Can you hear a sixty millisecond delay?

5 Responses to Can you hear a sixty millisecond delay?

1. Tim Wainwright says:

   February 5, 2017 at 5:12 pm

   Could probably hear less than that too….. my question is why did you post this? What’s significant about a 60ms delay?

   Tim
2. Stephen Dawson says:

   February 5, 2017 at 6:43 pm

   Hi Tim

   I’m doing an article on timing and I wanted to have a file somewhere so people could hear the time. Article will be in Connected magazine at some point.
3. Craig says:

   February 7, 2017 at 9:30 am

   I do Programme QC at a TV station, and can tell you that I can easily tell when an audio signal is 1 frame early or 1 frame late compared to the video. 40ms in 50Hz TV language.

   So I will either add 40ms delay or minus 40ms until the audio is perfectly synced with the video.

   I think 40ms might be the practical limit on what people can perceive. Below that, it gets really hard.
4. Tony Barron says:

   February 12, 2017 at 9:01 am

   60ms would be an eternity – https://www.youtube.com/watch?v=JLeCLRK8Ws8to this pair!
5. Bruce says:

   February 28, 2017 at 6:09 pm

   In “live” situations, it is not uncommon to play around with delay times down to 15 mSec, in order to pull the “image” back onto the stage.

   The advent of “everything digital” has actually played merry hell with “live” audio AND video.

   Every time the damn stuff moves, it is ripped apart, shuffled about, stuffed down a “pipe” at the end of which, its is “un-shuffled” and then shoved through a buffer and a DAC, in order for the punters assorted organs to comprehend it.

   In the “bad” old analogue audio days, we used to fret about “phase shift” in processors like crossovers or equalizers.

   Now we just shrug off 15 plus milliseconds of “delay”, quaintly called “latency” by some, and hope that the punters are as sonically illiterate as the equipment manufacturers.

   Then there’s digital video. In the broadcast world, I guess nobody cares how long it takes to get from the news-reader’s lips to the punter’s speaker, but, given the amount of data being “crunched” at both ends, it is significant. I remember when the analogue stations were still working. If you set up a digital TV beside an analogue rig, and tuned to the same “programme”, the “delay’ was VERY noticeable on the digital system.

   Then there are events like “big sports”….

   Camera’s with on-board digital processing, stuffing encrypted packets of photons down a long optical fibre? Check

   Optical signal being “converted” to electron flow “packets” that can be read by the “switch” gear? Check.

   A serious “DSP” engine to shuffle all the various bits of signal from the various vision sources around? Check.

   Buffered drivers to send the “mix” to a ginormous out-door LED screen display? Check.

   Huge amounts of “reprocessing’ to get the “encoded” stream shuffled around, re-scaled etc, to feed into the dozens of modules that make up these mega-screens.

   More re-shuffling to get the “data” organized so that the correct LED elements light up in the right place and sequence? Check.

   If anyone is at a “live” major event, try to keep one eye on the “meatspace” action and the other on the “big screen”. Its quite disturbing.

   Another example with which I am regularly involved is the horror of providing a “conductor” view image to off-stage (or, sometimes , ON-stage), so that singers and musicians can see the little white stick and thus keep time.

   In the “old” days there was NO appreciable delay of the analogue signal between the camera, through the VDA and at the various monitors,

   Now, they need an “assistant conductor” who watches the “action” on a LCD monitor and, whilst listening to a (hopefully) un-delayed audio feed, conducts IN ADVANCE., so that the off-stage chorus, or whatever, is in sync with the principles on stage.

   Quite some trick.

   Progress! Ain’t it wonderful?