Radio Tuning and Volume Controls, Part 1: The Rules
At the risk of too many technically dense posts in sequence, I’m following up my post on the minutiae of battery backups with two posts on the minutiae of radio tuning and volume controls! These “explainer” posts will likely be the most time-consuming for me to write, so I want to knock them out rather than turning them into Big Daunting Things in my head that I then procrastinate on.
In Part 2 of this post, we will explore the weirdnesses of radio tuning and volume controls. But first, we need to explore how they work in the first place. And before we explore that, we need to explore why alarm clocks have radios or other music-playing apparatuses in the first place. So let’s do it!
Why do so many alarm clocks have radios, CD players, or other music players?
There’s an obvious reason and a slightly less obvious reason! The obvious reason is that it saves space on a nightstand. I know my nightstand barely has enough space for everything on it, and I can imagine pretty much nobody wanted to cram a CD boombox and an alarm clock onto their bedside table. Combining these devices reduces their footprint!
The slightly less obvious reason is that these “combo” alarm clocks tried to give you a more pleasant sleeping and waking experience than alarm clocks of yore. Most people don’t enjoy waking up to bells ringing or obnoxious buzzing or beeping, though for some of us, it may be the only way to get us out of bed. But for others, it might be nicer to wake up to a favorite song, or the voice of your favorite anchor on NPR. That’s why alarm clocks with radios, CD players, or other audio sources typically let you set these sources as the alarm sound, which wouldn’t be possible if the radio or CD player was an entirely separate device.
Pretty much all of these alarm clocks also go a step further. They don’t just try to help you wake up peacefully, they also try to help you fall asleep peacefully too. Tons and tons of alarm clocks have a sleep timer, which shuts off the radio or CD player automatically after a set time. That way, you can put on soothing music or a boring news station to fall asleep to, and then have the sound shut off automatically once you’re asleep. I feel like sleep timers are something surprisingly few people use or even know about, though they’re included on practically every alarm clock with a radio or CD player ever made.
Now, here’s the tricky thing. The audio people want to fall asleep to is not the same as the audio they want to wake up to. (Or the audio they listen to during the day!) Maybe you’re the kind of person who puts on soothing classical at a low volume to lull you into slumber. But you’re a deep sleeper, so you need the guitars of heavy metal playing LOUD to get you out of bed. (If you’re that person, I applaud you for your rich and varied music tastes.)
I don’t think there are really that many people using their alarm clocks to the max in this way, setting the CD alarm, using the sleep timer, and letting their tastes meander across every genre and volume level of music. But when that rare human being comes along, alarm clocks have to be prepared. It’s helpful when they have the ability to play one thing at one volume (such as during the sleep timer), then switch themselves to a different thing at a different volume (such as for the alarm sound). And that leads nicely into our discussion today!
Analog vs. digital controls
If you’re young and sprightly like me, you may have no idea how radio works. (Well, I know a little about how radio works, but mostly because I’m an alarm clock nerd, not because I really listen to it. Though NPR slaps, I will say.) Both AM and FM radio stations broadcast at specific frequencies, measured in kilohertz (for AM) or megahertz (for FM). Using FM as an example, one station may be located at 91.1 MHz, then another at 91.3, then another at 91.5, etc. The important thing to know is that, unlike “stations” on an app like Spotify, real radio stations are arranged in a numeric sequence, and you change between them by changing the frequency the radio is set to receive. The process of changing this frequency to the number you want is called tuning.
If you’re an alarm clock designer, you might approach designing controls for radio tuning in a similar way as you might for volume. That’s because volume controls, like radio tuning controls, also need to move through a series of numbers in sequence. These numbers are more obvious. They are an arbitrary range the alarm clock designer chooses, from mute all the way up to super-super-loud.
Both radio tuning and volume controls (on alarm clocks or other devices) can be analog or digital. This is a surprisingly important distinction that I want to explain as carefully as I can.
Digital controls
I’m actually going to explain digital controls first, because they are more familiar to most people. With a digital control for radio tuning or volume, you press a button or turn a dial, and your action sends a command to the device’s motherboard, which changes the numeric value for radio frequency or volume by a preset amount. The resulting value is typically shown on a screen. You know when you press the volume-up button on your TV remote, and the screen shows that the volume changed from 29 to 30? That’s a digital control.
Below is a an alarm clock (a Sony ICF-CD853V) with a prototypical example of digital radio tuning. The radio frequency (87.5 MHz) is shown at the bottom of the screen. The “Tune / Time Set” buttons allow you to decrease or increase the radio frequency. And there are buttons numbered 1 through 5 on the top of the alarm clock for “Preset Tuning,” which is almost always a telltale sign of digital radio tuning. I’ll explain what those do in just a moment.
