The problem with the voice in the background

[Rom]

I have Audacity 2.2.2. i Win 8.1

I am trying to strengthen the voice of a child who is sitting in the back seat of a car recorded using a video recorder. I used noise removal and compression, but the effect is poor .. The child talks so nicely. Engine noise, however, is a bit bothering. Please help

[kozikowski]

I used noise removal and compression, but the effect is poor

I would expect it to work almost not at all. Compression is used to bring quiet sounds and louder sound closer together, not further apart. Noise Reduction only works on noises that don't change such as microphone hum, air conditioners, or refrigerators. The minute the driver changed speed, the effect would vanish.

I think whatever you have now is as good as it's going to get.

Koz

[steve]

You could reduce the low frequencies in the noise with the "High Pass" filter. https://manual.audacityteam.org/man/hig ... ilter.html
Try setting it to:
Frequency: 200 Hz
Roll-off: 48 dB/octave

As Koz wrote, there's not very much that is possible for this kind of problem.

[Rom]

Kozikowski and Stive, thank you very much for your help. I did what you proposed, but I guess you can not do anything more. Best wishes.