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Soundweb system latency prediction

PMACHADOPMACHADO Posts: 6
in London Architect with Soundweb London
After reading some manuals and documents about soundwebs I have a doubt about if it is possible to predict the latency for a system. In my case, I have a system with several soundwebs linked all together by blu-link. One of them is a Dante soundweb (BLU-806), one is an AVB (BLU-325), and 3 are BLU-120. I made a table with the latency of each element, analog input card, analog output card, AES/EBU input Card and AES/EBU output cards. With delay compensation ON on all soundwebs can I predict the overall latency for the system?

Thanks in advance.

Comments

  • Kevin BrownKevin Brown Posts: 50
    Calculating system latency involves numerous measurements. But it's all completely deterministic if you're willing to spend the time to perform the calculations and add up all the numbers.

    A/D and D/A latency involves knowing the hardware version of your cards, the sample rate of the devices in which they're installed, and then making the appropriate calculations based on the numbers published in the IO card datasheets. Processing latency is determined by double-clicking on the compiler and reading the number next to 'Output Latency' (Note: this is a PER CHASSIS number). Networked Audio latency involves knowing which transports you're using, if any (AVB, BLU link, CobraNet, Dante) and digging into the latency specs for that transport.

    But you said you wanted to measure SYSTEM latency (i.e. EVERYTHING, not just the BSS stuff). So you'll also need to take into account A/D latency, processing latency, and D/A latency for all components upstream and downstream of BSS (audio sources, power amps, and speakers). And you need to know cable lengths on all analog cables to determine cable latency based on speed of light. And, depending on your definition of 'system latency,' you need to know the elevation, temperature, humidity, and atmospheric pressure in the room to take into account speed of sound through free space.

    AND you would then need to calculate how much extra space you require in your trophy case for your new, shiny \"Geek of the Year\" trophy, which would be well deserved by then :)

    I'm not saying there's no reason to measure latency, but latency is almost always low enough in BLU systems to the point of simply not needing to worry about it. Therefore, all these calculations tend to be performed by either A) lunatics or B) people who are misinformed about latency and when it truly matters (not that I'm accusing you of being either :)
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