I have been using Audacity for 1 year, and today I wanted to make my song sound like from FM radio. I have been playing around with many effects, but I just can’t find what I’m looking for. I am on Windows 10, and I use Audacity version 2.4.2.
FM or AM radio?
FM has pretty good frequency response, up to about 15KHz.
AM on the other hand is limited to around 5KHz.
EFFECT —> EQUALIZATION
(Then select AM Radio).
FM
So you want just to cut some of the high end or also make the bass less punchy?
As if it’s being played from a small speaker?
You can modify the AM Radio profile.
Click and drag on the small points to move them.
On the low end, move them to start cutting from about 100Hz and at the high end, move them to about 8-9KHz.
Just add a small amount of FM carrier hiss
WC
I just can’t find what I’m looking for.
Do you have an example? Links?
FM sounds like a live performance.
Are you after what happens to an FM radio in your car when you drive too far away? That’s a distinctive crashing sound as the radio loses its mind.
As above, AM sound channel is 5KHz, so they have a muffled, low fidelity quality and between that and the compression, it’s a good theatrical effect, and not that hard.
Even more effective if the hero of the song gets into his car and switches between live and radio. Or changes historical eras, or does a flashback.
Koz
Just add a small amount of FM carrier hiss
True and some switching from stereo to mono and back again as the 19KHz stereo pilot tone is temporarily lost due to weak signal. 
I wanted to make my song sound like from FM radio.
What do you think it sounds like, and compared to what? And, I assume you’re starting with a good-modern, digital, recording?
FM itself is pretty good so it doesn’t have much of a particular “sound”. It’s low distortion and has wide frequency range with just a touch of background hiss, depending on how far you are from the broadcast station.
If you’re looking for the sound of a small desktop radio, equalization is what you’re looking for. You can just experiment (with the “preview”) to see what you can get. IMO - the Graphic Equalizer is easier to experiment with than the Filter Curve. With equalization you can simulate the sound (frequency response) of a tiny speaker or a larger speaker in a resonant wood box, with or without a tweeter, etc.
If you want to add some hiss, we can help you with that.
But how? Also, I am looking to make a FM effect when it is good signal.
To add noise -
With the existing track open…
Track → New (stereo if that’s what you have).
Click in the new-silent track and put the cursor at the beginning.
Generate → Noise → White with a duration to match the original file (you can also try pink noise). Try an amplitude of 0.01 to start (that’s -40dB).
When you play or export the noise and original track will be mixed.
Is this the effect you are looking for?
See below, a before and after.
The song is “Beat Thee” from https://freepd.com/
It’s creative commons.
I want to create a brighter, boomier and louder sound.
I want to create a brighter, boomier and louder sound.
That does not sound anything like FM radio, but more of a night club scene.
Louder is a relative term, you have to decide what is louder, “Amplify” will do that.
As for the brighter an boomier, use the graphic equalizer, probably something around 40Hz, 100Hz, 400Hz and 5KHz.
Plektron Devicer is a free plugin which works in Audacity on Windows.
It has a range of audio device simulations, including “Hi-Fi Stereo”.
(The “surround speakers” preset #14 may be what you’re looking for )
I want to create a brighter, boomier and louder sound.
You never answered what the source-sound is… Are you trying to make your voice sound like a radio announcer? That’s not the “FM radio”, that’s the announcer’s voice and maybe the microphone.
Most professional microphones are directional (“cardioid”) and a side-effect of the directional design is the [u]proximity effect[/u] which boosts the bass when you get close to the mic. Some male announcers like to take advantage of that effect, but most announces just have a good voice and they don’t get that close to the mic. In fact, one of the most popular radio mics is designed NOT to have the proximity effect.
P.S
If you have a good-clean recording and a reasonably-masculine voice you can use EQ (bass boost) to get a similar deep-voice effect.