SpectraFoo Rad 3 f17 Release Notes

This release is being made freely available to all registered users of MLM, SpectraFoo and SpectraFoo Complete, just as all previous updates to the SpectraFoo Range have been. This release contains two primary enhancements. The first enhancement is a compatibility addition. The second enhancement is a feature addition. We recommend that all customers update to this version of the software.

RTAS Support

The first enhancement is a compatibility addition: the TDM version of SpectraFoo now fully supports RTAS. This has two significant benefits for Pro Tools users: The TDM updater will automatically replace the Plug-in with the updated Universal/RTAS version of the SpectraFoo plug. This version of the plug supports Merle ("Classic") DSPs, MIX DSPs, and RTAS.

K-System Support

The second (and most significant) enhancement is the addition of full, elegant support for the K-System metering system as defined by Bob Katz. For a detailed description of the Metering System and its motivations, please see Bob's Paper "An Integrated Approach to Metering, Monitoring, and Leveling Practices" that appeared in the AES Journal. You may be able to find other relevant (and not-so relevant to the K-System but interesting and useful) information at his website <http://www.digido.com/> .

While SpectraFoo provided all of the components to implement the spirit of the K-System, it was not elegant. There are four issues that needed to be addressed in order to implement support for the K-System:

All the issues have been resolved in cooperation with Bob Katz. We have included K-20, K-14, and K-12 presets for the meters and K-20, K-14, and K-12 signal generator presets for calibration. The K-meter options may be used independently of each other to build other meters that are not fully K-System compliant by may still be useful and interesting in other contexts.

A configuration tip: In the meter options window: you can click on the numerical readouts to "popup" a text-entry box. This allows you set the parameter value precisely. We will be propagating this interface feature (or a similar implementation) to all of the controls in the various instruments in SpectraFoo in a future release of the Software. You can use this feature to create derivative slow forms of the K-meters for calibration. You would want to set the VU settling time from .600 s to 6 s for a slow, long term average.

If you calibrate your monitor system according to the K-System recommendations, you can configure SpectraFoo's global level calibration to provide SPL readouts using the SpectraFoo scale. To do this use the SPL reference offset, e.g. for K-20, -20dBFS RMS Pink = 83dB SPL, so 0dBFS RMS Pink = 103dB SPL. In the global level calibration (Menu Path: Analyzer->Level Calibration...) make 0 dBFS = 103 dBu and then ignore the dBu -- the reading is SPL when you configure a meter with the SpectraFoo scale and select the AES-17 compatibility mode (use the Meter Options).

NOTE: If you install this update using the updater your signal generator parameter files get moved to the Metric Halo Moved Items folder. Depending on your Mac system prefs, the Standard File dialog stays "stuck" to the folder, even after it has moved. So, when you go to open the file, it shows you the old files, which are, of course, the same as the new files minus the K-System files. After you mess around enough, you wind up resetting the Mac OS internal preference and you start seeing the proper folder in the Standard File Dialog. Make sure you navigate to the correct folder or open the file by double-clicking in the Finder.

Metric Halo would like to extend Special Thanks to Bob Katz for reviewing this implementation of his specification.

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Copyright ©2001, Metric Halo Distribution, Inc. All right reserved.

SpectraFoo is a trademark of Metric Halo Distribution. Pro Tools, TDM and RTAS are trademarks of Digidesign, a division of Avid, Inc.