latency delay ping timer

[kinicho]

Hi,

this is my first post.. please be kind..

I am trying to build a latency delay ping timer akin to the one found in cubase and nuendo to measure the latency caused by the audio card.

I hacked a little timer but my guess is that ruby Time is not accurate enough
-
ideally i would like to send a dirac spike and get a delay value in samples

any help and hints would be greatly appreciated.

greets kinicho

[MyCo]

Since you need sample accurate measurements there is only really one option: Measure the time in stream. I've attached a sample schematic that does exactly that. It counts the samples between two stream events.

You can hook up the 2 inputs to the code module to your detector (eg. the envelope followers). But since the envelope follower output is a continous up/down counting value you have to implement a hysteris converter, something like if value greater x output 1, else output 0.

[kinicho]

Wow! Amazing - thank you very much.
this makes a lot of sense.. I should be able to finish this now -

[kinicho]

I had a go, but did not get very far.
the ping back works I can trigger the start and stop but i get varying results:
I then tried a trigger delay to see if it would give me the same result - but it doesn't

could you explain?

[kinicho]

here's what i got so far:
using exo's sample player

[MyCo]

You can't have any green stuff in the measurement path, because green is not realtime. You can only measure as low as one buffersize when you use green. I've attached an example of how to use the measurement in stream only. It uses just the envelope followers and a converter code, that changes it output when the envelope follower crosses a threshold level.

[kinicho]

Ah I see - thanks very much MyCo!
I need to get into the DSP code module by the looks..
now i also understand your last post.