Version
menu_open

Downmix Tables

The downmixing equations are based on AC-3 standards. They have been designed to end up the same regardless of whether signals are downmixed directly (for example, 7.1 to stereo) or in several successive steps (for example, 7.1 to 5.1 to stereo).

How to read the downmix tables

Consider the following table, describing the downmix equations used when routing a 5.1 input to a stereo output.

Sample table: Routing 5.1 to stereo

Input Channels

L

R

FL

1

0

FR

0

1

C

1/√2

1/√2

SL

1/√2

0

SR

0

1/√2

The left and right channels of the resulting stereo signal are the weighted sum of the inputs into these equations:

            LOUT = FL + 1/√2 * C + 1/√2 * SL
            ROUT = FR + 1/√2 * C + 1/√2 * SR

Reference Tables

Like the above formula, you can calculate the output signal for each downmixed format by adding up the totals of each output channel column in the following reference downmix tables:

To Mono

Input Channels

C

FL

1/√2

FR

1/√2

C

1

SL

1/2

SR

1/2

BL

1/2

BR

1/2

Top

1

HFL

1/2

HFC

1/√2

HFR

1/2

HBL

1/(2√2)

HBR

1/(2√2)

To Stereo

Input Channels

L

R

FL

1

0

FR

0

1

C

1/√2

1/√2

SL

1/√2

0

SR

0

1/√2

BL

1/√2

0

BR

0

1/√2

Top

1/√2

1/√2

HFL

1/√2

0

HFC

1/2

1/2

HFR

0

1/√2

HBL

1/2

0

HBR

0

1/2

To 3.x

Input Channels

L

R

C

FL

1

0

0

FR

0

1

0

C

0

0

1

SL

1/√2

0

0

SR

0

1/√2

0

BL

1/√2

0

0

BR

0

1/√2

0

Top

1/√3

1/√3

1/√3

HFL

1/√2

0

0

HFC

0

0

1/√2

HFR

0

1/√2

0

HBL

1/2

0

0

HBR

0

1/2

0

To 4.x

Input Channels

L

R

SL

SR

FL

1

0

0

0

FR

0

1

0

0

C

1/√2

1/√2

0

0

SL

0

0

1

0

SR

0

0

0

1

BL

0

0

1

0

BR

0

0

0

1

Top

1/2

1/2

1/2

1/2

HFL

1/√2

0

0

0

HFC

1/2

1/2

0

0

HFR

0

1/√2

0

0

HBL

0

0

1/√2

0

HBR

0

0

0

1/√2

To 5.x

Input Channels

L

R

C

SL

SR

FL

1

0

0

0

0

FR

0

1

0

0

0

C

0

0

1

0

0

SL

0

0

0

1

0

SR

0

0

0

0

1

BL

0

0

0

1

0

BR

0

0

0

0

1

Top

1/√5

1/√5

1/√5

1/√5

1/√5

HFL

1/√2

0

0

0

0

HFC

0

0

1/√2

0

0

HFR

0

1/√2

0

0

0

HBL

0

0

0

1/√2

0

HBR

0

0

0

0

1/√2

To 6.x

Input Channels

L

R

SL

SR

BL

BR

FL

1

0

0

0

0

0

FR

0

1

0

0

0

0

C

1/√2

1/√2

0

0

0

0

SL

0

0

1

0

0

0

SR

0

0

0

1

0

0

BL

0

0

0

0

1

0

BR

0

0

0

0

0

1

Top

1/√6

1/√6

1/√6

1/√6

1/√6

1/√6

HFL

1/√2

0

0

0

0

0

HFC

1/2

1/2

0

0

0

0

HFR

0

1/√2

0

0

0

0

HBL

0

0

0

0

1/√2

0

HBR

0

0

0

0

0

1/√2

To 7.x

Input Channels

L

R

C

SL

SR

BL

BR

FL

1

0

0

0

0

0

0

FR

0

1

0

0

0

0

0

C

0

0

1

0

0

0

0

SL

0

0

0

1

0

0

0

SR

0

0

0

0

1

0

0

BL

0

0

0

0

0

1

0

BR

0

0

0

0

0

0

1

Top

1/√7

1/√7

1/√7

1/√7

1/√7

1/√7

1/√7

HFL

1/√2

0

0

0

0

0

0

HFC

0

0

1/√2

0

0

0

0

HFR

0

1/√2

0

0

0

0

0

HBL

0

0

0

0

0

1/√2

0

HBR

0

0

0

0

0

0

1/√2


Was this page helpful?

Need Support?

Questions? Problems? Need more info? Contact us, and we can help!

Visit our Support page

Tell us about your project. We're here to help.

Register your project and we'll help you get started with no strings attached!

Get started with Wwise