Latency Delay; Input/Output Latencies; Processing Latencies - EM Acoustics Di06 Product User Manual

Latency delay

All Digital Signal Processing, and conversion between different formats of signal –
analogue/digital/network etc., necessarily introduce some delay (latency) to the signal path. Of
course, we strive to minimise these latencies. Small as they are, it is sometimes useful to know their
precise values. The following describes the principal latencies introduced by various parts of the
Device product:

Input/Output Latencies

Analogue Input
OR Digital input at 96KHz sample rate
OR Digital input at 48KHz sample rate
Analogue Output
OR AES3 Output
OR Dante Output

Processing Latencies

Input HiShelf FIR
LIR Linear Phase crossover
VxLim Limiter (VX mode off)
OR VxLim Limiter (VX mode on)
** This latency figure is calculated using the crossover High-pass frequency (in kHz)
 This latency figure is calculated using the Vx Split frequency (in kHz)
Important tip: The processing latency is constant at 1.53ms unless LIR crossover filters or FIR HiShelf
EQs are used, so normally you would just need to add the Input and Output delays to this constant
value.
If LIR or FIR are in use, the Processing latency of a Drive Module may increase beyond this figure.
When LIR, is used the Vx Limiter can take the overall latency above the 1.53ms. When high pass
frequency is set below 40Hz the filter will automatically revert to Linkwitz riley, this is set so that the
latency will not exceed 30ms as stated.
Example:
Input/Output
Analogue Input
Analogue Output
Processing
Input HiShelf FIR (Off)
LIR Linear Phase crossover (500Hz) 2.38ms
VxLim Lim (VX mode on, 1KHz Fsplit)
Total
Note that the latencies within a Drive Module are equalised among outputs of that Drive Module. That
is, padding delay will be automatically added to some outputs such that the total latency is the same
in each output of a Drive Module.
This latency equalisation does not extend outside a Drive Module, so Drive Modules are not
guaranteed to have the same latency as one-another.
(limited to a minimum of 1.53ms):
0.385ms
0.5ms
0.66ms
0.402ms
0.1ms
0.5ms (TBC)
0.48ms (0ms if set to 'Off')
1.19ms/Fhp(kHz), limited to 30ms maximum **
0.12ms/Fhp(kHz), limited to 1.53ms maximum **
0.358ms/Fsplit(kHz), limited to 1.53ms max 
0.385ms
0.402ms
0ms
0.358ms
3.525ms
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