Sample Rates Overview

The M-32 AD Pro supports the following sample rates:

Supported sample rates

Single speed

44.1 kHz, 48 kHz

Double speed

88.2 kHz, 96 kHz

Quad speed

176.4 kHz, 192 kHz

If the device is clock master, these rates always correspond to the actual sample rate used.

Slave Mode

When the device is slave, certain deviations are automatically accepted to avoid interruption of the outgoing audio signal when the sample rate changes. This is called Intelligent Clock Control (ICC). It also handles deriving a sample rate of double or quad speed based on an incoming rate.

Intelligent Clock Control (ICC)

Input

Clock at input

Selected Sample Rate

Resulting Sample Rate

MADI

44.1

44.1

44.1

MADI

44.1

48

44.1 with warning

MADI

44.1

88.2

88.2

MADI

44.1

96

88.2 with warning

MADI

44.1

176.4

176.4

MADI

44.1

192

176.4 with warning

MADI

48

44.1

48 with warning

MADI

48

48

48

MADI

48

88.2

96 with warning

MADI

48

96

96

MADI

48

176.4

192 with warning

MADI

48

192

192

MADI 96k

88.2

44.1

warning (no sync)

MADI 96k

88.2

48

warning (no sync)

MADI 96k

88.2

88.2

88.2

MADI 96k

88.2

96

88.2 with warning

MADI 96k

88.2

176.4

warning (no sync)

MADI 96k

88.2

192

warning (no sync)

MADI 96k

96

44.1

warning (no sync)

MADI 96k

96

48

warning (no sync)

MADI 96k

96

88.2

96 with warning

MADI 96k

96

96

96

MADI 96k

96

176.4

warning (no sync)

MADI 96k

96

192

warning (no sync)

Word Clock

44.1

44.1

44.1

Word Clock

44.1

48

44.1 (with warning)

Word Clock

44.1, 88.2

88.2

88.2

Word Clock

44.1, 88.2

96

88.2 with warning

Word Clock

44.1, 88.2, 176.4

176.4

176.4

Word Clock

44.1, 88.2, 176.4

192

176.4 with warning

Word Clock

48

44.1

48 with warning

Word Clock

48

48

48

Word Clock

48, 96

88.2

96 with warning

Word Clock

48, 96

96

96

Word Clock

48, 96, 192

176.4

192 with warning

Word Clock

48, 96, 192

192

192

There is no ICC mechanism necessary for AVB; the device will always use the exact clock from the corresponding AVB stream.

It is not recommended to sync devices with a higher sample rate than the current sample rate, because two devices could choose different edges of the incoming clock signal.
ICC does not affect outgoing AVB streams. Outgoing AVB streams will always correspond to the sample rate set in the CLOCK section. If the reference clock changes its frequency, outgoing AVB streams will be interrupted.

Number of Channels

The supported number of channels per port or stream at different sample rates is shown in the following table.

Supported number of audio channels per stream/port and direction at different sample rates

44.1 kHz

48 kHz

88.2 kHz

96 kHz

176.4 kHz

192 kHz

MADI 56 Ch

56

56

28

28

14

14

MADI 64 Ch

64

64

32

32

16

16

MADI 56 Ch + 96k

---

---

28

28

---

---

MADI 64 Ch + 96k

---

---

32

32

---

---

AVB 1-8 Ch stream

1-8

1-8

1-8

1-8

1-8

1-8

AVB 12 Ch stream

12

12

12

12

---

---

AVB 16 Ch stream

16

16

---

---

---

---

Since there are two independent MADI ports, the total supported number of channels can be multiplied by two. Since there are eight independent AVB streams, the total supported number of channels can be multiplied by eight. The analog channel count is always 32 regardless of sample rate. The maximum amount of digital inputs is 192 channels (at 48 kHz, 64 Ch MADI). The maximum amount of digital outputs is 192 channels (at 48 kHz, 64 Ch MADI).

Selecting a Sample Rate

To configure the device sample rate on the device:
  1. Enter the CLOCK section. The cursor highlights the currently selected clock.

    Clock Rate
  2. Rotate the encoder to highlight the current sample rate.

  3. Push the encoder. Two blue arrows will appear to indicate that the encoder can now be used to change the current setting.

  4. Rotate the encoder until the preferred sample rate is shown.

  5. Push the encoder again to activate the setting.

To configure the device sample rate on the web remote:
  1. Locate the Select sample rate drop down menu in the CLOCK section.

  2. Select a sample rate from the drop down menu. The new rate is automatically applied.

Effects of Sample Rate Changes on Existing Routing

The M-32 AD Pro saves one routing table per preset, regardless of sample rate. A change of sample rate or MADI frame mode can reduce the number of input and output channels available for routing. This does not alter the routing table. Any existing routing is hidden until another change of sample rate re-enables the channels.

Example:

A routing is created at 96 kHz with 32 channels, sending the MADI coaxial Input 1-32 to optical MADI Output 1-32. If the sample rate is now changed to 176.4 kHz and the 56 Ch frame is activated, only the first 14 channels of MADI coaxial input are routed to the optical output. Switching the sample rate to 44.1 or 48 kHz will reveal the previous routing for 32 channels.