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Will two table radios always be in phase, out of phase/
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micky
Dec 25, 2022, 1:34:05 PM12/25/22
to
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 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.
micky
Dec 25, 2022, 4:12:25 PM12/25/22
to
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
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?
Ed Cryer
Dec 25, 2022, 4:14:04 PM12/25/22
to
an FM radio and a Wifi radio in the same room, there'll be a very
noticeable discrepancy.
This phenomenon is so well known that I don't need linger on the cause.
Added to that, you may have two wifi radios together, but processed by
different hardware/ software. And here again the cause needs no explanation.
Your second radio with the dodgy on/off button doesn't even contribute
to the mix; and it won't do so until it produces some output sound. A
faulty switch is a different problem from an echoing, out-of-sync
cacophony of sound.
Ed
Ed Cryer
Dec 25, 2022, 4:30:30 PM12/25/22
to
when I moved in; it comes through the vent fan which switches on with
the room switch.
I've been trying to figure out for years which station it's tuned to.
Mostly it seems classical, like a choir singing, but now and again it
has a bom-da-da-bom rhythm of rock music. I once heard it playing
Werewolves of London.
If you solve your problem, let me know. I'd love to find out which
station my bathroom is tuned into.
Ed
John Larkin
Dec 25, 2022, 4:31:29 PM12/25/22
to
On Sun, 25 Dec 2022 16:12:19 -0500, micky <NONONO...@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.
Try some contact cleaner.
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?
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.
micky
Dec 25, 2022, 5:55:40 PM12/25/22
to
In alt.home.repair, on Sun, 25 Dec 2022 16:56:38 -0500, Rachelle
Walenski <rw@2.Ø> wrote:
>micky wrote:
>>
>> 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?
>>
>
>Are the radios powered by the same 120v phase or on opposite legs (180
>degree out-of-phase)?
Yes, plugged into the same outlet.
Both are traditional over-the-air AM-FM radios, usually using FM. (One
has bluetooth but it's not in use. )
(To other poster, The radio with the bad speaker switch works well if
the switch stops in the right spot, and sometimes it will stay that way
for days. No access for contact cleaner at the moment.
Walenski <rw@2.Ø> wrote:
>micky wrote:
>>
>> 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?
>>
>
>degree out-of-phase)?
Yes, plugged into the same outlet.
Both are traditional over-the-air AM-FM radios, usually using FM. (One
has bluetooth but it's not in use. )
(To other poster, The radio with the bad speaker switch works well if
the switch stops in the right spot, and sometimes it will stay that way
for days. No access for contact cleaner at the moment.
rbowman
Dec 25, 2022, 7:12:13 PM12/25/22
to
On Sun, 25 Dec 2022 21:29:49 +0000, Ed Cryer wrote:
> If you solve your problem, let me know. I'd love to find out which
> station my bathroom is tuned into.
Don't you have another radio? It would be trivial to scan the frequencies
> If you solve your problem, let me know. I'd love to find out which
> station my bathroom is tuned into.
until you get a match. Doesn't the UK require broadcast stations to
periodically identify themselves?
https://www.transmissionzero.co.uk/radio/london-pirate-radio/
Perhaps it's a pirate with eclectic taste. The local university has a low
power FM station that's all over the map depending on who the DJ is for
the slot.
Dave Platt
Dec 26, 2022, 12:54:40 AM12/26/22
to
In article <m3fhqhpa8r1b700ol...@4ax.com>,
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.
micky <NONONO...@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
>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?
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?
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?
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.
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.
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?
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?
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.
Martin Brown
Dec 26, 2022, 4:30:57 AM12/26/22
to
On 25/12/2022 22:55, micky wrote:
> In alt.home.repair, on Sun, 25 Dec 2022 16:56:38 -0500, Rachelle
> In alt.home.repair, on Sun, 25 Dec 2022 16:56:38 -0500, Rachelle
> Walenski <rw@2.Ø> wrote:
>
>> micky wrote:
>>>
>>> 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?
>>>
>>
>> Are the radios powered by the same 120v phase or on opposite legs (180
>> degree out-of-phase)?
