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

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

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

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

"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

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

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

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

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

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