AM: Some Engineers Just Don’t Know How to Do It - Radio World
I would rather lose a bit on the fringe than lose everyone in the heart of my coverage

Larry Langford is owner of WGTO(AM) and W244ds in Cassopolis, Mich. He has been in radio since 1965. His commentaries on radio issues such as those facing AM owners are a recurring feature. Read his past articles by searching for “Langford.”

I was out of town and looking for a local station to get updates on a delayed NASCAR race. The website gave me a local FM frequency. Great! I tuned it in and all was good. Then for the fun of it I looked to see if this was a translator for an AM station.

Sure enough it was, so I checked the AM. Terrible! The carrier was strong and local, but the sound was mostly mush. I then checked other FM frequencies and found at least two other translators that were coupled to local AM stations, with the same result: The AM side sounded like hypercompressed babble that bore little resemblance to the FM side even though it was the same program. Yes, the AM stations were very LOUD — but not listenable.

It has become clear that the art of audio processing has been scrapped for the new AM goal of fighting noise and pushing coverage by making it loud then making it louder. What happened to engineers who knew how to get the best sound from AM, with all its limitations, without driving people away in droves? Long gone is the era when we understood the compromise of AM processing — the balance between increased coverage with dense modulation versus more relaxed, open sound that meant more time spent listening.

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It seems modern station engineers who apparently know more about computers than RF transmission just order the newest processing box turn it to “flamethrower” and walk away. They will tweak on the FM for hours; but AM gets a fast setup with the knobs on 10.

Yes, the noise floor is very high in most markets, and AM is suffering as a result. But there is a limit to what people will stand for in the way of distortion and zero dynamic range as you try to rise above that noise. Squeezing that extra mile out of the coverage is costing you untold listeners who are inside the noise-free area but still turn you off because the sound is so overprocessed it just plain sucks.

I attended the NAB convention this year and wanted to see the new super processing system that was to be unveiled by one of the big name manufacturers. In an effort to show how much “better “this new system is compared to the old stuff, they set up an A/B comparison. The new system sounded much louder but it sounded so bad that the people I talked to who gave it a listen said the old models sounded much cleaner.

We are definitely going the wrong way. Understand once and for all: AM has challenges and they are serious; but we must stop beating the modulation to death or we will chase away ALL of our listeners to FM. The radios sound bad enough by themselves; we don’t need to increase distortion and muddiness with bad tuning.

If you are tuning up the sound on an AM, try this: Set it up, then go home and listen to nothing for the rest of the evening. Then get up the next day and turn the AM station on. Listen for 15 seconds and ask yourself: Is that good? Is it comfortable, or just loud? Let your ears tell you the truth. If it sounds the least bit distorted or overprocessed, it probably is. Don’t blame it on being AM, turn it down! Again, it’s a compromise. What you want is to relax the processing as far as you can until you notice the loudness is really suffering, then turn it up a little and leave it alone. I would rather lose a bit on the fringe than lose everyone in the heart of my coverage.

Sure, translators have saved the day for many AM station. But us old guys will still tell you there is nothing like the rich warm sound of a properly processed AM music station! Some of the legacy music powerhouses still know how to do it, and they sound good. But your typical 1 kW mon-and-pop in many cases sounds almost unintelligible with the modulation meter standing still at 100% all the time.

It’s a shame but AM engineers who really understand the art of compromise are dying away. The result is devastating to the senior band. While today’s AM processors are capable of making music into square waves, I can’t put all the blame on them. Just because the processor has a lot available horsepower does not mean it’s best to use it all, all the time. It still comes down to knowing when enough is enough. Clint Eastwood said it best as Dirty Harry in “Magnum Force,” “A man’s got to know his limitations.” Especially true for pushing AM modulation.

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