What specific benefits does an FM in mono have over one in stereo in terms of signal and reach?
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FM stereo vs. mono
- Thread starter ajhenderson
- Start date
E
EasyPeazy
Guest
> What specific benefits does an FM in mono have over one in
> stereo in terms of signal and reach?
>
Not sure about signal and reach, but you wouldn't have to devote 9% modulation to the stereo pilot. That would mean 9% more modulation for loudness.
> stereo in terms of signal and reach?
>
Not sure about signal and reach, but you wouldn't have to devote 9% modulation to the stereo pilot. That would mean 9% more modulation for loudness.
C
CW
Guest
> > What specific benefits does an FM in mono have over one in
>
> > stereo in terms of signal and reach?
> >
> Not sure about signal and reach, but you wouldn't have to
> devote 9% modulation to the stereo pilot. That would mean
> 9% more modulation for loudness.
Actually the L-R subcarrier is no longer there in Mono so that helps a little, too...the figure I keep hearing is 23db S/N but that may be true only when comparing it on the fringe when you have a noisy stereo signal vs mono (because FM stereo uses an AM component for the L-R). As for reach, I really have not noticed much difference between mono and stereo signals at the same height, ERP, etc. Anyway most car radios blend to mono before the signal gets too noisy anyway..except for those aftermarket radios with a stereo/mono switch.
>
> > stereo in terms of signal and reach?
> >
> Not sure about signal and reach, but you wouldn't have to
> devote 9% modulation to the stereo pilot. That would mean
> 9% more modulation for loudness.
Actually the L-R subcarrier is no longer there in Mono so that helps a little, too...the figure I keep hearing is 23db S/N but that may be true only when comparing it on the fringe when you have a noisy stereo signal vs mono (because FM stereo uses an AM component for the L-R). As for reach, I really have not noticed much difference between mono and stereo signals at the same height, ERP, etc. Anyway most car radios blend to mono before the signal gets too noisy anyway..except for those aftermarket radios with a stereo/mono switch.
> ..FM stereo uses an AM component for the L-R.
___________
The L-R baseband spectrum is generated by a double-sideband, suppressed carrier AM process, but then that spectrum is transmitted/received as pure FM. Consider that the synchronous AM noise spec of a modern FM stereo analog broadcast tx is 50 dB or better, which would not be possible if L-R was transmitted by AM.
The 23 dB worse noise floor in FM stereo is the result of the greater r-f bandwidth needed to transmit it, and the distribution of noise in that spectrum.
RF (Harris Appl Engr, retired)
___________
The L-R baseband spectrum is generated by a double-sideband, suppressed carrier AM process, but then that spectrum is transmitted/received as pure FM. Consider that the synchronous AM noise spec of a modern FM stereo analog broadcast tx is 50 dB or better, which would not be possible if L-R was transmitted by AM.
The 23 dB worse noise floor in FM stereo is the result of the greater r-f bandwidth needed to transmit it, and the distribution of noise in that spectrum.
RF (Harris Appl Engr, retired)
W
webcastboy
Guest
> > ..FM stereo uses an AM component for the L-R.
> ___________
>
> The L-R baseband spectrum is generated by a double-sideband,
> suppressed carrier AM process, but then that spectrum is
> transmitted/received as pure FM. Consider that the
> synchronous AM noise spec of a modern FM stereo analog
> broadcast tx is 50 dB or better, which would not be possible
> if L-R was transmitted by AM.
>
> The 23 dB worse noise floor in FM stereo is the result of
> the greater r-f bandwidth needed to transmit it, and the
> distribution of noise in that spectrum.
>
> RF (Harris Appl Engr, retired)
>
FM mono also tends to be less susceptible to perceived multipath interference.
However, many listeners are trained to look for that little stereo pilot light to glow on their radio when they've got you tuned in, so the lack of it can throw them somewhat. This can become especially relevant when you're dealing with potential advertisters/underwriters - don't want them to become spooked over nothing just cause they can't see a stereo pilot light.
