preview monitors – how many to have?

Preview monitors are the TVs or video monitors that show you what’s happening on the various inputs to your video mixer or switcher. This ensures that you know what’s coming next when you are mixing video. The question is….how many do you need? As is often the case the easy answer is the most expensive answer – one per video input, but let’s look at some alternatives.

When you see a picture of a TV studio gallery, or an OB van, a recurring feature is a big bank of TV monitors. These are for previewing camera feeds, VCR feeds, graphics feeds etc. At LEAST one per feed. In live video it’s the same – the basic rule is one monitor per input. Simple. Unfortunately for those doing VLOBLIVE gigs it’s not quite that easy. Firstly more monitors means more money. Secondly it means more space to put them all somewhere, and finally the typical monitor available to use as a preview monitor at a VLOBLIVE gig, namely old domestic portable TVs do not lend themselves well to this role as they typically don’t have inputs and outputs on them to loop through the video signal on its way to the video mixer.

So, what to do?

Well, as usual you put your resources where they will do the most good.

Let’s deal with the Monitor vs TV issue first, as this will affect how many monitors you have available. Proper pro or broadcast preview monitors have loop through connections. In other words they let you take video into the monitor to display, but they also feed that same video signal back out again to let you take it somewhere else. This lets you connect the monitor ‘in line’ with your source, and you are guaranteed to see exactly what will appear at the input to your video mixer. Most basic video monitors or domestic TVs don’t have this feature, so how do you use those as preview monitors? Several options:

– for local sources, make use of multiple video outputs. If your DVD player has both an S-Video and a composite video output, then it’s fine to use BOTH of those at the same time. (you can use multiple outputs, but only one input) Just connect the S-Video to the mixer (better quality) and connect the composite to the preview monitor or TV and you are off! – remember that in Europe at least you will often get multiple outputs if you make use of both the phono AND the SCART connections on domestic VCRs or DVDs. Get yourself a SCART breakout lead or adapter. – an alternative is to use a video distribution amp to split the video signal and use one output to feed the mixer and the other to feed the preview monitor. – if you are buying new gear, consider buying portable units with built-in LCD monitors. Make sure they have good quality (S-Video) outputs though.

OK, so now that you have assembled your collection of monitors and TVs, how to use them?

If you only have one monitor.. Well, first of all, you’re not really trying hard enough are you? I mean – how many friends do you have? OK, bad question – how many relatives? How many TVs do they have between them? Portable TVs are pretty cheap to source and in the right setup can be fine as preview monitors.

But let’s assume you REALLY do only have one monitor. Most video mixers have some kind of preview output, so if you only have one monitor then you would put it on that, and it would let you see whichever input you have selected to be live next. (remember that the preview output on the Panasonic MX50 video mixer is pretty useless) In some cases these outputs will show up to four previews in four quarters of the screen. In others they show only what’s been selected on the inactive video bus, while still others have separate selection buttons to let you control exactly what you preview.

If you only have a few monitors.. If you have more than one monitor then you can start to put them on the video feeds that NEED cue-ing, e.g. VCRs or DVD players, or feeds that you have no other way of previewing. Stuff that has it’s own monitor (portable DVD players, camcorders etc) doesn’t need one, and stuff that never changes (static graphics etc.) don’t need it. Ask yourself ‘what am I most likely to screw up, if I can’t preview it?’

Another option is to buy/borrow/hire a simple switcher to let you switch between preview sources. On the basis that generally you ONLY need to preview what’s coming next, you can connect all the preview sources to a a single monitor via a switcher. Remember in this case the quality of the switcher doesn’t matter since you are not using the video for anything other than previewing – a cheap domestic AV switcher is fine.

If you are doing IMAG.. If you are doing IMAG, then clearly it’s vital that you can see what your camera feeds are sending you, so you know what you are able to switch to next at any moment. In this case I would suggest that one monitor per camera is pretty much essential. Yes you could do IMAG by switching the previews on the camera, or by using the preview output on the mixer, but my own personal experience is that if you can’t see all the camera feeds at the same time, then you forget to switch to the ones you can’t see and your mixing is compromised as a result.

The ideal here would be to source some nice 4-in-a-rack preview monitors that can sit in a rack right in front of you at all times, but do whatever you can to be able to see all camera feeds then just do it.


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