Magnitude of loudspeaker-room interaction
 

Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

With my set up it turned out to be my ears :-(


"John Phillips" wrote in message
...
Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

On 13 Dec 2004 20:53:46 GMT, John Phillips
wrote:

Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

At what frequencies? All?

Kal

Magnitude of loudspeaker-room interaction
 

In article , John Phillips
wrote:
Is a 2.7 dB left-right stereo imbalance reasonable for a
loudspeaker-room interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

if you've swapped everything in turn, inc the speakers, it does sound like
the room.

Are you able to get a 'mono' sound with a narrow central image?

What are you using as a source, etc?

How much effect does it have to move the speakers or angle them a little?

My experience is that unless you have fairly directional speakers the
actual frequency reponses from the two channels can be distinctly
different, and that this has more effect than the overall difference. The
snag being that you end up having to offset the balance to adjust this if
you can't make suitable alterations to the room or speaker arrangement.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.

Approaching 3dB seems a lot in my experience, particularly if the room is
near symmetric. However these things do vary a lot.

FWIW In my 'hi fi room' the imbalance with ESL63's was between 1dB and
0.5dB somewhere. In my living room I've got it close to spot-on. How
typical this is, I don't know.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Magnitude of loudspeaker-room interaction
 

In message , John Phillips
writes
Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.


Is this at spot frequencies, or were you using a 1/24th octave RTA with
pink noise?
--
Chris Morriss

Magnitude of loudspeaker-room interaction
 

In article , Kalman Rubinson wrote:
On 13 Dec 2004 20:53:46 GMT, John Phillips
wrote:

Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

At what frequencies? All?

Well it's 2.7 dB to give a properly central stereo image as I hear it,
over a range of material with a good central image to hear. Also I did
check this with a 250 Hz tone (nearly middle C) written in mono to a CD.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

In article , Chris Morriss wrote:
In message , John Phillips
writes
Is a 2.7 dB left-right stereo imbalance reasonable for a loudspeaker-room
interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.

Is this at spot frequencies, or were you using a 1/24th octave RTA with
pink noise?

No. It was much simpler. I did check the balance at 250 Hz but it
is mainly just set by ear to centralize the stereo image between the
speakers. Without the 2.7 dB attenuation in the left channel (0 dB in
the right) the stereo image is crowded towards the left speaker.

For clarity I run the variable output of my CD player into a power
amplifier through a pair of pi-topology fixed resitive attenuators (Z =
~5k ohms) whose voltage gain (as above) is computed from the resistor
values.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

In article , Garf wrote:
With my set up it turned out to be my ears :-(

Could be with me too. I'm 47 now and the limit to my frequency range is
already down to about 14.2 kHz. There may be other deteriorations too,
I suppose.

However I understand that lateral imbalance in hearing is measured as
a difference in hearing threshold and a difference of 2.7 dB would be
considered as unimportant. More than 10 dB (as I read it from the web,
anyway) is considered significant.

I could not find any material on hearing imbalance at other than hearing
threshold levels which might contribute to my needing to use a stereo
balance control.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

In article , Jim Lesurf wrote:
In article , John Phillips
wrote:
Is a 2.7 dB left-right stereo imbalance reasonable for a
loudspeaker-room interaction in a nearly symmetrical room?

My last system needed no tweaking of the left-right balance control to
get a central image. However my current system needs a 2.7 dB shift in
the balance control. I have checked the source balance and swapped all
components (including leads) and the imbalance remains in either the
room or my ears.

if you've swapped everything in turn, inc the speakers, it does sound like
the room.

Yes - I made notes as I did the swapping. I'll go back and review them to
be sure, but I think it was clearly from the room or my ears (in spite of
the effect not having been obvious on the previous system in that room).

Are you able to get a 'mono' sound with a narrow central image?

Yes. Certainly narrower than on the previous kit in that room.

What are you using as a source, etc?

Varies from CDs I have burned with mono test tones to commercial CDs
with solo instruments and singers (which I find are not all precisely
centred identically in the sounstage anyway - but the 2.7 dB gives a
good overall result).

How much effect does it have to move the speakers or angle them a little?

I have tried that and there's almost no difference in the balance.

