AJA T-Tap and VirtualForge Review

If you calibrate a TV or projector often you probably want to invest in a pattern generator. You can use calibration patterns on Blu-ray discs, including the free AVS HD 709 disc, but that introduces more issues. You have to know that the Blu-ray player is actually bit-perfect, many are not, and you have to manually control the patterns.

Manufacturer: SpectraCal
Model: VirtualForge
Review Date: December 15, 2013
Price: $295.00
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Using a dedicated pattern generator is both faster and easier. Software, including CalMAN, can directly control them to bring up the appropriate pattern. They are also designed to be bit-perfect since they are for people after accurate data. Every calibrator, professional or hobbyist, would own them if they were more affordable. The cheapest one with good support is the AccuPel DVG-5000 and it starts at $1,500.

Using a PC has long been though of as a great option, as many have HDMI outputs built-in. PC output can easily be incorrect due to their video card LUT and other system level settings making that a poor choice. Now we have a new option for using a PC: VirtualForge from SpectraCal. VirtualForce is a Mac-based program that is a software pattern generator for all your calibration needs. Because it is software based, it can do an infinite number of patterns and have more added as needed.

Since laptop video output is still unreliable, VirtualForge works with a selection of professional video output devices that allow complete control over the bits. The cheapest of these is the AJA T-Tap. Available for only $300, combined with the $500 cost of VirtualForge you have the ability to create a full pattern generator for only $800.

This setup offers a few big benefits to me. The T-Tap is tiny and powered off the Thunderbolt bus on a MacBook or Mac desktop. On my 15” MacBook Pro this allows me to run the T-Tap off a Thunderbolt port while still running an i1Pro and a C6 off the two available USB ports. I no longer need a USB hub to include the pattern generator, and I don’t need an external power supply. Everything I need to calibrate is on a single laptop.

AJA Review (1 of 1)

Because CalMAN runs fine in VMWare Fusion, it can run on the same machine as VirtualForge. Now I have my pattern source, calibration software, and everything else on a single system and it is far more portable than before. Using the VirtualForge setup from CalMAN simply requires you to start the software on the Mac, then point CalMAN to the IP address in the Settings.

Fast and Effective In Use

Once connected the VirtualForge offers a wide variety of settings. These are dependent on the device used, as some more expensive options offer 4K support while the T-Tap does not. You have a full selection of pattern sizes, from 2% windows up to 100% full field. There are Average Picture Level (APL) patterns in 10%, 18%, 25% and 50% available as well. Output resolution adjustments are done in the AJA control panel and not CalMAN. Almost all 720 and 1080 resolutions are available to use.

CalMAN T-Tap Screen

Patterns from VirtualForge on the T-Tap are exactly what you expect. The Brightness and Contrast patterns make it very easy to set those controls correctly and I prefer them to the AccuPel versions. Switching between patterns is very fast compared to both stand-alone pattern generators, the AccuPel and the Quantum Data 882, I have used in the past.

The segmented design also makes future upgrades cheaper for a calibrator. There is no affordable 4K pattern generator at this point. The VideoForge 4K unit costs $5,000 and is really only for professionals. The internal card that supports 4K with the VirtualForge, the BlackMagic Design DeckLink 4K Extreme, is only $1,000. Even with $500 for VirtualForge this is 30% of the price of a VideoForge. Once a Thunderbolt powered 4K unit is available that will allow myself, and others, to upgrade to a 4K pattern source for far less than we currently can.

A Few Drawbacks

The combination does what it should do: automates calibration with accurate patterns, and does it well. While there are a lot of benefits to the T-Tap and VirtualForge combination there are some drawbacks as well. Since it requires a computer, you can’t use it to easily set Brightness and Contrast on a display without having a laptop and a copy of CalMAN around. If you want to plug-in a generator and select a pattern, you still need a stand-alone unit.

VirtualForge MenuI also wish the VirtualForge software could do something without CalMAN driving it. Being able to display all the pattern categories and bring up a specific one without launching CalMAN would help. Being able to add your own custom patterns, as many calibrators have ones they prefer, would be a big benefit as well. Some pattern generators like the Quantum Data 882 offer this but many don’t.

You are also tied into using CalMAN for your calibration software. Other software, like ChromaPure, cannot support the VirtualForge right now. Those packages do support the AccuPel, Quantum Data units, and other stand-alone generators but not this software. The fact that you have to buy the calibration software as well as VirtualForge probably helps keep the cost low.

Finally the T-Tap gets hot. Using it to set the light output of a projector, the T-Tap is almost 130 degrees by the time I finish. I haven’t measured the effect on battery life for my laptop, but I’m sure it reduces it with that heat output.

My New Generator

I have used an AccuPel DVG-5000 for over a year now and really liked the unit. It is small, easy to use, and offers a wide selection of patterns. It also has continual updates to add new features to it over time. Despite that I will use VirtualForge with the T-Tap from now on. The convenience of fewer cables, no USB hub or power outlet, and more patterns is too convenient for me to pass on. SpectraCal was nice enough to loan me one to try out and I will buy it instead of returning it.

At $800 for the package it is probably too expensive for most hobbyist users but it is very cheap for a professional calibrator. The fact that I can easily move it around the house, connect to any display here for review, and measure it fast makes it a world ahead of stand-alone units. For some the drawbacks compared to other units are too high, but for most users I think it is fine. I’m glad to see another, more affordable, option on the market and look forward to it improving over time.

Review Summary
Product: SpectraCal VirtualForge and AJA T-Tap
Pros: Cheaper than hardware-only options, fewer cables and power outlets needed
Cons: Mac only, needs CalMAN, runs hot
Summary: $800 for a professional quality pattern generator setup is a remarkable price. Size and convenience will outweigh the drawbacks for many.
Value: 4.5/5
Performance: 4/5
Overall: 4/5

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2 Responses to AJA T-Tap and VirtualForge Review

  1. Bunnyshadow December 16, 2013 at 1:26 AM #

    Actually, if calibrating to watch movies on your Blu-ray player, or a HTPC you want to use a pattern source that uses the same image path, not a separate source.

    That way you will calibrate out any potential issues within the actual image path.

    This is a critical part of accurate calibration.

    • Chris Heinonen December 16, 2013 at 7:44 AM #

      You should always verify your calibration using the source device at the end. An HTPC is often a special case, as their range can be variable based on how it’s configured. In the case of a Blu-ray player, calibrating to match an incorrect output is the wrong way.

      Getting a Blu-ray player that is accuratre is $60 right now. Calibrating to one that is incorrect will result in an image with lower dynamic range and incorrect colors on every other source. There are some inaccurate sources out there, but usually replacing them is far more affordable, and will result in a better image, than trying to calibrate around the flaws.

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