BUILDING MATRIX SURROUND SOUND ENCODERS

FOR AN ORDINARY STEREO MIXER WITH 4 TO 10 SUBGROUPS


UniQuad Read the parent article to learn how to choose a mixer, and how to use the encoders.

Why two SQ decoders can function as an SQ encoder:

How two SQ decoders can function as an SQ encoder:


What you need, in addition to the mixer

What you might need, depending on your equipment and intent:

EQUIPMENT NEEDED FOR EACH ENTIRE ENCODING SYSTEM

Instructions (continued):

ENCODING SYSTEM EQUIPMENT REQUIREMENTS
ENCODING SYSTEM EQUIPMENT NEEDED
Bus
Swap
Switch
Phase
Inverter
Phase
Switch
SQ
Decoders
Advanced
Phase
Switch
RM/SQ
Mode
Switch
RM Acro
Aux
Send
Digital
Delay
Mix
Buses
Need
Cross
Faders
For n
Chan
Strips
For n
RM (Dolby Surround) Basic 1 4 n
RM with Acroperiphonic Delay 1 1 1 4 n
RM & Single SQ 1 1 6 − † n †
Single SQ, no RM 1 4 − † 1 †
RM & Double SQ 4−C 1 2 8 n 2n
RM & Double SQ 4−C, DGS 1 1 2 8 n 2n
RM & Double SQ 4−C, F−O 1 2 1 8 n 2n
RM & Double SQ 4−C, DGS, F−O, B−O 1 1 2 1 8 n 2n
Double SQ 4−C, DGS, F−O, B−O, no RM 1 2 1 4 n 2n
Switched RM or Double SQ 4−C 1 2 2−pos 4 n
Switched RM or Double SQ 4−C, DGS, F−O, B−O 1 †† 2 1 2−pos 4 n 2n
k Ultimate Encoder Pairs k k k k 3−pos 2k n 2n
k Ultimate Encoder Pairs & RM Acroperiphonic k k k k 3−pos 1 1 2k n 2n
k Ultimate Encoder Pairs & Back Sub Swap k k k k k 3−pos 2k n 2n

n is the number of sound sources used.

k is the number of encoding pairs used.

A Phlazex unit can be used as either a phase inverter or a phase switch.

† Need a cross fader and two channel strips for acroperiphonic panning.

†† The phase switch works for both (set to reverse for RM).

Variations:


CONSTRUCTING THE CABLES

Note that if several switched or controlled devices are needed, they could be combined on a common control panel.

mixer diagrams RM / DS Encoder

Patch cord A. Choose the selection that best fits your mixer:

  1. You have built a UniQuad Phlazex. Uses standard patch cords. Set it for Encode Surround Right-Biased.
  2. ENCODER INSERT jacks
  3. Fully balanced SUB OUT and ENCODER RETURN jacks
  4. Impedance balanced SUB OUT, fully balanced ENCODER RETURN
  5. Unbalanced SUB OUT, fully balanced ENCODER RETURN
  6. Unbalanced ENCODER RETURN
  7. You had hum problems using one of the balanced methods.

The sample illustrations show 1/4 inch phone plugs. Substitute the type of connector you are really using.

Acroperiphonic (AP) Encoder

Patch cord B. Find your AP RETURN type:

  1. Mono
  2. Tip-Ring-Sleeve stereo
  3. Stereo on two jacks

4−Corners Encoder Patch cord C. Find your AP AUX SEND type:

  1. Mono
  2. Tip-Ring-Sleeve stereo
  3. Stereo on two jacks

Basic 4−Corners SQ Encoder

All of the patchcords are standard patchcords, or insert patchcords that fit the inserts and the SQ decoder. Use the diagram on the right above:

The 4−Corners encoder is the only SQ encoder that does not need the crossfaders or two channel strips per source.

Diagonal−Split Encoder Basic 4−Corners and Diagonal−Split−Oriented SQ Encoder

All but one of the patchcords are standard patchcords, or insert patchcords that fit the inserts and the SQ decoder.

The basic phase switch is the one special cord:

  1. Build a custom phase reversing switch. Place it in the line for encoding the left back.
  2. You have built a UniQuad Phlazex. Uses standard patch cords. Connect to both lines for encoding SQ back.
  3. The basic phase switch does not give optimum encodings of the left and right sides. It gives the optimal diagonal splits.

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

Forward−Oriented Encoder Advanced 4−Corners and Forward−Oriented SQ Encoder

The advanced phase switch is a special cord set:

  1. Build the advanced phase reversing switch. Place it in the lines for encoding the left back and right back as labeled.
  2. The advanced phase switch changes the following abilities:

The normal phase position selects the 4−corners encoder, and the reverse position selects the forward−oriented encoder.

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

4−way Encoder Combined 4−Corners, Diagonal Split, Forward−oriented, and Backward−Oriented SQ Encoder

The basic phase switch (1) is the one special cord. The advanced phase switch (2) is a special cord set. Both are needed:

  1. Build the custom phase reversing switch. Place it in the line for encoding the left back.
  2. Build the advanced phase reversing switch. Place it in the lines for encoding the left back and right back as labeled.
  3. The advanced phase switch changes the following abilities:

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

See the general switch table below to operate.

