PAC's would melt were in fact wrong, so there :P )

 

Having looked at a couple of other forums I think we should be happy with the standards of the BR. But we might want to force people to read the lighting FAQ when they sign up !

 

Oh and finally, there's no such thing as stupid questions, just stupid people. <_<

[David A]

I'm sure you're probably technically correct, however of the 30+ venues I work in with vga's they all have either 15m or 30 m professional grade vga cables and to use 5m cables we would have to fly the presenter.Any degradation has been so slight that I have never once had the slightest problem which is why this thread has so surprised me.If this is correct why do all the suppliers supply 15 and 30m cables?

[pete LD]

As Mumbles points out, you soon get to know who is worth listening to, and who isn't. I know there are certain posters I skip past every time while there are others whose opinions and advice I would take every time.

 

I think members should make more use of the signature on there profile. This is a good way to know who's posting and what job they do! things like AC Lighting rep or Tech manager of xyz theatre.

this still doesn't stop 15yearolds who have a 2 parcans and some string pretending they own a large hire company but they normally stand out!

back to the OP budget plays the part in everything! I would love to have unlimited budgets to do everything properly but there are times when I need a cheep lot of DMX and have to use mic cable. It works and its cheaper but I use proper DMX when I have the budget to buy it! and ive never terminated DMX, ive never had a problem but then if I did I would work it out, find the fault and get the show on! I wont cry about it because I know if I'm cutting corners problems might happen!

 

I forget to query the 5M rule for vga cable, as I have never used anything shorter than 15M and usually 30M and I have never seen shorter cables in use and never had a hint of a problem I have to query this statement

 

I was wondering that as Ive never seen a short vga lead?

[Bobbsy]

Terminating Video/VGA/XGA (sorry if I dont meet you standards, but XGA is just a form of VGA output is it not? if fact describing a higher resolution but essentially the same type of signal (at a higher frequency though))

I'm confused by this statement. I understand you think that I should be terminating my Video and VGA cables, but I dont understand how I am supposed to do this. Where can I buy said terminators? and more importantly how do I connect them? I seem to have the slight obstacle of a piece of equpment attached to the end of the cable...... <_<

/pedant

 

If you have a single bit of gear at the end of your cable, that gear is your termination. Where the need for external terms comes up on video gear is where you have the ability to loop a signal through several bits of gear, or attempt to use a "T" connector on a coax video feed. The other place where a term would be appropriate is if you use a splitter on a VGA feed and have a spare output...such a spare should not be left unterminated.

 

Bob

[ianl]

long vga cables are sold because:

1. for optimum picture quality you would use an amplifier/eq box but you still need the long cable

2. in a lot of situations the resultant picture onthe end of a 20m or so cable is acceptable - for images in a nightclub or small presentations in work I would happily use just the cable, for a national conference I would make sure the picture was as good as it could be

 

short vga cables are common:

we use them when we double stack projectors, on every flat screen monitor and a number of presentations where the projrctor is sat on a table next to the laptop

 

some of our equipment has termination on/off switches and you can definatly see the diference between no termination , correct termination and double termination

some of our equipment is apparently auto terminating and can tell if it is on the end of the line

personally I've rarely seen a vga terminator, used one even less and wouldn't know where to get one, but then again I don't work often in the top end video market

 

I really can't get my head round doing multiple quotes in posts <_<

 

If you have a single bit of gear at the end of your cable, that gear is your termination. Where the need for external terms comes up on video gear is where you have the ability to loop a signal through several bits of gear,

Bob

 

having read this again...

 

surely the bit of gear at the end of the chain is your termination in the same way as the single bit of gear is, so there would be no nead for external trmination

 

 

 

also it amused me in a post about correctly terminating video signals to mention using T-pieces,

[andy_s]

The latest refers to running video along XLR (audio) cable, this is presumably because the person asking cannot be bothered to run the correct cable for the job and wants to run the signal down an audio multicore.

If we go back and look at the post refered to by the OP, we see that the question is being asked because trundle had seen someone else doing this, and quite sensibly, I would suggest, would like someone else to confirm whether it's a good idea or not before copying them.

 

So although it seems like a good springboard for the OP's thoughts on professionalism, perhaps it's a tad unfair to suggest that trundle is too lazy to do it properly.....

 

How can anyone argue with the "it's good to have standards" bit of the debate? I'm not, but I will say that there are plenty of professionals who take shortcuts, and conversely plenty of highly professional "amateurs". so perhaps our qualifications and definitions are a bit nebulous...

[paulears]

While appreciating the sentiment behind always doing it the 'correct' way - Canford Audio, home to many BBC and broadcast user accounts have been happily selling a range of bodge plugs.

 

http://www.canford.co.uk/images/itemimages/tn/49-300_01.jpg

 

Presumably the profesionals who buy these to keep in their spare kits use them as 'get out of jail' cards.

