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Why does FM sound better than AM?

(www.johndcook.com)
259 points zdw | 2 comments | 13 Oct 24 22:32 UTC | HN request time: 0s | source
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Optimal_Persona ◴[14 Oct 24 00:37 UTC] No.41833049[source]▶
Also the audio frequency bandwidth is narrower on AM, so fewer treble frequencies.

TBH I think music from up to the late '60s (especially if originally released in mono) sounds really good, or at least more "era-appropriate" on AM radio. I remember my grandparents tuning in to easy-listening AM stations as I grew up in the '70s and '80s, to my ear Tennessee Ernie Ford's "16 Tons" or a classic Phil Spector "Wall of Sound" production sounds more "right" coming through the AM bands.

And, in the age of cellphone speakers and compressed MP3/Bluetooth codecs - I'm not sure how much people actually care about audio quality.

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1. Johnythree ◴[14 Oct 24 13:38 UTC] No.41837419[source]▶
This is yet another myth:

The "Woolyness" of AM broadcast (at least in America) is due to the stations purposefully tailoring their audio processing to suit typical cheap AM receivers. And this in turn is because designers of cheap AM receivers fit narrow filters instead of using noise reduction techniques, eg a good outside antenna.

There was a period (in the rest of the world) where high quality AM receivers had a narrow/wide switch to give better audio response to stronger signals.

The good news is that modern SDR receivers usually have selectable bandwidth on AM so as to derive the full transmitted audio. And many of these have AM stereo decoders as well.

If you listen to a good quality AM broadcast (eg Gov AM stations in Australia) you will hear audio which are very hard to tell from FM audio.

Go back and read the many high-quality AM tuner articles in the electronic hobby magazines from the past.

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2. elzbardico ◴[15 Oct 24 01:23 UTC] No.41843999[source]▶
Yes, when I was a kid I used to listen to a few AM radios in a Marantz receiver from my dad (not in the US). Well, it was not as good as FM, but basically it was usable as a source of music.

Now, from time to time I buy a cheap portable AM radio, mostly out of nostalgia, but with the excuse of being good emergency preparedness, and the sound is annoyingly bad even with decent headphones.