Ultimate Encoder The Ultimate Encoder Pair or the switched RM / SQ Encoder

The basic phase switch (1) is a special cord. The advanced phase switch (2) is a special cord set. Both are needed, along with a stereo source selector. A swap switch can be added for CircleSurround:

  1. Build the custom phase reversing switch. Place it in the line for encoding the left feed.
  2. Build the advanced phase reversing switch. Place it in the lines for encoding the left back and right back as labeled.
  3. The advanced phase switch changes the following abilities:
  4. The source selector selects what kind of encoding will be done by the bus pair.
  5. The swap switch is used to encode CircleSurround instead of SQ.

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

See the general switch table below to operate.


CONNECTING THE CABLES TO THE MIXER

mixer diagramsRM / DS Encoder

Acroperiphonic Encoder

To install the acroperiphonic function, make the following connections:

  1. Connect the mixer end(s) of patch cord B above to your AP RETURN.
  2. Connect the delay end(s) of the patch cord B to the OUTPUT on the digital delay.
  3. Connect the mixer end(s) of patch cord C to your AUX SEND.
  4. Connect the delay end(s) of patch cord C to the INPUT on the digital delay.

mixer diagramsBasic SQ BACK Encoders

The SQ decoders used should NOT have logic.

Notice that the back connections to the SQ decoder are crossed. This is what turns the back channels of the decoder into an encoder.

To install the basic SQ BACK 4−corner encoding function, make the following connections:

  1. Connect the odd (left) submaster bus insert send to the right SQ decoder input.
  2. Connect the right back SQ decoder output to the odd (left) submaster bus insert return.
  3. Connect the even (right) submaster bus output to the left SQ decoder input.
  4. Connect the left back SQ decoder output to the even (right) submaster bus insert return.
  5. If such an ability is provided, disable the 10−40 blend of the decoder.

To install the basic SQ BACK 4−corner and forward−oriented encoding function, make the following connections:

  1. Connect the odd (left) submaster bus insert send to the basic phase switch input or the left Phlazex input, using a suitable cable.
  2. Connect the basic phase switch output or the left Phlazex output to the right SQ decoder input.
  3. Connect the right back SQ decoder output to the odd (left) submaster bus insert return.
  4. Connect the even (right) submaster bus output to the left SQ decoder input. If a Phlazex is used, insert the Phlazex right side into this cable.
  5. Connect the left back SQ decoder output to the even (right) submaster bus insert return.
  6. If such an ability is provided, disable the 10−40 blend of the decoder.

mixer diagramsAdvanced SQ BACK Encoders

The SQ decoders used should NOT have logic.

Notice that the back connections to the SQ decoder are crossed. This is what turns the back channels of the decoder into an encoder.

To install the advanced SQ BACK 4−corner and forward−oriented encoding function, make the following connections:

  1. Connect the odd (left) submaster bus insert send to the right SQ decoder input.
  2. Connect the left back SQ decoder output to the odd (left) advanced phase switch input.
  3. Connect the odd (left) advanced phase switch output to the odd (left) submaster bus insert return.
  4. Connect the even (right) submaster bus output to the left SQ decoder input.
  5. Connect the right back SQ decoder output to the even (right) advanced phase switch input.
  6. Connect the even (right) advanced phase switch output to the even (right) submaster bus insert return.
  7. If such an ability is provided, disable the 10−40 blend of the decoder.

To install the combined SQ BACK 4−corner and forward−oriented encoding function, make the following connections:

  1. Connect the odd (left) submaster bus insert send to the phase switch input or the left Phlazex input, using a suitable cable.
  2. Connect the phase switch output or the left Phlazex output to the right SQ decoder input.
  3. Connect the left back SQ decoder output to the odd (left) advanced phase switch input.
  4. Connect the odd (left) advanced phase switch output to the odd (left) submaster bus insert return.
  5. Connect the even (right) submaster bus output to the left SQ decoder input. If a Phlazex is used, insert the Phlazex right side into this cable.
  6. Connect the right back SQ decoder output to the even (right) advanced phase switch input.
  7. Connect the even (right) advanced phase switch output to the even (right) submaster bus insert return.
  8. If such an ability is provided, disable the 10−40 blend of the decoder.

SQ FRONT Encoder

Notice that the front connections to the second SQ decoder are not crossed. The front channels do not interact.

To install the SQ FRONT encoding function, make the following connections:

  1. Connect the odd (left) submaster bus insert send to the left input of the second SQ decoder.
  2. Connect the left front SQ decoder output to the odd (left) submaster bus insert return.
  3. Connect the even (right) submaster bus insert send to the right input of the second SQ decoder.
  4. Connect the right front SQ decoder output to the even (right) submaster bus insert return.
  5. If such an ability is provided, disable the 10−40 blend of the decoder.
  6. An optional phase inverter switch can be added to the left channel to provide for SQ backward−oriented encoding.