 

I think the dispute is between 'professional' and 'professionalism'. The caveat is knowledge and experience - what can be got away with depends very much on the person understanding the problem, analysing it and developing a plan 'B'. I'm talking about looking at a bit of mic cable and making a pretty good guesstimate of it's ability to say carry DMX or video. Some would be a real problem, others could handle it - experience makes the guess more likely. To me that is the mark of a true professional - somebody who can make the best out of a potential bad job.

[Bobbsy]

also it amused me in a post about correctly terminating video signals to mention using T-pieces,

 

Obviously in normal use a T piece is bad practice. However, over the years I have encountered certain items of gear...often test equipment...where a T connector with a proper termination (either a piece of gear or simple a BNC term) at the end of the chain was the recommended method of use.

 

Back on the bigger debate, one comment I'd like to make is that there is a world of difference between being able to say "this installation complies with IEEE 635.27 (don't look it up...I just made that one up) and, so long as everything remains the same, will work within specification" and "I've done it this way before and it's never gone wrong yet."

 

DMX down a mic cable is an example of this. We all know that 99.9% of the time you can get away with it. However, I hope we also all know that .1% of the time, some combination of cable, distance and equipment is going to come back and bite you. If your installation meets specification and the light at the end of the chain doesn't work, you have a comeback against the manufacturer. If you've used mic cable, it's your fault.

 

While I fully agree that there are some highly qualified amateurs out there, I think the above is an example of the difference between professionals and amateurs. For 35ish years, I've been accepting money for my technical skills, either on staff at a company or (in the latter years) as a consultant. There are certainly places where, if I was working purely for myself, I MIGHT be willing to accept a shortcut, as soon as I'm spending somebody elses money I have to be able to guarantee the results...and this means sticking to standards. I suspect we've all been there where we've tried to save money for a client and, with warnings of what can go wrong, ignored standards. Guess what. No matter how much you warn them in advance, when the "one in a thousand" chance happens in a couple of years and something goes wrong during a show, you still get the blame.

 

To a lesser extent, I think advice given in a forum like this has to follow the same rules. If I make a suggestion in a thread, there's at least a chance that somebody will spend money (or risk a show going wrong) based on that advice. Therefore, I'm going to tend to be conservative and make suggestions based on doing things properly. Yeah...you might get away with something else, but is it responsible to go on record as recommending it, especially if it's clear the questioner doesn't have the background knowledge to make an informed choice of the technical risk they're taking.

 

Bob

[digitalangel]

Please don't ban us am-dramers from the blue room!!! <_<

I'm speaking for myself personally, but as an unpaid 'amateur' I do what I do for one main reason - I do it because I love doing it! Because of this, I aim to do the best job I can within both my abilities/experience, the small budget I have to work with, and the time I have to get the job done outside of my 'day job'. And hey, even amateur productions have paying punters, for whom I always want to put on the best show possible.

Although I've picked up quite a bit of knowledge over the years, I find this sort of forum invaluble for advice on what to do if I have a query on a bit of kit I've not used previously or if I think someone may have a good idea of how to create an effect I'm after. It also gives us amateurs an outlet to learn from the pros the safe, correct way to do things and so we have a better chance of doing a professional job. But I do have a note on 'prof only' forums. I'm an associate member of the ABTT and a member of the ASP, so having to be a member of one of these wouldn't exclude all of us 'amateurs', and I regularly visit the forums of these associations as well as the blue room.

One more point. We am-dramers may be 'amateurs' in the theatrical industry, but quite a few of us have professional day jobs in other industries. I'm a Chemical Engineer and work in safety, so I have quite a few professional skills from this which I apply to my theatrical activities, things like project management, safety management, technical drawing/drafting, a bit of electrical engineering etc etc.

[paulears]

There is no question of 'amdrammers' being banned from the Blue Room - in fact we encourage membership from professionals and amateurs, who very often have almost identical aims. Actually, sometimes I feel that good amdram is better than so called pro theatre because they actually care - and sometimes this factor can be missing from the pro shows, where there are always a few rough diamonds who seem to hate what they do!

 

The problem that seems to be on the increase is that people overstate their qualfications (both paper and real world) and start to give out advice- often based on internet derived spec sheets and other secondary research.

 

I think we said the other day - somebody asked for basic advice, and got really helpful stuff back because he told the truth - he was a beginner and wanted to learn. Equally we get people with just a few posts under their belt who are still in school (remember, we all were once) who advise people on the purchase of kt costing in excess of £2000! This is the scary kind of post that doesn't do anyone, or the BR itself, any good.

 

I can only speak for myself, but these posts are the ones that quite a few members wish to distance themselves from. Personally, this is the kind of thing I'd like separated out - but I'm not sure that a pro/am division would work. As has been said, many members are seasoned amateurs with plenty of skill and experience, but they have a conventional daytime job.

 

Frankly I don't know how it would work - getting members to provide full details of themselves never seems popular in the normal signups, so some kind of vetting would have to take place, and I can see many not wanting this. Separating out some members also weakens the coverage. A subject may be really interesting in the 'old lags' section, but how many people could read it or join in. Maybe restricting members from posting in the 'oldlags' section, but allowing them to read it might work.

 

The mods are getting lots of comments from members, but nothing is really coming forward. I guess that we could really beef up policing and hide the dodgy posts, but this is never popular, but what do we do to keep the signal to noise ratio high? I don't know.

[mackerr]

I think both Bobbsy and Paulears have pointed out some of the shortcomings of getting reliable information on the Internet. The beauty of this, and other forums like it, is that over time certain participants get known for the quality of their advice. It might help speed up that process if the moderators jumped in and questioned the value of bad advice openly, or conversely, praised good advice. I read a lot of posts in a lot of forums, and I have a list in my head of who I pay attention to, and who I don't. I also have a lifetime in this business to help me pick and choose. There are many who don't have the experience to separate the wheat from the chaff, and some guidance from the mods might help them greatly. I know there are forums that have member ratings which are usually done by the general membership. I think that is mostly a popularity contest, and of no real value. Member ratings based only on input from the moderators, who we assume are experienced professionals, would be more useful in providing some provenance to the information and ideas spread around on the Internet.

 

Mac

[ojc123]

As an amateur (or possibly semi professional) I find all the posts useful and educational. I learn from the professional level discussions which make me realise how little I know and I have learned a lot about the right way to do things from the replies to the less advanced posts . I take more note of some posters than others.

 

When I have asked questions I have always had helpful replies, often from industry professionals whose time I could not afford to buy. I post less often now because I have learned how little I know, and I am more wary of passing on duff information or 'advice'. I also have learned how much there is to be found using the Search facility as I start to get more familiar with what I'm searching for. Perhaps the posting of apparently trivial questions is part of the Blue Room learning curve?

 

I believe that the Blue Room is less swamped with the trivial now than it was about six months ago. Perhaps the Mods are being active in filtering the posts? I did worry about the amateur - professional balance then.

 

FWIW the 'video down XLR' question seemed to me to be a sensibly phrased request for information from a young man who wanted to know a specific piece of information. I also think that the Original Poster of that question has probably learned a great deal from this forum if the tone and content of this question is compared with some of his earliest posts.

 

Also FWIW (and so as not to disappoint the OP), I've run video for CCTV down the sound multicore. It worked. It might not have done.

[dbuckley]

I'm really gald no-one told me I can't run VGA for more than 5 meters, as earlier this week I bought this 20m XVGA cable and used it for a ickle award show last night. Surprisingly, and perhaps shockingly, it worked. Glad about that, really. First time I've driven PowerPoint from show control, and I'd have hated it if the video signal got lost in the cable somewhere.

[soundo26]

OK!

 

Broadcast technician.....I agree, that's part of my point

mumbles....I agree, you get the point

Rob Beech....You too, I fully accept that there are members who are at the beginning of their career, I have no problems with that and will help them wherever I can, I'm still learning too, but my main beef is that with alarming regularity, people seem to be just looking for ways to cut corners, This is not good in my opinion.

David A.....I agree that sometimes bodges are necessary to get you out of a situation, we all do it when forced to, my objection is that people seem to be doing it as a matter of course, you only need to watch this, and other forums to see that.

Bryson.....Don't feel bitter, I respect you, I just wish to see "The Bar" raised. By the way, the paragraph about conferences/events is fantasy, no client these days has deep pockets, we are working within inadequate budgets for most of the time these days, but we never let that compromise the show, or our own professionalism.

Stutwo......I don't in any way consider myself elitist and do not wish for a pro Forum, I come here to learn, and to give advice when I feel I can. All I am saying here is that the same old cherries keep re-surfacing and it's all about not doing things correctly & professionally. As Ynot says, "professionalism is an attitude".

DavidA....The reason they sell longer VGA cables is for use with amplifiers and DA's which allow runs of about 250feet, otherwise we'd be using adaptors to join lots of little cables together.

AndrewR...Don't worry, you're in luck, most modern kit is self-terminating so you don't have to. But you still need to be aware so that when you meet kit that isn't, you know how to handle it.

PeteLD.........the issue of signatures is a good one but I think you'll find that it would be advertising which I believe is not allowed.

Bobbsy......If the kit has a pass through and is used in the middle of a run it should not and probably is not be terminated,The end piece is, or should be. Most modern kit is as said before, self terminating, it senses what is happening and adds termination if needed, this is true of splitters which are terminated if no kit is present. Oh.....and I wholly agree with your second post!

AndyS.....I concur, heartfelt apologies to trundle!

Paulears..........correct!!!!!!

 

Great debate guys, This is a great forum, all I want is for us all to keep up the standards. For those who have ever interviewed prospective techs for a job, you probably sympathise.