loudspeaker stereo imaging
 

Dave Plowman wrote:

In article ,
Ian Molton wrote:
I'd be impressed to see a speaker that can alter the time it takes for
the sound to reach your ear.

A sound which emanates from somewhere between two speakers will arrive at
*both* ears with a timing difference. Not so with headphones - unless you
introduce some form of 'bleed' between channels which has been tried with
limited success.


This is a common fallacy. This is why speakers sound worse than headphones.
The ear uses this imformation to determine that the sound is really coming
from two point sources, the speakers. headphones do not have this
limitation.

Ian

loudspeaker stereo imaging
 

In article , Ian Bell
wrote:
Dave Plowman wrote:

In article , Ian Bell
wrote:
But the ear positions sounds by more than just relative levels -
and this is lost on a conventional recording when listened to on
headphones.


How?

Well, it measures the time a sound takes to reach each ear, for a
start.


Yes and the time differences are mirrored in the recording not in the
transducer used to reproduce the sound. Speakers or headphones, makes
no difference you still hear the time delays.

Not quite. When you hear a 'fully left' sound from a loudspeaker in a room,
both of your ears hear the sound, but the sound at your left ear arrives
earlier and is louder than that arriving at your right ear.

However when you listen to the same sound on headphones, no sound at all
arrives at your right ear.

Hence the placement of the speakers with respect to your ears adds an extra
'layer' of time information and affects the relative time/amplitudes at the
ears in a way headphones do not.

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

loudspeaker stereo imaging
 

In article , Ian Bell
wrote:
Dave Plowman wrote:

In article , Ian Bell
wrote:
But the ear positions sounds by more than just relative levels -
and this is lost on a conventional recording when listened to on
headphones.


How?

Well, it measures the time a sound takes to reach each ear, for a
start.


Yes and the time differences are mirrored in the recording not in the
transducer used to reproduce the sound. Speakers or headphones, makes
no difference you still hear the time delays.

Not quite. When you hear a 'fully left' sound from a loudspeaker in a room,
both of your ears hear the sound, but the sound at your left ear arrives
earlier and is louder than that arriving at your right ear.

However when you listen to the same sound on headphones, no sound at all
arrives at your right ear.

Hence the placement of the speakers with respect to your ears adds an extra
'layer' of time information and affects the relative time/amplitudes at the
ears in a way headphones do not.

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

loudspeaker stereo imaging
 

Jim Lesurf wrote:

In article , Ian Bell
wrote:
Dave Plowman wrote:

In article , Ian Molton
wrote:
But this is a fallacy. You can't position sounds accurately with
headphones as you can with speakers.

say what?

two sonically independant drivers (ie. no sound leaks across from one
ear to the other)

But the ear positions sounds by more than just relative levels - and
this is lost on a conventional recording when listened to on
headphones.


How?

Various ways including;

1) Relative times of arrivals at the two ears.

2) Effects of diffraction/scattering from the ear-lobes being direction
dependent.

It is possible in principle to process the sound so that these effects are
pre-applied - hence some of the 'dummy head' recordings. However with most
stereo recordings and broadcasts the sound will be produced on the
assumption that you're listening via a pair of loudspeakers.

Slainte,

Jim


Exactly. And not one of these factors is inherently missing when listening
on headphones versus loudspeakers so the OPs contention that headphones
cannot produce the quality of stereo image that speakers can is false. I
agree that material *designed* to be heard via two speakers ought to sound
*better* on speakers but that was not the point under debate.

Ian

loudspeaker stereo imaging
 

Jim Lesurf wrote:

In article , Ian Bell
wrote:
Dave Plowman wrote:

In article , Ian Molton
wrote:
But this is a fallacy. You can't position sounds accurately with
headphones as you can with speakers.

say what?

two sonically independant drivers (ie. no sound leaks across from one
ear to the other)

But the ear positions sounds by more than just relative levels - and
this is lost on a conventional recording when listened to on
headphones.


How?

Various ways including;

1) Relative times of arrivals at the two ears.

2) Effects of diffraction/scattering from the ear-lobes being direction
dependent.

It is possible in principle to process the sound so that these effects are
pre-applied - hence some of the 'dummy head' recordings. However with most
stereo recordings and broadcasts the sound will be produced on the
assumption that you're listening via a pair of loudspeakers.

Slainte,

Jim


Exactly. And not one of these factors is inherently missing when listening
on headphones versus loudspeakers so the OPs contention that headphones
cannot produce the quality of stereo image that speakers can is false. I
agree that material *designed* to be heard via two speakers ought to sound
*better* on speakers but that was not the point under debate.

Ian

loudspeaker stereo imaging
 

"Ian Bell" wrote in message

Dave Plowman wrote:

In article ,
Ian Molton wrote:
I'd be impressed to see a speaker that can alter the time it takes
for the sound to reach your ear.

A sound which emanates from somewhere between two speakers will
arrive at *both* ears with a timing difference. Not so with
headphones - unless you introduce some form of 'bleed' between
channels which has been tried with limited success.

This is a common fallacy. This is why speakers sound worse than
headphones. The ear uses this imformation to determine that the sound
is really coming from two point sources, the speakers. headphones do
not have this limitation.

The correct answer is that the ears sense horizontal and vertical imaging by
a number of means, including the acoustic transfer function of the head.
These transfer functions have been studied extensively, and are well known
to audio specialists as HRTFs - Head Response Transfer Functions.

