Understanding FM #1 - Slow motion FM, frequency deviation, and how FM radio works

[@SousaphoneMusic]

I never realized that fm radio needs a band of frequencies to operate in but that makes so much sense

[@SoundVoltage]

@SousaphoneMusic - I know, I never really thought about it before this. And the width of the band? Literally the bandwidth. :)

[@modalmixture]

I’ve watched several other FM deep dives, but I already have a feeling this is going to be a good one. Strapped in and ready for the journey.

[@QuimFont]

very smooth and informative. Thank you for planning all of this so well and with such a smart delivery.

[@SoundVoltage]

Thank you!

[@ResonancePeriod]

I really appreciate all the work you're putting into this series!

[@CyberBlob69]

Nice video. FMCW radar is also a nice concept, where the range of the target is related to the frequency shift of the received signal.

[@IconOfSin]

I retuned FM filters (ie the RF transmission component) years ago on work experience, never expected EQ knowledge to come in so handy, literally just turning bolts to dial in a BP on a scope. Great idea for a series, looking forward to jumping down the rabbit hole!

[@LeoPerantoni]

Oh yes FM is definitely something Id want you to talk about and here we are!

[@speed0]

Since this is meant to be a complete overview of FM, i think its worth clarifying the whole "deviation range" thing. The way it was described it made it sound like all FM needs to have the carrier wave completely in the middle with equal deviation on other sides. FM can be done with the modulator being a unipolar wave which would only raise (or lower) the pitch of the carrier. Plenty of complex oscillators (ie Verbos Complex Oscillator) work this way, so i definitely think its worth noting at some point in the series. Looking forward to the rest of the series and future videos from you in general!

[@SoundVoltage]

@speed0 - That's good feedback, thanks. I was going to come back to deviation in the context of exponential FM where the carrier sits about 1/3 the way through the deviation rather than centered -- but I didn't know about the verbos, I'll mention that. Thanks.

[@NiamorH]

To be honest I think this is a bit quick as an explanation of how FM radio works. It could be interesting to go further into the details :)

[@SoundVoltage]

@NiamorH - Maybe I'll do a whole separate video on that. I didn't want to take people away from the synth side of things, but it is definitely worth more than the 60 seconds I gave it.

[@timnordberg7204]

maybe as an addendum to this series. It would have been cool to hear the carrier modulated with the VO during the FM radio part, though.

[@ryanstevens3822]

cant wait to dig into this, im so confused on my modular analog stuff wiht fm knobs vs my stuff with algorithsm

[@els1f]

This is going to be amazing 😌 You explain things so well that when I THOUGHT I understood them I realize by the end that I didn't REALLY understand them lol✌️

[@SoundVoltage]

Wow, thanks! It's going to be fun.

[@nickstokes9386]

Really looking forward to the rest of this series.

[@ramalshebl60]

lucky me, just finished the previous video about cv and analog oscillators, and you uploaded this yesterday! i don't have to wait!

[@apeirogonmusic]

Love FM Lets hope this series gets many parts

[@SoundVoltage]

@apeirogonmusic - The next one should be out today or tomorrow I hope!

[@fonesrphunny7242]

Recently found that cool DX7 emulator. Decided to practice FM with a more approachable device first. Now we're here. Maybe off by a week, but still good timing ;)

[@KenSwanson-p4i]

Yes, .. I never knew that FM radio signal's path had a width. I always thought of the signal, like a narrow, single rail .. versus a 3' wide sidewalk, relatively speaking. The FM stations around here .. indeed, they're spread quite far apart on the tuner range, in my location. And Mordax Data, .. what a cool tool. I never considered getting a 2nd one .. but, now I am. .. :)

[@murat_buyuk]

awesome. THANKS!

[@anicca3179]

Awesome! Looking forward to the next episodes. Thanks

[@SoundVoltage]

@anicca3179 - There should be one either today or tomorrow!

[@oliverb7897]

Already getting impatient for the next video!

[@SoundVoltage]

@oliverb7897 - I'm writing the script for #3 right now, and the demo recordings are all done. Friday, I believe!

[@Probbie]

Very nicely described 😊

[@SoundVoltage]

Thank you! Cheers!

[@meesvandenberg9468]

so clear!! your channel is a gem

[@SoundVoltage]

Wow, thank you!

[@sqwook]

That was awesome, thank you

[@SoundVoltage]

Glad you enjoyed it!

[@forestine_]

great explanation, as usual. thanks!

[@SoundVoltage]

Glad you liked it!

[@duncandreizehn]

pretty cool

[@TiniCakes]

i am so excited for this XD

[@Beatsbasteln]

I still don't understand the thing about the FM radio tbh. Like why does it need FM in the first place? Which problem is solved by applying FM to some music before sending it out there so car radios can pick it up? or is it before or after? what's each stage like?

[@SoundVoltage]

@Beatsbasteln - It's not really right to think of it as "applying FM before sending it out". Without any audio signal, the FM transmitter would just output a constant sine wave at the frequency of the station -- say 90.3 Mhz. That pure sine wave is modulated by whatever the audio is. It's not something done ahead of time, the transmitter does it on the fly, wiggling the oscillator a little faster or a little slower than 90.3 Mhz depending on the pitch and amplitude of the signal. That is literally what it means to broadcast in FM.

[@GillamtheGreatest]

do we get an am radio sidequest?

[@SoundVoltage]

Only upon reaching third level :)

[@GillamtheGreatest]

@@SoundVoltage xp grindcore lets go

[@teebeedahbow]

This is good, but you did the thing that scientifically literate, and especially mathematically literate people do, you jumped from one thing to another too quickly. What is it that FM Radio is really doing? After all, it isn't broadcasting sine tones! I get it about the broadcast width etc, but how does it carry songs by Elton John and The Wu Tang Clan? Not in the same way a DX7 carries sine tones, presumably.

[@SoundVoltage]

@teebeedahbow - the two are really very similar in terms of the actual modulation. In the DX-7, you have one audio rate sine wave modulated by an audio rate signal (another sine wave); on the radio you have a much, much higher-than-audio-rate sine wave modulated by an audio signal (Elton and Wu Tang - the crossover we've all been waiting for). Of course the DX-7 turns into audio, which vibrates the air and on into our ears; whereas an FM transmitter wiggles at the electromagnetic field, which is then picked up by an antenna. It's a fair criticism though, and maybe I should come back and do a longer video just on radio -- I didn't want to distract too much from the synthesis side of things, but radio definitely deserved more time. Thanks.

[@teebeedahbow]

@@SoundVoltage Thanks very much for the explanation. I really enjoyed your video. I was just disappointed with myself that I could make the jump from FM synthesis to FM radio.