That article seems to be on a solid foundation about what the issues are, and helpful even if you don't run one of those transmitters.
My opinion of high processing is, I don't like it! It's experimental radio, we have the freedom to be out from under corporate rules and thought patterns and do something different! Why follow what commercial stations are doing?
Commercial radio has been fed a line of propaganda in the name of competition with other stations and the processor manufacturer's ultimate profits. Radio stations are sucked into this vortex, and so are TV and the recording industry, louder, louder, LOUDER. They buy that line of thinking without question, because they've been conditioned to it for decades, exploited into buying ripoff processors.
I want to see a post-radio environment where this doesn't matter, and I think I'm hearing it on the AM band, a reduction in the loudness wars.
In my experience once you have the basic lineup, ALC, compression, limiting, HF limit and clipping, you're there, AM or FM. Adjust to keep control of average and peak levels and stop, and it can be hard to tell there's even processing. I've totally tamed the big problem I had, overloads on some tracks and different voice levels being hard to hear or being blasting and over loud.
Getting a radio station as loud as possible is only a small part of a larger picture.
Everything starts with the dynamic range of human hearing, and the second big factor is the dynamic range of musical instruments and speech complicated by environmental acoustic conditions, such as traffic noise on the road and vacuum cleaners, dogs, other people's activities, power lawn equipment, aircraft...
We reasonable want our radio signal to ride above all of it and deliver pleasure to the ear.
It's another one of life's games.
If the general manager is happy, do no more.
A well is a very deep subject. What I've found is that music is pretty tight with levels, especially with any new commercial pop or county, you can set the level at the beginning of the track and it will stay right there. That's the benefit of having a full studio to record in.
Classical and Legacy progressive rock, jazz, any of the older music always seems to have more dynamics and you have to watch the levels more. I used to be like one of those sound engineers in the Hamilton article, adjusting levels as the songs played, before I got simple processing.
The biggest problem was with voice, learning to modulate and control your own levels as you speak. I watched concerts and recording sessions with a vocalist on mic, and some adjust the distance from the mic as they sing, like it's the slide on a trombone.
I do it a little, pulling back from the mic if I'm going to be loud. Guest's don't always know mic technique and can trail off then jump right into the mic when they speak, causing distortion because you've turned them up. The limiter did a lot to help the overloads
I wanted the sound to be constant like I heard on the radio at one time, then heard the recordings, and liked how it was different from radio, more conversational sounding and easier on the ears with more dynamics.
Now days, most podcasts are recorded without much processing, people listening on headphones so it's right in their head, and they don't need always on sound blasting loud, which could be annoying.
One of the main reasons for audio processing & the resulting loud sound with Part 15 AM is increased range.
If Part 15'ers were allowed to use more power, then that processing wouldn't be as important. I don't believe that we want to sound just like all the other stations.
The iAM transmitter has some processing on it to give it that Big station sound. I heard Phill Collins on it from Youtube. Then they played the older Talking House's audio and you can hear the difference. So processing does make the difference and with that processing it does sound rather nice.
There is NO processing on the V5. Some changes to improve audio bandpass.
Here at KDX Worldround Radio we'll be conducting an audio processing workshop to compare the two audio processing methods we use and how they interact.
Our station audio is processed by Stereo Tools to keep average modulation easy to hear for the listener, but when I produce I radio show like Low Power Hour I apply some compression/limiting to the audiofile to improve the sound quality for radio stations, but when both kinds of processing are happening at the same time it might be overkill.
Experiments are beginning and results will be shared.
I changed one electolitic cap in my TH II which is at the input to the audio op-amp.
Increasing from 4.7uf to 47uf really opened up the bass frequencies.
As it was, the calculated low end response cutoff frequency was 300 Hz. Should go down to 30 Hz now.
That's a very good improvement, MRAM, 300 Hz is lower mid-range, about the bottom of voice frequencies. Maybe the original designer only anticipated voice and filtered the low end to evade possible hum in mic lines.
Music needs to go down to at least 80 or lower (loudspeakers don't always reproduce the lowest musical frequencies).
@Nate
The reason you don't need to adjust levels on today's music is because it has already been processed to hell and back. Complete with hardcore clipping to make it as loud as possible. Older music couldn't do this because the needle would jump off the record Rendering it unplayable.
AM needs processing to stay loud and above the noise. By the pure nature of the mode, louder audio = more power and farther listanable range.
A great example of this is the 250 Watt AM I work at. When I started the Optimod 9000A's settings were light and weak. As such the station's sound was light and lacked punch and our signal suffered. I cranked that Optimod as loud as it can go, with some beefy booming sound to get the audio modulating as high as it legally can, to the point where if it were any louder the transmitter would shut down.
The result, I gained 20 miles of previously unheard coverage.
Our friends on FM however need to lay off on loudness, they don't need it.
I've always thought that 250 Watt AM licenses were something a plain person could almost afford.
I'm sure we had a 250 Watter here in town, but it must have gotten a power increase, because the lowest power around here now is 500 Watts.
I'm not counting those goofy nighttime powers that some stations have which are very close to Part 15, there's a 60 Watter downtown, just like a light bulb.
Yeah, I know about the Loudness Wars and digital music being right to the wall with loudness, country music is played so loud that it's turned into rock and roll, but any pop music is pretty much having loudness issues.
There are some videos about the Loudness Wars, and it seems that it's producers are all wanting their tunes to sound louder than the competition. I had another theory, some of it's the way people listen, lots of times through small headphones, laptop, tablet and PC speakers that are so tiny. In the hifi era, people listened to FM radio and vinyl on tower speakers sometimes 4 big speakers.
That could be it, a commercial station with high power and an Optimod, that would make a difference. I had a hobby transmitter, and older processors, and software. I still thought it should work just like commercial stations, just in smaller form.
With almost no processing I did have what seemed like a weak signal with more noise. Close in it sounded great, wide as heck and punchy, a sound like you never hear on AM! It was when I got a certain distance that some songs and voices sounded like they'd need a little more oomph, making me think I wish I could turn this up.
I did a whole bunch of experiments with the processing, many hours of testing over time. I concluded that with my setup, once I got a consistently loud sound, an evenly high level, that was good enough for range. The volume of most audio is high, but not so much that drums sound crushed, and it allows for quiet intros to be heard a little less than full volume.
I did some setups recommended for AM use, those sounded louder but raunchy, and what I found was in the distance, that didn't really get much more range over the previous settings. In fact, the range increase was inconclusive, not certain.
I thought if I wanted to make more unpleasant sound for alll listeners, to reach a few more in the distance? Software tested was Sound Solution, Sonos Limit, Sonos 4, Breakaway, and the one Carl uses, name slipped my mind, it was demo and I didn't use it for too long. One of the others was a hacked full version, and Sonos Limt and 4 were freeware.
Here's a page that give a good breakdown on processing, from Innovonics. I have a better opinion of these guys, they seem not to be pushing station clients toward louder and louder to sell more boxes, so this seems to be fair and balanced treatment.
http://www.inovonicsbroadcast.com/on-air-audio-processing-broadcast-audio-processor
I've seen powers listed as low as 1 watt on the AM band! Radio-locator showed a little less than a mile of local red circle range, and secondary coverage to several miles. Most stations seem to have night power, but I don't know if they're all using it.
There are two religious stations locally that use their very low night power because they have nearby churches buy time to carry their recorded services. Probably an ego boost for the ministers.