I have tried several toe-in angles from zero to having the driver axis
cross just in front of the listening chair. I have kept the speakers
about 0.9 metres from the backwall and adjusted the position relative
to the sidewalls from 0.3 to 0.6 metres. Very little difference.

My experience is that unless you have fairly directional speakers the
actual frequency reponses from the two channels can be distinctly
different, and that this has more effect than the overall difference. The
snag being that you end up having to offset the balance to adjust this if
you can't make suitable alterations to the room or speaker arrangement.

I'll go back and see if I can investigate this a little (although I am
content with the current result and therefore not highly driven to do
too much more experimenting). It's higher frequencies that contribute
most to directionality I assume? Maybe I should burn some innovative
combination test tones to CD to see if this is what's happening.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chinmey breast
is the main asymmetry, apart from furniture.

Approaching 3dB seems a lot in my experience, particularly if the room is
near symmetric. However these things do vary a lot.

That's what I suspected and that's why I am thinking about the effect
and seeking comment. Now that it's all adjusted for balance there seems
to be no problem - the stereo soundstage is all there; it's much wider
and more precise than with the old system.

FWIW In my 'hi fi room' the imbalance with ESL63's was between 1dB and
0.5dB somewhere. In my living room I've got it close to spot-on. How
typical this is, I don't know.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

In article , John Phillips
wrote:
In article , Jim Lesurf wrote:


Are you able to get a 'mono' sound with a narrow central image?

Yes. Certainly narrower than on the previous kit in that room.

Ok. That is usually a 'good sign' so far as room and speakers are
concerned.

What are you using as a source, etc?

Varies from CDs I have burned with mono test tones to commercial CDs
with solo instruments and singers (which I find are not all precisely
centred identically in the sounstage anyway

Balance of the stereo imaging is one of those things to which I seem to be
sensitive. I used to use a 'fine' balance control I'd set up and found that
changes of the order of just a few tenths of a dB made a noticable
difference. And as you indicate, many recordings vary more than this.

FWIW I sometimes find that deliberately using 'cross bleed' resistors to
bring the stereo seperation down to about 20dB actually gives a *better*
image. This gives a better spread for many sources, and slightly reduces
the sensitivity to imbalance from one CD, etc, to another.

- but the 2.7 dB gives a good overall result).

How much effect does it have to move the speakers or angle them a
little?

I have tried that and there's almost no difference in the balance.

I have tried several toe-in angles from zero to having the driver axis
cross just in front of the listening chair. I have kept the speakers
about 0.9 metres from the backwall and adjusted the position relative to
the sidewalls from 0.3 to 0.6 metres. Very little difference.

OK. This isn't my experience as I find even small movements tend to change
the stereo image quite a lot. But this is a general comment, not one on the
average imbalance, and I'm using ESLs which have different diectionality,
etc, to many speakers. Not sure if your report is 'good' or 'bad' news, but
it implies that you are not getting an effect due to unfortunate speaker
placement, etc.

My experience is that unless you have fairly directional speakers the
actual frequency reponses from the two channels can be distinctly
different, and that this has more effect than the overall difference.
The snag being that you end up having to offset the balance to adjust
this if you can't make suitable alterations to the room or speaker
arrangement.

I'll go back and see if I can investigate this a little (although I am
content with the current result and therefore not highly driven to do
too much more experimenting). It's higher frequencies that contribute
most to directionality I assume?

Not sure. Depends on circumstances. IIUC below about 800 Hz we tend to use
phase/time differences, and above that amplitude differences and the
interference effects of the ear lobes, etc. But I suspect the results vary
from one person to another, and one sort of music to another!

Maybe I should burn some innovative combination test tones to CD to see
if this is what's happening.

If you wish to check as a function of frequency, then some 1/3rd octave or
narrower 'mono noise' bands might be useful.

FWIW The 'USHER' disc Musaeus MZCD-T-200 can be useful for stereo
imaging tests as it has sets of tests where the same sound is played with
varied time and amplitude offsets. This is nominally to synthesise
different mic techniques, but it also serves to check the perceived effect
of time and amplitude variation for your hearing in your room and using
your system.

I assume this imbalance is a loudspeaker-room interaction. The room
is not perfectly symmetrical but not far out. An intruding chinmey
breast is the main asymmetry, apart from furniture.

Approaching 3dB seems a lot in my experience, particularly if the room
is near symmetric. However these things do vary a lot.

That's what I suspected and that's why I am thinking about the effect
and seeking comment. Now that it's all adjusted for balance there seems
to be no problem - the stereo soundstage is all there; it's much wider
and more precise than with the old system.

Provided the 'swap' tests showed this stayed firmly in the same 'direction'
so far as perception was concerned I assume your equipment is fine. If the
image is reasonably narrow and well defined, then it is probably OK just to
resign yourself to using the offset and getting results that then sound
fine! About all it then implies is that one speaker might be being driven a
bit harder than the other.

Cheers,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Magnitude of loudspeaker-room interaction
 

"John Phillips" wrote in message


Is a 2.7 dB left-right stereo imbalance reasonable for a
loudspeaker-room interaction in a nearly symmetrical room?

You might want to swap the speakers, as its not unusual for speakers to
depart from spec by a dB or two. That means that a pair, each unit at the
opposite ends of spec, could vary this much.

My last system needed no tweaking of the left-right balance control to
get a central image.

If you want a really well-matched pair of speakers, get a eq and tweak the
channels in with it. This will address both sensitivity and frequency
response issues.

If you want a really nicely resolved central image, put in a center channel
speaker. I don't mean one of these gutted little lost puppies they sell to
the HT crowd, I mean a full-tilt speaker sitting in the middle of the other
two, or close to it. Drive it with its own power amp and a L+R matrix.

However my current system needs a 2.7 dB shift
in the balance control. I have checked the source balance and
swapped all components (including leads) and the imbalance remains in
either the room or my ears.

I assume this imbalance is a loudspeaker-room interaction. The room is
not perfectly symmetrical but not far out. An intruding chimney
breast is the main asymmetry, apart from furniture.

If you've swapped *everything* you will be especially well-advised to
consider my comments about equalizers and center speakers.

Magnitude of loudspeaker-room interaction
 

On 14 Dec 2004 07:59:46 GMT, John Phillips
wrote:

In article , Garf wrote:
With my set up it turned out to be my ears :-(

Could be with me too. I'm 47 now and the limit to my frequency range is
already down to about 14.2 kHz. There may be other deteriorations too,
I suppose.

However I understand that lateral imbalance in hearing is measured as
a difference in hearing threshold and a difference of 2.7 dB would be
considered as unimportant. More than 10 dB (as I read it from the web,
anyway) is considered significant.

I could not find any material on hearing imbalance at other than hearing
threshold levels which might contribute to my needing to use a stereo
balance control.

The reason there's little about it is that small imbalances like this
are almost always readily adapted since we use this for localization
and navigation. If you have no indications of such imbalance outside
your stereo environment, it is probably something in the system/room.
I suggest that you do a more careful frequency-by-frequency
measurement in order to distinguish a simple imbalance from a
lateralized frequency aberration.

Kal

Magnitude of loudspeaker-room interaction
 

"Kalman Rubinson" wrote in message
...
On 14 Dec 2004 07:59:46 GMT, John Phillips
wrote:

In article , Garf
wrote:
With my set up it turned out to be my ears :-(

Could be with me too. I'm 47 now and the limit to my frequency range is
already down to about 14.2 kHz. There may be other deteriorations too,
I suppose.

However I understand that lateral imbalance in hearing is measured as
a difference in hearing threshold and a difference of 2.7 dB would be
considered as unimportant. More than 10 dB (as I read it from the web,
anyway) is considered significant.

I could not find any material on hearing imbalance at other than hearing
threshold levels which might contribute to my needing to use a stereo
balance control.

The reason there's little about it is that small imbalances like this
are almost always readily adapted since we use this for localization
and navigation. If you have no indications of such imbalance outside
your stereo environment, it is probably something in the system/room.
I suggest that you do a more careful frequency-by-frequency
measurement in order to distinguish a simple imbalance from a
lateralized frequency aberration.

Kal


No, in my case it really is my ears, I'm going deaf in the right one. As for
adaptation for localisation & navigation, an imbalance of 2.7dB would not be
considered as insignificant to any specialist wrt to interpreting a "stereo"
image.

Normal limits are 0-20 dBHL (decibel Hearing Level) mild hearing loss is
diagnosed at 25--39 dBHL (me in one ear!). A 2.7dB imbalance would be 10%
(or greater dependant on the best lug hole level) imbalance from normal
levels and certainly would be noticeable in determining source and
soundstage from stereo speakers.

Nature does compensate to a degree by adaptation but in nature we do not
find artificial representations of stereo soundstages. I first noticed my
problem when I had to adjust balance to "feel comfortable" with certain
tracks, now it's all tracks and I have been diagnosed as an decrepit old
fart who's going deaf in one ear. I don't notice this much at all in any
other circumstances but eventually I know that will be able to avoid all of
my wife's nagging simply by sitting to her left! (There's always a positive
spin)

Simple test, sit with your back to the speakers, does the imbalance change?

Garf

Magnitude of loudspeaker-room interaction
 

On Tue, 14 Dec 2004 20:20:16 -0000, "Garf"
wrote:

"Kalman Rubinson" wrote in message
.. .
On 14 Dec 2004 07:59:46 GMT, John Phillips
wrote:

In article , Garf
wrote:
With my set up it turned out to be my ears :-(

Could be with me too. I'm 47 now and the limit to my frequency range is
already down to about 14.2 kHz. There may be other deteriorations too,
I suppose.

However I understand that lateral imbalance in hearing is measured as
a difference in hearing threshold and a difference of 2.7 dB would be
considered as unimportant. More than 10 dB (as I read it from the web,
anyway) is considered significant.

I could not find any material on hearing imbalance at other than hearing
threshold levels which might contribute to my needing to use a stereo
balance control.

The reason there's little about it is that small imbalances like this
are almost always readily adapted since we use this for localization
and navigation. If you have no indications of such imbalance outside
your stereo environment, it is probably something in the system/room.
I suggest that you do a more careful frequency-by-frequency
measurement in order to distinguish a simple imbalance from a
lateralized frequency aberration.

Kal


No, in my case it really is my ears, I'm going deaf in the right one. As for
adaptation for localisation & navigation, an imbalance of 2.7dB would not be
considered as insignificant to any specialist wrt to interpreting a "stereo"
image.

Normal limits are 0-20 dBHL (decibel Hearing Level) mild hearing loss is
diagnosed at 25--39 dBHL (me in one ear!). A 2.7dB imbalance would be 10%
(or greater dependant on the best lug hole level) imbalance from normal
levels and certainly would be noticeable in determining source and
soundstage from stereo speakers.

Nature does compensate to a degree by adaptation but in nature we do not
find artificial representations of stereo soundstages. I first noticed my
problem when I had to adjust balance to "feel comfortable" with certain
tracks, now it's all tracks and I have been diagnosed as an decrepit old
fart who's going deaf in one ear. I don't notice this much at all in any
other circumstances but eventually I know that will be able to avoid all of
my wife's nagging simply by sitting to her left! (There's always a positive
spin)

Simple test, sit with your back to the speakers, does the imbalance change?

Garf

I understand but I was responding regarding a 2.7dB loss, not to your
larger deficit. (Please accept sympathy on that score.) As such is
readily adapted to in the 'real world,' there is little different
about the stereo system situation. Now, put an ear plug in one ear of
a 'normal' individual and, short term, the balances are off.

Another issue is that the losses we are talking of are rarely evenly
effective across the audible range. Since it occurs initially and
mostly at higher frequencies, its interaction with loudspeakers and
room acoustics could well be different than in natural settings.

Kal

Magnitude of loudspeaker-room interaction
 

"Kalman Rubinson" wrote in message
...
On Tue, 14 Dec 2004 20:20:16 -0000, "Garf"
wrote:

"Kalman Rubinson" wrote in message
.. .
On 14 Dec 2004 07:59:46 GMT, John Phillips
wrote:

In article , Garf
wrote:
With my set up it turned out to be my ears :-(

Could be with me too. I'm 47 now and the limit to my frequency range
is
already down to about 14.2 kHz. There may be other deteriorations
too,
I suppose.

However I understand that lateral imbalance in hearing is measured as
a difference in hearing threshold and a difference of 2.7 dB would be
considered as unimportant. More than 10 dB (as I read it from the
web,
anyway) is considered significant.

I could not find any material on hearing imbalance at other than
hearing
threshold levels which might contribute to my needing to use a stereo
balance control.

The reason there's little about it is that small imbalances like this
are almost always readily adapted since we use this for localization
and navigation. If you have no indications of such imbalance outside
your stereo environment, it is probably something in the system/room.
I suggest that you do a more careful frequency-by-frequency
measurement in order to distinguish a simple imbalance from a
lateralized frequency aberration.

Kal


No, in my case it really is my ears, I'm going deaf in the right one. As
for
adaptation for localisation & navigation, an imbalance of 2.7dB would not
be
considered as insignificant to any specialist wrt to interpreting a
"stereo"
image.

Normal limits are 0-20 dBHL (decibel Hearing Level) mild hearing loss is
diagnosed at 25--39 dBHL (me in one ear!). A 2.7dB imbalance would be 10%
(or greater dependant on the best lug hole level) imbalance from normal
levels and certainly would be noticeable in determining source and
soundstage from stereo speakers.

Nature does compensate to a degree by adaptation but in nature we do not
find artificial representations of stereo soundstages. I first noticed my
problem when I had to adjust balance to "feel comfortable" with certain
tracks, now it's all tracks and I have been diagnosed as an decrepit old
fart who's going deaf in one ear. I don't notice this much at all in any
other circumstances but eventually I know that will be able to avoid all
of
my wife's nagging simply by sitting to her left! (There's always a
positive
spin)

Simple test, sit with your back to the speakers, does the imbalance
change?

Garf

I understand but I was responding regarding a 2.7dB loss, not to your
larger deficit. (Please accept sympathy on that score.) As such is
readily adapted to in the 'real world,' there is little different
about the stereo system situation. Now, put an ear plug in one ear of
a 'normal' individual and, short term, the balances are off.

Another issue is that the losses we are talking of are rarely evenly
effective across the audible range. Since it occurs initially and
mostly at higher frequencies, its interaction with loudspeakers and
room acoustics could well be different than in natural settings.

Kal

Hi Kal

have to disagree, the "norm" dbHL is zero to 20 dB, e.g lugs can clearly
identify sound at say 18dB levels = normal Mr Average.

If one lug identifies at 18dB and the other lug at 20.7dB you have a 15%
imbalance between ears, this is more than enough to have Mr Average reaching
for the balance control if the sound is a focussed from TWO separate,
equidistant sources roughly located on each side of his head (Speakers in
this case, assuming he sits on a couch looking at the wood)

It is not enough for the same Mr Average to have issues in conversation or
in location of direction as we normally listen to ONE source (plus
background noise) and hear it in both ears to locate direction.

My larger deficit is not that much larger, 21 dB in left lug, 26 in the
right and took ten years for me to visit the specialist so probably started
at a much lower, but clearly noticeable imbalance. BTW sympathy not needed,
I just had to get used to the balance knob not sitting straight up.

Don't get me wrong, hear (sic). I know the value of speaker positioning,
room characteristics et al but I did have quite a few frustrating years of
speaker and room shuffling before I went to the docs and learnt not to blame
my speakers, room or wife.

The more you love music, are passionate about the sound then the more you
will notice subtle changes and "imbalances". We (and this is true cos that's
why we read this NG) pack the wife off in the bath, kids off to bed,
silence the house and sit in our listening position to hear our music. It
has to be perfect, it has to be in perfect balance with a clear defined
soundstage, we should not be surprised that audiophiles can notice a 2-3 dB
imbalance. We are after all perfectionists.

Nice thread, thank you and goodnight

Garf

Magnitude of loudspeaker-room interaction
 

In article , Arny Krueger wrote:
"John Phillips" wrote in message


Is a 2.7 dB left-right stereo imbalance reasonable for a
loudspeaker-room interaction in a nearly symmetrical room?

You might want to swap the speakers, as its not unusual for speakers to
depart from spec by a dB or two. That means that a pair, each unit at the
opposite ends of spec, could vary this much.

I did that on first noticing the problem. The imbalance stayed with
the room or the CD+amplifier. It was after that that I did the checks
on the CD player, amplifier and cables to eliminate them.

However I have now moved a small book-case from against the wall nearly
behind one of the speakers and the imbalance has improved (I can't tell
how much immediately). I may go back and see if adjusting the speaker
position will do more good than it did previously.