>
> Yes, plugged into the same outlet.
The radio will convert it to DC anyway so that doesn't matter.
>
>> micky wrote:
>>>
>>> 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?
>>>
>>
>> Are the radios powered by the same 120v phase or on opposite legs (180
>> degree out-of-phase)?
>
> Yes, plugged into the same outlet.
>
> Both are traditional over-the-air AM-FM radios, usually using FM. (One
> has bluetooth but it's not in use. )
Chances are one will be a few hundred ns time shifted relative to the
> Both are traditional over-the-air AM-FM radios, usually using FM. (One
> has bluetooth but it's not in use. )
other since the amplifiers in each stage of detection are unlikely to
have exactly the same delay or frequency phase response.
Propagation of sound waves in the room will have a much larger effect on
what you hear. Positioning of the speakers relative to hard surfaces.
>
> (To other poster, The radio with the bad speaker switch works well if
> the switch stops in the right spot, and sometimes it will stay that way
> for days. No access for contact cleaner at the moment.
If you really want massive flanging effects try two different digital
> (To other poster, The radio with the bad speaker switch works well if
> the switch stops in the right spot, and sometimes it will stay that way
> for days. No access for contact cleaner at the moment.
radios or SDR decoders within earshot. The difference in delays then can
be fractions of a second or seconds when compared to an FM radio.
DAB is completely useless in an emergency situation unless you have a
shed load of batteries. Uses a set every 8 hours of run time. A decent
FM radio will run for a week or more on just one set of batteries.
--
Regards,
Martin Brown
Clive Arthur
Dec 26, 2022, 5:48:09 AM12/26/22
to
On 25/12/2022 22:55, micky wrote:
> In alt.home.repair, on Sun, 25 Dec 2022 16:56:38 -0500, Rachelle
> Walenski <rw@2.Ø> wrote:
>
>> micky wrote:
>>>
>>> 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?
>>>
>>
>> Are the radios powered by the same 120v phase or on opposite legs (180
>> degree out-of-phase)?
>
> Yes, plugged into the same outlet.
>
> Both are traditional over-the-air AM-FM radios, usually using FM. (One
> has bluetooth but it's not in use. )
>
> (To other poster, The radio with the bad speaker switch works well if
> the switch stops in the right spot, and sometimes it will stay that way
> for days. No access for contact cleaner at the moment.
I would expect two radios of the same make and model to be in phase, but
>
>> micky wrote:
>>>
>>> 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?
>>>
>>
>> Are the radios powered by the same 120v phase or on opposite legs (180
>> degree out-of-phase)?
>
> Yes, plugged into the same outlet.
>
> Both are traditional over-the-air AM-FM radios, usually using FM. (One
> has bluetooth but it's not in use. )
>
> (To other poster, The radio with the bad speaker switch works well if
> the switch stops in the right spot, and sometimes it will stay that way
> for days. No access for contact cleaner at the moment.
different radios will have different amplifier designs and speaker
arrangements which will likely give phase differences at different
frequencies. Plus it is possible that the two loudspeakers are simply
connected in opposite polarity anyway.
--
Cheers
Clive
upsid...@downunder.com
Dec 26, 2022, 7:50:00 AM12/26/22
to
On Sun, 25 Dec 2022 17:55:35 -0500, micky <NONONO...@fmguy.com>
wrote:
>
>Both are traditional over-the-air AM-FM radios, usually using FM.
Even if two radios produce in phase audio on AM (with equal number of
audio inverting stages) the radio may produce opposite phase audio on
FM. One might have the local oscillator (LO) below the received
frequency (RF), while in the other the LO is above the RF frequency.
wrote:
>
>Both are traditional over-the-air AM-FM radios, usually using FM.
audio inverting stages) the radio may produce opposite phase audio on
FM. One might have the local oscillator (LO) below the received
frequency (RF), while in the other the LO is above the RF frequency.
Bill Gill
Dec 26, 2022, 9:02:34 AM12/26/22
to
about. The difference in phase of the RF signal will have no effect.
