What did the makers of AM/FM Radios start to make the AM Receivers poor sound?
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AM Radio Receivers
- Thread starter MarioMania
- Start date
Really? This is a simple question
Like newer Radios .. In the 2000's
I have to turn it up to hear it
I have to turn it up to hear it
Well, let's start with YOU, your hearing. Has it changed? Mine has. How much of what you are hearing (or not hearing) is the problem of radio receiver design and construction, and how much is an ear issue?
There have been cheap, shabby radios around for a long time, but "back in the day" the retailers wanted to build a reputation that they were smart enought to know good merchandise from bad so they tended to avoid bad radios. (I'm talking 60 or 70 years back.) The nation had come out of 'The Depression' and WW II and there was a thirst for good merchandise. Well, those of us who are naive want to believe that is how the market has worked at times in our history.)
I had a station owner tell me about the station he and his partner put on the air in a small market in the late 1940s. They had a retailer buy a schedule and had them write copy about a $5.00 radio they were selling... and you could buy it for 5-cents down, and make payments of 5-cents per week. The radio people were taken aback!!! Do you really want to mess with all that paper-work? The store owner smiled and said: If I can get someone into my store every week, every week for a couple of years.... YEAH! Even in 1946 dollars, I suspect a $5 radio was not a prize winner.
In the old days, half of America lived in rural areas. Cheap radios didn't get you what you wanted. You had to have a receiver with some GUTS in it! Today with almost everyone living as "huddled masses" in town and cities and big metro areas, just about any piece of crap will pick up a few stations. And whether you are buying hair dryers, coffee makers, or MP3 players, retailers no longer worry about getting the reputation that they sell cheap junk. They would rather sell a dozen CHEAP radios today than one GOOD radio every five days.
But the big change came back when the FCC rules changed and someone else will have to fill in the date here... maybe the 1980s? In order to crowd more and more stations onto the dial, the FCC told the stations to cut back on their band-pass of audio frequencies on AM radio. If the station can't broadcast really, really great audio, why would anyone make and anyone buy, a really, really great radio? And once the manufacturing and retail industries realized people would settle for second class audio on AM, they decided to try selling receivers with second class sound on the FM side and they found out that consumers wanted economy worse than they wanted quality.
Aren't you glad you asked?
There have been cheap, shabby radios around for a long time, but "back in the day" the retailers wanted to build a reputation that they were smart enought to know good merchandise from bad so they tended to avoid bad radios. (I'm talking 60 or 70 years back.) The nation had come out of 'The Depression' and WW II and there was a thirst for good merchandise. Well, those of us who are naive want to believe that is how the market has worked at times in our history.)
I had a station owner tell me about the station he and his partner put on the air in a small market in the late 1940s. They had a retailer buy a schedule and had them write copy about a $5.00 radio they were selling... and you could buy it for 5-cents down, and make payments of 5-cents per week. The radio people were taken aback!!! Do you really want to mess with all that paper-work? The store owner smiled and said: If I can get someone into my store every week, every week for a couple of years.... YEAH! Even in 1946 dollars, I suspect a $5 radio was not a prize winner.
In the old days, half of America lived in rural areas. Cheap radios didn't get you what you wanted. You had to have a receiver with some GUTS in it! Today with almost everyone living as "huddled masses" in town and cities and big metro areas, just about any piece of crap will pick up a few stations. And whether you are buying hair dryers, coffee makers, or MP3 players, retailers no longer worry about getting the reputation that they sell cheap junk. They would rather sell a dozen CHEAP radios today than one GOOD radio every five days.
But the big change came back when the FCC rules changed and someone else will have to fill in the date here... maybe the 1980s? In order to crowd more and more stations onto the dial, the FCC told the stations to cut back on their band-pass of audio frequencies on AM radio. If the station can't broadcast really, really great audio, why would anyone make and anyone buy, a really, really great radio? And once the manufacturing and retail industries realized people would settle for second class audio on AM, they decided to try selling receivers with second class sound on the FM side and they found out that consumers wanted economy worse than they wanted quality.
Aren't you glad you asked?
If it's a digital SW portable radio, the AM section probably uses the same ceramic filter that the SW section uses (the AM band and SW band use the same IF amp section in most SW radios).
The ceramic filter narrows the bandwidth of signals received, to reduce interference from nearby channels. There are other ways to have narrow selectivity (like Digital signal processing, and crystal and mechanical filters), but the ceramic filter seems to be the most popular way to give a radio better selectivity, probably because it's cheaper.
The plus of having a ceramic filter is that you can listen to a DX station on 760 and not get so much interference from the strong station on 750. The negative is that when you reduce the bandwidth from 8 or 9 khz (like your average GE Superadio probably has) to 6 khz or less, you lose some high fidelity (because the filter is narrowing the bandwidth, cutting out a lot of the highs) and you also can lose some volume.
Ceramic filters are great if you want to DX, or listen to a fringe-area AM station with less local interference. And some radios with ceramic filters don't have bad sound -- but most AM radios that have them tend to have a midrangy or bassy-midrangy tone to the AM sound. Not all ceramic filter supplied radios sound bad. I have a boombox that sounds good on AM, and it has a ceramic filter. I have a walkman style radio that also has one -- AM sounds pretty good on it also.
My take on it is if you want to listen to AM radio with decent fidelity, get a GE Superadio (it uses 4 IF cans to get its selectivity instead of a ceramic filter) or a transistor portable radio made in the 60's or 70's (or even a tube AM radio from earlier). A digital SW portable radio is probably the last radio you'd want to use for pleasant AM listening. Most of them I've heard do not have a full AM sound. Some of them are great for DXing, but don't have great fidelity on AM.
Another trick, try the headphone jack. Most SW portables (including digital SW portables) I've tried have better sound through headphones than they do through their speaker.
Also, like GRC said, I read somewhere that AM stations adopted a standard (maybe in the 80's?) that reduced the bandwidth of their transmissions.
Some of our younger readers, and some who are fans of radio rather than participants, may not quite get the picture of those changes.
The FCC decided to change TRANSMITTER standards so that stations could be "packed closer together" without destroying the signals of each other, so the FCC granted the request of those people drooling over the idea of getting just one more station in the market of their choice. The TRANSMITTERS are not allowed (on AM) to broadcast what we think of as a flat, full frequency range audio.
The receiver industry realized it was a waste of money to build high quality, full fidelity AM receivers. Who would buy them. There would be no high quality, full fidelity AM signals to be receive. Thus the consumer would consider such a receiver to be a waste of money.
Back in the 50s and 60s,... and into the 70s.... there were some bodacious AM signals to be received.
I guess if you want to pay the really big bucks, there are some great FM receivers available today, but in my spare time I wander through the Thrift Stores... thinking that one of these days I will come across a really great AM/FM receiver from the era at a bargain price. (I have one that isn' shabby.... but it is nothing special at picking distant stations out of the noise. But it beats anything I see in the retail stores today.)
All the NRSC did was limit max audio bandwidth on the xmtrs to 10 kHz..but the receivers still were narrow well before that...It did not change same market adjacent channel spacing when that happened...
At 10kHz in a AM Stereo CQUAM AMAX radio, it is hard to tell the difference between an AM and FM signal with the same song and processing done right..
At 10kHz in a AM Stereo CQUAM AMAX radio, it is hard to tell the difference between an AM and FM signal with the same song and processing done right..
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