If you've swapped *everything* you will be especially well-advised to
consider my comments about equalizers and center speakers.

I was eyeing a TACT adaptive room equalizer but I think I will wait for
the price to come down a bit.

--
John Phillips

Magnitude of loudspeaker-room interaction
 

"John Phillips" wrote in message


I was eyeing a TACT adaptive room equalizer but I think I will wait
for the price to come down a bit.

There are a ton of other, less-costly alternatives.

Magnitude of loudspeaker-room interaction
 

In article , Jim Lesurf wrote:
Provided the 'swap' tests showed this stayed firmly in the same 'direction'
so far as perception was concerned I assume your equipment is fine. If the
image is reasonably narrow and well defined, then it is probably OK just to
resign yourself to using the offset and getting results that then sound
fine! About all it then implies is that one speaker might be being driven a
bit harder than the other.

Well, I think I finally have it right (or close to) after all,

Having moved a small book-case I noticed an improvement. I was prompted
to go back to adjusting the speakers' positions. Now I have the stereo
image well balanced with no artificial adjustment.

It looks (from an optical perspective) like the adjustments have got the
side-wall accoustic reflection environment more symmetrical. There is
now some damping of the accoustic reflection at the right points on both
side-walls, whereas previously there was damping on only one side and
a bare wall on the other. Maybe this was the cause of the imbalance.
Some guides (e.g. from Audio Physic) make much of side-wall reflections.

Anyway, regardless of the exact issue, I guess it was the room after all.
It looks like I didn't spend long enough to position the speakers earlier
before resorting to the "balance control".

--
John Phillips

Magnitude of loudspeaker-room interaction
 

In article , John Phillips
wrote:
In article , Jim Lesurf wrote:
Provided the 'swap' tests showed this stayed firmly in the same
'direction' so far as perception was concerned I assume your equipment
is fine. If the image is reasonably narrow and well defined, then it
is probably OK just to resign yourself to using the offset and getting
results that then sound fine! About all it then implies is that one
speaker might be being driven a bit harder than the other.

Well, I think I finally have it right (or close to) after all,

Excellent. :-)

Having moved a small book-case I noticed an improvement. I was prompted
to go back to adjusting the speakers' positions. Now I have the stereo
image well balanced with no artificial adjustment.

It looks (from an optical perspective) like the adjustments have got the
side-wall accoustic reflection environment more symmetrical. There is
now some damping of the accoustic reflection at the right points on both
side-walls, whereas previously there was damping on only one side and a
bare wall on the other. Maybe this was the cause of the imbalance. Some
guides (e.g. from Audio Physic) make much of side-wall reflections.

The above makes sense to me. Sidewall reflections can have a distinct
effect on the stereo image, so what you describe fits well with what I'd
expect.

Anyway, regardless of the exact issue, I guess it was the room after
all. It looks like I didn't spend long enough to position the speakers
earlier before resorting to the "balance control".

FWIW I find it pays dividends to spend a fair bit of time on speaker
placement, etc. During the first few days of using 'new' speakers in a room
I tend to move them (and other things) around lot. Then I tend to go
through a repeated process of leaving things for a while, then making some
small changes and giving them a time to see what I prefer. This tends to
involve longer and longer 'settling' periods between experiments, and
smaller and smaller movements. The result being that it can take months to
iterate down to what seems decent solution. But I do feel that doing this
can end up with a sound that is preferred to what was obtained after the
first week or two.

e.g. Having bought new speakers in the spring, a couple of weeks ago I
slightly altered the angling of the speakers, and after a few days decided
that it was slightly better in the new arrangement.

How much of this is imagination in my case, I don't know, but it is
harmless fun, and gives me an excuse to 'rediscover' old recordings. :-)

Slainte,

Jim

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Magnitude of loudspeaker-room interaction
 

"Jim Lesurf" wrote in message
...

Big snip

e.g. Having bought new speakers in the spring, a couple of weeks ago I
slightly altered the angling of the speakers, and after a few days
decided
that it was slightly better in the new arrangement.

How much of this is imagination in my case, I don't know, but it is
harmless fun, and gives me an excuse to 'rediscover' old recordings. :-)

Slainte,

Jim

You could always do a DBT and find out, Jim :-)

Alan