CHOOSING AN ENCODING SYSTEM

Why two SQ decoders can function as an SQ encoder:

How two SQ decoders can function as an SQ encoder:

AVAILABLE MATRIX SYSTEMS AND FEATURES

Instructions:

Print Table 1 and Table 2 (not the one in the inset) in this document
Read each table.
Check the desired boxes in the left column of the Table 1 below.
For each check in the left column of Table 1, check all of the boxes in the same row.

TABLE 1 - MINIMUM ENCODER SPECIFICATIONS
QUADRAPHONIC MATRIX SYSTEM		ENCODER CIRCUITS NEEDED
[ ] RM	Regular Matrix (Incl. Dolby Surround (DS), Stereo-4, QS, and Dynaquad)	[ ] RM Front	[ ] RM Back	-
[ ] RM AP	Acroperiphonics (overhead sounds) in RM	[ ] RM Front	[ ] SQ B-O Front or [ ] or RM AP
[ ] SQ 4-C	The original SQ 4-corners matrix	[ ] SQ Front	[ ] SQ 4-C Back	-
[ ] SQ DGS	SQ encoder optimized for diagonal splits	[ ] SQ Front	[ ] SQ DGS Back	-
[ ] SQ F-O	The SQ Forward-Oriented encoder	[ ] SQ Front	[ ] SQ F-O Back	-
[ ] SQ B-O	The SQ Backward-Oriented encoder	[ ] SQ B-O Front	[ ] SQ B-O Back	-
[ ] SQ AP	Acroperiphonics (overhead sounds) in SQ	[ ] RM Front	[ ] SQ 4-C Back	-
[ ] UM	Denon basic matrix of the UMX system.	[ ] SQ Front	[ ] SQ F-O Back	-
[ ] CS	CircleSurround (done by switching SQ back cables)	[ ] SQ Front	[ ] SQ F-O Back	-
[ ] RM 3D	The 3D Dolby Surround variations	[ ] SQ Front	[ ] SQ B-O Front	[ ] SQ F-O Back

Other systems:

HM - The BBC Matrix H is not supported here.
BH - Ambisonics is not supported.

System Usage:

SQ - The CBS SQ system was used extensively in the 1970s.
RM includes Dolby Surround, QS, Dynaquad, and the old EV system. RM was used worldwide.

Minimum number of SQ Decoders needed:

No SQ decoder is needed for RM encoding.
One SQ decoder encodes either SQ front pair or SQ back pair.
One SQ decoder is needed for SQ Acroperiphonic.
Two SQ decoders can be connected as a full SQ encoder.
Two SQ decoders are needed for UMX basic or RM 3D.

Don't forget an additional SQ decoder for monitoring.

WHY SO MANY SQ ENCODERS?

Because SQ is a matrix with points of inflection in its encoding set of modulations, pannings between different speaker pairs require different phases on the channels. At most three pairs of speakers can be encoded correctly with one encoder.

SQ ENCODER	LF-RF	LB-RB	LF-LB	RF-RB	LF-RB	LB-RF
4-C: 4-Corners Matrix	BEST	BEST	Odd	Odd	BEST	No
AP: Acroperiphonic	BEST	BEST	Odd	Odd	Odd	Odd
DGS: Diagonal Split	BEST	No	Odd	Odd	BEST	BEST
F-O: Forward-Oriented	BEST	No	BEST	BEST	Odd	Odd
B-O: Backward-Oriented	No	BEST	BEST	BEST	Odd	Odd

BEST - Optimum encoding
Odd - Odd but usable encoding locations
No - Encodes in the wrong direction

Note that, even with full SQ encoding, the listener does not hear sides and diagonal splits correctly without special decoding.

CHOOSE WHAT TO BUILD

Instructions (continued):

If an encoder circuit is checked in Table 1 (above), check it in the top row of the Table 2 (below).
In Table 2, check the right end of each row with "yes" entries in every column with a check at the top.

TABLE 2 - ENCODING SYSTEM CHOICE
ENCODER CIRCUITS NEEDED									ENCODING SYSTEM
[ ] RM Front	[ ] RM Back	[ ] RM AP Aux	[ ] SQ Front	[ ] SQ B−O Front	[ ] SQ 4−C Back	[ ] SQ DGS Back	[ ] SQ F−O Back	[ ] SQ B−O Back	ENCODING SYSTEM
YES	YES	-	-	-	-	-	-	-	[ ] RM (Dolby Surround) Basic
YES	YES	YES	-	-	-	-	-	-	[ ] RM with Acroperiphonic Delay
YES	YES	-	-	-	YES	-	-	-	[ ] RM & Single SQ
YES	-	-	-	-	YES	-	-	-	[ ] Single SQ, no RM
YES	YES	-	YES	-	YES	-	-	-	[ ] RM & Double SQ 4-C
YES	YES	-	YES	-	YES	YES	-	-	[ ] RM & Double SQ 4-C, DGS
YES	YES	-	YES	-	YES	-	YES	-	[ ] RM & Double SQ 4-C, F-O
YES	YES	-	YES	YES	YES	YES	YES	YES	[ ] RM & Double SQ 4-C, DGS, F-O, B-O
-	-	-	YES	YES	YES	YES	YES	YES	[ ] Double SQ 4-C, DGS, F-O, B-O, no RM
YES	YES	-	YES	-	YES	-	-	-	[ ] Switched RM or Double SQ 4-C
YES	YES	-	YES	YES	YES	YES	YES	YES	[ ] Switched RM or Double SQ 4-C, DGS, F-O, B-O
YES	YES	-	YES	YES	YES	YES	YES	YES	[ ] Ultimate Encoder Pairs
YES	YES	YES	YES	YES	YES	YES	YES	YES	[ ] Ultimate Encoder Pairs with RM Acroperiphonic
YES	YES	-	YES	YES	YES	YES	YES	YES	[ ] Ultimate Encoder Pairs with Back Sub Swap

CHECK THE CAPABILITIES

Instructions (continued):

Check the chosen encoding system against its capabilities.
4-C = 4-Corner, DGS = Diagonal Split, F-O = Forward-Oriented, B-O = Backward-Oriented.

TABLE 3 - ENCODING SYSTEM CAPABILITIES
ENCODING SYSTEM	QUADRAPHONIC MATRIX SYSTEM
ENCODING SYSTEM	RM	RM AP	SQ 4-C	SQ DGS	SQ F-O	SQ B-O	SQ AP	UM	CS	RM 3D
RM (Dolby Surround) Basic	YES	-	-	-	-	-	-	-	-	-
RM with Acroperiphonic Delay	YES	MAX	-	-	-	-	-	-	-	-
RM & Single SQ	YES	-	YES	-	-	-	-	alt	-	alt
Single SQ, no RM	-	-	YES	-	-	-	-	-	-	-
RM & Double SQ 4-C	YES	alt	YES	-	-	-	YES	alt	-	alt
RM & Double SQ 4-C, DGS	YES	alt	YES	YES	-	-	YES	alt	-	alt
RM & Double SQ 4-C, F-O	YES	alt	YES	-	YES	-	YES	YES	-	alt
RM & Double SQ 4-C, DGS, F-O, B-O	YES	YES	YES	YES	YES	YES	YES	YES	-	add
Double SQ 4-C, DGS, F-O, B-O, no RM	alt	-	YES	YES	YES	YES	-	YES	-	alt
Switched RM or Double SQ 4-C	YES	alt	YES	-	-	-	YES	alt	-	add
Switched RM or Double SQ 4-C, DGS, F-O, B-O	YES	YES	YES	YES	YES	YES	YES	YES	-	add
Ultimate Encoder Pairs *	YES	YES	YES	YES	YES	YES	YES	YES	-	YES
Ultimate Encoder Pairs with RM Acroperiphonic *	YES	MAX	YES	YES	YES	YES	YES	YES	-	YES
Ultimate Encoder Pairs with Back Sub Swap *	YES	YES	YES	YES	YES	YES	YES	YES	YES	YES

* Assumes at least 4 buses so equipped.
MAX - Does a better job than the others.
alt - Does an acceptable job, but not as good as the others.
add - Needs two complete sets for mixing all pan positions.

EQUIPMENT NEEDED FOR EACH BUS PAIR

Instructions (continued):

Find Out What Equipment is Needed.