SQ Bypass Switches

SQ diagrams The SQ Bypass Switches can be:

The following table can be used for any of the SQ setups above.

If a switch is not included in your setup, its setting must be normal or SQ.

Setting the switches:

BYPASS SWITCH TABLE
OPERATION FRONT
BYPASS
SWITCH
BACK
BYPASS
SWITCH
PHASE
SWITCH
1
PHASE
SWITCH
2
PHASE
SWITCH
3
RM Encoder RM RM Reverse Normal
Stereo RM RM Normal Normal
SQ 4−Corners Encoder SQ SQ Normal Normal Normal
SQ Diagonal−Split Encoder SQ SQ Reverse Normal Normal
SQ Forward−Oriented Encoder SQ SQ Normal Reverse Normal
SQ Backward−Oriented Encoder SQ SQ Reverse Reverse Reverse
RM Acroperiphonic Encoder SQ RM Reverse Normal
RM Alternate Acroperiphonic ‡ SQ RM Normal Reverse
SQ Acroperiphonic Encoder RM SQ Normal Normal Normal

‡ The front input buses in the setting encode back channels, and the back input buses encode front channels.

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

Ultimate RM SQ UM CS Encoder The Ultimate Encoder Pair with CircleSurround capability:

The Ultimate Encoder Pair with the CircleSurround swap switch. Do all of the following:

  1. Trade the left and right decoder input lines (for the left back and right back signals).
  2. Put the swap switch at the mixer bus outputs.
  3. Add a switchable phase inverter (1) to the left source (going to the right input).
  4. Add a switchable phase inverter and line swap (2) to the back outputs.
  5. Trade the left front and right front output lines.
  6. Add the RM−SQF−SQB switch (can use a stereo source selector switch) as shown.

All of the various switches for the Ultimate Encoder could be put in the same box and wired together.

Setting the switches - If a switch is not included in your setup, its setting must be normal or SQ:

GENERAL SWITCH TABLE
OPERATION CHANNELS SWAP
SWITCH
PHASE
SWITCH
1
PHASE
SWITCH
2
MODE
SWITCH
PAN POT
CONTROLS
CROSS−FADE
CONTROLS
Stereo Pass−Through Stereo Normal Normal RM L − F − R not used
Phased Normal Normal SQF L − F − R not used
RM Encoder Front Normal Normal RM L − LF − F − RF − R not used
Use Flip Buses
Back Normal Reverse RM L −LB − B − RB − R
RM Acroperiphonic Encoder Front Normal Normal RM L − LF − F − RF − R F − C − B
Back Normal Reverse SQF L − LB − B − RB − R
SQ 4−Corners Encoder Front Normal Normal SQF LF − F − RF not used
Use Flip Buses
Back Normal Normal Normal SQB LB − B − RB
SQ Diagonal−Split Encoder Front Normal Normal SQF LF − F − RF F − Split − B
Back Normal Reverse Normal SQB LB − F − RB
SQ Forward−Oriented Encoder Front Normal Normal SQF LF − F − RF F − Side − B
Back Normal Normal Reverse SQB LB − F − RB
SQ Backward−Oriented Encoder Front Normal Reverse SQF LF − B − RF F − Side − B
Back Normal Reverse Reverse SQB LB − B − RB
SQ Acroperiphonic Encoder Front Normal Normal RM LF − F − RF F − C − B
Back Normal Normal Normal SQB LB − B − RB
OPERATION CHANNELS SWAP
SWITCH
PHASE
SWITCH
1
PHASE
SWITCH
2
MODE
SWITCH
PAN POT
CONTROLS
CROSS−FADE
CONTROLS
UMX Basic Encoder Left−Right Normal Normal SQF L − C − R [L−R] − C − [F−B]
Front−Back Normal Normal Reverse SQB F − C − B
RM 3D Front Encoder Front Normal Normal SQF L − LF − F − RF − R Horiz − Oblique − Vert
Down−Up Normal Normal Reverse SQB N − NF − F − ZF − Z
RM 3D Back Encoder Back Normal Reverse SQF L − LB − B − RB − R Horiz − Oblique − Vert
Down−Up Normal Reverse Reverse SQB N − NB − B − ZB − Z
CircleSurround Encoder Front Normal Normal SQF LF − F − RF F − Side − B
Back Swap Normal Reverse SQB LB − F − RB

Two channel strips and a crossfader are needed to encode the sides or the diagonal splits.

Combining the Ultimate Encoder Pair controls on a control panel

The controls for several Ultimate Encoder Pairs can be built into a common control panel.

The switches are mounted left to right on the panel in the order they are listed in the table above.

Normal positions indicate that the switches on the panel are thrown to the left.

The controls are shown set as follows:

Ultimate Encoder Panel Meanings of the abbreviations on the control panel:

Output

Connect the destination (a tape recorder, CD recorder, or a surround sound decoder feeding a PA) of the encoded surround sound to the mixer MAIN L and R outputs. Also connect a surround sound decoder so you can monitor the results.


What happens if the SQ 10−40 blend can not be disabled?

The effects on the encoder if the SQ decoders still have their 10−40 blends:


LINKS: