Will two table radios always be in phase, out of phase/...

[micky]

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?


I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

 

[John Larkin]

On Sun, 25 Dec 2022 16:12:19 -0500, micky <NONONOmisc07@fmguy.com>
wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

Phase is probably constant for each radio, but random between
different types.

Measure it.

Sound waves are short so you\'d have to be equidistant from both
speakers, without wall reflections, to have phasing mean much.

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Try some contact cleaner.

 

[John Larkin]

On Sun, 25 Dec 2022 16:12:19 -0500, micky <NONONOmisc07@fmguy.com>
wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

Phase is probably constant for each radio, but random between
different types.

Measure it.

Sound waves are short so you\'d have to be equidistant from both
speakers, without wall reflections, to have phasing mean much.

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Try some contact cleaner.

 

[John Larkin]

On Sun, 25 Dec 2022 16:12:19 -0500, micky <NONONOmisc07@fmguy.com>
wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

Phase is probably constant for each radio, but random between
different types.

Measure it.

Sound waves are short so you\'d have to be equidistant from both
speakers, without wall reflections, to have phasing mean much.

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Try some contact cleaner.

 

[Dave Platt]

In article <m3fhqhpa8r1b700ol2pk2j6ru33aol4r47@4ax.com>,
micky <NONONOmisc07@fmguy.com> wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

To a very close approximation, the movement of their speaker cones
will be in phase (assuming that the radios are of identical design).
The speed of light (and radio) is fast enough that you need a lot of
separation between two identical radios, before the outputs will
develop a perceptible phase shift.

The in-phase-vs-out-of-phase behavior at the actual listening location,
and its effect on specific frequencies, is dominated by the distance
from each speaker cone to the listener\'s ear. Since sound moves at only
about 1 foot per millisecond, changing the distances by an inch or two can
make a big difference in which frequencies cancel and which ones reinforce.

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

They do. However, you\'re less likely to notice it, for a number of
reasons.

At the higher frequencies, our ears (and brains) are constantly
dealing with the reinforcement and cancellation of different
frequencies, as the sound waves bounce off of floors and ceilings and
create all sorts of \"multipath\" interference which changes every time
we move a few inches. This happens even for a single sound source
(mono radio, person speaking, etc.). Our brains have evolved to
perceive sound sources even in the face of this sort of multipath
interference and the resulting \"comb filter\" effect. So, we just
don\'t notice it consciously when it\'s happening. You can see the
effect on a spectrogram (pick up the REW software and a good
microphone if you want to experiment).

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

\"In phase\" where and at what frequencies? At the speaker cones? At
your current listening position? At the position you\'ll be in ten
seconds, after you move your head a bit?

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

Look at it this way. At a frequency of 1000 Hz (roughly in the middle
of the speech-frequency range), a full wave of the sound is about a
foot long (in air). If you stand between the two radios, and then
move three inches one way or the other, you\'ll increase one path
length by a quarter-wavelength and reduce the other by a
quarter-wavelength, and thus change the timing difference by half
a wavelength. You\'ll go from \"reinforcement\" to \"cancellation\" (or
vice versa) at this one frequency, just by making this simple little
movement of your head.

At higher frequencies, moving as little as an inch has this same
effect. At lower frequencies, yoh have to move further to change
cancellation into reinforcement.

As you move, you\'re probably also going to be changing the collection of
reflective paths from each radio to your head, and these changes will
also alter the cancellations and reinforcements. \"Multipath\" can be
extremely complicated.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

No, that\'s too simple a model of how the sound-in-air is related to the
signal-by-radio. It doesn\'t really work that way.

In FM radio, the position of the speaker cone (pushed towards you or
pulled back to you) depends on the frequency of the RF (above or below
the nominal FM carrier frequency), *not* on the phase of the RF at any
given instant. Delaying the RF by a few cycles will result in only a
negligible delay in the phase of the speaker cone
motion... approximately 1 nanosecond of timing change per foot.

AM detection works somewhat similarly, in that the amplitude of the
signal fed to the speaker is proportional to the _envelope_ of the
RF signal, and not to its instantaneous value or phase.

So, in both AM and FM, the amount of phase shift in the speaker-cone
output caused by moving the radio towards, or away from the transmitter
is tiny. The effect of changing the length of the sound path (in air)
between radio and listener are far, far larger.

(Move the radio 1 foot closer to the transmitter, and you change the
speaker-cone timing by at most a nanosecond or so. At the same time,
you change the speaker-cone-to-ear sound travel timing by as much as
a millisecond. That\'s a million-to-one difference! Radio fast, sound
slow.)

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?

Essentially irrelevant, once the heterodyned IF signal hits the
detector (FM detector such as a ratio or quadrature detector, or an AM
envelope or product detector). At this point, the heterodyned IF
signal per se ceases to exist, and we start looking at an audio signal
which is based on a longer-term \"measurement\" of the IF (its envelope,
or its frequency deviation from nominal center) which doesn\'t depend
significantly on the phase of the IF or the original RF.

**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times?

Switches and relays are (in my experience) often the weakest point in
radios and etc. The contacts wear out or bend, the contacts get dirty or
contaminated (tobacco and cannabis smoke leave a nasty, insulating tar),
the plastic switch body wears out, etc.

Yes, they may be \"supposed to\" last for hundreds of thousands, or even
millions of cycles, *if* the manufacturer chose a really good switch
and if it\'s been kept clean. Often, neither of these is the case.
OEMs often \"economize\" on such things to save a few cents per unit.
If it lasts until after the warranty expires... for many brands,
that\'s plenty good enough.

I\'ve gotten quite a few radios and so forth \"back from the dead\" by giving
switches a good cleaning, or (when necessary) replacing them.

 

[Dave Platt]

In article <m3fhqhpa8r1b700ol2pk2j6ru33aol4r47@4ax.com>,
micky <NONONOmisc07@fmguy.com> wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

To a very close approximation, the movement of their speaker cones
will be in phase (assuming that the radios are of identical design).
The speed of light (and radio) is fast enough that you need a lot of
separation between two identical radios, before the outputs will
develop a perceptible phase shift.

The in-phase-vs-out-of-phase behavior at the actual listening location,
and its effect on specific frequencies, is dominated by the distance
from each speaker cone to the listener\'s ear. Since sound moves at only
about 1 foot per millisecond, changing the distances by an inch or two can
make a big difference in which frequencies cancel and which ones reinforce.

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

They do. However, you\'re less likely to notice it, for a number of
reasons.

At the higher frequencies, our ears (and brains) are constantly
dealing with the reinforcement and cancellation of different
frequencies, as the sound waves bounce off of floors and ceilings and
create all sorts of \"multipath\" interference which changes every time
we move a few inches. This happens even for a single sound source
(mono radio, person speaking, etc.). Our brains have evolved to
perceive sound sources even in the face of this sort of multipath
interference and the resulting \"comb filter\" effect. So, we just
don\'t notice it consciously when it\'s happening. You can see the
effect on a spectrogram (pick up the REW software and a good
microphone if you want to experiment).

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

\"In phase\" where and at what frequencies? At the speaker cones? At
your current listening position? At the position you\'ll be in ten
seconds, after you move your head a bit?

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

Look at it this way. At a frequency of 1000 Hz (roughly in the middle
of the speech-frequency range), a full wave of the sound is about a
foot long (in air). If you stand between the two radios, and then
move three inches one way or the other, you\'ll increase one path
length by a quarter-wavelength and reduce the other by a
quarter-wavelength, and thus change the timing difference by half
a wavelength. You\'ll go from \"reinforcement\" to \"cancellation\" (or
vice versa) at this one frequency, just by making this simple little
movement of your head.

At higher frequencies, moving as little as an inch has this same
effect. At lower frequencies, yoh have to move further to change
cancellation into reinforcement.

As you move, you\'re probably also going to be changing the collection of
reflective paths from each radio to your head, and these changes will
also alter the cancellations and reinforcements. \"Multipath\" can be
extremely complicated.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

No, that\'s too simple a model of how the sound-in-air is related to the
signal-by-radio. It doesn\'t really work that way.

In FM radio, the position of the speaker cone (pushed towards you or
pulled back to you) depends on the frequency of the RF (above or below
the nominal FM carrier frequency), *not* on the phase of the RF at any
given instant. Delaying the RF by a few cycles will result in only a
negligible delay in the phase of the speaker cone
motion... approximately 1 nanosecond of timing change per foot.

AM detection works somewhat similarly, in that the amplitude of the
signal fed to the speaker is proportional to the _envelope_ of the
RF signal, and not to its instantaneous value or phase.

So, in both AM and FM, the amount of phase shift in the speaker-cone
output caused by moving the radio towards, or away from the transmitter
is tiny. The effect of changing the length of the sound path (in air)
between radio and listener are far, far larger.

(Move the radio 1 foot closer to the transmitter, and you change the
speaker-cone timing by at most a nanosecond or so. At the same time,
you change the speaker-cone-to-ear sound travel timing by as much as
a millisecond. That\'s a million-to-one difference! Radio fast, sound
slow.)

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?

Essentially irrelevant, once the heterodyned IF signal hits the
detector (FM detector such as a ratio or quadrature detector, or an AM
envelope or product detector). At this point, the heterodyned IF
signal per se ceases to exist, and we start looking at an audio signal
which is based on a longer-term \"measurement\" of the IF (its envelope,
or its frequency deviation from nominal center) which doesn\'t depend
significantly on the phase of the IF or the original RF.

**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times?

Switches and relays are (in my experience) often the weakest point in
radios and etc. The contacts wear out or bend, the contacts get dirty or
contaminated (tobacco and cannabis smoke leave a nasty, insulating tar),
the plastic switch body wears out, etc.

Yes, they may be \"supposed to\" last for hundreds of thousands, or even
millions of cycles, *if* the manufacturer chose a really good switch
and if it\'s been kept clean. Often, neither of these is the case.
OEMs often \"economize\" on such things to save a few cents per unit.
If it lasts until after the warranty expires... for many brands,
that\'s plenty good enough.

I\'ve gotten quite a few radios and so forth \"back from the dead\" by giving
switches a good cleaning, or (when necessary) replacing them.

 

[Dave Platt]

In article <m3fhqhpa8r1b700ol2pk2j6ru33aol4r47@4ax.com>,
micky <NONONOmisc07@fmguy.com> wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

To a very close approximation, the movement of their speaker cones
will be in phase (assuming that the radios are of identical design).
The speed of light (and radio) is fast enough that you need a lot of
separation between two identical radios, before the outputs will
develop a perceptible phase shift.

The in-phase-vs-out-of-phase behavior at the actual listening location,
and its effect on specific frequencies, is dominated by the distance
from each speaker cone to the listener\'s ear. Since sound moves at only
about 1 foot per millisecond, changing the distances by an inch or two can
make a big difference in which frequencies cancel and which ones reinforce.

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

They do. However, you\'re less likely to notice it, for a number of
reasons.

At the higher frequencies, our ears (and brains) are constantly
dealing with the reinforcement and cancellation of different
frequencies, as the sound waves bounce off of floors and ceilings and
create all sorts of \"multipath\" interference which changes every time
we move a few inches. This happens even for a single sound source
(mono radio, person speaking, etc.). Our brains have evolved to
perceive sound sources even in the face of this sort of multipath
interference and the resulting \"comb filter\" effect. So, we just
don\'t notice it consciously when it\'s happening. You can see the
effect on a spectrogram (pick up the REW software and a good
microphone if you want to experiment).

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?

\"In phase\" where and at what frequencies? At the speaker cones? At
your current listening position? At the position you\'ll be in ten
seconds, after you move your head a bit?

I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

Look at it this way. At a frequency of 1000 Hz (roughly in the middle
of the speech-frequency range), a full wave of the sound is about a
foot long (in air). If you stand between the two radios, and then
move three inches one way or the other, you\'ll increase one path
length by a quarter-wavelength and reduce the other by a
quarter-wavelength, and thus change the timing difference by half
a wavelength. You\'ll go from \"reinforcement\" to \"cancellation\" (or
vice versa) at this one frequency, just by making this simple little
movement of your head.

At higher frequencies, moving as little as an inch has this same
effect. At lower frequencies, yoh have to move further to change
cancellation into reinforcement.

As you move, you\'re probably also going to be changing the collection of
reflective paths from each radio to your head, and these changes will
also alter the cancellations and reinforcements. \"Multipath\" can be
extremely complicated.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

No, that\'s too simple a model of how the sound-in-air is related to the
signal-by-radio. It doesn\'t really work that way.