There are two crucial things to understand about digital controls. First, they change radio frequency or volume in discrete steps, rather than continuously. If volume is on a scale from 0 to 30, you can’t set the volume to 5.5, or 3.3333333, or 2.57684749249. You can set it to 2, or 3, or 4, or 5. This could be considered limiting for a volume control, because what if you want to listen to music at 5.5, and 5 is too quiet and 6 is too loud, gosh darn it? But alarm clock designers can usually resolve this problem by including enough volume options. And changing in discrete steps is actually really helpful for radio tuning, because radio stations are arranged in discrete steps. You want to move from 91.1 FM to 91.3 FM without ending up in between. If you end up at 91.2 FM, where no station exists, I believe you'll hear a little bit of both radio stations on either side simultaneously, which is what we call “not ideal.”
Second, you can use a digital control to change radio frequency or volume, or the electronics within the device can change the radio frequency or volume themselves. There are so, so many reasons why this is important. With radio frequency, it allows for preset stations, where you save the stations you listen to most, and at the touch of a button, the electronics within the device can leap from the old frequency to the one you selected, regardless of how far apart they are. (That’s what those 1 through 5 buttons do on the alarm clock pictured above! I could save NPR as preset 1 and jump to it whenever I want.) With alarm clocks specifically, digital controls also allow you to set a radio frequency or volume level for the alarm that is different from whatever you were last listening to. At the alarm time, the clock can change itself to the new radio frequency or volume level. Finally, digital controls also allow you to adjust the radio frequency or volume without physically interacting with the device, such as by using a remote control.
Analog controls
This is all in contrast to analog controls. With an analog control for radio tuning or volume, you turn a dial, and the dial physically interacts with the circuitry of the device in a way that I honestly don’t fully understand, and the radio frequency or volume changes along a continuum (not stepwise or discretely). The resulting radio frequency or volume is not shown on a screen, because (a) the device doesn’t know exactly what radio frequency or volume it’s set to (yes, really), and (b) the radio frequency or volume isn’t an exact, discrete number.
Below is an alarm clock (a Sony ICF-C630) with a prototypical example of analog radio tuning. An estimate of the radio frequency is shown on the dial scale, which looks like a ruler and is located below the display. The radio tuning dial is the small gray wheel on the lower-right side of the clock. As you rotate the dial, a mechanical linkage moves the red pointer on the dial scale, showing you roughly which station you are tuned to. (If you’re wondering why the frequencies on the dial scale are weird numbers, it’s because this isn’t a U.S.-market clock, and radio frequencies work differently in different countries.)
Analog controls will probably make more sense if we discuss the physical controls themselves. Both analog and digital controls can be dials. But a digital dial can make more than one full rotation, while an analog dial is restricted to one full rotation or less. An analog dial also never clicks from one “step” to the next, while some digital dials do. Using volume as an example, an analog volume control is usually a little dial or wheel on the side of a device that smoothly, freely rotates from one endpoint (mute) to another endpoint (the loudest volume possible). If you’ve ever had a Nintendo device (like a 3DS) with a volume slider on the side, that’s a perfect example of an analog volume control. (Though on alarm clocks, dials are much more common than sliders.)
As I said earlier, analog controls change radio frequency or volume continuously, not stepwise or discretely. They have an infinite amount of settings between their two endpoints. So you can dial in the perfect volume level for your listening (though you may get sucked into an obsessive loop doing it), but you can also find yourself tuned between two radio stations, which sucks. You’ll rarely, if ever, tune perfectly to 91.1 FM, so you better get comfortable with “good enough.” Devices with analog controls also can’t change these controls themselves. So if an alarm clock’s radio tuning dial or volume dial is set to a particular station or volume, that’s the station or volume the alarm clock will be using, until you physically rotate the dial. So no preset radio stations, no programming a unique radio station or volume level for the alarm, and no changing the station or volume using a remote control.
Analog volume controls don’t typically indicate the volume level, but it’s easy enough to hear if the music is already playing. Analog radio tuning controls do typically indicate the estimated radio frequency, because you don’t always know which station you’re on just by listening to it, unless the announcers tell you. Above, I showed you an example of a dial scale, which is the most common kind of radio frequency display for analog tuning. But there are others. Sometimes radio frequency numbers mechanically rotate through a little plastic window, like on the Sony ICF-CD815, shown below-left. And sometimes the radio frequency numbers are printed on the dial itself, like on the HoMedics SS-6000, shown below-right. (You might need to zoom in to see the radio tuning dial, which is on the lower-right side of the clock.)
Time for a break!
I know this is a pretty technically dense post, and I really appreciate you bearing with me. Here’s the good news: now that you’ve learned all this information, you will be better able to appreciate the weird and fun things I’m going to show you in Part 2! So go get hydrated, have a snack, touch grass, and then join me for Part 2!
Image credits:
Sony ICF-CD853V (digital tuning): Poshmark
Sony ICF-C630 (analog tuning with dial scale): Google Images
Sony ICF-CD815 (analog tuning with frequency windows): Google
HoMedics SS-6000 (analog tuning with numbers on the dial): eBay
