[PD] PD + JACK = more than 2 blocks of latency?

[Matthias Geier]

Dear list.

I found several threads regarding latency, but none of them answered
my question:

I did this: Play audio data from a JACK client (in my case Audacity),
loop it through a pd-patch (which is just a short-circuit), and then
record it again (also with Audacity).

In all cases that I tried, the recorded signal had a delay of 2 JACK
blocks ("periods") plus 64 samples.
I tried the -blocksize and -audiobuf options, but they didn't seem to
change anything.
I read about the -frags and -fragsize options, but they didn't seem to
exist in my pd version (I tried both pd-extended 0.40.3 and pd vanilla
0.41.4 from Debian "Squeeze").

When I do the same thing with other JACK clients, I get the expected
and desired 1 block of delay.

I know, that less than one block of delay is impossible, but is it
possible to reduce pd's latency to one JACK block?

cheers,
Matthias