[LAU] using jdelay

[Jan Weil]

On Thu, Apr 02, 2009 at 11:16:39AM +0200, Atte André Jensen wrote:
> I tried measuring my latency with jdelay. Started in on the commandline, 
> first it said
> 
> Signal below threshold...
> 
> Then I connected it's input to the output of system:capture_1 with my 
> microphone connected and it output to the input of system:playback_1+2. 
> Now I get a squareish tone and when "singing" into the microphone I get 
> reading like these:
>   22442.483 Inv
>   58010.411 ??
>   43602.390 ?? Inv
>   43474.474
>   43474.474 ?? Inv
> Signal below threshold...
> Signal below threshold...
> Signal below threshold...
>   25549.731 ??
>   25549.731 ?? Inv
>   37749.225 ??
>   37749.225 ?? Inv
>   37749.225 ??
>   24653.357 ??
>   24653.228 ?? Inv
>   25677.165 ??
>   11013.134 ?? Inv
>   25677.153 ??
>    2821.046 ?? Inv
>    2821.046 ??
> 
> The man page says the values are in samples, so for instance a value of 
> 37749.225 should be 0.77 seconds at 48000, right? This seems bogus 
> (qjackctl reports 10 ms).
> 
> What am I doing wrong?

As far as I know you are not supposed to sing (at least to get proper
results from jack_delay it is not needed). :)

Just make a closed loop. jack_delay generates its own testing signals
(which are probably much easier to analyze than what you sing).

Hope this helps.

Jan