In FM radio, the position of the speaker cone (pushed towards you or
pulled back to you) depends on the frequency of the RF (above or below
the nominal FM carrier frequency), *not* on the phase of the RF at any
given instant. Delaying the RF by a few cycles will result in only a
negligible delay in the phase of the speaker cone
motion... approximately 1 nanosecond of timing change per foot.

AM detection works somewhat similarly, in that the amplitude of the
signal fed to the speaker is proportional to the _envelope_ of the
RF signal, and not to its instantaneous value or phase.

So, in both AM and FM, the amount of phase shift in the speaker-cone
output caused by moving the radio towards, or away from the transmitter
is tiny. The effect of changing the length of the sound path (in air)
between radio and listener are far, far larger.

(Move the radio 1 foot closer to the transmitter, and you change the
speaker-cone timing by at most a nanosecond or so. At the same time,
you change the speaker-cone-to-ear sound travel timing by as much as
a millisecond. That\'s a million-to-one difference! Radio fast, sound
slow.)

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?

Essentially irrelevant, once the heterodyned IF signal hits the
detector (FM detector such as a ratio or quadrature detector, or an AM
envelope or product detector). At this point, the heterodyned IF
signal per se ceases to exist, and we start looking at an audio signal
which is based on a longer-term \"measurement\" of the IF (its envelope,
or its frequency deviation from nominal center) which doesn\'t depend
significantly on the phase of the IF or the original RF.

**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times?

Switches and relays are (in my experience) often the weakest point in
radios and etc. The contacts wear out or bend, the contacts get dirty or
contaminated (tobacco and cannabis smoke leave a nasty, insulating tar),
the plastic switch body wears out, etc.

Yes, they may be \"supposed to\" last for hundreds of thousands, or even
millions of cycles, *if* the manufacturer chose a really good switch
and if it\'s been kept clean. Often, neither of these is the case.
OEMs often \"economize\" on such things to save a few cents per unit.
If it lasts until after the warranty expires... for many brands,
that\'s plenty good enough.

I\'ve gotten quite a few radios and so forth \"back from the dead\" by giving
switches a good cleaning, or (when necessary) replacing them.

 

[Carlos E.R.]

On 2022-12-25 22:12, micky wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Each capacitor or coil inserts a phase difference between voltage and
current.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

--
Cheers, Carlos.

 

[Carlos E.R.]

On 2022-12-25 22:12, micky wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Each capacitor or coil inserts a phase difference between voltage and
current.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

--
Cheers, Carlos.

 

[Carlos E.R.]

On 2022-12-25 22:12, micky wrote:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Each capacitor or coil inserts a phase difference between voltage and
current.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

--
Cheers, Carlos.

 

[John Larkin]

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
<robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.

Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

 

[John Larkin]

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
<robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.

Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

 

[John Larkin]

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
<robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.

Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.

So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

 

[Rink]

Op 25-12-2022 om 22:12 schreef micky:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?


I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Windows-10 radio\'s or speakers?

I think you can post this question in an audio or a radio newsgroup
e.g. uk.tech.broadcast (for radio signals)
maybe rec.audio.tech ? ( I do not read this group)

But you got some good answers here!
(probably from the repair or design groups)

If you change the wires of one speaker you get a 180 degree
difference on all audio frequencies.
If from two speakers at the some radio (left and right), one is wrong
connected, you can hear that at exactly the middle between the speakers
where there is a fase-out for all audio frequencies.


Rink
(sorry for my English, it\'s not my first language)

 

[Rink]

Op 25-12-2022 om 22:12 schreef micky:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?


I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Windows-10 radio\'s or speakers?

I think you can post this question in an audio or a radio newsgroup
e.g. uk.tech.broadcast (for radio signals)
maybe rec.audio.tech ? ( I do not read this group)

But you got some good answers here!
(probably from the repair or design groups)

If you change the wires of one speaker you get a 180 degree
difference on all audio frequencies.
If from two speakers at the some radio (left and right), one is wrong
connected, you can hear that at exactly the middle between the speakers
where there is a fase-out for all audio frequencies.


