Your english is just fine - better than most anyway.
Please note the interpolations. You may need to try some temporary
measures to eliminate some possibilities even if you do not find a
complete solution.
I must apologize for not being specific in my question. the two main
speakers are full range, five drivers floorstanders, rated to 22hz.
the rel stadium III subwoofer is connected with the typical neutrik
cable. in paralel (high level?), the crossover setting is 22hz, which
is what bugs me... the reason I have the sub is to complement only
the last octave of the sound spectrum.
I still get this strange mid bass suckuout problem in one of the two
speakers whenever the sub is activated and dependently from the phase
setting, 0 or 180, the L or R speakers will be affected.
This really does sound like you are getting cancellation waves. What
happens is that the output from one speaker cancels the output from
another - almost as if you were to have two different individuals wave
a loose rope between them different frequencies. It is possible that
the distance between the two speakers and their distance from the SW
is some multiple of those midrange frequencies that are being
cancelled, which would also explain the R/L phenomenon.
the mains are in phase with each other. I checked the connections
several times.
OK - that has been established. However, is there something about the
internal crossovers within the speakers that affect the phasing? Are
the mids set up differently than the woofers? What brand of speakers
are these? I know that the AR9, for example, had side-firing woofers -
something like this is important to know when setting up the
speakers.
unfortunately the system is located in an L shaped living room. one
speaker seats in the corner with the sub behind, and the other
speakeris in the open, meaning that it does not have a side wall and
associated reflections. just the wall behind.
I cannot move speakers around, they are heavy and the living room is
saturated with objects and furniture.
This will be a problem. True full-range, standard driver speakers
absolutely *DO NOT* like corners, and all sorts of crazy thing happen
when they are forced into one. This could also be the cause of a
standing wave that would explain what is happening to you.
my question is: why the subwoofer appears to be in phase with one
speaker only -while the two mains are in phase with each other? Is
phase problrem directly proportional to the distance between sub and
speakres? I say that because one speaker is definitely closer to the
sub then the other.
See "standing wave" above.
http://www.asc-hifi.com/articles/ht2.htm
http://www.psaudio.com/articles/settingupastereo.asp
There is a lot of good information out there on standing waves, and a
lot of bad information as well. Suffice it to say that you need to
understand what they are and what they mean, you *do not* have to go
out and purchase a bunch of expensive tripe to deal with them. That
can be done with some clever care on your part.
however I could easily live with this "problem",
I would like to understand why that happens.
*TEMPORARILY*, you may need to experiment with speaker placement. See
if placing the SW in the middle of the floor, for instance, about 1/3
- 2/3 between the main speakers, and at least 4 woofer-diameters in
front of them, firing away from them does not alter the response or
cure the problem. Try moving (again temporarily) the speaker out of
the corner and try moving both away from the back wall (by at least
one woofer diameter).
All of these things are to determine whether you have an electrical
problem (phasing) or a placement problem (cancellation/standing
waves). There are ways to deal with wave issues, but they may be
disruptive to your decorating.
As a complete aside, you are not by any means the first person to deal
with this issue. One of the major pioneers in speaker design and
contributors to the audio world, Roy Allison, designed an entire line
of speakers in recognition of real-world placement problems. A brief
article on it may be found he
http://www.stereophile.com/interview...ur/index2.html
He and Edgar Villchur worked together for years at AR.
Good luck and let us know.
Peter Wieck
Wyncote, PA