OTOH, don't want them to have a crappy radio that can't get a clean static-free stereo reception, either...as already mentioned, stereo has a higher noise floor.
However, if you're wondering about how to wire a studio facility and studio-to-transmitter link, always do all your wiring in stereo; make the stereo/mono decision at the transmitter. You don't want to limit yourself today and find you need to re-do a lot of work tomorrow...especially since HD Radio (or something else digital) will be coming your way sooner or later and there is no benefit at all to being mono in HD Radio.
Generally speaking, staying in mono is not worth the hit in listener perception unless the vast majority (at least 90%) of your programming is in mono anyways. For example, I know of only two FM stations in Boston that broadcast in mono; both are public radio outlets that switch to mono for news programs but stay in stereo for music or for more-music-ish news programs.
> ___________
>
> The L-R baseband spectrum is generated by a double-sideband,
> suppressed carrier AM process, but then that spectrum is
> transmitted/received as pure FM. Consider that the
> synchronous AM noise spec of a modern FM stereo analog
> broadcast tx is 50 dB or better, which would not be possible
> if L-R was transmitted by AM.
>
> The 23 dB worse noise floor in FM stereo is the result of
> the greater r-f bandwidth needed to transmit it, and the
> distribution of noise in that spectrum.
>
> RF (Harris Appl Engr, retired)
>
FM mono also tends to be less susceptible to perceived multipath interference.
However, many listeners are trained to look for that little stereo pilot light to glow on their radio when they've got you tuned in, so the lack of it can throw them somewhat. This can become especially relevant when you're dealing with potential advertisters/underwriters - don't want them to become spooked over nothing just cause they can't see a stereo pilot light.
OTOH, don't want them to have a crappy radio that can't get a clean static-free stereo reception, either...as already mentioned, stereo has a higher noise floor.
However, if you're wondering about how to wire a studio facility and studio-to-transmitter link, always do all your wiring in stereo; make the stereo/mono decision at the transmitter. You don't want to limit yourself today and find you need to re-do a lot of work tomorrow...especially since HD Radio (or something else digital) will be coming your way sooner or later and there is no benefit at all to being mono in HD Radio.
Generally speaking, staying in mono is not worth the hit in listener perception unless the vast majority (at least 90%) of your programming is in mono anyways. For example, I know of only two FM stations in Boston that broadcast in mono; both are public radio outlets that switch to mono for news programs but stay in stereo for music or for more-music-ish news programs.
> Generally speaking, staying in mono is not worth the hit in
> listener perception unless the vast majority (at least 90%)
> of your programming is in mono anyways. For example, I know
> of only two FM stations in Boston that broadcast in mono;
> both are public radio outlets that switch to mono for news
> programs but stay in stereo for music or for more-music-ish
> news programs.
Isn't 'TKK in mono, seeing that their mostly syndicated fare comes off the sat in mono? This would seem to make sense to me, but maybe not.
> listener perception unless the vast majority (at least 90%)
> of your programming is in mono anyways. For example, I know
> of only two FM stations in Boston that broadcast in mono;
> both are public radio outlets that switch to mono for news
> programs but stay in stereo for music or for more-music-ish
> news programs.
Isn't 'TKK in mono, seeing that their mostly syndicated fare comes off the sat in mono? This would seem to make sense to me, but maybe not.
C
cranium
Guest
I've never owned a Chrysler or Dodge...but I understood at one time that their radios depended upon the stereo pilot to detect before the radio would "land."
I could always be wrong.
I could always be wrong.
A
Andy_Brown
Guest
> I've never owned a Chrysler or Dodge...but I understood at
> one time that their radios depended upon the stereo pilot to
> detect before the radio would "land."
>
> I could always be wrong.
>
If memory serves, that was one of many car rcvrs that had a distant/local
switch and in the local mode, if there was no detectable pilot, it would
mute the radio. These switches were called different things depending on the
brand (automute, etc.). Some 70's home consumer tuners/receivers also had this.<P ID="signature">______________
Electricity is really just organized lightning.
~George Carlin</P>
> one time that their radios depended upon the stereo pilot to
> detect before the radio would "land."
