How noisy is it?

[Greg Strickland]

My opinion-

1. Receiver manufacturers decision making was probably not changed by NRSC.
2. Radio station multi-band audio processing has as much impact on the high end as a fixed pre-emphasis curve. Many stations already had similar fixed EQ dialed in prior to NRSC suggested pre-emphasis.
3. Some may have felt 5 Khz or 6 Khz audio bandwidth sounded better on most radios. It may in fact have sounded better; depending on how the audio processing was adjusted before the switch to 5 KHz or 6 kHz was made.

Could be my personality and ego driving this opinion... but I truly believe most of the audio quality problems of radio (AM or FM) are caused by the people adjusting or directing audio processing. It's been a long time since the technology itself was impairing audio quality.

 

[boombox4]

My opinion-

1. Receiver manufacturers decision making was probably not changed by NRSC.
2. Radio station multi-band audio processing has as much impact on the high end as a fixed pre-emphasis curve. Many stations already had similar fixed EQ dialed in prior to NRSC suggested pre-emphasis.
3. Some may have felt 5 Khz or 6 Khz audio bandwidth sounded better on most radios. It may in fact have sounded better; depending on how the audio processing was adjusted before the switch to 5 KHz or 6 kHz was made.

Could be my personality and ego driving this opinion... but I truly believe most of the audio quality problems of radio (AM or FM) are caused by the people adjusting or directing audio processing. It's been a long time since the technology itself was impairing audio quality.

I wonder how much of it is a given cluster's lack of concern over AM station audio. In the 1980's there was a local station that was the AM poor sister to an FM -- it still had listeners, though, as it was well known in r o c k music and alternative music circles. The audio was lacking, sadly enough. The current version of the station (they changed owners a few years ago) sounds better.

 

[kevtronics]

Could be my personality and ego driving this opinion... but I truly believe most of the audio quality problems of radio (AM or FM) are caused by the people adjusting or directing audio processing. It's been a long time since the technology itself was impairing audio quality.

Also the poor design of many AM tuners causes lots of distortion when the negative modulation exceeds 95%, but yet many stations would rather squeeze out that extra 5% of modulation than have much cleaner-sounding audio.

Now that so many radios (even very cheap ones) are DSP-based, it would be trivial to implement a synchronous detector to eliminate this problem -- and to also get rid of that annoying "Daffy Duck" distortion during directional signal nulls, selective fading, and groundwave/skywave cancellation -- but they fail to do so.

Even the radio in my 2018 VW Jetta, which must have a synchronous detector in it somewhere because it supports HD Radio on AM, sounds like it uses a plain envelope detector for analog AM signals. But I recently put a Sansui TU-S77AMX tuner from 1983 with synchronous detector and multi-system AM Stereo into my home stereo system, and it is astonishing how much cleaner it makes AM sound, even under adverse reception conditions.

 

[wadio]

I'll bet most car makers don't put any effort into making AM listenable in their cars. The AM in my vehicle emits a loud high-pitched sound when I take my foot off the brake pedal. When I took it to the dealer for them to try to fix (which they never did) they loaned me a different model brand new car that had very bad engine ignition interference on AM. I think whether AM is viable in late model cars is hit or miss.

 

[vchimpanzee]

I'll bet most car makers don't put any effort into making AM listenable in their cars. The AM in my vehicle emits a loud high-pitched sound when I take my foot off the brake pedal.

I've had the problem when I put my foot on the brake pedal. Ever since I got a new alternator, I don't seem to have as much interference.

 

[kenglish]

Is it just me, or has anyone else noticed....?:
Seems like when a totally brand new station comes on the air, and the equipment vendors send their grey-haired guys to help put it together, and the pocket-protector consulting engineers get done with it, it sounds absolutely fantastic for a while.
Then, as people start diddling with it, and letting someone sell them the latest "boxes", it starts to sound like "everybody else".
Even back in the 70's and 80's, I noticed this...those were my favorite stations, until they stopped sounding good.
Of course, most of those guys retired or died, taking their ears, their tricks and much of their knowledge with them.

 

[Oldie919]

Is it just me, or has anyone else noticed....?:
Seems like when a totally brand new station comes on the air, and the equipment vendors send their grey-haired guys to help put it together, and the pocket-protector consulting engineers get done with it, it sounds absolutely fantastic for a while.
Then, as people start diddling with it, and letting someone sell them the latest "boxes", it starts to sound like "everybody else".
Even back in the 70's and 80's, I noticed this...those were my favorite stations, until they stopped sounding good.
Of course, most of those guys retired or died, taking their ears, their tricks and much of their knowledge with them.

Several stations in my area -- that were once considered "creme de la creme" when it came to super clean audio -- fell victim to "tweaking"....
Trying to get that last fraction of a db of gain to get a leg up on their competition...
Overall.....IMHO, it has failed miserably!!
One or two of the stations have made some POSITIVE adjustments to their audio chain over the last few months.....and DO sound "better"....
But NOTHING compared to their sound of, say, a decade or so ago.....
Re: "....the latest 'boxes'...." --- Despite what the manufacturer may claim....YES....you CAN make the "Super XYZ" sound BAD.....if you "tweak' it enough!!!
The finest factory-tuned sports car will start performing badly if it's "tweaked" the wrong way, by people who try to maximize what I call the "Tim Taylor Effect" (after Tim Allen's "Home Improvement" show......):
"MORE POWER!!! MORE POWER!!"
And......yeah, OK..... I'm one of those "gray-haired guys"......and, trust me, I earned every one of 'em!!

 

[wadio]

I've always felt that processing belongs in the receiver - not at the station. It should be user settable with defaults according to the intended environment. When you're in a noisy car you need lots of compression. At home you don't.

Back in the day that would have been cost prohibitive, but today it would require a relatively inexpensive chip.

Unfortunately that ship has sailed.

 

[TheBigA]

Unfortunately that ship has sailed.

Huh? If what you're saying is true, it should apply to any audio source, whether it's an FM radio, a smart speaker, or a home theater? No?

 

[davideduardo]

I've always felt that processing belongs in the receiver - not at the station. It should be user settable with defaults according to the intended environment. When you're in a noisy car you need lots of compression. At home you don't.

The original purpose of processing was to remain legal: peak limiting.

Then processing development allowed leveling (AGC) to make listening levels consistent, and not widely different from peaks to soft points.

Both of these have to be done at the transmission end to avoid illegal peaks and to keep low level audio high enough to be well above the noise floor.

Some stations process too aggressively, but today's digital processors like the current Omnia and Optimod models can be set to be both loud and quite transparent without noticeable artifacts.

While receivers have AGC circuits, that is mostly to compensate for differences in signal strength and not to adjust tone or EQ.

 

[wadio]

Huh? If what you're saying is true, it should apply to any audio source, whether it's an FM radio, a smart speaker, or a home theater? No?

Yes! In fact today's streaming content is often what radio would be like with NO processing. (As David points out, some processing is necessary for broadcasting.) On the internet, levels are all over the place. Although I'd say that's getting better I use a software processor on a computer I listen to streaming on at home to keep levels in check.