RE: Boss RC-50 update is available

["Andrew Koenig" <ark@acm.org>]

> I have no idea what the new updates do. I do not understand what they 
>mean
> when they're trying to explain it in the manual. Anyone have any clue?

I installed the update and tried it.  As far as I can tell (1) it doesn't
seem to be very useful, but (2) it gave me new insight into the glitch.

So here's what I found.  The update adds a new mode to the RC-50, which you
can select only at power-on time, and once selected remains set until you
select its opposite.  The two choices are

        1) Begin playback at the beginning of the beat.
        2) Begin playback at the beginning of the recording.

(1) is the default choice.  The mode appears to be relevant only when the
"loop synchronize" light is not lit, though I may be mistaken about that.

Here is how to hear the difference between the two modes.  Start with a
blank patch and turn the rhythm guide off, so that "loop synchronize" is 
not
in effect.  Use the "tap tempo" button to set a very slow tempo.  Turn off
"auto record."

Now start recording half way through a beat, record for a while, and go 
into
playback mode.  In mode (1), the playback will start at the next beat.  In
mode (2), it will start immediately, even though it's off the beat.

At first I thought this behavior would be useful.  However, when I overdub
in mode (2), it causes a permanent glitch in the sound at the instant the
overdub starts.  So unless you can start the overdub (i.e. hit the foot
switch) during a moment of silence, it's useless.

However, playing around with mode (1) (which I think is the way the RC-50
behaved before the update) made me realize that maybe the glitch I had been
experiencing isn't a glitch at all.

Here's why.  Start again with a blank patch, and this time turn on the
rhythm guide, which enables "loop synchronize."  Turn "auto record" on, and
start recording.

Now, suppose you hit the pedal to go into playback mode, and you do so a
tiny bit after a beat.  Because "loop synchronize" is on, the RC-50 will
want to make the loop a whole number of beats long.  There are only two 
ways
of doing that:

        1) Start the loop at the beginning of the next beat;
        2) Start the loop at the beginning of the current beat.

If you were only a little after the beat, (2) is less surprising.  However,
that means that part of the beat has already gone by, which means that
playback cannot include the beginning of the current beat because it's in
the past.  Which means that playback has to exclude the little bit of that
beat.  That comes out as a glitch.

The way to prevent that glitch seems to be to be sure to go into playback
mode a tiny bit *before* the end of the beat.  Again, "loop synchronize"
will cause the RC-50 to extend the loop until the end of the beat, but now
when it starts it will include the entire beat and no glitch will be
audible.

At least that is what I have found with my experiments so far.

If anyone with a pre-updated RC-50 wants to try to find a way of 
reproducing
the glitch, I will be happy to try the same experiment on my RC-50 both 
ways
and report the results.



                                                                Regards,


                                                                Andrew
Koenig