An ordinary stereo recording played through headphones lacks the effects of
HRTFs, a fact which is audible a number of different ways. If a acoustically
correct dummy head is used to make the recording, then the effects of HRTFs
are imposed on the recording and it sounds far more realistic when played
over headphones.

HRTFs can be approximated with electrical networks and computer programs,
and their proper manipulation can give rise to a number of striking effects,
such as a strong image of a sound source behind you created by two speakers
in front of you. HRTFs can also be applied to conventional recordings to
simulate the sound of "dummy head" recordings for headphone listeners.

It is impossible to generalize very much about how stereo recordings are
made since so many are made by ad hoc means, vis-a-vis spatiality, etc.
However, some recordings that are made using minimalist micing methodologies
implement what is known technically as "intensity stereo", that is a stereo
system in which time differences due to source position are minimized, and
only amplitude differences are captured.

loudspeaker stereo imaging
 

"Ian Bell" wrote in message

Dave Plowman wrote:

In article ,
Ian Molton wrote:
I'd be impressed to see a speaker that can alter the time it takes
for the sound to reach your ear.

A sound which emanates from somewhere between two speakers will
arrive at *both* ears with a timing difference. Not so with
headphones - unless you introduce some form of 'bleed' between
channels which has been tried with limited success.

This is a common fallacy. This is why speakers sound worse than
headphones. The ear uses this imformation to determine that the sound
is really coming from two point sources, the speakers. headphones do
not have this limitation.

The correct answer is that the ears sense horizontal and vertical imaging by
a number of means, including the acoustic transfer function of the head.
These transfer functions have been studied extensively, and are well known
to audio specialists as HRTFs - Head Response Transfer Functions.

An ordinary stereo recording played through headphones lacks the effects of
HRTFs, a fact which is audible a number of different ways. If a acoustically
correct dummy head is used to make the recording, then the effects of HRTFs
are imposed on the recording and it sounds far more realistic when played
over headphones.

HRTFs can be approximated with electrical networks and computer programs,
and their proper manipulation can give rise to a number of striking effects,
such as a strong image of a sound source behind you created by two speakers
in front of you. HRTFs can also be applied to conventional recordings to
simulate the sound of "dummy head" recordings for headphone listeners.

It is impossible to generalize very much about how stereo recordings are
made since so many are made by ad hoc means, vis-a-vis spatiality, etc.
However, some recordings that are made using minimalist micing methodologies
implement what is known technically as "intensity stereo", that is a stereo
system in which time differences due to source position are minimized, and
only amplitude differences are captured.

loudspeaker stereo imaging
 

In article , Duncan L.
Armstrong wrote:
"Jim Lesurf" wrote in message
...


Depends upon what you call "little LF response". In my listening room
their
output is only about 3dB at 30-35Hz. This is better than many
cone-and-box
speakers. :-)


You can hear 3dB?? You must have super-human hearing Jim. ;)

Given we're talking about LF you probably should regard me as 'sub
human'... ;-

(I assume you meant 3dB down at 30-35Hz. :) )

Yes. Sorry, should have written "-3dB" but managed to fail to type the
negative sign. :-)

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

loudspeaker stereo imaging
 

In article , Duncan L.
Armstrong wrote:
"Jim Lesurf" wrote in message
...


Depends upon what you call "little LF response". In my listening room
their
output is only about 3dB at 30-35Hz. This is better than many
cone-and-box
speakers. :-)


You can hear 3dB?? You must have super-human hearing Jim. ;)

Given we're talking about LF you probably should regard me as 'sub
human'... ;-

(I assume you meant 3dB down at 30-35Hz. :) )

Yes. Sorry, should have written "-3dB" but managed to fail to type the
negative sign. :-)

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

loudspeaker stereo imaging
 

In article , Ian Bell
wrote:
Jim Lesurf wrote:


1) Relative times of arrivals at the two ears.

2) Effects of diffraction/scattering from the ear-lobes being
direction dependent.

It is possible in principle to process the sound so that these effects
are pre-applied - hence some of the 'dummy head' recordings. However
with most stereo recordings and broadcasts the sound will be produced
on the assumption that you're listening via a pair of loudspeakers.

Slainte,

Jim


Exactly. And not one of these factors is inherently missing when
listening on headphones

I would disagree.

When you listen to - for example - a 'left only' sound source you hear it
with both ears if listening via speakers, and one ear tends to hear it at a
different time and level to the other. By contrast a 'left only' sound on
headphones provides no input to the right ear. Hence there is quite a
distinct difference in what arrives at the two ears between headphones and
loudspeakers even if we negelect things like room reverberation.

Also, sounds arriving from a loudspeaker are modified by the scattering
effects of the ear lobes in a manner than depends upon the direction of
arrival at the ear. Sounds from a headphone tend to arrive perpendictular
to the ear, and the effects of the lobes altered by the phone's physical
presence on the ear. Hence here again there is a distinct difference.


versus loudspeakers so the OPs contention that headphones cannot produce
the quality of stereo image that speakers can is false. I agree that
material *designed* to be heard via two speakers ought to sound *better*
on speakers but that was not the point under debate.

The above differences exist, and are measurable. However the degree to
which they affect the perceived result will depend upon circumstances,
including the choce of listener. What is "better" is a matter of
circumstances and personal preference.

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