TABLE 4 - EQUIPMENT PER MIXING BUS PAIR
ENCODING CIRCUIT	EQUIPMENT PER PAIR
ENCODING CIRCUIT	Bus Swap Switch	Phase Inverter	Phase Switch	SQ Decoders	Advanced Phase Sw	RM/SQ Mode Switch	RM Acro aux send	Digital Delay
RM Front	-	-	-	-	-	-	-	-
RM Back	-	1	-	-	-	-	-	-
RM Acroperiphonic Front & Aux	-	1	-	-	-	-	1	1
SQ Front	-	-	-	1	-	-	-	-
SQ Backward-Oriented Front	-	-	1	1	-	-	-	-
SQ 4-Corners Back	-	-	-	1	-	-	-	-
SQ Diagonal Split Back	-	-	1	1	-	-	-	-
SQ Forward-Oriented Back	-	-	-	1	1	-	-	-
SQ Backward-Oriented Back	-	-	1	1	1	-	-	-
Switched RM or SQ 4-Corners Front	-	-	-	1	-	2-pos	-	-
Switched RM or SQ all-matrix Front	-	-	1	1	-	2-pos	-	-
Switched RM or SQ 4-Corners Back	-	1	-	1	-	2-pos	-	-
Switched RM or SQ all-matrix Back	-	-	1	1	1	2-pos	-	-
Ultimate Encoder Pair *	-	-	1	1	1	3-pos	-	-
Ultimate Encoder Pair with RM Acroperiphonic *	-	-	1	1	1	3-pos	1	1
Ultimate Encoder Pair with CS Sub Swap *	1	-	1	1	1	3-pos	-	-

EQUIPMENT NEEDED FOR EACH SOUND SOURCE USED

Instructions (continued):

Find Out What Equipment is Needed.

TABLE 5 - EQUIPMENT NEEDED PER SOURCE
QUADRAPHONIC MATRIX	EQUIPMENT PER SOURCE
QUADRAPHONIC MATRIX	Channel Strips	Cross Faders	Bus Pair Sets	Bus Pair 1	Bus Pair 2	Bus Pair 3	Bus Pair 4
RM, Dolby Surround	1	-	2	RM Front	RM Back	-	-
RM Acroperiphonic Delay	1	-	2	RM Front	RM Back	-	-
RM, Acroperiphonic Phase	1	-	2	RM Front	SQ B-O Front	-	-
RM Combined	2	1	4	RM Front	RM Back	SQ B-O Front	-
SQ 4-Corners Basic	1	-	2	SQ Front	SQ 4-C Back	-	-
SQ P4-Corners Pan	2	1	2	SQ Front-	SQ 4-C Back	-	-
SQ, Diagonal Splits	2	1	2	SQ Front	SQ DGS Back	-	-
SQ Forward-Oriented	2	1	2	SQ Front-	SQ F-O Back	-	-
SQ Backward-Oriented	1	-	2	SQ B-O Front	SQ B-O Back	-	-
SQ Acroperiphonic Phase	2	1	2	RM Front-	SQ 4-C Back	-	-
SQ Combined Matrix	2	1	2	SQ Front	SQ F-O Back	SQ B-O Front	SQ B-O Back
RM 3D, Dolby 3D	2	1	4	SQ Front-	SQ B-O Front	SQ F-O Back	SQ B-O Back
UMX Basic	2	1	2	SQ Front	SQ F-O Back	-	-
CircleSurround	2	1	2	SQ Front-	Swap SQ F-O Back	-	-

EQUIPMENT NEEDED FOR EACH ENTIRE ENCODING SYSTEM

Instructions (continued):

Find Out What Equipment is Needed for n Sources.
4-C = 4-Corner, DGS = Diagonal Split, F-O = Forward-Oriented, B-O = Backward-Oriented.

TABLE 6 - ENCODING SYSTEM EQUIPMENT REQUIREMENTS
ENCODING SYSTEM	EQUIPMENT NEEDED
ENCODING SYSTEM	Bus Swap Switch	Phase Inverter	Phase Switch	SQ Decoders	Advanced Phase Switch	RM/SQ Mode Switch	RM Acro Aux Send	Digital Delay	Mix Buses Needed	Cross Faders For n	Channel 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).

SELECTING THE MIXER:

A 4 SUBGROUP, a 2+2 Subgroup or a larger (6 or 8 subgroup) audio mixer can be used. The following are needed:

At least the number of subgroup buses in the table above are needed.
One pair may be the MAIN group if channel strip assignment to it can be switched off
Channel assignment switching is needed (Alt 3-4 works fine for 4 buses).
Subgroup inserts are needed for each of the subgroups used.
If the mixer has no subgroup inserts, subgroup outputs and stereo channel strips or aux returns can be used.
A small stereo mixer can be used to combine the returns.
A solo system with both pre-fader (PFL) and after-fader (AFL) listen is preferred. Solo in place (SIP) is the same as AFL.
A solo system with after-fader (AFL) listen is necessary.

For the RM acroperiphonic (AP) system, the following connections are needed:

Any of these unused inputs
- One stereo AUX RETURN. It can be stereo TRS.
- One stereo input channel
- One or two mono input channels
Any of these unused outputs
- An after-fader effects send.
- An extra stereo subgroup pair.

