Improving an FM Radio broadcast track

I am “trying” to improve the sound quality of a live concert broadcast on FM radio, obviously im not expecting miracles, but I wondered what you experienced audacity users would do in this scenario.
The source isnt that bad its clear but lacks bass and mid range if that makes sense.
I have “messed” with Bass Boost in the Graphic Equaliser options and it does improve it, but what else could do to try and improve it. I see all these features Audacity has but dont understand them if im honest so hence I usually just use the easier options.
As the source isnt brilliant im fully aware im never going to get an audiophile qualtiy, but even slight improvements would be great

Apologies, I am using Windows 10 and Audacity 3.1.3…

A free (simple) expander plugin called “La Petit excite” does a good job of enhancing bass …

alternatively there is a free (complicated) plugin called ToneBoosters FLX which can be set to expand bass …

[Audacity does not come with an expander effect]

I think the first thing I would try is get of of the FM Stereo intercarrier hiss. It should respond well to Effect > Noise Reduction. The only trick is going to be to find a brief segment of the performance with “silence” and no performance. That’s Noise Reduction’s “Profile.”

An FM signal gets noisier and noisier the wider and more complex the radio channel. The broadcast regulators were determined to adopt a broadcast system where you could listen to a stereo broadcast on your mono receiver. So they broadcast a sum of left and right just like they always did, but hid the separation sound in a special part of the broadcast channel that was, well, noisy.

Say you have a violin on the left. The main channel will just broadcast the violin, but the stereo receiver will go looking for where to put it. The separation information might know, for example, that the violin is on the left. But knowing that comes with a noise penalty. If you have a radio where you can switch from mono to stereo, the violin will suddenly whip to the left and the background sound will go fffffffffffffffff.

It’s not weak FM signal or bad antenna. The stereo system was designed to do that.

In addition to that, FM stations have compressors and volume processors. In days gone by, those were two different boxes. One box set the relaxed, overall volume of the show and the other one quickly grabbed the instantaneous loudness tips and peaks to keep them from causing the transmitter to overload or misbehave. You can’t get rid of either of those effects.

Past that, the system should be relatively flat and without damage. Stations are required to periodically certify that their sound channels are distortion-free. So if you have a performance with low bass or other distortion, that may have come to the station like that, and you are fighting all those FM tricks plus whoever supplied the original tape.

So to summarize, get rid of the intercarrier hiss and then just launch the tone controls or equalizers and trim until it sounds good to you. There’s no standard correction.

It’s not unusual for a listener to switch to mono just to get rid of the hiss. It can be pretty annoying. I used to record an FM talk show that way. There is no good reason to know that one interviewer is on the left.


you can check the error caused by a loose signal connection wire or a broken ground transmission line is also a cause of this situation.

I’d guess that it’s too late to make changes to the radio receiver. My guess is that Efiste2 is trying to fix a recording that was broadcast live some time in the past.

Yes, sorry for the vague description. Its a recording of a live broadcast, I have downloaded “La Petit excite”, can you adivse me how to import it into Audacity and apply it. Many thanks for the responses :wink:

If you’re using the current 64-bit Audacity 3.1.3 for Windows, you will need the 64-bit VST2 version of the plug-in.
For installation / enabling, see:

“La Petit excite” is a [VST] plugin which when installed in Audacity appears on the effects menu, (along with the native effects).
How to install VST plugins in Audcaity … https ://
''La Petite Excite'' in Audcaity.jpg