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[edited from support email]
I have a questions about the hardware required to make full use of DirectRT's capabilities. I have heard that old CRT monitors are superior to flat screen LCD monitors because they have faster refresh rates. Is it true that subliminal priming is best done on CRTs rather than LCDs?
Both will work. You just need to know the refresh rates available for the resolutions in which you want to run your studies. Remember that any visual stimulus needs to be shown in intervals equal to the refresh rate. So a 60hz refresh rate means that stimuli are on screen in intervals of about 17ms (1000ms/60=16.66ms). That's far from subliminal and 60hz is often the standard refresh rate* on LCD screens (there are some faster ones available now). Bottom line is that if you really need subliminal, a fast CRT is probably the way to go. Ilyama makes some CRTs that support up to 200hz in 800x600--that's a 5ms refresh rate! One other consideration with LCDs is that they look great but usually in only 1 display resolution--they stretch to accommodate others and that doesn’t look so nice. On the other hand if you don’t need blinding speed and don’t mind a single native resolution, then an LCD can be a great way to go.
There are also other issues involved with subliminal exposure of course.. see e.g., http://www.empirisoft.com/support/showthread.php?t=55
* Definitional Note: LCD screens don't techincally have a "refresh rate" in the same way that CRTs do. They have a "response time" which is how long it takes for the pixels to be updated (since only those that need to change will be redrawn). For simplicity and practicality, we are referring to an LCD's "response time" as its "refresh rate"
[edited from support email]
I read the information and now understand the refresh rate, etc. The question now is what is the alternative? In the literature we are drawing on the exposure is typically 1 ms. Is there an alternative to using a CRT?
Either a 1000hz display (you could ask the CIA) or a good old fashioned tachistoscope.
Considering LCD screens problematic "refresh rate", is it out of the question to use them for subliminal priming? if not, is there a particular kind that the company recommends? or what sort of chipset for the screen?
New large LCD screens are being sold that are claimed to have a 120 Hz refresh rate. This means you could display images for a little as ~8.3 milliseconds. The rationale for the new rate in LCDs is that it provides for better movie/video game watching. If that's for real then we may be seeing laptops with similar specs (or they may be out there already). If you check around and find "regular" sized LCD monitors and/or laptops with this new 120Hz rate, please feel free to post the info here.
if the term "refresh rate" is irrelevant for LCD screens, what should we be looking for in a computer? what do we need to check? have you any recommendations for a specific model/company?
It's not really irrelevant so much as it's referred to sometimes a a response time on LCDs (see above). We don't claim to be experts on the matter of makes and models. I would search for a qualified review on the internet and do look ones that have the faster response times (which may be referred to as refresh rates anyways). We have been using Samsungs here for testing and they work nicely, but our models are a few years old now and use the standard 60 Hz-equivalent response times. Let us know if you find any useful information!
