Spec 7.1 7.1 Channel Addendum
Table of Contents Installation... 2 Introduction... 2 DSP Load... 3 SPEC Control Panel... 3 Slice... 4 ArcTan... 5 ArcTan Blends Etc. Control Panel... 6 ZPan... 7 Free Mastering and Limiters... 8 Z Automatic Gain... 8 ZMon 7.1... 9 Surround Meter... 10 Installation Spec 7.1 has its own unique plugins so installation of Spec 7.1 will not affect any existing 5.1 versions you may have (other than perhaps pulling down a newer version of Plogue, if needed). Introduction Spec 7.1 is the 7.1 channel version of Spec 5.1 (5.1 channels). For the most part it functions the same as the 5.1 version, with a few additions to accommodate the added channels. The layout should look familiar:
The only obvious change is the Surround Meter, which will be discussed towards the end of this document. The labeling convention and channel ordering is: LF, RF, C, LFE, LS, RS, LBS, RBS Where LBS stands for Left Back Surround, and RBS stands for Right Back Surround. It may be helpful to think of LS and RS as Left Side and Right Side, vs. surround. Note that your audio device may have a different layout. E.G. my Nvidia Video card s order is: LF, RF, C, LFE, LBS, RBS, LS, RS So my connections from Zmon to the audio device for the side and back channels are crossed. The default speaker angles are C 0, Front 30, Side, 110, and Back 150, etc. (change in ZPan Speaker Angles Control Panel). DSP Load The DSP Load of the 7.1 channel layout is proportionately higher than that of the 5.1 version. On my two Windows 7 machines, it runs between 70 and 85% with SR: 44.1Khz FFT Size:8192, Overlap: 16. This means I can live monitor (with the occasional glitch) at those settings but not at any higher settings (ArcTan with Free Mastering Bypassed). SPEC Control Panel
As you can see the SPEC control panel has additional gain controls for the LBS, and RBS channels. In this version the seldom used CC and LCR methods have been removed. At the bottom of the Control Panel are labels showing you the current DSP settings for Sample Rate, FFT Size, and FFT Overlap. Slice Slice has two more Humidity controls, to cover another Slice stage for the Left Surround Back, and Right Surround Back channels. There are no Wrap Rears controls, as in a 7.1 setup the back speakers are (relatively) close together. I have not, as yet, developed recommended settings for the Humidity Controls. All inputs welcome. The same Humidity Controls appear in the ArcTan Blends Etc. Control Panel, for Slice Blended Rears. Other additional controls are the LBS ZPan control and a 7.0 (Normal) mode for Bass Routing.
Note that Bypass and 7.0 (Normal) produce the same routing, but bypass taking less DSP. It helps to toggle Bypass on and off with Slice selected as the mode and processing on, to ensure full bypass. ArcTan ArcTan is switchable between 7.0 and 5.0 modes. At this time it is the only part of the layout that has that capability, but you could use it to switch between 5.0 and 7.0 modes to compare results (you will want to readjust the widths). In 5.0 mode the back channels will be silent. In 5.0 mode you can adjust the Center and Front widths, with the Rear width being calculated (and greyed out) from those two. In 7.0 mode you can adjust the Center, Front, and Rear (or Side ) widths, with the Back width being calculated (and greyed out) from those three. This ArcTan variant currently has different mode selectors (Sum, Across, Diagonal) for each set of channels.
ArcTan Blends Etc. Control Panel As mentioned in the section on Slice, the Slice Humidity Controls are included here for when you have selected Slice as a blend source.
There are additional Blend controls for the 7.0 version of Slice. In this version of ArcTan the Rear Src selector controls the source for both the Side (surround) and Back channels. The Adjacent Speaker Wet control functionality has been modified for 7.0 channels. This Control Panel also includes extra channel subtraction sliders for the Back Channels. While there are actually 24 possible combinations of channel subtraction pairs, in a 7.0 layout, 11 have been included here. I am open to adding or removing additional controls if needed. As mentioned in the section on Slice, the Bass Routing control has an additional 7.0 (Normal) setting, which is functionally the same as Bypass. Bypass will, however, have lower DSP. To ensure lower DSP you should switch Bypass on and off with processing on and ArcTan Selected as a method. ZPan ZPan has been expanded to cover 7.0 channels. Remember that the Left hand channels should all have negative degree values. The default ITU settings are shown above. Panning Center adds DSP load.
ZPan and ArcTan both depend on understanding the angles your speakers are actually placed at. For both ZPan and ArcTan, you set those angles in the the ZPan Speaker Angle Control Panel: Remember that the Knob s label is ABOVE each knob. The numbering convention for these controls is 0 to 360 CW, however CW represents more to the LEFT (until you pass 180). The default ITU settings are: LF 30, RF 330, C 0, LS 110, RS 250, LBS 150, RBS 210. You can right click on a knob to set or reset precise values. Free Mastering and Limiters The Free Mastering and Limters groups have been expanded with additional VSTs for the additional back channels. Z Automatic Gain Zag has one additional control, the Backs to Fronts level. There are also additional meters and results/measurements for the Back channels. Peak Capture has been expanded to cover the Back channels.
ZMon 7.1 ZMon has additional Solo and Mute checkboxes for the back channels. The Meter Control (Controls Audio to the last two output pins, for connection to a stereo meter VST) have been expanded with more combinations to allow for phase and level checking between 7.1 channels. A new Mixdown control has been added. Its purpose is to assist in producing a 7.1 (5.1 compatible, via DTS-HD MA) conversion when you only have a 5.1 speaker system to monitor with. None 7.1 in 7.1 out 7.1 5.1 Side (surround) channels are mixed with the back channels, and other volume s adjusted to match. This simulates the default 5.1 mixdown settings in DTS Master Audio Suite. With this setting you will hear what listeners with 5.1 systems would hear. C=LF+C+RF, Fronts=S, Rears=BS Fronts and Center are mixed together and presenter in the Center speaker only. The Front Speakers get the 7.1 side channels, and the Rear Speakers get the 7.1 Back channels. This mode would be used for hearing the 7.1 Side and Back channels separately, on a 5.1 speaker setup. Again, assuming you wanted to future proof your conversion by producing a 7.1 conversion, even if you only currently have a 5.1 speaker setup, this is another tool to help ensure a quality conversion for both 7.1 and 5.1 listeners. Stereo The 7.1 signals are mixed back down to stereo. How does it sound, compared to the original stereo? Mono The 7.1 signals are mixed down to mono. When working with muliti-channel sound, it s always a good idea to check the mono mixdown as any phase problems, etc. will be more apparent.
Tip: When figuring out which channels are which on your audio device or trouble shooting connection problems, be sure the Mixdown selector is set to None. Surround Meter Lastly, I found that when working in 7.1 it was helpful to have meters presented in a Non ITU order, with the Center ch. in the center of the meter and the left hand speakers in order to the left, and right hand speakers in order to the right: So, the order, from left to right, is LBS, LS, LF, C, RF, RS, RBS, and LFE (on could argue that LFE maybe should be next to C. Feel free to change the wiring). Unfortunately the meters cannot be renamed with the Channel names. To see the Surround Meters, with processing on, right click the Surround Meter bidule and select Monitor (nothing will happen if you forgot to turn processing on).