Note that either of the combined RM and SQ systems can provide some AP capability without the above AP devices.

Mixer Suggestions - these mixers are known to work:

Mackie SR 24.4, or SR 32.4 (The page author has used a 24.4) - 6 Buses
Mackie CR1604 (Requires the fixes listed as Special Mackies, because selecting the SUB bus mutes the after-fader AUX SENDs) - 4 Buses
Mackie LM3204 (Requires the fixes listed as Special Mackies, has no PFL) - 8 Buses
Samson PL2404 (The page author currently uses this with the Phlazex for the RM/DS system) - 4 Buses
Samson MPL1204 (Use the transformer TRS insert method or the Phlazex) - 4 Buses
Behringer UB2222FX and MX2642 - 4-Buses
Behringer UB2442Fx (The Page Author uses this too), MX2442, MX2432, SL2442, and SL3242 - 6 Buses
Behringer MX3282 - 8 Buses
Alesis Studio 24 or 32 -4 Buses
Note that a mixer with an assignable aux return can use the Special Mackies setup, if desired.

CHOOSING THE SUBS, SENDS, AND RETURNS:

Choose the first assignable bus pair to be SUB 1-2.
Choose the second assignable bus pair to be SUB 3-4.
Choose the third assignable bus pair to be SUB 5-6.
Choose the fourth assignable bus pair to be SUB 7-8.

4-C = 4-Corner, DGS = Diagonal Split, F-O = Forward-Oriented, B-O = Backward-Oriented.

TABLE 7 - MIXER SUBMASTER BUS ASSIGNMENTS
ENCODING SYSTEM	MIXER CONNECTIONS
ENCODING SYSTEM	Buses Needed	Sub 1-2	Sub 3-4	Sub 5-6	Sub 7-8	Sub 9-10	Aux Send	Stereo Return
RM (Dolby Surround) Basic	4 or 2+2	RM Front	RM Back	-	-	-	-	-
RM with Acroperiphonic Delay	4 or 2+2	RM Front	RM Back	-	-	-	Acro Send	Acro Rtn
RM & Single SQ	6	RM Front	RM Back	SQ Back	-	-	-	-
Single SQ, no RM	4	RM Front	SQ Back	-	-	-	-	-
RM & Double SQ 4-C	8	RM Front	RM Back	SQ Front	SQ Back	-	-	-
RM & Double SQ 4-C, DGS	8	RM Front	RM Back	SQ Front	SQ Back	-	-	-
RM & Double SQ 4-C, F-O	8	RM Front	RM Back	SQ Front	SQ Back	-	-	-
RM & Double SQ 4-C, DGS, F-O, B-O	8	RM Front	RM Back	SQ Front	SQ Back	-	-	-
Double SQ 4-C, DGS, F-O, B-O, no RM	4	SQ Front	SQ Back	-	-	-	-	-
Switched RM or Double SQ 4-C	4	RM/SQ Front	RM/SQ Back	-	-	-	-	-
Switched RM or Double SQ 4-C, DGS, F-O, B-O	4	RM/SQ Front	RM/SQ Back	-	-	-	-	-
k Ultimate Encoder Pairs	2k, 4 min	Pair 1-2	Pair 3-4	Pair 5-6	Pair 7-8	Pair 9-10	-	-
k Ultimate Encoder Pairs & RM Acroperiphonic	2k, 4 min	Pair 1-2	Pair 3-4	Pair 5-6	Pair 7-8	Pair 9-10	Acro Send	Acro Rtn
k Ultimate Encoder Pairs & Back Sub Swap	2k, 4 min	Pair 1-2	Pair 3-4	Pair 5-6	Pair 7-8	Pair 9-10	-	-

k is the number of encoding pairs used.

Variations:

If the subgroup buses have no inserts:
- Choose one stereo input for each bus pair in the chosen plan except RM FRONT.
- It may be a stereo AUX RETURN, a stereo channel strip, or a pair of panable mono inputs.
- Name them RM BACK RETURN, SQ FRONT RETURN, and/or SQ BACK RETURN as used.
- Do NOT assign the subs themselves to the main output. Assign the returns chosen instead.
If the subgroups have inserts, Name them RM BACK INSERT, SQ FRONT INSERT, and/or SQ BACK INSERT as used.
To add the RM Acroperiphonic capability:
- Select an after-fader AUX SEND (or EFFECTS OUT). Label it AP SEND.
- Also select a mono panable input channel or mono-capable AUX RETURN.
  For the Special Mackies, this input must be assignable to subgroups.
  Label it AP RETURN. The digital delay will be connected to the send and return
Note: If you chose channel inputs for any of the returns, setting the return level uses the channel fader plus any trim controls available. Assign the channel strips to RM FRONT.
Note: If you chose channel inputs for any of the returns, you can use a second small stereo mixer to mix all of the sub returns together, and use a single channel strip to return them. Assign the single strip to RM FRONT.

