Dorrough 40-A Specifications download pdf (Page 34)

Goniometer – Vectorscope

The Goniometer is automatically chosen when StarFish® or JellyFish® are enabled and only 2 channels are

routed to the Bargraph section (please the Matrix section for further details).

The Goniometer or Vectorscope displays phase and amplitude information on the Left and Right input channels.

Phase correlation

When the Goniometer, StarFish® or JellyFish® are selected, the left most part of the display is a phase

Bargraph with purple graticule lines. This displays information on the main left/right inputs, with the factory

supplied default for this being the first AES input. Other signals can be chosen using the internal matrix.

Audio meters are rarely used to display pure sine waves and the term “in-phase” is applied here meaning a

signal where the mono sum is equal to or greater than the higher of the left and right signals. “Out of phase” is a

signal where the mono sum would be less than the higher of the left and right signals.

Signals which are predominantly “in phase” have a green marker in the upper half of the range. Fully correlated

signals such as double mono read on the +1 mark. Signals which are “out of phase” are shown with a red

marker in the lower half of the range.

With no input, with only the left or right driven or with correlated mono but with a 90 phase shift, the marker

position is the halfway point with the upper section of the marker green and the lower part red.

StarFish®

The StarFish® is the development in the JellyFish® surround audio

display, developed by TSL Products many years ago. It provides a

picture of a 5.1 surround audio field. The display has the front center

channel arranged towards the top with other directions as marked.

The image here shows the StarFish® display with equal audio on all

legs. Typical sound fields have energy in a variety of directions and

more complex shapes are created which give an indication of the

directions having significant amplitudes. Unlike the earlier JellyFish®

display which with the same signal would have shown a circle, the

StarFish® takes into account the summation occurs when there is coherent (in-phase) content between legs

such as left and centre. Polarity inverted (out of phase) signals can cause the shape to be pulled inwards

towards the centre point, reflecting the perceived cancellation that

occurs.

A yellow coloured trace indicates that there is a high degree of

coherent signal content.

When the signals are largely un-correlated, the trace becomes

blue.

When the predominant content is polarity inverted, a red section of

trace shows highlights that might have produce a phasing problem.

The randomness of typical surround signals means an occasional

glimpse of red should not be a cause for concern, though red showing

for extended periods should be investigated as it can be a sign of a

signal that will not fold-down well into stereo and mono.

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 42 43

No comments

Dorrough 40-A Specifications Page 34