Rink
(sorry for my English, it\'s not my first language)

 

[Rink]

Op 25-12-2022 om 22:12 schreef micky:

sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

And why is it low frequencies are famous for cancelling out when out of
phase when high frequencies are just as likely, 0.5, I think, to cancel
each other out?

Can I just turn off one radio for a few seconds and turn it on again so
that the total odds over both times have increased that by the second
time the radios will be in phase?


I have a radio and tv in one bathroom but neither in the other, which is
smaller and adjoins the bedroom. Sometimes I want to hear the radio
which only gets \'loud\' if you are in the same room. I can hear it from
the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33
years when the speaker switch started to fail**, and I turn that one on
too, to the same station, also at maximum volume, and I can hear in the
bathroom just fine, but I wonder if some frequencies are out of phase
from one radio to the other, cancelling each other, and I\'m not hearing
them.

It seems to me, if one radio is farther from the transmitting antenna,
by 1/2 wave length, the speakers in the two radios will always be going
in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the
xmtr is very similar. But what about within the radio, when the
heterodyning frequency starts. What if it starts have a cycle after the
first radio?



**So I bought the second radio. The first one has a pushbutton switch
meant to connect/disconnect a wooden-cabinet stereo speaker, which I
have no room for, and unless I get the switch just right, no sound comes
out at all. (even the on/off momementary contact switch no longer works
well, after only 33 years, maybe using it at most 6 times a day, so that
6x365x33=66,000 times. Aren\'t switches supposed to last into the
millions of times? --- It\'s failing isn\'t nearly as bad, because I just
keep pushing until it works. The speaker switch OTOH has a spring that
pushes it out, past its sweet spot, so now it\'s hard to get to connect
at all.

Windows-10 radio\'s or speakers?

I think you can post this question in an audio or a radio newsgroup
e.g. uk.tech.broadcast (for radio signals)
maybe rec.audio.tech ? ( I do not read this group)

But you got some good answers here!
(probably from the repair or design groups)

If you change the wires of one speaker you get a 180 degree
difference on all audio frequencies.
If from two speakers at the some radio (left and right), one is wrong
connected, you can hear that at exactly the middle between the speakers
where there is a fase-out for all audio frequencies.


Rink
(sorry for my English, it\'s not my first language)

 

[Phil Hobbs]

John Larkin wrote:

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.


Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.


So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

That\'s all true for AM, and mostly true for FM, but not for SSB. The
BFO phase comes out in the audio signal, so the audio phase will vary at
infrasonic or low-audio rates.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

John Larkin wrote:

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.


Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.


So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

That\'s all true for AM, and mostly true for FM, but not for SSB. The
BFO phase comes out in the audio signal, so the audio phase will vary at
infrasonic or low-audio rates.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

John Larkin wrote:

On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.


Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.


So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.

That\'s all true for AM, and mostly true for FM, but not for SSB. The
BFO phase comes out in the audio signal, so the audio phase will vary at
infrasonic or low-audio rates.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Mon, 2 Jan 2023 10:01:44 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Sun, 1 Jan 2023 22:14:49 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

On 2022-12-25 22:12, micky wrote:
sci.electronics.design added.

Technical qustion about wave valleys and troughs and if two radio
playing the same station will be in phase wrt all frequencies, or if
some will cancel out?

If I remember correctly, each amplifier stage inserts a delay and a
phase shift in the signal it processes.

Microseconds. Equivalent to a tiny fraction of an inch at sound
propagation speed.


Each capacitor or coil inserts a phase difference between voltage and
current.

Tiny.


So, you can assume that if they are the same model, the should be in
phase. Not trivial to calculate.


Then, if the distance to the transmitter is one half wave lenght, there
will be a 180 phase difference in the high frequency arriving.

Which won\'t affect the audio.


That\'s all true for AM, and mostly true for FM, but not for SSB. The
BFO phase comes out in the audio signal, so the audio phase will vary at
infrasonic or low-audio rates.

Cheers

Phil Hobbs

Table radios aren\'t SSB! What\'s worse is that unlocked SSB shifts the
audio frequencies, which mangles all the harmonics.

Every foot you move a radio away from the station, its sound is
delayed about a nanosecond. Every foot your ear moves from the
speaker, the sound is delayed about a millisecond.

1 million to one often matters.