How to achieve that clear-crisp radio FM sound!

FM radio compresses and amplifies their music like crazy, and i love it more than listening to my ipod in my car… i just love the clear-crisp sound of radio and i really want to achieve this by using audacity. I’ve experimented and toyed around, but its difficult not knowing what im doing. Anyone have any tips or tricks?? Thanks

You may be in love with the compression more than the quality. FM radio only has audio response up to 15000 Hz and very little past that, but you’re right, they are all compressed.

I’d probably be working in Audacity 1.3 because those tools are much better than earlier programs.

Start with the equalizer. Select your audio. Effect > Equalization.

I created the FM frequency response equalizer curves in Audacity 1.3.

That’s the basic curve. The important part is on the right. You can grab the corner of the equalizer tool window and keep making it larger until you can see what you’re doing.

For some completely boring reasons, the frequency response of FM goes pretty good until 15000 and drops as a rock. It has to be completely gone by 19000. Click on the blue line and push it around until it looks like these illustrations.

The curve on the left isn’t that important. It starts dipping at 50, but isn’t a big deal.

While you’re figuring out how to get your equalizer to do that, I’ll go to bed and worry about the compressor tomorrow, assuming somebody else doesn’t jump in first.


Try the SC4 compressor. (and yes, you will probably find Audacity 1.3.x better for what you want).
(see top of the page for where to get it).

I have to admit this is the first time I’ve ever heard anyone describe FM radio as crisp and clean. It sounds unrealistically loud to me because of the compression.

I know what you mean alatham, but it’s good for listening to in the car without the quiet bits getting drowned out by road and engine noise.

In fact, there is a compressor plug-in for Audacity that has been specifically designed for listening to Classical music in cars:
(works great for this purpose with the default settings)

Ah thankyou verrry much! Though i couldnt tell the difference by my own speakers in my bedroom, i’ll have to go and test it out for a drive in my car soon to see if it worked.

I downloaded Audacity beta 1.3x, opened up an mp3 music file and applied the equalization settings (though i admit it was complicated to get your exact settings) i strived to make it work… and then applied the default settings with the SC4 compressor…

I went to that page to look at the settings, but is it just descriptions of what each setting means? Or am i supposed to download something?

I tested both songs old and new in my car, they sound a little different… but this brings me to a whole new question…

Is there a way i can increase volume on my mp3s using audacity? My itrip doesnt play my ipod in the car loud enough. Thanks

Too much technology.

We gave you the settings to make your show sound like an FM transmitter channel and then you put the show through MP3 (which adds distortion) and through an iTrip (which is an actual FM transmitter and adds distortion) to listen in the noisy car on an FM auto radio.

Did I get all that?

What you really wanted way at the top was to make your iPod louder. I haven’t messed with the compressor settings of any sort yet, so I bow to the experiences of others. Dynamic range compressors are the accepted way that everyone from AM Radio, to FM Radio, to trance and rap performances makes things louder. Louder is good. Remember the music producer that appeared in the back of Wired magazine whose one-to-ten sound system was never lower than eleven? He probably has a hearing aid now, but that’s the way it works.


I’m guessing this isn’t Classical music. Google for “LADSPA Fast Lookahead Limiter” - you can compress the heck out of your music with that, then Normalize to -0.1dB, then Export as MP3 (use one of the LAME presets in Audacity 1.3)

Maybe i misinterpreted, I do want to obtain the radio FM compressed sound, but i’d also like to learn how to increase the volume of an mp3 file…

When i listen to the radio in my car i can turn it up all the way and be satisfied, but with my ipod forwhatever reason it only goes up so far.

Ive done exactly what was shown to me above, the equalization process… do you know how to compress it?

<<<Google for “LADSPA Fast Lookahead Limiter” >>>

I’m guessin’ that’s too fuzzy. Which file exactly, how do I decompress it, where do install it so Audacity sees it, and how do I set it up for FM compression?


Just a thought - you haven’t by any chance set that little setting on your iPod (Settings > Volume Limit) which limits the sound output level have you?

Also you would be much better off having a car radio that you directly connect an iPod to with wires - rather than using the iTrip. Have you checked if your current car radio has the necessary inputs? Out of necessity I use an iPod/iTrip combination in my car - it provides adequate results, never good results…


I’m really confused again, are you asking me these questions? … or are these the questions you believe im asking… ?

I have turned the volume limit all the way up on my ipod, im pretty technical, except when it comes to audacity. So far i did a few songs in audacity using the equalization preset Koz gave to me, as well as that plugin for dynamics compression, all in all it seems to be working fine in my car, just need a way to get the volume LOUDER on mp3 files

The maximum amplitude that any digital audio will go is 0dB - this corresponds to a waveform that just touches the top and bottom of the track (+1 to -1). Any attempt to make it louder than this will produce distortion because the peaks and troughs of the waveform will be cut off (clipped).
An easy way to amplify any track to 0dB is to select the track, then use “Normalize” from the effects menu and normalize to 0dB (I actually prefer to go just a little below this as some players handle 0dB badly, so -0.1dB )

The only way to make something sound louder than this is to use “dynamic range compression” (also sometimes just called “compression”, but should not be confused with data compression formats such as mp3).

To do this, use a compressor (such as the SC4) or limiter (such as the Ladspa Fast lookahead limiter) to reduce the dynamic range, then use “Normalize” to bring the amplitude back up to 0dB.

For further information about compression, limiting and loudness:

Hi. This is my first post. I want to try to actually change an AM audio recording into FM sound quality. If you can do it the other way round, how do yo do the opposite so that it sounds like FM?

I have removed all the background noise but still have AM type sound and wnat to make it sound “crispy”. The wave you posted I cannot get that to work properly.

I am currently using Audcity 2.0.1 on Windows XP.

I have not upgraded as I particularly like the bassboost feature which has aparently been removed on later issues.

Thanks for your help

It may not be possible.

Going from “FM quality” to “AM quality” is mostly a matter of removing very low and very high frequencies.
To go the other way, you would need to boost the very low and very high frequencies, but if the audio is really “AM quality”, then there will be no very low or very high frequencies, other than noise.

There is a plug-in version of the Bass Boost effect here:
Installation instructions here:

Note that Audacity 2.2.2 is the last version to support XP, and requires SP3.

Actuallly 2.1.3 is the last official version for support on 2.1.3 (when we discontinued future support).
See this Wiki page:

It just happened to work on versions up to 2.2.2 - it does not work on the recently released 2.3.0