Getting an overview of UnWrap for the System 6000

Question

How should I use UnWrap ?

Answer

Setting up:

We suggest that you try UnWrap with the output being monitored through the Toolbox 5.1 (e.g. by loading preset “5.1 Monitor Matrix”). This way you can collapse the 5.1 signal to stereo or mono, and make sure the result is still list enable.

Try loading some of the UnWrap presets. You can A/B the process by pressing Bypass on the UnWrap engine, or collapse the signal to stereo again by selecting Stereo format on the Toolbox engine, if it’s inserted downstream as suggested above.

Time alignment:

When all delays are set at “0”, all outputs from UnWrap are aligned with sample precision. The basic delay through the algorithm in this case is 3.6 ms at 44.1 and 48 kHz. Try offsetting the delays in samples and ms, and note the shift in image.

Delays may be used...

  • on the surround channels to ensure that sounds appear to originate from the front speakers. 
  • on the center channel to compensate for its position. 
  • on the LFE channel to compensate for speaker position or to advance/delay it for artistic reasons.

When the front channels are not assigned the same delay, please note that a subsequent stereo down-mix may not work so well.

Bit Transparency:

When 0% L/R Processing is selected, Input Trims and Output Levels are at 0 dB, the inputs are bit transparently cloned to the L Front and R Front outputs.

Main Page:

Input trims are provided to carefully match the L/R balance. If working from analog tape, adjust balance with a 1kHz calibration tone. If working from a digital master with stereo levels at full scale, it may be necessary to adjust down input levels a little bit to avoid UnWrap overloads.

The L/R Processing parameter determines how much the L and R front channels are processed. At 0% UnWrap only adds sound to the 4 other channels preserving the original L and R as they were. Somewhere between 60 and 70% the width of the original mix is typically preserved even though a center channel is added. Tip: A/B the width soloing the three front channels and toggle bypass.

UnWrap may derive an LFE signal from the input. It is recommended to lowpass it between 40 and 120 Hz using a 2nd or 4th order filter.

Center Page:

To better separate and optimize the center output, Eq and contour controls are provided.

First set the Ref. Level control at the approximate reference level of the input signal. For a typical level, set Ref. Level at -10 to -18 dB. With a full scale digital input, Ref. Level would be set high, typically 0 to -12 dB. With a quiet or highly dynamic input, set it between -15 and -25 dB.

Then choose between the Contour Styles, and finally apply Eq to the center channel if desired.

UnWrap’s 48 bit eq can work wonders on most signals and be used to selectively suppress spectral ranges where the L/R width could otherwise get compromised, or to boost selected frequencies to strengthen the center anchor function.

Surround Page:

To control the surround channels, decorrelation, Eq and contour controls are provided.

First set the Ref. Level control at the approximate reference level of the input signal. For a typical level, set Ref. Level at -10 to -18 dB. With a full scale digital input, Ref. Level would be set high, typically 0 to -12 dB. With a quiet or highly dynamic input, set it between -15 and -25 dB.

Then choose between the Contour Styles, and select a Decorrelation style complementing your program material. The different decorrelation styles should always be tried. They are highly subjective and best evaluated with the Focus control set at “0”. When a style is found, try changing the Focus control to check if further optimization is possible. It may prove convenient to solo the surround channels while doing so.

Now adjust the Decorrelation Tone and Eq parameters.

Tuning of the surround parameters is an iterative process and should include the delay settings as well.


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