The RF part of the signal is taken out in the receiver and only the
audio is there to be affected by the location of the 2. And that will
have no effect, because the wavelength of audio signals is over 9 miles
for the high end (20 kHz) frequency and goes up from there as the
frequency goes down. There will not be enough difference to have
any effect.
And it isn't even April 1.
Bill
micky
Dec 26, 2022, 11:01:25 AM12/26/22
to
In alt.home.repair, on Mon, 26 Dec 2022 14:49:54 +0200,
Thanks everyone. Clive raised points that I had thought of -- that was
reassuring -- and everyone else gave me plenty of information to think
about.
reassuring -- and everyone else gave me plenty of information to think
about.
Carlos E.R.
Jan 1, 2023, 4:16:16 PM1/1/23
to
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
> 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?
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
Jan 1, 2023, 4:20:32 PM1/1/23
to
On Sun, 1 Jan 2023 22:14:49 +0100, "Carlos E.R."
<robin_...@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
<robin_...@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.
propagation speed.
>
>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.
Rink
Jan 2, 2023, 8:48:16 AM1/2/23
to
Op 25-12-2022 om 22:12 schreef micky:
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)
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
Jan 2, 2023, 10:01:49 AM1/2/23
to
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
Jan 2, 2023, 10:10:59 AM1/2/23
to
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.
Phil Hobbs
Jan 2, 2023, 1:28:40 PM1/2/23
to
> Table radios aren't SSB! What's worse is that unlocked SSB shifts
> the audio frequencies, which mangles all the harmonics.
Well, maybe _your_ table radio isn't. ;) If I even possessed a table
> the audio frequencies, which mangles all the harmonics.
radio, I'd certainly want something like a Hammarlund Super Pro or a
National HRO or a Hallicrafters SX-122. ;)
>
> 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.
difference in the carrier phases comes out in the baseband signal. In
optics the wavelength contrast is even more stark.
An AM radio uses the unsuppressed carrier as the phase reference for the
detector (which can therefore be as simple as a single diode), so you
need a hell of a d phi / df (aka group delay) to make much of a
difference there.
wmartin
Jan 2, 2023, 1:31:13 PM1/2/23
to
Phil Hobbs
Jan 2, 2023, 5:07:13 PM1/2/23
to
The phase changes at the beat frequency between the BFO and the place
where the carrier would be if it were still there. You want that to be
slow, because it's annoying if it's in the audio range.
Brian Gregory
Jan 2, 2023, 9:30:32 PM1/2/23
to
On 02/01/2023 13:48, Rink wrote:
> 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.
I've never heard an audible null between out of phase speakers. It
> 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.
usually just ruins the stereo effect, makes it sound almost like two
separate lots of music (or whatever).
--
Brian Gregory (in England).
Clive Arthur
Jan 3, 2023, 5:10:48 AM1/3/23
to
bass in the centre. Block one ear and the effect is clearer and at
higher frequencies too.
A long time ago, when stereo records were often mixed with the vocals in
the middle and other instruments to the sides, inverting one channel and
adding it to the other channel (ie subtracting it) could do a
not-too-bad job of removing the vocals for karaoke.
--
Cheers
Clive
Arie de Muijnck
Jan 3, 2023, 9:24:19 AM1/3/23
to
An old trick solved the problem: put the two boxes very close, front to front, and test with a mono signal. Improper phasing removes most of the sound, proper phasing gives full volume.
Arie
sticks
Jan 3, 2023, 10:39:18 AM1/3/23
to
sticks
Jan 3, 2023, 11:04:50 AM1/3/23
to
DecadentLinux...@decadence.org
Jan 3, 2023, 10:32:06 PM1/3/23
to
Clive Arthur <cl...@nowaytoday.co.uk> wrote in
news:tp0uv4$23lge$1...@dont-email.me:
And then, in 1971 IIRC, came "quadrophonic"
Heathkit had an amp and there were quadrophonic album pressings.
news:tp0uv4$23lge$1...@dont-email.me:
Heathkit had an amp and there were quadrophonic album pressings.
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