>> 2) Moved KDE settings away from alsa device hw:2.7
>
>not sure what that would(n't) do as I am not too familiar with kde,but it
>makes sense.

Just to make sure that nothing is, even in the least bit, is interested in device hw:2.7

>> 6) jackd creates a system playback sink.
>
>Not quite the terminology I am used to with jack, but assuming same as
>pulse, good.

>Question: how are you starting jack? 

jackd from a terminal.

>Are you running jackd or jackdbus?

jackd

>(both are shipped in the jackd2 package) What do the logs say? How are you
>seeing the logging output of jack?

At the terminal.  Looks like this:

bill@dvr-1:~$ /usr/bin/jackd  -T -R -ndefault -d alsa -P hw:2,7 -r 44100 
jackdmp 1.9.10
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2013 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
no message buffer overruns
no message buffer overruns
no message buffer overruns
JACK server starting in realtime mode with priority 10
audio_reservation_init
Acquire audio card Audio0
Acquire audio card Audio2
creating alsa driver ... hw:2,7|-|1024|2|44100|0|0|nomon|swmeter|-|32bit
configuring for 44100Hz, period = 1024 frames (23.2 ms), buffer = 2 periods
ALSA: final selected sample format for playback: 32bit integer little-endian
ALSA: use 2 periods for playback
^CJack main caught signal 2
Released audio card Audio0
Released audio card Audio2
audio_reservation_finish
JackTemporaryException : now quits...
bill@dvr-1:~$

Note: "^C" is my keying Control-C to shut it down.

> How are you seeing the system sink? with what command or application?

patchage

> If you run alsamixer in a terminal can you turn all the levels up, are any channels muted?

No channels muted, all at 100%

> So it appears, audio is getting to jack just fine and jack is sending the
> signal on. However jack does not control output levels, that has to be
> done manually. Running alsamixer from a terminal is the most surefire way
> of knowing you are dealing with the right controls. Use F6 to select your
> hw:2.7 sounds card.

Did the whole alsamixer thing, F6 and all.  All was well.

Continuing to play after I posted, I happened to start Audacity while everything was wired up and "playing" (not).  Once Audacity opened, there was a short 3-4 second burst of sound, followed by more silence.  The process repeated itself, with intermittent periods of sound/silence.  I noticed (on patchage) that during the silence the system was racking up dropouts.  During the sound playing periods dropouts stopped counting up.

So I went off looking in dropouts.  I had already established my account has both realtime and memlock permissions.   When I started playing with all this, jackd was reporting that it could not accomplish these two functions, and no longer is reporting the warnings since I fixed the permissions. At least jackd seems to think realtime and memlock are good now.

The system is an nearly idle  i5@3.3Gh and 32Gb of memory.  CPU load is near zero, with or without realtime scheduling.  The test audio file being played into jack by mplayer is read off a SSD.  The system hasn't actually swapped anything, at all, since I've owned it.

I've played with jack's periods/buffers, -S,  and such and not much changed for the better, although I can surely make the dropouts worse using these parameters, but never better enough to produce useful sound.  And, I always have to rely on Audacity to kick in any sound at all.