>
> I could always be wrong.
>
If memory serves, that was one of many car rcvrs that had a distant/local
switch and in the local mode, if there was no detectable pilot, it would
mute the radio. These switches were called different things depending on the
brand (automute, etc.). Some 70's home consumer tuners/receivers also had this.<P ID="signature">______________
Electricity is really just organized lightning.
~George Carlin</P>
W
westlife
Guest
> However, many listeners are trained to look for that little
> stereo pilot light to glow on their radio when they've got
> you tuned in, so the lack of it can throw them somewhat.
> This can become especially relevant when you're dealing with
> potential advertisters/underwriters - don't want them to
> become spooked over nothing just cause they can't see a
> stereo pilot light.
This isn't much of an issue on today's car radios, as many aftermarket radios have such a small "ST" indicator that it's nearly indistinguishable, and many factory-equipped radios don't have any FM Stereo indicator at all. Also, many of these radios will blend even moderately strong signals to mono, so especially if you're a "rimshot", most of your listeners will already be hearing your audio in mono anyway. There are also radios which have too sharp of a threshold on the blend-to-mono feature and constant whip back and forth between mono and stereo, in which case a signal that's mono to begin with would sound much more consistent and much less annoying.
A station with a big centrally-located signal covering flat terrain will have little reason to switch to mono. But a rimshot covering mountainous terrain would have a lot more to gain from switching to mono, even with a music format. Then there are especially challenging situations, like KOIT in San Francisco, where a simulcast on AM actually makes the most sense.
<P ID="signature">______________
It's a common mistake to not use punctuation in its proper form.
<a target="_blank" href=http://www.cgl.uwaterloo.ca/~csk/its.html>Be kind to your friend, the apostrophe.</a></P>
> stereo pilot light to glow on their radio when they've got
> you tuned in, so the lack of it can throw them somewhat.
> This can become especially relevant when you're dealing with
> potential advertisters/underwriters - don't want them to
> become spooked over nothing just cause they can't see a
> stereo pilot light.
This isn't much of an issue on today's car radios, as many aftermarket radios have such a small "ST" indicator that it's nearly indistinguishable, and many factory-equipped radios don't have any FM Stereo indicator at all. Also, many of these radios will blend even moderately strong signals to mono, so especially if you're a "rimshot", most of your listeners will already be hearing your audio in mono anyway. There are also radios which have too sharp of a threshold on the blend-to-mono feature and constant whip back and forth between mono and stereo, in which case a signal that's mono to begin with would sound much more consistent and much less annoying.
A station with a big centrally-located signal covering flat terrain will have little reason to switch to mono. But a rimshot covering mountainous terrain would have a lot more to gain from switching to mono, even with a music format. Then there are especially challenging situations, like KOIT in San Francisco, where a simulcast on AM actually makes the most sense.
<P ID="signature">______________
It's a common mistake to not use punctuation in its proper form.
<a target="_blank" href=http://www.cgl.uwaterloo.ca/~csk/its.html>Be kind to your friend, the apostrophe.</a></P>
J
joshleblanc
Guest
> > I've never owned a Chrysler or Dodge...but I understood at
>
> > one time that their radios depended upon the stereo pilot
> to
> > detect before the radio would "land."
> >
> > I could always be wrong.
> >
>
> If memory serves, that was one of many car rcvrs that had a
> distant/local
> switch and in the local mode, if there was no detectable
> pilot, it would
> mute the radio. These switches were called different things
> depending on the
> brand (automute, etc.). Some 70's home consumer
> tuners/receivers also had this.
>
I have 6 month old Denon Home Theater Receiver that does that (auto muting weak mono signals), it also has a blend to mono option on noisy distant stereo signals, for a new model it has excellent sensitivity/selectivity.
>
> > one time that their radios depended upon the stereo pilot
> to
> > detect before the radio would "land."
> >
> > I could always be wrong.
> >
>
> If memory serves, that was one of many car rcvrs that had a
> distant/local
> switch and in the local mode, if there was no detectable
> pilot, it would
> mute the radio. These switches were called different things
> depending on the
> brand (automute, etc.). Some 70's home consumer
> tuners/receivers also had this.
>
I have 6 month old Denon Home Theater Receiver that does that (auto muting weak mono signals), it also has a blend to mono option on noisy distant stereo signals, for a new model it has excellent sensitivity/selectivity.
D
dickfry
Guest
> What specific benefits does an FM in mono have over one in
> stereo in terms of signal and reach?
>
I have done A-B tests with the only change being turning the stereo generator off in the hilly terrain of a West Coast city. There was a dramatic improvement in noise and multipath when the transmitted signal went from stereo to mono. Many areas that were unlistenable in stereo were clear in mono.
This is with a small signal and relatively low antenna. For a full Class B or C station this probably would not be an issue. But if a Class A or a higher power rimshot has fringe reception with a large population, it makes sense to look at it.
Most people can't tell the difference between stereo and mono. If it has two or more speakers, it must be stereo. Go ahead, ask people what they think stereo is if you want to be discouraged about the technical knowledge of your neighbors.
I'm not aware of any current car radios that refuse to lock onto a mono signal. There are better ways to sense RF level. This is an bit of urban myth used to frighten the uneducated, and it's tiring to see it trotted out again and again as if it actually mattered. Certainly this fairy tale is not a good reason to refuse to consider mono on a bad FM signal.
Mono good. Stereo good too. Good mono signal better than bad stereo signal.
Also, stereo hiss is not an issue with mono. There's much less noise in mono than stereo outside the prime reception area.
Engineer: test the A-B test yourself on an actual station. The reality defies a lot of the supposed 'wisdom' being passed off by 'seasoned engineers' who have never actually taken the time to prove the facts that they so happily spout as gospel because they misread something in an Orban manual a decade or two back.
-Real World Dick
> stereo in terms of signal and reach?
>
I have done A-B tests with the only change being turning the stereo generator off in the hilly terrain of a West Coast city. There was a dramatic improvement in noise and multipath when the transmitted signal went from stereo to mono. Many areas that were unlistenable in stereo were clear in mono.
This is with a small signal and relatively low antenna. For a full Class B or C station this probably would not be an issue. But if a Class A or a higher power rimshot has fringe reception with a large population, it makes sense to look at it.
Most people can't tell the difference between stereo and mono. If it has two or more speakers, it must be stereo. Go ahead, ask people what they think stereo is if you want to be discouraged about the technical knowledge of your neighbors.
I'm not aware of any current car radios that refuse to lock onto a mono signal. There are better ways to sense RF level. This is an bit of urban myth used to frighten the uneducated, and it's tiring to see it trotted out again and again as if it actually mattered. Certainly this fairy tale is not a good reason to refuse to consider mono on a bad FM signal.
Mono good. Stereo good too. Good mono signal better than bad stereo signal.
Also, stereo hiss is not an issue with mono. There's much less noise in mono than stereo outside the prime reception area.
Engineer: test the A-B test yourself on an actual station. The reality defies a lot of the supposed 'wisdom' being passed off by 'seasoned engineers' who have never actually taken the time to prove the facts that they so happily spout as gospel because they misread something in an Orban manual a decade or two back.
-Real World Dick
One also has to question if the full 15Khz bandwidth is really necessary. Just look at the additional number of stations we could have if we reduced the FM transmitted spectrum to, say 7.5 KHz in addition to dropping stereo! Everyone knows the audience knows nothing about fidelity, and most people in thier vehicles have the bass so jacked up they won't even notice the lack of high-end.
<P ID="signature">______________
Never hold a cat and a dustbuster at the same time.</P>
<P ID="signature">______________
Never hold a cat and a dustbuster at the same time.</P>
R
RadioDoc
Guest
>
> Engineer: test the A-B test yourself on an actual station.
> The reality defies a lot of the supposed 'wisdom' being
> passed off by 'seasoned engineers' who have never actually
> taken the time to prove the facts that they so happily spout
> as gospel because they misread something in an Orban manual
> a decade or two back.
>
>
> -Real World Dick
>
I agree with you 100%. I have an low power Aux transmitter that suffers from an unfortunate antenna location (multipath city). I run that site in mono, and the signal improvement is dramatic. It's a music station, and I've never gotten a single comment about the lack of a stereo light.<P ID="signature">______________
</P>
> Engineer: test the A-B test yourself on an actual station.
> The reality defies a lot of the supposed 'wisdom' being
> passed off by 'seasoned engineers' who have never actually
> taken the time to prove the facts that they so happily spout
> as gospel because they misread something in an Orban manual
> a decade or two back.
>
>
> -Real World Dick
>
I agree with you 100%. I have an low power Aux transmitter that suffers from an unfortunate antenna location (multipath city). I run that site in mono, and the signal improvement is dramatic. It's a music station, and I've never gotten a single comment about the lack of a stereo light.<P ID="signature">______________
</P>
C
CW
Guest
> One also has to question if the full 15Khz bandwidth is
> really necessary. Just look at the additional number of
> stations we could have if we reduced the FM transmitted
> spectrum to, say 7.5 KHz in addition to dropping stereo!
> Everyone knows the audience knows nothing about fidelity,
> and most people in thier vehicles have the bass so jacked up
> they won't even notice the lack of high-end.
Hmmmm if I didnt know better, you sound like Jeff Littlejohn
Actually your math is a bit off anyway..FM bandwidth is much more than just the max audio...FM bandwidth equation is BW=2x(highest freq of modulation + deviation) so for a 15 khz audio b/w and a 75 kHz deviation it is 180 kHz..(2x 15 + 2x75)
IF we dropped deviation to 50kHz that would reduce RF BW to 130 kHz...still too much to drop spacing from 200 kHz to 100 kHz..if we drop dev and audio both by half, we can make it sound like an AM station
The FM deviation was determined to be as it is for specific reasons (modulation index and capture effect as well as subcarrier requirements and other issues)..
TV is only 25 kHz dev but its audio is not as good as FM broadcast....(not bad but not as good!)...
BUT I will agree with your last sentence
> really necessary. Just look at the additional number of
> stations we could have if we reduced the FM transmitted
> spectrum to, say 7.5 KHz in addition to dropping stereo!
> Everyone knows the audience knows nothing about fidelity,
> and most people in thier vehicles have the bass so jacked up
> they won't even notice the lack of high-end.
Hmmmm if I didnt know better, you sound like Jeff Littlejohn
Actually your math is a bit off anyway..FM bandwidth is much more than just the max audio...FM bandwidth equation is BW=2x(highest freq of modulation + deviation) so for a 15 khz audio b/w and a 75 kHz deviation it is 180 kHz..(2x 15 + 2x75)
IF we dropped deviation to 50kHz that would reduce RF BW to 130 kHz...still too much to drop spacing from 200 kHz to 100 kHz..if we drop dev and audio both by half, we can make it sound like an AM station
The FM deviation was determined to be as it is for specific reasons (modulation index and capture effect as well as subcarrier requirements and other issues)..
TV is only 25 kHz dev but its audio is not as good as FM broadcast....(not bad but not as good!)...
BUT I will agree with your last sentence
A
Andy_Brown
Guest
> > What specific benefits does an FM in mono have over one in
> > stereo in terms of signal and reach?
>
> Most people can't tell the difference between stereo and
> mono. If it has two or more speakers, it must be stereo. Go
> ahead, ask people what they think stereo is if you want to
> be discouraged about the technical knowledge of your
> neighbors.
As an engineer, I don't disagree with the analyses in this thread.
Droll as it all sounds, everyone here pretty much understands the fragility
of an envelope with sidebands, etc. etc.
I think there is a point not being made. and the musician and listener within me wishes to make it. I chose this place to post not because of any other reason than the paragraph(s) above that I quoted.
First, in the non engineering world of marketing, "reach" has a different meaning than it does to us. Keep that in mind. To them it's a word that indicates how many potential listeners there are, not how many uvolts are present or what the S/N is, etc. etc.
Yes, you are correct when you point out the general knowledge of the consuming public on stereo and hi fidelity. But they DO know that when given the option of hearing (pardon my dated example) Jimmy Page's guitar solo in Whole Lotta Love moving from left to right and back OR barely hearing it at all because of the phase cancellation in mono, guess which one they will choose.
And having worked for teakettle 1KW and 5kw AM'ers in my infancy, it is a fact that people will indeed put up with inferior quality of signal if the content is something they can not get elsewhere. This has become less and less of an issue as the industry has become commoditized and so many small independent thinking outlets have been forced to serve up the same baloney that the bigger signals carry.
So if you're competing with the same garbage music as the 100kw Class C's and not technically capable of covering in stereo, mono may give you a larger "reach" but if those folks can get the same programming in stereo, that's where they will be listening. Then again, if you offer unique programming that listeners want to hear, it makes no sense to take material created in stereo and downgrade it. So switching to mono may have technical benefits, but most of the radio world revolves around listenership and if the programming is music and you change the listener experience there may be a negative to consider. Frankly, that's why so few FM stations even consider mono as relevant any more. Stereo broadcasting was authorized in 1963 and is considered the norm (for a short while longer anyway).
This will all soon be a moot point when the U.S. finally comes up to speed on digital broadcasting.
It's great being an engineer. It's fed me all these years. But it's only part of what made radio great (until the government ruined it).
<P ID="signature">______________
Electricity is really just organized lightning.
~George Carlin</P>
> > stereo in terms of signal and reach?
>
> Most people can't tell the difference between stereo and
> mono. If it has two or more speakers, it must be stereo. Go
> ahead, ask people what they think stereo is if you want to
> be discouraged about the technical knowledge of your
> neighbors.
As an engineer, I don't disagree with the analyses in this thread.
Droll as it all sounds, everyone here pretty much understands the fragility
of an envelope with sidebands, etc. etc.
I think there is a point not being made. and the musician and listener within me wishes to make it. I chose this place to post not because of any other reason than the paragraph(s) above that I quoted.
First, in the non engineering world of marketing, "reach" has a different meaning than it does to us. Keep that in mind. To them it's a word that indicates how many potential listeners there are, not how many uvolts are present or what the S/N is, etc. etc.
Yes, you are correct when you point out the general knowledge of the consuming public on stereo and hi fidelity. But they DO know that when given the option of hearing (pardon my dated example) Jimmy Page's guitar solo in Whole Lotta Love moving from left to right and back OR barely hearing it at all because of the phase cancellation in mono, guess which one they will choose.
And having worked for teakettle 1KW and 5kw AM'ers in my infancy, it is a fact that people will indeed put up with inferior quality of signal if the content is something they can not get elsewhere. This has become less and less of an issue as the industry has become commoditized and so many small independent thinking outlets have been forced to serve up the same baloney that the bigger signals carry.
So if you're competing with the same garbage music as the 100kw Class C's and not technically capable of covering in stereo, mono may give you a larger "reach" but if those folks can get the same programming in stereo, that's where they will be listening. Then again, if you offer unique programming that listeners want to hear, it makes no sense to take material created in stereo and downgrade it. So switching to mono may have technical benefits, but most of the radio world revolves around listenership and if the programming is music and you change the listener experience there may be a negative to consider. Frankly, that's why so few FM stations even consider mono as relevant any more. Stereo broadcasting was authorized in 1963 and is considered the norm (for a short while longer anyway).
This will all soon be a moot point when the U.S. finally comes up to speed on digital broadcasting.
It's great being an engineer. It's fed me all these years. But it's only part of what made radio great (until the government ruined it).
<P ID="signature">______________
Electricity is really just organized lightning.
~George Carlin</P>
> > One also has to question if the full 15Khz bandwidth is
> > really necessary. Just look at the additional number of
> > stations we could have if we reduced the FM transmitted
> > spectrum to, say 7.5 KHz in addition to dropping stereo!
> > Everyone knows the audience knows nothing about fidelity,
> > and most people in thier vehicles have the bass so jacked
> up
> > they won't even notice the lack of high-end.
>
> Hmmmm if I didnt know better, you sound like Jeff Littlejohn
>
>
> Actually your math is a bit off anyway..FM bandwidth is much
> more than just the max audio...FM bandwidth equation is
> BW=2x(highest freq of modulation + deviation) so for a 15
> khz audio b/w and a 75 kHz deviation it is 180 kHz..(2x 15 +
> 2x75)
>
> IF we dropped deviation to 50kHz that would reduce RF BW to
> 130 kHz...still too much to drop spacing from 200 kHz to 100
> kHz..if we drop dev and audio both by half, we can make it
> sound like an AM station
>
> The FM deviation was determined to be as it is for specific
> reasons (modulation index and capture effect as well as
> subcarrier requirements and other issues)..
> TV is only 25 kHz dev but its audio is not as good as FM
> broadcast....(not bad but not as good!)...
>
> BUT I will agree with your last sentence
>
But did you notice that the sarcasm pilot LED was lit during my post?
<P ID="signature">______________
Never hold a cat and a dustbuster at the same time.</P>
> > really necessary. Just look at the additional number of
> > stations we could have if we reduced the FM transmitted
> > spectrum to, say 7.5 KHz in addition to dropping stereo!
> > Everyone knows the audience knows nothing about fidelity,
> > and most people in thier vehicles have the bass so jacked
> up
> > they won't even notice the lack of high-end.
>
> Hmmmm if I didnt know better, you sound like Jeff Littlejohn
>
>
> Actually your math is a bit off anyway..FM bandwidth is much
> more than just the max audio...FM bandwidth equation is
> BW=2x(highest freq of modulation + deviation) so for a 15
> khz audio b/w and a 75 kHz deviation it is 180 kHz..(2x 15 +
> 2x75)
>
> IF we dropped deviation to 50kHz that would reduce RF BW to
> 130 kHz...still too much to drop spacing from 200 kHz to 100
> kHz..if we drop dev and audio both by half, we can make it
> sound like an AM station
>
> The FM deviation was determined to be as it is for specific
> reasons (modulation index and capture effect as well as
> subcarrier requirements and other issues)..
> TV is only 25 kHz dev but its audio is not as good as FM
> broadcast....(not bad but not as good!)...
>
> BUT I will agree with your last sentence
>
But did you notice that the sarcasm pilot LED was lit during my post?
<P ID="signature">______________
Never hold a cat and a dustbuster at the same time.</P>
For example, I know
> of only two FM stations in Boston that broadcast in mono;
> both are public radio outlets that switch to mono for news
> programs but stay in stereo for music or for more-music-ish
> news programs.
>
I'm pretty sure hip hop station WJMN (in Boston) is in mono, but they are running the pilot becuase I can't hear a difference when switching from stereo to mono.
> of only two FM stations in Boston that broadcast in mono;
> both are public radio outlets that switch to mono for news
> programs but stay in stereo for music or for more-music-ish
> news programs.
>
I'm pretty sure hip hop station WJMN (in Boston) is in mono, but they are running the pilot becuase I can't hear a difference when switching from stereo to mono.
There are still reasons to be concerned with both Stereo and Mono FM b-casts
IMHO it is still wise to be concerned with quality of the mono signal on any broadcast that can be heard in both mono and stereo.
In the days when stereo reel decks and cart machines were the norm, while listening in mono you could literally tell just by the audio quality when any of those sources were in need of realignment or replacement of worn out heads and rollers.
Yes we’ve transitioned over to digital technology now, but I still think it’s still good to keep an ear on the mono quality, especially for stations still playing older music. You may not always be able to judge the mastering quality from analog master tapes to CD’s by the record companies, unless you listen in mono.
I’ve heard a few songs on commercially released CD’s from the 1970’s that sound good in Stereo. But in mono, the wow effects are so bad I’d swear the CD was mastered from a cassette tape! Try listening to “I’m Still in Love with You” by Al Green, “Midnight Train to Georgia” from Gladys Knight / The Pips or almost anything from Chic, in mono. I have quite a few copies of the Gladys Knight song on CD’s released by various companies. When played in mono, some copies are excellent, while others sound as I have described above.
I’m sure 20 to 40 years from now, when music up to the 1980’s has been permanently shelved by radio, we can forget about the mono audio quality altogether.
R
> So
> switching to mono may have technical benefits, but most of
> the radio world revolves around listenership and if the
> programming is music and you change the listener experience
> there may be a negative to consider. Frankly, that's why so
> few FM stations even consider mono as relevant any more.
> Stereo broadcasting was authorized in 1963 and is considered
> the norm (for a short while longer anyway).
IMHO it is still wise to be concerned with quality of the mono signal on any broadcast that can be heard in both mono and stereo.
In the days when stereo reel decks and cart machines were the norm, while listening in mono you could literally tell just by the audio quality when any of those sources were in need of realignment or replacement of worn out heads and rollers.
Yes we’ve transitioned over to digital technology now, but I still think it’s still good to keep an ear on the mono quality, especially for stations still playing older music. You may not always be able to judge the mastering quality from analog master tapes to CD’s by the record companies, unless you listen in mono.
I’ve heard a few songs on commercially released CD’s from the 1970’s that sound good in Stereo. But in mono, the wow effects are so bad I’d swear the CD was mastered from a cassette tape! Try listening to “I’m Still in Love with You” by Al Green, “Midnight Train to Georgia” from Gladys Knight / The Pips or almost anything from Chic, in mono. I have quite a few copies of the Gladys Knight song on CD’s released by various companies. When played in mono, some copies are excellent, while others sound as I have described above.
I’m sure 20 to 40 years from now, when music up to the 1980’s has been permanently shelved by radio, we can forget about the mono audio quality altogether.
R
> So
> switching to mono may have technical benefits, but most of
> the radio world revolves around listenership and if the
> programming is music and you change the listener experience
> there may be a negative to consider. Frankly, that's why so
> few FM stations even consider mono as relevant any more.
> Stereo broadcasting was authorized in 1963 and is considered
> the norm (for a short while longer anyway).
W
webcastboy
Guest
> Isn't 'TKK in mono, seeing that their mostly syndicated fare
> comes off the sat in mono? This would seem to make sense to
> me, but maybe not.
>
You'd think 96.9 would be in mono, but nope - they're in stereo. I think it's because a lot of their commercials are in stereo, and IIRC the Imus in the Morning show is in stereo with some of the peanut gallery being panned left and right. I vaguely remember that from when Imus was on 103.7 in Rhode Island.
Although some of the commercials I've heard on WTKK are the most hideous audio quality. One I heard sounded like a 16kbps MP3...ugh!
> comes off the sat in mono? This would seem to make sense to
> me, but maybe not.
>
You'd think 96.9 would be in mono, but nope - they're in stereo. I think it's because a lot of their commercials are in stereo, and IIRC the Imus in the Morning show is in stereo with some of the peanut gallery being panned left and right. I vaguely remember that from when Imus was on 103.7 in Rhode Island.
Although some of the commercials I've heard on WTKK are the most hideous audio quality. One I heard sounded like a 16kbps MP3...ugh!
> I agree with you 100%. I have an low power Aux transmitter
> that suffers from an unfortunate antenna location (multipath
> city). I run that site in mono, and the signal improvement
> is dramatic. It's a music station, and I've never gotten a
> single comment about the lack of a stereo light.
>
Is it WXSS or WMYX that is signal challenged on the aux. tower? I know I've had problems listening to WMYX while driving along I-43 around downtown Milwaukee when they transmit on the primary tower.
> that suffers from an unfortunate antenna location (multipath
> city). I run that site in mono, and the signal improvement
> is dramatic. It's a music station, and I've never gotten a
> single comment about the lack of a stereo light.
>
Is it WXSS or WMYX that is signal challenged on the aux. tower? I know I've had problems listening to WMYX while driving along I-43 around downtown Milwaukee when they transmit on the primary tower.
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