Frequently asked questions

What is the latency of SuperMAC and HyperMAC?

The link latencies at each supported sampling frequency are:-

48-channel	44.1 kHz	24-bit PCM	3 Samples	68.02 μs
48-channel	48 kHz	24-bit PCM	3 Samples	62.50 μs
24-channel	88.2 kHz	24-bit PCM	6 Samples	68.02 μs
24-channel	96 kHz	24-bit PCM	6 Samples	62.50 μs
12-channel	176.4 kHz	24-bit PCM	12 Samples	68.02 μs
12-channel	192 kHz	24-bit PCM	12 Samples	62.50 μs
6 Channels	352.8 kHz	24-bit PCM	24 Samples	68.02 μs
6 Channels	384 kHz	24-bit PCM	24 Samples	62.50 μs

SuperMAC differs from the AES50 standard with regard to the number of samples delay incurred for the link latencies at sampling frequencies above 96 kHz and that the Direct-Stream Digital (DSD) format is not specifically supported.

Currently HyperMAC only supports 96 kHz operation (support for other sampling frequencies will be added for the HyperMAC Software Development Kit release), and latency is:-

192-channel

96 kHz

24-bit PCM

4 Samples

41.66 μs

Whilst the AES50 standard specifies base sampling frequencies of 44.1 kHz and 48 kHz and multiples thereof, Midas and Klark Teknik have internally standardised on 96 kHz operation (twice the base sampling frequency of 48 kHz) for both SuperMAC and HyperMAC, to minimise latencies when converting between analogue and digital domains, where a single SuperMAC connection can carry 24 bidirectional channels and a single HyperMAC connection can carry 192 bidirectional channels. These channel counts double for 44.1 kHz and 48 kHz sampling frequency operation.

Per Annex D of the AES50 standard, the latency per link of SuperMAC is fixed at six samples at twice the base sampling frequency, which for 96 kHz is 6 x 10.42 μs (one sample at 96 kHz), or 62.50 μs. Additionally, depending on the implementation of the interface to the SuperMAC core at both ends of the transmission link, a further delay up to of one base sampling frequency sample and one sampling frequency sample will be incurred converting to and from an internal data format such as I²S, although typically this can be limited to just the base sampling frequency sample in most implementations.

Likewise, HyperMAC has a fixed latency per link of four samples at 96 kHz is 4 x 10.42 μs, or 41.66 μs. An additional delay, similar to that of SuperMAC, will be incurred interfacing to the HyperMAC core at the two ends of the transmission link.

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