DIY Calibration Software - Update: CalMAN 4.1



The first thing that I did was integrate the Duo into my system. As I only use one source in my theater, this was fairly easy. I ran a HDMI cable from my Oppo BDP-83 to the input on the Duo and ran the output of the Duo to my Integra 80.2 pre-amp/processor. The integration was very easy – I didn’t even have to set-up my remote control : the Duo is capable of detecting when the Oppo is switched on via HDMI communication and automatically powers up and down depending on what state the player is in. I set the Duo to output 1080p and the set frame rate to 1:1 (so 24 Hz sources were output at 24 Hz). I also confirmed that the color space output of the Duo was YCbCr 4:4:4 as my Integra doesn’t pass 4:2:2 properly.

Once I had the Duo integrated into my system, I went on to actually set-up all of the calibration equipment. In order to use the interactive calibration feature you need three different components: the color meter, the computer and the calibration source (video processor, TV, etc). If your calibration source can’t produce its own patterns, you’ll need a fourth piece: a pattern generator. I ended up with quite a few wires and was happy that my theater was small – if I had my equipment in a separate room, interacting with a distant video processor might have proved difficult. I know that my Audyssey Professional calibration has abandoned serial based communication with devices in favor of IP based interaction - maybe this is something that SpectraCal can look at in the future to reduce the number of wires present in the system (I imagine that any TV that CalMAN will interact with will also be Internet ready).

I set up my Chroma5 colorimeter facing my screen, careful that it wasn’t reading off of the shadow cast from my JVC RS-25, and connected my laptop to the Duo via USB -> Serial Port converter. I’ve had a lot of problems with these converters in the past and I was very happy to see that SpectraCal provides a reliable unit with every Duo they sell. As might have been anticipated, there were some drivers to install and firmwares to update. Once I had the firmware updated on the Duo and the driver installed for the USB/Serial converter, I was ready to go. My last step was to set my projector to an uncalibrated, factory default input.

Upon starting the CalMAN software for the first time I was greeted with an “Introduction” work-flow that outlines the basic set-up of the new program. As a previous CalMAN user I can confirm: the interface looks and feel different than the previous version 3 release. The work-flow “tree” is still present on the left hand side, but everything else looks quite different. In this “Introduction” work-flow, a new user is walked through how a calibration session is set-up and all of the various options that one would have to work with before getting started. I’ll commend SpectraCal here - this set-up is very nicely laid out and not only takes away from the complexity of the new interface but also hints to the overall power that this software possesses for one who chooses to really dig deep. Because I was most interested in the Interactive calibration work-flow - I selected this as my default work-flow for use of the software.

The software first asked me to connect an interactive calibration device - in this case the DVDO Duo that SpectraCal provided. I was next asked to connect my Chroma5 meter. After answering a few more questions I was ready to take initial readings. Oops! One problem: nothing happened. It seemed that even though I was set-up to control the Duo as a calibration source, the software didn’t make the jump that this was also going to be my pattern generator. I see why this would be the case: some interactive sources may not have internal patterns and thus a different source would have to be used – but this was not the case here. I went into the settings and easily set-up the Duo as my source. I would have preferred to see this question be part of the work-flow or asked of me when I started the Duo as the calibration source.

Interactive Calibration

After taking some initial readings, the software begins to walk you through the steps of actual calibration - these were all straight forward and fairly easy. The goal of these steps were to get your display relatively close before allowing the Duo to take over the calibration. I selected a preset color temperature and gamma as well as set the basic brightness, contrast, color and tint settings. Once I was done with these I moved on to Grayscale tracking and my first in-home attempt at interactive calibration.

The first interactive calibration screen is “Interactive Grayscale”. This allows you to calibrate both an 11 point grayscale and gamma calibration in one pass: the software calibrates both the luminance at each white point (gamma) as well as the color temperature (grayscale) allowing for you to do both the gamma and grayscale simultaneously.

The interactive calibration is straightforward. After doing an initial 0-100% white read, I was faced with a collection of bar graphs with 4 bars per white point: red, green, blue and white. Each represented my grayscale and luminance at each point. I simply followed the instructions on the screen and moved the bar for luminance to the proper point and the software then took over, changing both the luminance and red/green/blue for each point until it got close to its target. I did this for each point down to 20% (measurements below 20% white are unreliable).

While it was very easy do to, the actual process was a little time consuming for me. The Chroma5 is known as a fairly fast meter, but not as fast (or expensive) as the Klein K-10 that I used in the bootcamp class, so there ended up being quite a bit of waiting on my part. If my cables had been long enough, I might have brought the laptop to the kitchen and had a bowl of ice cream while doing each point.

When I was done I had basically perfect grayscale and gamma tracking. Another full reading confirmed that things were looking very close to perfect with dE values all well below the visually detectable 3. Once through the process, I realized that it might have been faster to do a 2-point grayscale calibration on my own, then come back in with the interactive control to correct any lingering problems. Historically we use external boxes to correct problems that were out of the reach of the displays internal capabilities- starting first with the displays controls and then moving to an external solution. Given that basic adjustments for 2-point grayscale are fairly ubiquitous these days, I would have preferred to use these controls first to get the projector a bit closer so the Duo would have had less work to do and subsequently the interactive process would have been a little faster. Luckily, CalMAN allows for this type of customization and I could easily add a two-point calibration step and create my own Interactive Work-flow - but I think that this should be a standard part of the workflow from the start. Obviously as we move towards displays that CalMAN can interact with directly for calibration, this won’t be necessary, but until then it is a step I would welcome.

I then moved on to color gamut calibration, which also uses interactive graphs and functions similarly to the Interactive Grayscale. The JVC has very oversaturated colors but these were easily tamed using the Duo and Calman. Simply follow the directions on the screen and drag the color points to where they need to be. I was able to get the colors on my projector spot-on using the Duo and CalMAN. Again, I would have preferred for a bit of a hybrid approach here as I think my interaction with the projector directly would have been a bit faster. My JVC RS-25 has a fairly easy to use and full-featured CMS. I would have liked to be able to incorporate some of these features in my calibration, then come back in with the Duo and interactive calibration to get me closer or fix any problems where the JVC fell short.

After this step, the calibration was essentially finished. I was navigated back to a screen to take some final measurements to confirm things looked good. My grayscale and colors were all spot-on now - with the Duo applying real time color corrections to make things super accurate. As one should always do at the end of a calibration, I threw on some of my favorite content to verify that things looked correct...and they did. Using the Duo, it was easy to turn on and off the corrections to see just how much work the it was doing and the resulting picture looked fantastic.