CONSTRUCTING THE ENCODING CIRCUITS:

Click here for: Building Matrix Surround Sound Encoders

MORE ON PAIR ENCODING:

Different encoding pairs can be combined on the same mixer. Many produce useful encodings:

4-C = 4-Corner, DGS = Diagonal Split, F-O = Forward-Oriented, B-O = Backward-Oriented,
AP = Acroperiphonic, Ph = Phase method, Del = Delay method.

TABLE 8 - RESULTS OF COMBINING ENCODING PAIRS
FRONT PAIR	BACK PAIR
FRONT PAIR	RM Front	RM Back	SQ B-O Front	SQ 4-C Back	SQ DGS Back	SQ F-O Back	SQ B-O Back
RM Front	Stereo	RM	RM AP Ph	SQ AP Ph	Weird SQ	Weird SQ	SQ AP Ph
RM AP Aux	Stereo Del	RM AP Del	RM AP Both	SQ AP Del	SQ AP Del	SQ AP Del	SQ AP Del
SQ Front	Ph Stereo	RM AP Ph	RM	SQ 4-C	SQ DGS	SQ F-O	SQ 4-C
SQ B-O Front	RM AP Flip	RM Back	RM Back	SQ B-O	Weird SQ	Weird SQ	SQ B-O

The following are groups of possible pair combinations on an 8-bus mixer:

4-C = 4-Corner, DGS = Diagonal Split, F-O = Forward-Oriented, B-O = Backward-Oriented,
AP = Acroperiphonic, Ph = Phase method, Del = Delay method.

TABLE 9 - RESULTS OF SELECTED 8-BUS ENCODING PAIRS
PAIR SELECTION					CROSSFADE PAIR COMBINATIONS
NAME	Pair 1-2	Pair 3-4	Pair 5-6	Pair 7-8	Pairs 1-2 & 3-4	Pairs 1-2 & 5-6	Pairs 1-2 & 7-8	Pairs 3-4 & 5-6	Pairs 3-4 & 7-8	Pairs 5-6 & 7-8
RM-SQ	RM Front	SQ Front	RM Back	SQ 4-C Back	Ph Stereo	RM	SQ AP Ph	RM AP Ph	SQ 4-C	SQ B-O AP
FO-BO	SQ Front	SQ B-O Front	SQ F-O Back	SQ B-O Back	RM	SQ F-O	SQ 4-C	Weird SQ	SQ B-O	Weird SQ
SQ 3	SQ Front	SQ DGS Back	SQ F-O Back	SQ B-O Back	SQ DGS	SQ F-O	SQ 4-C	Weird SQ	Weird SQ	Weird SQ
RF-SQ	RM Front	SQ B-O Front	SQ F-O Back	SQ B-O Back	RM AP Ph	SQ F-O AP	SQ AP Ph	Weird SQ	SQ B-O	Weird SQ

SPECIAL RESULTS OF SELECTED 8-BUS ENCODING PAIRS
PAIR SELECTION					CROSSFADE PAIR COMBINATIONS
NAME	Pair 1-2	Pair 3-4	Pair 5-6	Pair 7-8	Pairs 1-2 & 3-4	Pairs 1-2 & 5-6	Pairs 1-2 & 7-8	Pairs 3-4 & 5-6	Pairs 3-4 & 7-8	Pairs 5-6 & 7-8
FO-BO	SQ Front	SQ B-O Front	SQ F-O Back	SQ B-O Back	RM	UMX	SQ 4-C	Weird SQ	UMX 3D UP	Weird SQ
FO-BO	SQ Front	SQ B-O Front	SQ F-O Back	SQ B-O Back	RM	RM 3D Front	SQ 4-C	Weird SQ	RM 3D Back	Weird SQ
SQ 6	SQ Front	SQ B-O Front	SQ DGS Back	SQ B-O Back	RM	SQ DGS	SQ 4-C	Weird SQ	SQ B-O	Weird SQ

These are recommended combinations. FO-BO has multiple uses. And SQ 6 can do all 6 speaker pair pans in SQ simultaneously.

LINKS: